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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * linux/net/sunrpc/xdr.c
- *
- * Generic XDR support.
- *
- * Copyright (C) 1995, 1996 Olaf Kirch <[email protected]>
- */
- #include <linux/module.h>
- #include <linux/slab.h>
- #include <linux/types.h>
- #include <linux/string.h>
- #include <linux/kernel.h>
- #include <linux/pagemap.h>
- #include <linux/errno.h>
- #include <linux/sunrpc/xdr.h>
- #include <linux/sunrpc/msg_prot.h>
- #include <linux/bvec.h>
- #include <trace/events/sunrpc.h>
- static void _copy_to_pages(struct page **, size_t, const char *, size_t);
- /*
- * XDR functions for basic NFS types
- */
- __be32 *
- xdr_encode_netobj(__be32 *p, const struct xdr_netobj *obj)
- {
- unsigned int quadlen = XDR_QUADLEN(obj->len);
- p[quadlen] = 0; /* zero trailing bytes */
- *p++ = cpu_to_be32(obj->len);
- memcpy(p, obj->data, obj->len);
- return p + XDR_QUADLEN(obj->len);
- }
- EXPORT_SYMBOL_GPL(xdr_encode_netobj);
- __be32 *
- xdr_decode_netobj(__be32 *p, struct xdr_netobj *obj)
- {
- unsigned int len;
- if ((len = be32_to_cpu(*p++)) > XDR_MAX_NETOBJ)
- return NULL;
- obj->len = len;
- obj->data = (u8 *) p;
- return p + XDR_QUADLEN(len);
- }
- EXPORT_SYMBOL_GPL(xdr_decode_netobj);
- /**
- * xdr_encode_opaque_fixed - Encode fixed length opaque data
- * @p: pointer to current position in XDR buffer.
- * @ptr: pointer to data to encode (or NULL)
- * @nbytes: size of data.
- *
- * Copy the array of data of length nbytes at ptr to the XDR buffer
- * at position p, then align to the next 32-bit boundary by padding
- * with zero bytes (see RFC1832).
- * Note: if ptr is NULL, only the padding is performed.
- *
- * Returns the updated current XDR buffer position
- *
- */
- __be32 *xdr_encode_opaque_fixed(__be32 *p, const void *ptr, unsigned int nbytes)
- {
- if (likely(nbytes != 0)) {
- unsigned int quadlen = XDR_QUADLEN(nbytes);
- unsigned int padding = (quadlen << 2) - nbytes;
- if (ptr != NULL)
- memcpy(p, ptr, nbytes);
- if (padding != 0)
- memset((char *)p + nbytes, 0, padding);
- p += quadlen;
- }
- return p;
- }
- EXPORT_SYMBOL_GPL(xdr_encode_opaque_fixed);
- /**
- * xdr_encode_opaque - Encode variable length opaque data
- * @p: pointer to current position in XDR buffer.
- * @ptr: pointer to data to encode (or NULL)
- * @nbytes: size of data.
- *
- * Returns the updated current XDR buffer position
- */
- __be32 *xdr_encode_opaque(__be32 *p, const void *ptr, unsigned int nbytes)
- {
- *p++ = cpu_to_be32(nbytes);
- return xdr_encode_opaque_fixed(p, ptr, nbytes);
- }
- EXPORT_SYMBOL_GPL(xdr_encode_opaque);
- __be32 *
- xdr_encode_string(__be32 *p, const char *string)
- {
- return xdr_encode_array(p, string, strlen(string));
- }
- EXPORT_SYMBOL_GPL(xdr_encode_string);
- __be32 *
- xdr_decode_string_inplace(__be32 *p, char **sp,
- unsigned int *lenp, unsigned int maxlen)
- {
- u32 len;
- len = be32_to_cpu(*p++);
- if (len > maxlen)
- return NULL;
- *lenp = len;
- *sp = (char *) p;
- return p + XDR_QUADLEN(len);
- }
- EXPORT_SYMBOL_GPL(xdr_decode_string_inplace);
- /**
- * xdr_terminate_string - '\0'-terminate a string residing in an xdr_buf
- * @buf: XDR buffer where string resides
- * @len: length of string, in bytes
- *
- */
- void xdr_terminate_string(const struct xdr_buf *buf, const u32 len)
- {
- char *kaddr;
- kaddr = kmap_atomic(buf->pages[0]);
- kaddr[buf->page_base + len] = '\0';
- kunmap_atomic(kaddr);
- }
- EXPORT_SYMBOL_GPL(xdr_terminate_string);
- size_t xdr_buf_pagecount(const struct xdr_buf *buf)
- {
- if (!buf->page_len)
- return 0;
- return (buf->page_base + buf->page_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
- }
- int
- xdr_alloc_bvec(struct xdr_buf *buf, gfp_t gfp)
- {
- size_t i, n = xdr_buf_pagecount(buf);
- if (n != 0 && buf->bvec == NULL) {
- buf->bvec = kmalloc_array(n, sizeof(buf->bvec[0]), gfp);
- if (!buf->bvec)
- return -ENOMEM;
- for (i = 0; i < n; i++) {
- buf->bvec[i].bv_page = buf->pages[i];
- buf->bvec[i].bv_len = PAGE_SIZE;
- buf->bvec[i].bv_offset = 0;
- }
- }
- return 0;
- }
- void
- xdr_free_bvec(struct xdr_buf *buf)
- {
- kfree(buf->bvec);
- buf->bvec = NULL;
- }
- /**
- * xdr_inline_pages - Prepare receive buffer for a large reply
- * @xdr: xdr_buf into which reply will be placed
- * @offset: expected offset where data payload will start, in bytes
- * @pages: vector of struct page pointers
- * @base: offset in first page where receive should start, in bytes
- * @len: expected size of the upper layer data payload, in bytes
- *
- */
- void
- xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
- struct page **pages, unsigned int base, unsigned int len)
- {
- struct kvec *head = xdr->head;
- struct kvec *tail = xdr->tail;
- char *buf = (char *)head->iov_base;
- unsigned int buflen = head->iov_len;
- head->iov_len = offset;
- xdr->pages = pages;
- xdr->page_base = base;
- xdr->page_len = len;
- tail->iov_base = buf + offset;
- tail->iov_len = buflen - offset;
- xdr->buflen += len;
- }
- EXPORT_SYMBOL_GPL(xdr_inline_pages);
- /*
- * Helper routines for doing 'memmove' like operations on a struct xdr_buf
- */
- /**
- * _shift_data_left_pages
- * @pages: vector of pages containing both the source and dest memory area.
- * @pgto_base: page vector address of destination
- * @pgfrom_base: page vector address of source
- * @len: number of bytes to copy
- *
- * Note: the addresses pgto_base and pgfrom_base are both calculated in
- * the same way:
- * if a memory area starts at byte 'base' in page 'pages[i]',
- * then its address is given as (i << PAGE_CACHE_SHIFT) + base
- * Alse note: pgto_base must be < pgfrom_base, but the memory areas
- * they point to may overlap.
- */
- static void
- _shift_data_left_pages(struct page **pages, size_t pgto_base,
- size_t pgfrom_base, size_t len)
- {
- struct page **pgfrom, **pgto;
- char *vfrom, *vto;
- size_t copy;
- BUG_ON(pgfrom_base <= pgto_base);
- if (!len)
- return;
- pgto = pages + (pgto_base >> PAGE_SHIFT);
- pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
- pgto_base &= ~PAGE_MASK;
- pgfrom_base &= ~PAGE_MASK;
- do {
- if (pgto_base >= PAGE_SIZE) {
- pgto_base = 0;
- pgto++;
- }
- if (pgfrom_base >= PAGE_SIZE){
- pgfrom_base = 0;
- pgfrom++;
- }
- copy = len;
- if (copy > (PAGE_SIZE - pgto_base))
- copy = PAGE_SIZE - pgto_base;
- if (copy > (PAGE_SIZE - pgfrom_base))
- copy = PAGE_SIZE - pgfrom_base;
- vto = kmap_atomic(*pgto);
- if (*pgto != *pgfrom) {
- vfrom = kmap_atomic(*pgfrom);
- memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
- kunmap_atomic(vfrom);
- } else
- memmove(vto + pgto_base, vto + pgfrom_base, copy);
- flush_dcache_page(*pgto);
- kunmap_atomic(vto);
- pgto_base += copy;
- pgfrom_base += copy;
- } while ((len -= copy) != 0);
- }
- /**
- * _shift_data_right_pages
- * @pages: vector of pages containing both the source and dest memory area.
