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- // SPDX-License-Identifier: GPL-2.0
- /*
- * This is a module to test the HMM (Heterogeneous Memory Management)
- * mirror and zone device private memory migration APIs of the kernel.
- * Userspace programs can register with the driver to mirror their own address
- * space and can use the device to read/write any valid virtual address.
- */
- #include <linux/init.h>
- #include <linux/fs.h>
- #include <linux/mm.h>
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/cdev.h>
- #include <linux/device.h>
- #include <linux/memremap.h>
- #include <linux/mutex.h>
- #include <linux/rwsem.h>
- #include <linux/sched.h>
- #include <linux/slab.h>
- #include <linux/highmem.h>
- #include <linux/delay.h>
- #include <linux/pagemap.h>
- #include <linux/hmm.h>
- #include <linux/vmalloc.h>
- #include <linux/swap.h>
- #include <linux/swapops.h>
- #include <linux/sched/mm.h>
- #include <linux/platform_device.h>
- #include <linux/rmap.h>
- #include <linux/mmu_notifier.h>
- #include <linux/migrate.h>
- #include "test_hmm_uapi.h"
- #define DMIRROR_NDEVICES 4
- #define DMIRROR_RANGE_FAULT_TIMEOUT 1000
- #define DEVMEM_CHUNK_SIZE (256 * 1024 * 1024U)
- #define DEVMEM_CHUNKS_RESERVE 16
- /*
- * For device_private pages, dpage is just a dummy struct page
- * representing a piece of device memory. dmirror_devmem_alloc_page
- * allocates a real system memory page as backing storage to fake a
- * real device. zone_device_data points to that backing page. But
- * for device_coherent memory, the struct page represents real
- * physical CPU-accessible memory that we can use directly.
- */
- #define BACKING_PAGE(page) (is_device_private_page((page)) ? \
- (page)->zone_device_data : (page))
- static unsigned long spm_addr_dev0;
- module_param(spm_addr_dev0, long, 0644);
- MODULE_PARM_DESC(spm_addr_dev0,
- "Specify start address for SPM (special purpose memory) used for device 0. By setting this Coherent device type will be used. Make sure spm_addr_dev1 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
- static unsigned long spm_addr_dev1;
- module_param(spm_addr_dev1, long, 0644);
- MODULE_PARM_DESC(spm_addr_dev1,
- "Specify start address for SPM (special purpose memory) used for device 1. By setting this Coherent device type will be used. Make sure spm_addr_dev0 is set too. Minimum SPM size should be DEVMEM_CHUNK_SIZE.");
- static const struct dev_pagemap_ops dmirror_devmem_ops;
- static const struct mmu_interval_notifier_ops dmirror_min_ops;
- static dev_t dmirror_dev;
- struct dmirror_device;
- struct dmirror_bounce {
- void *ptr;
- unsigned long size;
- unsigned long addr;
- unsigned long cpages;
- };
- #define DPT_XA_TAG_ATOMIC 1UL
- #define DPT_XA_TAG_WRITE 3UL
- /*
- * Data structure to track address ranges and register for mmu interval
- * notifier updates.
- */
- struct dmirror_interval {
- struct mmu_interval_notifier notifier;
- struct dmirror *dmirror;
- };
- /*
- * Data attached to the open device file.
- * Note that it might be shared after a fork().
- */
- struct dmirror {
- struct dmirror_device *mdevice;
- struct xarray pt;
- struct mmu_interval_notifier notifier;
- struct mutex mutex;
- };
- /*
- * ZONE_DEVICE pages for migration and simulating device memory.
- */
- struct dmirror_chunk {
- struct dev_pagemap pagemap;
- struct dmirror_device *mdevice;
- bool remove;
- };
- /*
- * Per device data.
- */
- struct dmirror_device {
- struct cdev cdevice;
- unsigned int zone_device_type;
- struct device device;
- unsigned int devmem_capacity;
- unsigned int devmem_count;
- struct dmirror_chunk **devmem_chunks;
- struct mutex devmem_lock; /* protects the above */
- unsigned long calloc;
- unsigned long cfree;
- struct page *free_pages;
- spinlock_t lock; /* protects the above */
- };
- static struct dmirror_device dmirror_devices[DMIRROR_NDEVICES];
- static int dmirror_bounce_init(struct dmirror_bounce *bounce,
- unsigned long addr,
- unsigned long size)
- {
- bounce->addr = addr;
- bounce->size = size;
- bounce->cpages = 0;
- bounce->ptr = vmalloc(size);
- if (!bounce->ptr)
- return -ENOMEM;
- return 0;
- }
- static bool dmirror_is_private_zone(struct dmirror_device *mdevice)
- {
- return (mdevice->zone_device_type ==
- HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ? true : false;
- }
- static enum migrate_vma_direction
- dmirror_select_device(struct dmirror *dmirror)
- {
- return (dmirror->mdevice->zone_device_type ==
- HMM_DMIRROR_MEMORY_DEVICE_PRIVATE) ?
