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- // SPDX-License-Identifier: GPL-2.0
- /* XDP user-space packet buffer
- * Copyright(c) 2018 Intel Corporation.
- */
- #include <linux/init.h>
- #include <linux/sched/mm.h>
- #include <linux/sched/signal.h>
- #include <linux/sched/task.h>
- #include <linux/uaccess.h>
- #include <linux/slab.h>
- #include <linux/bpf.h>
- #include <linux/mm.h>
- #include <linux/netdevice.h>
- #include <linux/rtnetlink.h>
- #include <linux/idr.h>
- #include <linux/vmalloc.h>
- #include "xdp_umem.h"
- #include "xsk_queue.h"
- static DEFINE_IDA(umem_ida);
- static void xdp_umem_unpin_pages(struct xdp_umem *umem)
- {
- unpin_user_pages_dirty_lock(umem->pgs, umem->npgs, true);
- kvfree(umem->pgs);
- umem->pgs = NULL;
- }
- static void xdp_umem_unaccount_pages(struct xdp_umem *umem)
- {
- if (umem->user) {
- atomic_long_sub(umem->npgs, &umem->user->locked_vm);
- free_uid(umem->user);
- }
- }
- static void xdp_umem_addr_unmap(struct xdp_umem *umem)
- {
- vunmap(umem->addrs);
- umem->addrs = NULL;
- }
- static int xdp_umem_addr_map(struct xdp_umem *umem, struct page **pages,
- u32 nr_pages)
- {
- umem->addrs = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
- if (!umem->addrs)
- return -ENOMEM;
- return 0;
- }
- static void xdp_umem_release(struct xdp_umem *umem)
- {
- umem->zc = false;
- ida_free(&umem_ida, umem->id);
- xdp_umem_addr_unmap(umem);
- xdp_umem_unpin_pages(umem);
- xdp_umem_unaccount_pages(umem);
- kfree(umem);
- }
- static void xdp_umem_release_deferred(struct work_struct *work)
- {
- struct xdp_umem *umem = container_of(work, struct xdp_umem, work);
- xdp_umem_release(umem);
- }
- void xdp_get_umem(struct xdp_umem *umem)
- {
- refcount_inc(&umem->users);
- }
- void xdp_put_umem(struct xdp_umem *umem, bool defer_cleanup)
- {
- if (!umem)
- return;
- if (refcount_dec_and_test(&umem->users)) {
- if (defer_cleanup) {
- INIT_WORK(&umem->work, xdp_umem_release_deferred);
- schedule_work(&umem->work);
- } else {
- xdp_umem_release(umem);
- }
- }
- }
- static int xdp_umem_pin_pages(struct xdp_umem *umem, unsigned long address)
- {
- unsigned int gup_flags = FOLL_WRITE;
- long npgs;
- int err;
- umem->pgs = kvcalloc(umem->npgs, sizeof(*umem->pgs), GFP_KERNEL | __GFP_NOWARN);
- if (!umem->pgs)
- return -ENOMEM;
- mmap_read_lock(current->mm);
- npgs = pin_user_pages(address, umem->npgs,
- gup_flags | FOLL_LONGTERM, &umem->pgs[0], NULL);
- mmap_read_unlock(current->mm);
- if (npgs != umem->npgs) {
- if (npgs >= 0) {
- umem->npgs = npgs;
- err = -ENOMEM;
- goto out_pin;
- }
- err = npgs;
- goto out_pgs;
- }
- return 0;
- out_pin:
- xdp_umem_unpin_pages(umem);
- out_pgs:
- kvfree(umem->pgs);
- umem->pgs = NULL;
- return err;
- }
- static int xdp_umem_account_pages(struct xdp_umem *umem)
- {
- unsigned long lock_limit, new_npgs, old_npgs;
- if (capable(CAP_IPC_LOCK))
- return 0;
- lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
- umem->user = get_uid(current_user());
- do {
- old_npgs = atomic_long_read(&umem->user->locked_vm);
- new_npgs = old_npgs + umem->npgs;
- if (new_npgs > lock_limit) {
- free_uid(umem->user);
- umem->user = NULL;
- return -ENOBUFS;
- }
- } while (atomic_long_cmpxchg(&umem->user->locked_vm, old_npgs,
- new_npgs) != old_npgs);
- return 0;
- }
- static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
- {
- bool unaligned_chunks = mr->flags & XDP_UMEM_UNALIGNED_CHUNK_FLAG;
- u32 chunk_size = mr->chunk_size, headroom = mr->headroom;
- u64 addr = mr->addr, size = mr->len;
- u32 chunks_rem, npgs_rem;
- u64 chunks, npgs;
- int err;
- if (chunk_size < XDP_UMEM_MIN_CHUNK_SIZE || chunk_size > PAGE_SIZE) {
- /* Strictly speaking we could support this, if:
- * - huge pages, or*
- * - using an IOMMU, or
- * - making sure the memory area is consecutive
- * but for now, we simply say "computer says no".
- */
- return -EINVAL;
- }
- if (mr->flags & ~XDP_UMEM_UNALIGNED_CHUNK_FLAG)
- return -EINVAL;
- if (!unaligned_chunks && !is_power_of_2(chunk_size))
- return -EINVAL;
- if (!PAGE_ALIGNED(addr)) {
- /* Memory area has to be page size aligned. For
- * simplicity, this might change.
- */
- return -EINVAL;
- }
- if ((addr + size) < addr)
- return -EINVAL;
- npgs = div_u64_rem(size, PAGE_SIZE, &npgs_rem);
- if (npgs_rem)
- npgs++;
- if (npgs > U32_MAX)
- return -EINVAL;
- chunks = div_u64_rem(size, chunk_size, &chunks_rem);
- if (!chunks || chunks > U32_MAX)
- return -EINVAL;
- if (!unaligned_chunks && chunks_rem)
- return -EINVAL;
- if (headroom >= chunk_size - XDP_PACKET_HEADROOM)
- return -EINVAL;
- umem->size = size;
- umem->headroom = headroom;
- umem->chunk_size = chunk_size;
- umem->chunks = chunks;
- umem->npgs = npgs;
- umem->pgs = NULL;
- umem->user = NULL;
- umem->flags = mr->flags;
- INIT_LIST_HEAD(&umem->xsk_dma_list);
- refcount_set(&umem->users, 1);
- err = xdp_umem_account_pages(umem);
- if (err)
- return err;
- err = xdp_umem_pin_pages(umem, (unsigned long)addr);
- if (err)
- goto out_account;
- err = xdp_umem_addr_map(umem, umem->pgs, umem->npgs);
- if (err)
- goto out_unpin;
- return 0;
- out_unpin:
- xdp_umem_unpin_pages(umem);
- out_account:
- xdp_umem_unaccount_pages(umem);
- return err;
- }
- struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)
- {
- struct xdp_umem *umem;
- int err;
- umem = kzalloc(sizeof(*umem), GFP_KERNEL);
- if (!umem)
- return ERR_PTR(-ENOMEM);
- err = ida_alloc(&umem_ida, GFP_KERNEL);
- if (err < 0) {
- kfree(umem);
- return ERR_PTR(err);
- }
- umem->id = err;
- err = xdp_umem_reg(umem, mr);
- if (err) {
- ida_free(&umem_ida, umem->id);
- kfree(umem);
- return ERR_PTR(err);
- }
- return umem;
- }
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