- * @pgto_base: page vector address of destination
- * @pgfrom_base: page vector address of source
- * @len: number of bytes to copy
- *
- * Note: the addresses pgto_base and pgfrom_base are both calculated in
- * the same way:
- * if a memory area starts at byte 'base' in page 'pages[i]',
- * then its address is given as (i << PAGE_SHIFT) + base
- * Also note: pgfrom_base must be < pgto_base, but the memory areas
- * they point to may overlap.
- */
- static void
- _shift_data_right_pages(struct page **pages, size_t pgto_base,
- size_t pgfrom_base, size_t len)
- {
- struct page **pgfrom, **pgto;
- char *vfrom, *vto;
- size_t copy;
- BUG_ON(pgto_base <= pgfrom_base);
- if (!len)
- return;
- pgto_base += len;
- pgfrom_base += len;
- pgto = pages + (pgto_base >> PAGE_SHIFT);
- pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
- pgto_base &= ~PAGE_MASK;
- pgfrom_base &= ~PAGE_MASK;
- do {
- /* Are any pointers crossing a page boundary? */
- if (pgto_base == 0) {
- pgto_base = PAGE_SIZE;
- pgto--;
- }
- if (pgfrom_base == 0) {
- pgfrom_base = PAGE_SIZE;
- pgfrom--;
- }
- copy = len;
- if (copy > pgto_base)
- copy = pgto_base;
- if (copy > pgfrom_base)
- copy = pgfrom_base;
- pgto_base -= copy;
- pgfrom_base -= copy;
- vto = kmap_atomic(*pgto);
- if (*pgto != *pgfrom) {
- vfrom = kmap_atomic(*pgfrom);
- memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
- kunmap_atomic(vfrom);
- } else
- memmove(vto + pgto_base, vto + pgfrom_base, copy);
- flush_dcache_page(*pgto);
- kunmap_atomic(vto);
- } while ((len -= copy) != 0);
- }
- /**
- * _copy_to_pages
- * @pages: array of pages
- * @pgbase: page vector address of destination
- * @p: pointer to source data
- * @len: length
- *
- * Copies data from an arbitrary memory location into an array of pages
- * The copy is assumed to be non-overlapping.
- */
- static void
- _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
- {
- struct page **pgto;
- char *vto;
- size_t copy;
- if (!len)
- return;
- pgto = pages + (pgbase >> PAGE_SHIFT);
- pgbase &= ~PAGE_MASK;
- for (;;) {
- copy = PAGE_SIZE - pgbase;
- if (copy > len)
- copy = len;
- vto = kmap_atomic(*pgto);
- memcpy(vto + pgbase, p, copy);
- kunmap_atomic(vto);
- len -= copy;
- if (len == 0)
- break;
- pgbase += copy;
- if (pgbase == PAGE_SIZE) {
- flush_dcache_page(*pgto);
- pgbase = 0;
- pgto++;
- }
- p += copy;
- }
- flush_dcache_page(*pgto);
- }
- /**
- * _copy_from_pages
- * @p: pointer to destination
- * @pages: array of pages
- * @pgbase: offset of source data
- * @len: length
- *
- * Copies data into an arbitrary memory location from an array of pages
- * The copy is assumed to be non-overlapping.
- */
- void
- _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
- {
- struct page **pgfrom;
- char *vfrom;
- size_t copy;
- if (!len)
- return;
- pgfrom = pages + (pgbase >> PAGE_SHIFT);
- pgbase &= ~PAGE_MASK;
- do {
- copy = PAGE_SIZE - pgbase;
- if (copy > len)
- copy = len;
- vfrom = kmap_atomic(*pgfrom);
- memcpy(p, vfrom + pgbase, copy);
- kunmap_atomic(vfrom);
- pgbase += copy;
- if (pgbase == PAGE_SIZE) {
- pgbase = 0;
- pgfrom++;
- }
- p += copy;
- } while ((len -= copy) != 0);
- }
- EXPORT_SYMBOL_GPL(_copy_from_pages);
- static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
- unsigned int len)
- {
- if (base >= iov->iov_len)
- return;
- if (len > iov->iov_len - base)
- len = iov->iov_len - base;
- memset(iov->iov_base + base, 0, len);
- }
- /**
- * xdr_buf_pages_zero
- * @buf: xdr_buf
- * @pgbase: beginning offset
- * @len: length
- */
- static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
- unsigned int len)
- {
- struct page **pages = buf->pages;
- struct page **page;
- char *vpage;
- unsigned int zero;
- if (!len)
- return;
- if (pgbase >= buf->page_len) {
- xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
- return;
- }
- if (pgbase + len > buf->page_len) {
- xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
- len = buf->page_len - pgbase;
- }
- pgbase += buf->page_base;
- page = pages + (pgbase >> PAGE_SHIFT);
- pgbase &= ~PAGE_MASK;
- do {
- zero = PAGE_SIZE - pgbase;
- if (zero > len)
- zero = len;
- vpage = kmap_atomic(*page);
- memset(vpage + pgbase, 0, zero);
- kunmap_atomic(vpage);
- flush_dcache_page(*page);
- pgbase = 0;
- page++;
- } while ((len -= zero) != 0);
- }
- static unsigned int xdr_buf_pages_fill_sparse(const struct xdr_buf *buf,
- unsigned int buflen, gfp_t gfp)
- {
- unsigned int i, npages, pagelen;
- if (!(buf->flags & XDRBUF_SPARSE_PAGES))
- return buflen;
- if (buflen <= buf->head->iov_len)
- return buflen;
- pagelen = buflen - buf->head->iov_len;
- if (pagelen > buf->page_len)
- pagelen = buf->page_len;
- npages = (pagelen + buf->page_base + PAGE_SIZE - 1) >> PAGE_SHIFT;
- for (i = 0; i < npages; i++) {
- if (!buf->pages[i])
- continue;
- buf->pages[i] = alloc_page(gfp);
- if (likely(buf->pages[i]))
- continue;
- buflen -= pagelen;
- pagelen = i << PAGE_SHIFT;
- if (pagelen > buf->page_base)
- buflen += pagelen - buf->page_base;
- break;
- }
- return buflen;
- }
- static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
- {
- struct kvec *head = buf->head;
- struct kvec *tail = buf->tail;
- unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
- unsigned int free_space, newlen;
- if (sum > buf->len) {
- free_space = min_t(unsigned int, sum - buf->len, len);
- newlen = xdr_buf_pages_fill_sparse(buf, buf->len + free_space,
- GFP_KERNEL);
- free_space = newlen - buf->len;
- buf->len = newlen;
- len -= free_space;
- if (!len)
- return;
- }
- if (buf->buflen > sum) {
- /* Expand the tail buffer */
- free_space = min_t(unsigned int, buf->buflen - sum, len);
- tail->iov_len += free_space;
- buf->len += free_space;
- }
- }
- static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *tail = buf->tail;
- unsigned int to = base + shift;
- if (to >= tail->iov_len)
- return;
- if (len + to > tail->iov_len)
- len = tail->iov_len - to;
- memmove(tail->iov_base + to, tail->iov_base + base, len);
- }
- static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *tail = buf->tail;
- unsigned int to = base + shift;
- unsigned int pglen = 0;
- unsigned int talen = 0, tato = 0;
- if (base >= buf->page_len)
- return;
- if (len > buf->page_len - base)
- len = buf->page_len - base;
- if (to >= buf->page_len) {
- tato = to - buf->page_len;
- if (tail->iov_len >= len + tato)
- talen = len;
- else if (tail->iov_len > tato)
- talen = tail->iov_len - tato;
- } else if (len + to >= buf->page_len) {
- pglen = buf->page_len - to;
- talen = len - pglen;
- if (talen > tail->iov_len)
- talen = tail->iov_len;
- } else
- pglen = len;
- _copy_from_pages(tail->iov_base + tato, buf->pages,
- buf->page_base + base + pglen, talen);
- _shift_data_right_pages(buf->pages, buf->page_base + to,
- buf->page_base + base, pglen);
- }
- static void xdr_buf_head_copy_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *head = buf->head;
- const struct kvec *tail = buf->tail;
- unsigned int to = base + shift;
- unsigned int pglen = 0, pgto = 0;
- unsigned int talen = 0, tato = 0;
- if (base >= head->iov_len)
- return;
- if (len > head->iov_len - base)
- len = head->iov_len - base;
- if (to >= buf->page_len + head->iov_len) {
- tato = to - buf->page_len - head->iov_len;
- talen = len;
- } else if (to >= head->iov_len) {
- pgto = to - head->iov_len;
- pglen = len;
- if (pgto + pglen > buf->page_len) {
- talen = pgto + pglen - buf->page_len;
- pglen -= talen;