- MIGRATE_VMA_SELECT_DEVICE_PRIVATE :
- MIGRATE_VMA_SELECT_DEVICE_COHERENT;
- }
- static void dmirror_bounce_fini(struct dmirror_bounce *bounce)
- {
- vfree(bounce->ptr);
- }
- static int dmirror_fops_open(struct inode *inode, struct file *filp)
- {
- struct cdev *cdev = inode->i_cdev;
- struct dmirror *dmirror;
- int ret;
- /* Mirror this process address space */
- dmirror = kzalloc(sizeof(*dmirror), GFP_KERNEL);
- if (dmirror == NULL)
- return -ENOMEM;
- dmirror->mdevice = container_of(cdev, struct dmirror_device, cdevice);
- mutex_init(&dmirror->mutex);
- xa_init(&dmirror->pt);
- ret = mmu_interval_notifier_insert(&dmirror->notifier, current->mm,
- 0, ULONG_MAX & PAGE_MASK, &dmirror_min_ops);
- if (ret) {
- kfree(dmirror);
- return ret;
- }
- filp->private_data = dmirror;
- return 0;
- }
- static int dmirror_fops_release(struct inode *inode, struct file *filp)
- {
- struct dmirror *dmirror = filp->private_data;
- mmu_interval_notifier_remove(&dmirror->notifier);
- xa_destroy(&dmirror->pt);
- kfree(dmirror);
- return 0;
- }
- static struct dmirror_chunk *dmirror_page_to_chunk(struct page *page)
- {
- return container_of(page->pgmap, struct dmirror_chunk, pagemap);
- }
- static struct dmirror_device *dmirror_page_to_device(struct page *page)
- {
- return dmirror_page_to_chunk(page)->mdevice;
- }
- static int dmirror_do_fault(struct dmirror *dmirror, struct hmm_range *range)
- {
- unsigned long *pfns = range->hmm_pfns;
- unsigned long pfn;
- for (pfn = (range->start >> PAGE_SHIFT);
- pfn < (range->end >> PAGE_SHIFT);
- pfn++, pfns++) {
- struct page *page;
- void *entry;
- /*
- * Since we asked for hmm_range_fault() to populate pages,
- * it shouldn't return an error entry on success.
- */
- WARN_ON(*pfns & HMM_PFN_ERROR);
- WARN_ON(!(*pfns & HMM_PFN_VALID));
- page = hmm_pfn_to_page(*pfns);
- WARN_ON(!page);
- entry = page;
- if (*pfns & HMM_PFN_WRITE)
- entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
- else if (WARN_ON(range->default_flags & HMM_PFN_WRITE))
- return -EFAULT;
- entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
- if (xa_is_err(entry))
- return xa_err(entry);
- }
- return 0;
- }
- static void dmirror_do_update(struct dmirror *dmirror, unsigned long start,
- unsigned long end)
- {
- unsigned long pfn;
- void *entry;
- /*
- * The XArray doesn't hold references to pages since it relies on
- * the mmu notifier to clear page pointers when they become stale.
- * Therefore, it is OK to just clear the entry.
- */
- xa_for_each_range(&dmirror->pt, pfn, entry, start >> PAGE_SHIFT,
- end >> PAGE_SHIFT)
- xa_erase(&dmirror->pt, pfn);
- }
- static bool dmirror_interval_invalidate(struct mmu_interval_notifier *mni,
- const struct mmu_notifier_range *range,
- unsigned long cur_seq)
- {
- struct dmirror *dmirror = container_of(mni, struct dmirror, notifier);
- /*
- * Ignore invalidation callbacks for device private pages since
- * the invalidation is handled as part of the migration process.