- }
- } else {
- pglen = len - to;
- if (pglen > buf->page_len) {
- talen = pglen - buf->page_len;
- pglen = buf->page_len;
- }
- }
- len -= talen;
- base += len;
- if (talen + tato > tail->iov_len)
- talen = tail->iov_len > tato ? tail->iov_len - tato : 0;
- memcpy(tail->iov_base + tato, head->iov_base + base, talen);
- len -= pglen;
- base -= pglen;
- _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base,
- pglen);
- base -= len;
- memmove(head->iov_base + to, head->iov_base + base, len);
- }
- static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *tail = buf->tail;
- if (base >= tail->iov_len || !shift || !len)
- return;
- xdr_buf_tail_copy_right(buf, base, len, shift);
- }
- static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- if (!shift || !len)
- return;
- if (base >= buf->page_len) {
- xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
- return;
- }
- if (base + len > buf->page_len)
- xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
- shift);
- xdr_buf_pages_copy_right(buf, base, len, shift);
- }
- static void xdr_buf_head_shift_right(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *head = buf->head;
- if (!shift)
- return;
- if (base >= head->iov_len) {
- xdr_buf_pages_shift_right(buf, head->iov_len - base, len,
- shift);
- return;
- }
- if (base + len > head->iov_len)
- xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len,
- shift);
- xdr_buf_head_copy_right(buf, base, len, shift);
- }
- static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base,
- unsigned int len, unsigned int shift)
- {
- const struct kvec *tail = buf->tail;
- if (base >= tail->iov_len)
- return;
- if (len > tail->iov_len - base)
- len = tail->iov_len - base;
- /* Shift data into head */
- if (shift > buf->page_len + base) {
- const struct kvec *head = buf->head;
- unsigned int hdto =
- head->iov_len + buf->page_len + base - shift;
- unsigned int hdlen = len;
- if (WARN_ONCE(shift > head->iov_len + buf->page_len + base,
- "SUNRPC: Misaligned data.\n"))
- return;
- if (hdto + hdlen > head->iov_len)
- hdlen = head->iov_len - hdto;
- memcpy(head->iov_base + hdto, tail->iov_base + base, hdlen);
- base += hdlen;
- len -= hdlen;
- if (!len)
- return;
- }
- /* Shift data into pages */
- if (shift > base) {
- unsigned int pgto = buf->page_len + base - shift;
- unsigned int pglen = len;
- if (pgto + pglen > buf->page_len)
- pglen = buf->page_len - pgto;
- _copy_to_pages(buf->pages, buf->page_base + pgto,
- tail->iov_base + base, pglen);
- base += pglen;
- len -= pglen;
- if (!len)
- return;
- }
- memmove(tail->iov_base + base - shift, tail->iov_base + base, len);
- }
- static void xdr_buf_pages_copy_left(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- unsigned int pgto;
- if (base >= buf->page_len)
- return;
- if (len > buf->page_len - base)
- len = buf->page_len - base;
- /* Shift data into head */
- if (shift > base) {
- const struct kvec *head = buf->head;
- unsigned int hdto = head->iov_len + base - shift;
- unsigned int hdlen = len;
- if (WARN_ONCE(shift > head->iov_len + base,
- "SUNRPC: Misaligned data.\n"))
- return;
- if (hdto + hdlen > head->iov_len)
- hdlen = head->iov_len - hdto;
- _copy_from_pages(head->iov_base + hdto, buf->pages,
- buf->page_base + base, hdlen);
- base += hdlen;
- len -= hdlen;
- if (!len)
- return;
- }
- pgto = base - shift;
- _shift_data_left_pages(buf->pages, buf->page_base + pgto,
- buf->page_base + base, len);
- }
- static void xdr_buf_tail_shift_left(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- if (!shift || !len)
- return;
- xdr_buf_tail_copy_left(buf, base, len, shift);
- }
- static void xdr_buf_pages_shift_left(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- if (!shift || !len)
- return;
- if (base >= buf->page_len) {
- xdr_buf_tail_shift_left(buf, base - buf->page_len, len, shift);
- return;
- }
- xdr_buf_pages_copy_left(buf, base, len, shift);
- len += base;
- if (len <= buf->page_len)
- return;
- xdr_buf_tail_copy_left(buf, 0, len - buf->page_len, shift);
- }
- static void xdr_buf_head_shift_left(const struct xdr_buf *buf,
- unsigned int base, unsigned int len,
- unsigned int shift)
- {
- const struct kvec *head = buf->head;
- unsigned int bytes;
- if (!shift || !len)
- return;
- if (shift > base) {
- bytes = (shift - base);
- if (bytes >= len)
- return;
- base += bytes;
- len -= bytes;
- }
- if (base < head->iov_len) {
- bytes = min_t(unsigned int, len, head->iov_len - base);
- memmove(head->iov_base + (base - shift),
- head->iov_base + base, bytes);
- base += bytes;
- len -= bytes;
- }
- xdr_buf_pages_shift_left(buf, base - head->iov_len, len, shift);
- }
- /**
- * xdr_shrink_bufhead
- * @buf: xdr_buf
- * @len: new length of buf->head[0]
- *
- * Shrinks XDR buffer's header kvec buf->head[0], setting it to
- * 'len' bytes. The extra data is not lost, but is instead
- * moved into the inlined pages and/or the tail.
- */
- static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len)
- {
- struct kvec *head = buf->head;
- unsigned int shift, buflen = max(buf->len, len);
- WARN_ON_ONCE(len > head->iov_len);
- if (head->iov_len > buflen) {
- buf->buflen -= head->iov_len - buflen;
- head->iov_len = buflen;
- }
- if (len >= head->iov_len)
- return 0;
- shift = head->iov_len - len;
- xdr_buf_try_expand(buf, shift);
- xdr_buf_head_shift_right(buf, len, buflen - len, shift);
- head->iov_len = len;
- buf->buflen -= shift;
- buf->len -= shift;
- return shift;
- }
- /**
- * xdr_shrink_pagelen - shrinks buf->pages to @len bytes
- * @buf: xdr_buf
- * @len: new page buffer length
- *
- * The extra data is not lost, but is instead moved into buf->tail.
- * Returns the actual number of bytes moved.
- */
- static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
- {
- unsigned int shift, buflen = buf->len - buf->head->iov_len;
- WARN_ON_ONCE(len > buf->page_len);
- if (buf->head->iov_len >= buf->len || len > buflen)
- buflen = len;
- if (buf->page_len > buflen) {
- buf->buflen -= buf->page_len - buflen;
- buf->page_len = buflen;
- }
- if (len >= buf->page_len)
- return 0;
- shift = buf->page_len - len;
- xdr_buf_try_expand(buf, shift);
- xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
- buf->page_len = len;
- buf->len -= shift;
- buf->buflen -= shift;
- return shift;
- }
- void
- xdr_shift_buf(struct xdr_buf *buf, size_t len)
- {
- xdr_shrink_bufhead(buf, buf->head->iov_len - len);
- }
- EXPORT_SYMBOL_GPL(xdr_shift_buf);
- /**
- * xdr_stream_pos - Return the current offset from the start of the xdr_stream
- * @xdr: pointer to struct xdr_stream
- */
- unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
- {
- return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_pos);
- static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
- {
- unsigned int blen = xdr->buf->len;
- xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
- }
- static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
- {
- xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
- }
- /**
- * xdr_page_pos - Return the current offset from the start of the xdr pages
- * @xdr: pointer to struct xdr_stream
- */
- unsigned int xdr_page_pos(const struct xdr_stream *xdr)
- {
- unsigned int pos = xdr_stream_pos(xdr);
- WARN_ON(pos < xdr->buf->head[0].iov_len);
- return pos - xdr->buf->head[0].iov_len;
- }
- EXPORT_SYMBOL_GPL(xdr_page_pos);
- /**
- * xdr_init_encode - Initialize a struct xdr_stream for sending data.