- */
- if (range->event == MMU_NOTIFY_MIGRATE &&
- range->owner == dmirror->mdevice)
- return true;
- if (mmu_notifier_range_blockable(range))
- mutex_lock(&dmirror->mutex);
- else if (!mutex_trylock(&dmirror->mutex))
- return false;
- mmu_interval_set_seq(mni, cur_seq);
- dmirror_do_update(dmirror, range->start, range->end);
- mutex_unlock(&dmirror->mutex);
- return true;
- }
- static const struct mmu_interval_notifier_ops dmirror_min_ops = {
- .invalidate = dmirror_interval_invalidate,
- };
- static int dmirror_range_fault(struct dmirror *dmirror,
- struct hmm_range *range)
- {
- struct mm_struct *mm = dmirror->notifier.mm;
- unsigned long timeout =
- jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
- int ret;
- while (true) {
- if (time_after(jiffies, timeout)) {
- ret = -EBUSY;
- goto out;
- }
- range->notifier_seq = mmu_interval_read_begin(range->notifier);
- mmap_read_lock(mm);
- ret = hmm_range_fault(range);
- mmap_read_unlock(mm);
- if (ret) {
- if (ret == -EBUSY)
- continue;
- goto out;
- }
- mutex_lock(&dmirror->mutex);
- if (mmu_interval_read_retry(range->notifier,
- range->notifier_seq)) {
- mutex_unlock(&dmirror->mutex);
- continue;
- }
- break;
- }
- ret = dmirror_do_fault(dmirror, range);
- mutex_unlock(&dmirror->mutex);
- out:
- return ret;
- }
- static int dmirror_fault(struct dmirror *dmirror, unsigned long start,
- unsigned long end, bool write)
- {
- struct mm_struct *mm = dmirror->notifier.mm;
- unsigned long addr;
- unsigned long pfns[64];
- struct hmm_range range = {
- .notifier = &dmirror->notifier,
- .hmm_pfns = pfns,
- .pfn_flags_mask = 0,
- .default_flags =
- HMM_PFN_REQ_FAULT | (write ? HMM_PFN_REQ_WRITE : 0),
- .dev_private_owner = dmirror->mdevice,
- };
- int ret = 0;
- /* Since the mm is for the mirrored process, get a reference first. */
- if (!mmget_not_zero(mm))
- return 0;
- for (addr = start; addr < end; addr = range.end) {
- range.start = addr;
- range.end = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
- ret = dmirror_range_fault(dmirror, &range);
- if (ret)
- break;
- }
- mmput(mm);
- return ret;
- }
- static int dmirror_do_read(struct dmirror *dmirror, unsigned long start,
- unsigned long end, struct dmirror_bounce *bounce)
- {
- unsigned long pfn;
- void *ptr;
- ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK);
- for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
- void *entry;
- struct page *page;
- void *tmp;
- entry = xa_load(&dmirror->pt, pfn);
- page = xa_untag_pointer(entry);
- if (!page)
- return -ENOENT;
- tmp = kmap(page);
- memcpy(ptr, tmp, PAGE_SIZE);
- kunmap(page);
- ptr += PAGE_SIZE;
- bounce->cpages++;
- }
- return 0;
- }
- static int dmirror_read(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
- {
- struct dmirror_bounce bounce;
- unsigned long start, end;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- int ret;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- ret = dmirror_bounce_init(&bounce, start, size);
- if (ret)
- return ret;
- while (1) {
- mutex_lock(&dmirror->mutex);
- ret = dmirror_do_read(dmirror, start, end, &bounce);
- mutex_unlock(&dmirror->mutex);
- if (ret != -ENOENT)
- break;
- start = cmd->addr + (bounce.cpages << PAGE_SHIFT);
- ret = dmirror_fault(dmirror, start, end, false);
- if (ret)
- break;
- cmd->faults++;
- }
- if (ret == 0) {
- if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr,
- bounce.size))
- ret = -EFAULT;
- }
- cmd->cpages = bounce.cpages;
- dmirror_bounce_fini(&bounce);
- return ret;
- }
- static int dmirror_do_write(struct dmirror *dmirror, unsigned long start,
- unsigned long end, struct dmirror_bounce *bounce)
- {
- unsigned long pfn;
- void *ptr;
- ptr = bounce->ptr + ((start - bounce->addr) & PAGE_MASK);
- for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
- void *entry;
- struct page *page;
- void *tmp;
- entry = xa_load(&dmirror->pt, pfn);
- page = xa_untag_pointer(entry);
- if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE)
- return -ENOENT;
- tmp = kmap(page);
- memcpy(tmp, ptr, PAGE_SIZE);
- kunmap(page);
- ptr += PAGE_SIZE;
- bounce->cpages++;
- }
- return 0;
- }
- static int dmirror_write(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd)
- {
- struct dmirror_bounce bounce;
- unsigned long start, end;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- int ret;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- ret = dmirror_bounce_init(&bounce, start, size);
- if (ret)
- return ret;
- if (copy_from_user(bounce.ptr, u64_to_user_ptr(cmd->ptr),
- bounce.size)) {
- ret = -EFAULT;
- goto fini;
- }
- while (1) {
- mutex_lock(&dmirror->mutex);
- ret = dmirror_do_write(dmirror, start, end, &bounce);
- mutex_unlock(&dmirror->mutex);
- if (ret != -ENOENT)
- break;
- start = cmd->addr + (bounce.cpages << PAGE_SHIFT);
- ret = dmirror_fault(dmirror, start, end, true);
- if (ret)
- break;
- cmd->faults++;
- }
- fini:
- cmd->cpages = bounce.cpages;
- dmirror_bounce_fini(&bounce);
- return ret;
- }
- static int dmirror_allocate_chunk(struct dmirror_device *mdevice,
- struct page **ppage)
- {
- struct dmirror_chunk *devmem;
- struct resource *res = NULL;
- unsigned long pfn;
- unsigned long pfn_first;
- unsigned long pfn_last;
- void *ptr;
- int ret = -ENOMEM;
- devmem = kzalloc(sizeof(*devmem), GFP_KERNEL);
- if (!devmem)
- return ret;
- switch (mdevice->zone_device_type) {
- case HMM_DMIRROR_MEMORY_DEVICE_PRIVATE:
- res = request_free_mem_region(&iomem_resource, DEVMEM_CHUNK_SIZE,
- "hmm_dmirror");
- if (IS_ERR_OR_NULL(res))
- goto err_devmem;
- devmem->pagemap.range.start = res->start;
- devmem->pagemap.range.end = res->end;
- devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
- break;
- case HMM_DMIRROR_MEMORY_DEVICE_COHERENT:
- devmem->pagemap.range.start = (MINOR(mdevice->cdevice.dev) - 2) ?