- * @xdr: pointer to xdr_stream struct
- * @buf: pointer to XDR buffer in which to encode data
- * @p: current pointer inside XDR buffer
- * @rqst: pointer to controlling rpc_rqst, for debugging
- *
- * Note: at the moment the RPC client only passes the length of our
- * scratch buffer in the xdr_buf's header kvec. Previously this
- * meant we needed to call xdr_adjust_iovec() after encoding the
- * data. With the new scheme, the xdr_stream manages the details
- * of the buffer length, and takes care of adjusting the kvec
- * length for us.
- */
- void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
- struct rpc_rqst *rqst)
- {
- struct kvec *iov = buf->head;
- int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
- xdr_reset_scratch_buffer(xdr);
- BUG_ON(scratch_len < 0);
- xdr->buf = buf;
- xdr->iov = iov;
- xdr->p = (__be32 *)((char *)iov->iov_base + iov->iov_len);
- xdr->end = (__be32 *)((char *)iov->iov_base + scratch_len);
- BUG_ON(iov->iov_len > scratch_len);
- if (p != xdr->p && p != NULL) {
- size_t len;
- BUG_ON(p < xdr->p || p > xdr->end);
- len = (char *)p - (char *)xdr->p;
- xdr->p = p;
- buf->len += len;
- iov->iov_len += len;
- }
- xdr->rqst = rqst;
- }
- EXPORT_SYMBOL_GPL(xdr_init_encode);
- /**
- * xdr_init_encode_pages - Initialize an xdr_stream for encoding into pages
- * @xdr: pointer to xdr_stream struct
- * @buf: pointer to XDR buffer into which to encode data
- * @pages: list of pages to decode into
- * @rqst: pointer to controlling rpc_rqst, for debugging
- *
- */
- void xdr_init_encode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
- struct page **pages, struct rpc_rqst *rqst)
- {
- xdr_reset_scratch_buffer(xdr);
- xdr->buf = buf;
- xdr->page_ptr = pages;
- xdr->iov = NULL;
- xdr->p = page_address(*pages);
- xdr->end = (void *)xdr->p + min_t(u32, buf->buflen, PAGE_SIZE);
- xdr->rqst = rqst;
- }
- EXPORT_SYMBOL_GPL(xdr_init_encode_pages);
- /**
- * __xdr_commit_encode - Ensure all data is written to buffer
- * @xdr: pointer to xdr_stream
- *
- * We handle encoding across page boundaries by giving the caller a
- * temporary location to write to, then later copying the data into
- * place; xdr_commit_encode does that copying.
- *
- * Normally the caller doesn't need to call this directly, as the
- * following xdr_reserve_space will do it. But an explicit call may be
- * required at the end of encoding, or any other time when the xdr_buf
- * data might be read.
- */
- void __xdr_commit_encode(struct xdr_stream *xdr)
- {
- size_t shift = xdr->scratch.iov_len;
- void *page;
- page = page_address(*xdr->page_ptr);
- memcpy(xdr->scratch.iov_base, page, shift);
- memmove(page, page + shift, (void *)xdr->p - page);
- xdr_reset_scratch_buffer(xdr);
- }
- EXPORT_SYMBOL_GPL(__xdr_commit_encode);
- /*
- * The buffer space to be reserved crosses the boundary between
- * xdr->buf->head and xdr->buf->pages, or between two pages
- * in xdr->buf->pages.
- */
- static noinline __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
- size_t nbytes)
- {
- int space_left;
- int frag1bytes, frag2bytes;
- void *p;
- if (nbytes > PAGE_SIZE)
- goto out_overflow; /* Bigger buffers require special handling */
- if (xdr->buf->len + nbytes > xdr->buf->buflen)
- goto out_overflow; /* Sorry, we're totally out of space */
- frag1bytes = (xdr->end - xdr->p) << 2;
- frag2bytes = nbytes - frag1bytes;
- if (xdr->iov)
- xdr->iov->iov_len += frag1bytes;
- else
- xdr->buf->page_len += frag1bytes;
- xdr->page_ptr++;
- xdr->iov = NULL;
- /*
- * If the last encode didn't end exactly on a page boundary, the
- * next one will straddle boundaries. Encode into the next
- * page, then copy it back later in xdr_commit_encode. We use
- * the "scratch" iov to track any temporarily unused fragment of
- * space at the end of the previous buffer:
- */
- xdr_set_scratch_buffer(xdr, xdr->p, frag1bytes);
- /*
- * xdr->p is where the next encode will start after
- * xdr_commit_encode() has shifted this one back:
- */
- p = page_address(*xdr->page_ptr);
- xdr->p = p + frag2bytes;
- space_left = xdr->buf->buflen - xdr->buf->len;
- if (space_left - frag1bytes >= PAGE_SIZE)
- xdr->end = p + PAGE_SIZE;
- else
- xdr->end = p + space_left - frag1bytes;
- xdr->buf->page_len += frag2bytes;
- xdr->buf->len += nbytes;
- return p;
- out_overflow:
- trace_rpc_xdr_overflow(xdr, nbytes);
- return NULL;
- }
- /**
- * xdr_reserve_space - Reserve buffer space for sending
- * @xdr: pointer to xdr_stream
- * @nbytes: number of bytes to reserve
- *
- * Checks that we have enough buffer space to encode 'nbytes' more
- * bytes of data. If so, update the total xdr_buf length, and
- * adjust the length of the current kvec.
- */
- __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
- {
- __be32 *p = xdr->p;
- __be32 *q;
- xdr_commit_encode(xdr);
- /* align nbytes on the next 32-bit boundary */
- nbytes += 3;
- nbytes &= ~3;
- q = p + (nbytes >> 2);
- if (unlikely(q > xdr->end || q < p))
- return xdr_get_next_encode_buffer(xdr, nbytes);
- xdr->p = q;
- if (xdr->iov)
- xdr->iov->iov_len += nbytes;
- else
- xdr->buf->page_len += nbytes;
- xdr->buf->len += nbytes;
- return p;
- }
- EXPORT_SYMBOL_GPL(xdr_reserve_space);
- /**
- * xdr_reserve_space_vec - Reserves a large amount of buffer space for sending
- * @xdr: pointer to xdr_stream
- * @vec: pointer to a kvec array
- * @nbytes: number of bytes to reserve
- *
- * Reserves enough buffer space to encode 'nbytes' of data and stores the
- * pointers in 'vec'. The size argument passed to xdr_reserve_space() is
- * determined based on the number of bytes remaining in the current page to
- * avoid invalidating iov_base pointers when xdr_commit_encode() is called.
- */
- int xdr_reserve_space_vec(struct xdr_stream *xdr, struct kvec *vec, size_t nbytes)
- {
- int thislen;
- int v = 0;
- __be32 *p;
- /*
- * svcrdma requires every READ payload to start somewhere
- * in xdr->pages.
- */
- if (xdr->iov == xdr->buf->head) {
- xdr->iov = NULL;
- xdr->end = xdr->p;
- }
- while (nbytes) {
- thislen = xdr->buf->page_len % PAGE_SIZE;
- thislen = min_t(size_t, nbytes, PAGE_SIZE - thislen);
- p = xdr_reserve_space(xdr, thislen);
- if (!p)
- return -EIO;
- vec[v].iov_base = p;
- vec[v].iov_len = thislen;
- v++;
- nbytes -= thislen;
- }
- return v;
- }
- EXPORT_SYMBOL_GPL(xdr_reserve_space_vec);
- /**
- * xdr_truncate_encode - truncate an encode buffer
- * @xdr: pointer to xdr_stream
- * @len: new length of buffer
- *
- * Truncates the xdr stream, so that xdr->buf->len == len,
- * and xdr->p points at offset len from the start of the buffer, and
- * head, tail, and page lengths are adjusted to correspond.
- *
- * If this means moving xdr->p to a different buffer, we assume that
- * the end pointer should be set to the end of the current page,
- * except in the case of the head buffer when we assume the head
- * buffer's current length represents the end of the available buffer.
- *
- * This is *not* safe to use on a buffer that already has inlined page
- * cache pages (as in a zero-copy server read reply), except for the
- * simple case of truncating from one position in the tail to another.
- *
- */
- void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
- {
- struct xdr_buf *buf = xdr->buf;
- struct kvec *head = buf->head;
- struct kvec *tail = buf->tail;
- int fraglen;
- int new;
- if (len > buf->len) {
- WARN_ON_ONCE(1);
- return;
- }
- xdr_commit_encode(xdr);
- fraglen = min_t(int, buf->len - len, tail->iov_len);
- tail->iov_len -= fraglen;
- buf->len -= fraglen;
- if (tail->iov_len) {
- xdr->p = tail->iov_base + tail->iov_len;
- WARN_ON_ONCE(!xdr->end);
- WARN_ON_ONCE(!xdr->iov);
- return;
- }
- WARN_ON_ONCE(fraglen);
- fraglen = min_t(int, buf->len - len, buf->page_len);
- buf->page_len -= fraglen;
- buf->len -= fraglen;
- new = buf->page_base + buf->page_len;
- xdr->page_ptr = buf->pages + (new >> PAGE_SHIFT);
- if (buf->page_len) {
- xdr->p = page_address(*xdr->page_ptr);
- xdr->end = (void *)xdr->p + PAGE_SIZE;
- xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
- WARN_ON_ONCE(xdr->iov);
- return;
- }
- if (fraglen)
- xdr->end = head->iov_base + head->iov_len;
- /* (otherwise assume xdr->end is already set) */
- xdr->page_ptr--;
- head->iov_len = len;
- buf->len = len;
- xdr->p = head->iov_base + head->iov_len;
- xdr->iov = buf->head;
- }
- EXPORT_SYMBOL(xdr_truncate_encode);
- /**
- * xdr_restrict_buflen - decrease available buffer space
- * @xdr: pointer to xdr_stream
- * @newbuflen: new maximum number of bytes available
- *
- * Adjust our idea of how much space is available in the buffer.
- * If we've already used too much space in the buffer, returns -1.
- * If the available space is already smaller than newbuflen, returns 0
- * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
- * and ensures xdr->end is set at most offset newbuflen from the start
- * of the buffer.
- */
- int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
- {
- struct xdr_buf *buf = xdr->buf;
- int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
- int end_offset = buf->len + left_in_this_buf;
- if (newbuflen < 0 || newbuflen < buf->len)
- return -1;
- if (newbuflen > buf->buflen)
- return 0;
- if (newbuflen < end_offset)
- xdr->end = (void *)xdr->end + newbuflen - end_offset;
- buf->buflen = newbuflen;
- return 0;
- }
- EXPORT_SYMBOL(xdr_restrict_buflen);
- /**
- * xdr_write_pages - Insert a list of pages into an XDR buffer for sending
- * @xdr: pointer to xdr_stream
- * @pages: list of pages
- * @base: offset of first byte
- * @len: length of data in bytes
- *
- */
- void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int base,
- unsigned int len)
- {
- struct xdr_buf *buf = xdr->buf;
- struct kvec *iov = buf->tail;
- buf->pages = pages;
- buf->page_base = base;
- buf->page_len = len;
- iov->iov_base = (char *)xdr->p;
- iov->iov_len = 0;
- xdr->iov = iov;
- if (len & 3) {
- unsigned int pad = 4 - (len & 3);
- BUG_ON(xdr->p >= xdr->end);
- iov->iov_base = (char *)xdr->p + (len & 3);
- iov->iov_len += pad;
- len += pad;
- *xdr->p++ = 0;
- }
- buf->buflen += len;
- buf->len += len;
- }
- EXPORT_SYMBOL_GPL(xdr_write_pages);
- static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
- unsigned int base, unsigned int len)
- {
- if (len > iov->iov_len)
- len = iov->iov_len;
- if (unlikely(base > len))
- base = len;
- xdr->p = (__be32*)(iov->iov_base + base);
- xdr->end = (__be32*)(iov->iov_base + len);
- xdr->iov = iov;
- xdr->page_ptr = NULL;
- return len - base;
- }
- static unsigned int xdr_set_tail_base(struct xdr_stream *xdr,
- unsigned int base, unsigned int len)
- {
- struct xdr_buf *buf = xdr->buf;
- xdr_stream_set_pos(xdr, base + buf->page_len + buf->head->iov_len);
- return xdr_set_iov(xdr, buf->tail, base, len);
- }
- static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
- unsigned int base, unsigned int len)
- {
- unsigned int pgnr;
- unsigned int maxlen;
- unsigned int pgoff;
- unsigned int pgend;
- void *kaddr;
- maxlen = xdr->buf->page_len;
- if (base >= maxlen)
- return 0;
- else
- maxlen -= base;
- if (len > maxlen)
- len = maxlen;
- xdr_stream_page_set_pos(xdr, base);
- base += xdr->buf->page_base;
- pgnr = base >> PAGE_SHIFT;
- xdr->page_ptr = &xdr->buf->pages[pgnr];
- kaddr = page_address(*xdr->page_ptr);
- pgoff = base & ~PAGE_MASK;
- xdr->p = (__be32*)(kaddr + pgoff);
- pgend = pgoff + len;
- if (pgend > PAGE_SIZE)
- pgend = PAGE_SIZE;
- xdr->end = (__be32*)(kaddr + pgend);
- xdr->iov = NULL;
- return len;
- }
- static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
- unsigned int len)
- {
- if (xdr_set_page_base(xdr, base, len) == 0) {
- base -= xdr->buf->page_len;
- xdr_set_tail_base(xdr, base, len);
- }
- }
- static void xdr_set_next_page(struct xdr_stream *xdr)
- {
- unsigned int newbase;
- newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
- newbase -= xdr->buf->page_base;
- if (newbase < xdr->buf->page_len)
- xdr_set_page_base(xdr, newbase, xdr_stream_remaining(xdr));
- else
- xdr_set_tail_base(xdr, 0, xdr_stream_remaining(xdr));
- }
- static bool xdr_set_next_buffer(struct xdr_stream *xdr)
- {
- if (xdr->page_ptr != NULL)
- xdr_set_next_page(xdr);
- else if (xdr->iov == xdr->buf->head)
- xdr_set_page(xdr, 0, xdr_stream_remaining(xdr));
- return xdr->p != xdr->end;
- }
- /**
- * xdr_init_decode - Initialize an xdr_stream for decoding data.
- * @xdr: pointer to xdr_stream struct
- * @buf: pointer to XDR buffer from which to decode data
- * @p: current pointer inside XDR buffer
- * @rqst: pointer to controlling rpc_rqst, for debugging
- */
- void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
- struct rpc_rqst *rqst)
- {
- xdr->buf = buf;
- xdr_reset_scratch_buffer(xdr);
- xdr->nwords = XDR_QUADLEN(buf->len);
- if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
- xdr_set_page_base(xdr, 0, buf->len) == 0)
- xdr_set_iov(xdr, buf->tail, 0, buf->len);
- if (p != NULL && p > xdr->p && xdr->end >= p) {
- xdr->nwords -= p - xdr->p;
- xdr->p = p;
- }
- xdr->rqst = rqst;
- }
- EXPORT_SYMBOL_GPL(xdr_init_decode);
- /**
- * xdr_init_decode_pages - Initialize an xdr_stream for decoding into pages
- * @xdr: pointer to xdr_stream struct
- * @buf: pointer to XDR buffer from which to decode data
- * @pages: list of pages to decode into
- * @len: length in bytes of buffer in pages
- */
- void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
- struct page **pages, unsigned int len)
- {
- memset(buf, 0, sizeof(*buf));
- buf->pages = pages;
- buf->page_len = len;
- buf->buflen = len;
- buf->len = len;
- xdr_init_decode(xdr, buf, NULL, NULL);
- }
- EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
- static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
- {
- unsigned int nwords = XDR_QUADLEN(nbytes);
- __be32 *p = xdr->p;
- __be32 *q = p + nwords;
- if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
- return NULL;
- xdr->p = q;
- xdr->nwords -= nwords;
- return p;
- }
- static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
- {
- __be32 *p;
- char *cpdest = xdr->scratch.iov_base;
- size_t cplen = (char *)xdr->end - (char *)xdr->p;
- if (nbytes > xdr->scratch.iov_len)
- goto out_overflow;
- p = __xdr_inline_decode(xdr, cplen);
- if (p == NULL)
- return NULL;
- memcpy(cpdest, p, cplen);
- if (!xdr_set_next_buffer(xdr))
- goto out_overflow;
- cpdest += cplen;
- nbytes -= cplen;
- p = __xdr_inline_decode(xdr, nbytes);
- if (p == NULL)
- return NULL;
- memcpy(cpdest, p, nbytes);
- return xdr->scratch.iov_base;
- out_overflow:
- trace_rpc_xdr_overflow(xdr, nbytes);
- return NULL;
- }
- /**
- * xdr_inline_decode - Retrieve XDR data to decode
- * @xdr: pointer to xdr_stream struct
- * @nbytes: number of bytes of data to decode
- *
- * Check if the input buffer is long enough to enable us to decode
- * 'nbytes' more bytes of data starting at the current position.
- * If so return the current pointer, then update the current
- * pointer position.
- */
- __be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
- {
- __be32 *p;
- if (unlikely(nbytes == 0))
- return xdr->p;
- if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
- goto out_overflow;
- p = __xdr_inline_decode(xdr, nbytes);
- if (p != NULL)
- return p;
- return xdr_copy_to_scratch(xdr, nbytes);
- out_overflow:
- trace_rpc_xdr_overflow(xdr, nbytes);
- return NULL;
- }
- EXPORT_SYMBOL_GPL(xdr_inline_decode);
- static void xdr_realign_pages(struct xdr_stream *xdr)
- {
- struct xdr_buf *buf = xdr->buf;
- struct kvec *iov = buf->head;
- unsigned int cur = xdr_stream_pos(xdr);
- unsigned int copied;
- /* Realign pages to current pointer position */
- if (iov->iov_len > cur) {
- copied = xdr_shrink_bufhead(buf, cur);
- trace_rpc_xdr_alignment(xdr, cur, copied);
- xdr_set_page(xdr, 0, buf->page_len);
- }
- }
- static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
- {
- struct xdr_buf *buf = xdr->buf;
- unsigned int nwords = XDR_QUADLEN(len);
- unsigned int copied;
- if (xdr->nwords == 0)
- return 0;
- xdr_realign_pages(xdr);
- if (nwords > xdr->nwords) {
- nwords = xdr->nwords;
- len = nwords << 2;
- }
- if (buf->page_len <= len)
- len = buf->page_len;
- else if (nwords < xdr->nwords) {
- /* Truncate page data and move it into the tail */
- copied = xdr_shrink_pagelen(buf, len);
- trace_rpc_xdr_alignment(xdr, len, copied);
- }
- return len;
- }
- /**
- * xdr_read_pages - align page-based XDR data to current pointer position
- * @xdr: pointer to xdr_stream struct
- * @len: number of bytes of page data
- *
- * Moves data beyond the current pointer position from the XDR head[] buffer
- * into the page list. Any data that lies beyond current position + @len
- * bytes is moved into the XDR tail[]. The xdr_stream current position is
- * then advanced past that data to align to the next XDR object in the tail.
- *
- * Returns the number of XDR encoded bytes now contained in the pages
- */
- unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
- {
- unsigned int nwords = XDR_QUADLEN(len);
- unsigned int base, end, pglen;
- pglen = xdr_align_pages(xdr, nwords << 2);
- if (pglen == 0)
- return 0;
- base = (nwords << 2) - pglen;
- end = xdr_stream_remaining(xdr) - pglen;
- xdr_set_tail_base(xdr, base, end);
- return len <= pglen ? len : pglen;
- }
- EXPORT_SYMBOL_GPL(xdr_read_pages);
- /**
- * xdr_set_pagelen - Sets the length of the XDR pages
- * @xdr: pointer to xdr_stream struct
- * @len: new length of the XDR page data
- *
- * Either grows or shrinks the length of the xdr pages by setting pagelen to
- * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
- * when growing any data beyond the current pointer is moved into the tail.
- *
- * Returns True if the operation was successful, and False otherwise.
- */
- void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
- {
- struct xdr_buf *buf = xdr->buf;
- size_t remaining = xdr_stream_remaining(xdr);
- size_t base = 0;
- if (len < buf->page_len) {
- base = buf->page_len - len;
- xdr_shrink_pagelen(buf, len);
- } else {
- xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
- buf->page_len, remaining);
- if (len > buf->page_len)
- xdr_buf_try_expand(buf, len - buf->page_len);
- }
- xdr_set_tail_base(xdr, base, remaining);
- }
- EXPORT_SYMBOL_GPL(xdr_set_pagelen);
- /**
- * xdr_enter_page - decode data from the XDR page
- * @xdr: pointer to xdr_stream struct
- * @len: number of bytes of page data
- *
- * Moves data beyond the current pointer position from the XDR head[] buffer
- * into the page list. Any data that lies beyond current position + "len"
- * bytes is moved into the XDR tail[]. The current pointer is then
- * repositioned at the beginning of the first XDR page.
- */
- void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
- {
- len = xdr_align_pages(xdr, len);
- /*
- * Position current pointer at beginning of tail, and
- * set remaining message length.
- */
- if (len != 0)
- xdr_set_page_base(xdr, 0, len);
- }
- EXPORT_SYMBOL_GPL(xdr_enter_page);
- static const struct kvec empty_iov = {.iov_base = NULL, .iov_len = 0};
- void xdr_buf_from_iov(const struct kvec *iov, struct xdr_buf *buf)
- {
- buf->head[0] = *iov;
- buf->tail[0] = empty_iov;
- buf->page_len = 0;
- buf->buflen = buf->len = iov->iov_len;
- }
- EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
- /**
- * xdr_buf_subsegment - set subbuf to a portion of buf
- * @buf: an xdr buffer
- * @subbuf: the result buffer
- * @base: beginning of range in bytes
- * @len: length of range in bytes
- *
- * sets @subbuf to an xdr buffer representing the portion of @buf of
- * length @len starting at offset @base.
- *
- * @buf and @subbuf may be pointers to the same struct xdr_buf.
- *
- * Returns -1 if base or length are out of bounds.
- */
- int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
- unsigned int base, unsigned int len)
- {
- subbuf->buflen = subbuf->len = len;
- if (base < buf->head[0].iov_len) {
- subbuf->head[0].iov_base = buf->head[0].iov_base + base;
- subbuf->head[0].iov_len = min_t(unsigned int, len,
- buf->head[0].iov_len - base);
- len -= subbuf->head[0].iov_len;
- base = 0;
- } else {
- base -= buf->head[0].iov_len;
- subbuf->head[0].iov_base = buf->head[0].iov_base;
- subbuf->head[0].iov_len = 0;
- }
- if (base < buf->page_len) {
- subbuf->page_len = min(buf->page_len - base, len);
- base += buf->page_base;
- subbuf->page_base = base & ~PAGE_MASK;
- subbuf->pages = &buf->pages[base >> PAGE_SHIFT];
- len -= subbuf->page_len;
- base = 0;
- } else {
- base -= buf->page_len;
- subbuf->pages = buf->pages;
- subbuf->page_base = 0;
- subbuf->page_len = 0;
- }
- if (base < buf->tail[0].iov_len) {
- subbuf->tail[0].iov_base = buf->tail[0].iov_base + base;
- subbuf->tail[0].iov_len = min_t(unsigned int, len,
- buf->tail[0].iov_len - base);
- len -= subbuf->tail[0].iov_len;
- base = 0;
- } else {
- base -= buf->tail[0].iov_len;
- subbuf->tail[0].iov_base = buf->tail[0].iov_base;
- subbuf->tail[0].iov_len = 0;
- }
- if (base || len)
- return -1;
- return 0;
- }
- EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
- /**
- * xdr_stream_subsegment - set @subbuf to a portion of @xdr
- * @xdr: an xdr_stream set up for decoding
- * @subbuf: the result buffer
- * @nbytes: length of @xdr to extract, in bytes
- *
- * Sets up @subbuf to represent a portion of @xdr. The portion
- * starts at the current offset in @xdr, and extends for a length
- * of @nbytes. If this is successful, @xdr is advanced to the next
- * XDR data item following that portion.
- *
- * Return values:
- * %true: @subbuf has been initialized, and @xdr has been advanced.
- * %false: a bounds error has occurred
- */
- bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
- unsigned int nbytes)
- {
- unsigned int start = xdr_stream_pos(xdr);
- unsigned int remaining, len;
- /* Extract @subbuf and bounds-check the fn arguments */
- if (xdr_buf_subsegment(xdr->buf, subbuf, start, nbytes))
- return false;
- /* Advance @xdr by @nbytes */
- for (remaining = nbytes; remaining;) {
- if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
- return false;
- len = (char *)xdr->end - (char *)xdr->p;
- if (remaining <= len) {
- xdr->p = (__be32 *)((char *)xdr->p +
- (remaining + xdr_pad_size(nbytes)));
- break;
- }
- xdr->p = (__be32 *)((char *)xdr->p + len);
- xdr->end = xdr->p;
- remaining -= len;
- }
- xdr_stream_set_pos(xdr, start + nbytes);
- return true;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
- /**
- * xdr_stream_move_subsegment - Move part of a stream to another position
- * @xdr: the source xdr_stream
- * @offset: the source offset of the segment
- * @target: the target offset of the segment
- * @length: the number of bytes to move
- *
- * Moves @length bytes from @offset to @target in the xdr_stream, overwriting
- * anything in its space. Returns the number of bytes in the segment.
- */
- unsigned int xdr_stream_move_subsegment(struct xdr_stream *xdr, unsigned int offset,
- unsigned int target, unsigned int length)
- {
- struct xdr_buf buf;
- unsigned int shift;
- if (offset < target) {
- shift = target - offset;
- if (xdr_buf_subsegment(xdr->buf, &buf, offset, shift + length) < 0)
- return 0;
- xdr_buf_head_shift_right(&buf, 0, length, shift);
- } else if (offset > target) {
- shift = offset - target;
- if (xdr_buf_subsegment(xdr->buf, &buf, target, shift + length) < 0)
- return 0;
- xdr_buf_head_shift_left(&buf, shift, length, shift);
- }
- return length;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_move_subsegment);
- /**
- * xdr_stream_zero - zero out a portion of an xdr_stream
- * @xdr: an xdr_stream to zero out
- * @offset: the starting point in the stream
- * @length: the number of bytes to zero
- */
- unsigned int xdr_stream_zero(struct xdr_stream *xdr, unsigned int offset,
- unsigned int length)
- {
- struct xdr_buf buf;
- if (xdr_buf_subsegment(xdr->buf, &buf, offset, length) < 0)
- return 0;
- if (buf.head[0].iov_len)
- xdr_buf_iov_zero(buf.head, 0, buf.head[0].iov_len);
- if (buf.page_len > 0)
- xdr_buf_pages_zero(&buf, 0, buf.page_len);
- if (buf.tail[0].iov_len)
- xdr_buf_iov_zero(buf.tail, 0, buf.tail[0].iov_len);
- return length;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_zero);
- /**
- * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
- * @buf: buf to be trimmed
- * @len: number of bytes to reduce "buf" by
- *
- * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
- * that it's possible that we'll trim less than that amount if the xdr_buf is
- * too small, or if (for instance) it's all in the head and the parser has
- * already read too far into it.
- */
- void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
- {
- size_t cur;
- unsigned int trim = len;
- if (buf->tail[0].iov_len) {
- cur = min_t(size_t, buf->tail[0].iov_len, trim);
- buf->tail[0].iov_len -= cur;
- trim -= cur;
- if (!trim)
- goto fix_len;
- }
- if (buf->page_len) {
- cur = min_t(unsigned int, buf->page_len, trim);
- buf->page_len -= cur;
- trim -= cur;
- if (!trim)
- goto fix_len;
- }
- if (buf->head[0].iov_len) {
- cur = min_t(size_t, buf->head[0].iov_len, trim);
- buf->head[0].iov_len -= cur;
- trim -= cur;
- }
- fix_len:
- buf->len -= (len - trim);
- }
- EXPORT_SYMBOL_GPL(xdr_buf_trim);
- static void __read_bytes_from_xdr_buf(const struct xdr_buf *subbuf,
- void *obj, unsigned int len)
- {
- unsigned int this_len;
- this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
- memcpy(obj, subbuf->head[0].iov_base, this_len);
- len -= this_len;
- obj += this_len;
- this_len = min_t(unsigned int, len, subbuf->page_len);
- _copy_from_pages(obj, subbuf->pages, subbuf->page_base, this_len);
- len -= this_len;
- obj += this_len;
- this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
- memcpy(obj, subbuf->tail[0].iov_base, this_len);
- }
- /* obj is assumed to point to allocated memory of size at least len: */
- int read_bytes_from_xdr_buf(const struct xdr_buf *buf, unsigned int base,
- void *obj, unsigned int len)
- {
- struct xdr_buf subbuf;
- int status;
- status = xdr_buf_subsegment(buf, &subbuf, base, len);
- if (status != 0)
- return status;
- __read_bytes_from_xdr_buf(&subbuf, obj, len);
- return 0;
- }
- EXPORT_SYMBOL_GPL(read_bytes_from_xdr_buf);
- static void __write_bytes_to_xdr_buf(const struct xdr_buf *subbuf,
- void *obj, unsigned int len)
- {
- unsigned int this_len;
- this_len = min_t(unsigned int, len, subbuf->head[0].iov_len);
- memcpy(subbuf->head[0].iov_base, obj, this_len);
- len -= this_len;
- obj += this_len;
- this_len = min_t(unsigned int, len, subbuf->page_len);
- _copy_to_pages(subbuf->pages, subbuf->page_base, obj, this_len);
- len -= this_len;
- obj += this_len;
- this_len = min_t(unsigned int, len, subbuf->tail[0].iov_len);
- memcpy(subbuf->tail[0].iov_base, obj, this_len);
- }
- /* obj is assumed to point to allocated memory of size at least len: */
- int write_bytes_to_xdr_buf(const struct xdr_buf *buf, unsigned int base,
- void *obj, unsigned int len)
- {
- struct xdr_buf subbuf;
- int status;
- status = xdr_buf_subsegment(buf, &subbuf, base, len);
- if (status != 0)
- return status;
- __write_bytes_to_xdr_buf(&subbuf, obj, len);
- return 0;
- }
- EXPORT_SYMBOL_GPL(write_bytes_to_xdr_buf);
- int xdr_decode_word(const struct xdr_buf *buf, unsigned int base, u32 *obj)
- {
- __be32 raw;
- int status;
- status = read_bytes_from_xdr_buf(buf, base, &raw, sizeof(*obj));
- if (status)
- return status;
- *obj = be32_to_cpu(raw);
- return 0;
- }
- EXPORT_SYMBOL_GPL(xdr_decode_word);
- int xdr_encode_word(const struct xdr_buf *buf, unsigned int base, u32 obj)
- {
- __be32 raw = cpu_to_be32(obj);
- return write_bytes_to_xdr_buf(buf, base, &raw, sizeof(obj));
- }
- EXPORT_SYMBOL_GPL(xdr_encode_word);
- /* Returns 0 on success, or else a negative error code. */
- static int xdr_xcode_array2(const struct xdr_buf *buf, unsigned int base,
- struct xdr_array2_desc *desc, int encode)
- {
- char *elem = NULL, *c;
- unsigned int copied = 0, todo, avail_here;
- struct page **ppages = NULL;
- int err;
- if (encode) {
- if (xdr_encode_word(buf, base, desc->array_len) != 0)
- return -EINVAL;
- } else {
- if (xdr_decode_word(buf, base, &desc->array_len) != 0 ||
- desc->array_len > desc->array_maxlen ||
- (unsigned long) base + 4 + desc->array_len *
- desc->elem_size > buf->len)
- return -EINVAL;
- }
- base += 4;
- if (!desc->xcode)
- return 0;
- todo = desc->array_len * desc->elem_size;
- /* process head */
- if (todo && base < buf->head->iov_len) {
- c = buf->head->iov_base + base;
- avail_here = min_t(unsigned int, todo,
- buf->head->iov_len - base);
- todo -= avail_here;
- while (avail_here >= desc->elem_size) {
- err = desc->xcode(desc, c);
- if (err)
- goto out;
- c += desc->elem_size;
- avail_here -= desc->elem_size;
- }
- if (avail_here) {
- if (!elem) {
- elem = kmalloc(desc->elem_size, GFP_KERNEL);
- err = -ENOMEM;
- if (!elem)
- goto out;
- }
- if (encode) {
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- memcpy(c, elem, avail_here);
- } else
- memcpy(elem, c, avail_here);
- copied = avail_here;
- }
- base = buf->head->iov_len; /* align to start of pages */
- }
- /* process pages array */
- base -= buf->head->iov_len;
- if (todo && base < buf->page_len) {
- unsigned int avail_page;
- avail_here = min(todo, buf->page_len - base);
- todo -= avail_here;
- base += buf->page_base;
- ppages = buf->pages + (base >> PAGE_SHIFT);
- base &= ~PAGE_MASK;
- avail_page = min_t(unsigned int, PAGE_SIZE - base,
- avail_here);
- c = kmap(*ppages) + base;
- while (avail_here) {
- avail_here -= avail_page;
- if (copied || avail_page < desc->elem_size) {
- unsigned int l = min(avail_page,
- desc->elem_size - copied);
- if (!elem) {
- elem = kmalloc(desc->elem_size,
- GFP_KERNEL);
- err = -ENOMEM;
- if (!elem)
- goto out;
- }
- if (encode) {
- if (!copied) {
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- }
- memcpy(c, elem + copied, l);
- copied += l;
- if (copied == desc->elem_size)
- copied = 0;
- } else {
- memcpy(elem + copied, c, l);
- copied += l;
- if (copied == desc->elem_size) {
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- copied = 0;
- }
- }
- avail_page -= l;
- c += l;
- }
- while (avail_page >= desc->elem_size) {
- err = desc->xcode(desc, c);
- if (err)
- goto out;
- c += desc->elem_size;
- avail_page -= desc->elem_size;
- }
- if (avail_page) {
- unsigned int l = min(avail_page,
- desc->elem_size - copied);
- if (!elem) {
- elem = kmalloc(desc->elem_size,
- GFP_KERNEL);
- err = -ENOMEM;
- if (!elem)
- goto out;
- }
- if (encode) {
- if (!copied) {
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- }
- memcpy(c, elem + copied, l);
- copied += l;
- if (copied == desc->elem_size)
- copied = 0;
- } else {
- memcpy(elem + copied, c, l);
- copied += l;
- if (copied == desc->elem_size) {
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- copied = 0;
- }
- }
- }
- if (avail_here) {
- kunmap(*ppages);
- ppages++;
- c = kmap(*ppages);
- }
- avail_page = min(avail_here,
- (unsigned int) PAGE_SIZE);
- }
- base = buf->page_len; /* align to start of tail */
- }
- /* process tail */
- base -= buf->page_len;
- if (todo) {
- c = buf->tail->iov_base + base;
- if (copied) {
- unsigned int l = desc->elem_size - copied;
- if (encode)
- memcpy(c, elem + copied, l);
- else {
- memcpy(elem + copied, c, l);
- err = desc->xcode(desc, elem);
- if (err)
- goto out;
- }
- todo -= l;
- c += l;
- }
- while (todo) {
- err = desc->xcode(desc, c);
- if (err)
- goto out;
- c += desc->elem_size;
- todo -= desc->elem_size;
- }
- }
- err = 0;
- out:
- kfree(elem);
- if (ppages)
- kunmap(*ppages);
- return err;
- }
- int xdr_decode_array2(const struct xdr_buf *buf, unsigned int base,
- struct xdr_array2_desc *desc)
- {
- if (base >= buf->len)
- return -EINVAL;
- return xdr_xcode_array2(buf, base, desc, 0);
- }
- EXPORT_SYMBOL_GPL(xdr_decode_array2);
- int xdr_encode_array2(const struct xdr_buf *buf, unsigned int base,
- struct xdr_array2_desc *desc)
- {
- if ((unsigned long) base + 4 + desc->array_len * desc->elem_size >
- buf->head->iov_len + buf->page_len + buf->tail->iov_len)
- return -EINVAL;
- return xdr_xcode_array2(buf, base, desc, 1);
- }
- EXPORT_SYMBOL_GPL(xdr_encode_array2);
- int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset,
- unsigned int len,
- int (*actor)(struct scatterlist *, void *), void *data)
- {
- int i, ret = 0;
- unsigned int page_len, thislen, page_offset;
- struct scatterlist sg[1];
- sg_init_table(sg, 1);
- if (offset >= buf->head[0].iov_len) {
- offset -= buf->head[0].iov_len;
- } else {
- thislen = buf->head[0].iov_len - offset;
- if (thislen > len)
- thislen = len;
- sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
- ret = actor(sg, data);
- if (ret)
- goto out;
- offset = 0;
- len -= thislen;
- }
- if (len == 0)
- goto out;
- if (offset >= buf->page_len) {
- offset -= buf->page_len;
- } else {
- page_len = buf->page_len - offset;
- if (page_len > len)
- page_len = len;
- len -= page_len;
- page_offset = (offset + buf->page_base) & (PAGE_SIZE - 1);
- i = (offset + buf->page_base) >> PAGE_SHIFT;
- thislen = PAGE_SIZE - page_offset;
- do {
- if (thislen > page_len)
- thislen = page_len;
- sg_set_page(sg, buf->pages[i], thislen, page_offset);
- ret = actor(sg, data);
- if (ret)
- goto out;
- page_len -= thislen;
- i++;
- page_offset = 0;
- thislen = PAGE_SIZE;
- } while (page_len != 0);
- offset = 0;
- }
- if (len == 0)
- goto out;
- if (offset < buf->tail[0].iov_len) {
- thislen = buf->tail[0].iov_len - offset;
- if (thislen > len)
- thislen = len;
- sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
- ret = actor(sg, data);
- len -= thislen;
- }
- if (len != 0)
- ret = -EINVAL;
- out:
- return ret;
- }
- EXPORT_SYMBOL_GPL(xdr_process_buf);
- /**
- * xdr_stream_decode_opaque - Decode variable length opaque
- * @xdr: pointer to xdr_stream
- * @ptr: location to store opaque data
- * @size: size of storage buffer @ptr
- *
- * Return values:
- * On success, returns size of object stored in *@ptr
- * %-EBADMSG on XDR buffer overflow
- * %-EMSGSIZE on overflow of storage buffer @ptr
- */
- ssize_t xdr_stream_decode_opaque(struct xdr_stream *xdr, void *ptr, size_t size)
- {
- ssize_t ret;
- void *p;
- ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
- if (ret <= 0)
- return ret;
- memcpy(ptr, p, ret);
- return ret;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque);
- /**
- * xdr_stream_decode_opaque_dup - Decode and duplicate variable length opaque
- * @xdr: pointer to xdr_stream
- * @ptr: location to store pointer to opaque data
- * @maxlen: maximum acceptable object size
- * @gfp_flags: GFP mask to use
- *
- * Return values:
- * On success, returns size of object stored in *@ptr
- * %-EBADMSG on XDR buffer overflow
- * %-EMSGSIZE if the size of the object would exceed @maxlen
- * %-ENOMEM on memory allocation failure
- */
- ssize_t xdr_stream_decode_opaque_dup(struct xdr_stream *xdr, void **ptr,
- size_t maxlen, gfp_t gfp_flags)
- {
- ssize_t ret;
- void *p;
- ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
- if (ret > 0) {
- *ptr = kmemdup(p, ret, gfp_flags);
- if (*ptr != NULL)
- return ret;
- ret = -ENOMEM;
- }
- *ptr = NULL;
- return ret;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_decode_opaque_dup);
- /**
- * xdr_stream_decode_string - Decode variable length string
- * @xdr: pointer to xdr_stream
- * @str: location to store string
- * @size: size of storage buffer @str
- *
- * Return values:
- * On success, returns length of NUL-terminated string stored in *@str
- * %-EBADMSG on XDR buffer overflow
- * %-EMSGSIZE on overflow of storage buffer @str
- */
- ssize_t xdr_stream_decode_string(struct xdr_stream *xdr, char *str, size_t size)
- {
- ssize_t ret;
- void *p;
- ret = xdr_stream_decode_opaque_inline(xdr, &p, size);
- if (ret > 0) {
- memcpy(str, p, ret);
- str[ret] = '\0';
- return strlen(str);
- }
- *str = '\0';
- return ret;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_decode_string);
- /**
- * xdr_stream_decode_string_dup - Decode and duplicate variable length string
- * @xdr: pointer to xdr_stream
- * @str: location to store pointer to string
- * @maxlen: maximum acceptable string length
- * @gfp_flags: GFP mask to use
- *
- * Return values:
- * On success, returns length of NUL-terminated string stored in *@ptr
- * %-EBADMSG on XDR buffer overflow
- * %-EMSGSIZE if the size of the string would exceed @maxlen
- * %-ENOMEM on memory allocation failure
- */
- ssize_t xdr_stream_decode_string_dup(struct xdr_stream *xdr, char **str,
- size_t maxlen, gfp_t gfp_flags)
- {
- void *p;
- ssize_t ret;
- ret = xdr_stream_decode_opaque_inline(xdr, &p, maxlen);
- if (ret > 0) {
- char *s = kmemdup_nul(p, ret, gfp_flags);
- if (s != NULL) {
- *str = s;
- return strlen(s);
- }
- ret = -ENOMEM;
- }
- *str = NULL;
- return ret;
- }
- EXPORT_SYMBOL_GPL(xdr_stream_decode_string_dup);
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