- spm_addr_dev0 :
- spm_addr_dev1;
- devmem->pagemap.range.end = devmem->pagemap.range.start +
- DEVMEM_CHUNK_SIZE - 1;
- devmem->pagemap.type = MEMORY_DEVICE_COHERENT;
- break;
- default:
- ret = -EINVAL;
- goto err_devmem;
- }
- devmem->pagemap.nr_range = 1;
- devmem->pagemap.ops = &dmirror_devmem_ops;
- devmem->pagemap.owner = mdevice;
- mutex_lock(&mdevice->devmem_lock);
- if (mdevice->devmem_count == mdevice->devmem_capacity) {
- struct dmirror_chunk **new_chunks;
- unsigned int new_capacity;
- new_capacity = mdevice->devmem_capacity +
- DEVMEM_CHUNKS_RESERVE;
- new_chunks = krealloc(mdevice->devmem_chunks,
- sizeof(new_chunks[0]) * new_capacity,
- GFP_KERNEL);
- if (!new_chunks)
- goto err_release;
- mdevice->devmem_capacity = new_capacity;
- mdevice->devmem_chunks = new_chunks;
- }
- ptr = memremap_pages(&devmem->pagemap, numa_node_id());
- if (IS_ERR_OR_NULL(ptr)) {
- if (ptr)
- ret = PTR_ERR(ptr);
- else
- ret = -EFAULT;
- goto err_release;
- }
- devmem->mdevice = mdevice;
- pfn_first = devmem->pagemap.range.start >> PAGE_SHIFT;
- pfn_last = pfn_first + (range_len(&devmem->pagemap.range) >> PAGE_SHIFT);
- mdevice->devmem_chunks[mdevice->devmem_count++] = devmem;
- mutex_unlock(&mdevice->devmem_lock);
- pr_info("added new %u MB chunk (total %u chunks, %u MB) PFNs [0x%lx 0x%lx)\n",
- DEVMEM_CHUNK_SIZE / (1024 * 1024),
- mdevice->devmem_count,
- mdevice->devmem_count * (DEVMEM_CHUNK_SIZE / (1024 * 1024)),
- pfn_first, pfn_last);
- spin_lock(&mdevice->lock);
- for (pfn = pfn_first; pfn < pfn_last; pfn++) {
- struct page *page = pfn_to_page(pfn);
- page->zone_device_data = mdevice->free_pages;
- mdevice->free_pages = page;
- }
- if (ppage) {
- *ppage = mdevice->free_pages;
- mdevice->free_pages = (*ppage)->zone_device_data;
- mdevice->calloc++;
- }
- spin_unlock(&mdevice->lock);
- return 0;
- err_release:
- mutex_unlock(&mdevice->devmem_lock);
- if (res && devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
- release_mem_region(devmem->pagemap.range.start,
- range_len(&devmem->pagemap.range));
- err_devmem:
- kfree(devmem);
- return ret;
- }
- static struct page *dmirror_devmem_alloc_page(struct dmirror_device *mdevice)
- {
- struct page *dpage = NULL;
- struct page *rpage = NULL;
- /*
- * For ZONE_DEVICE private type, this is a fake device so we allocate
- * real system memory to store our device memory.
- * For ZONE_DEVICE coherent type we use the actual dpage to store the
- * data and ignore rpage.
- */
- if (dmirror_is_private_zone(mdevice)) {
- rpage = alloc_page(GFP_HIGHUSER);
- if (!rpage)
- return NULL;
- }
- spin_lock(&mdevice->lock);
- if (mdevice->free_pages) {
- dpage = mdevice->free_pages;
- mdevice->free_pages = dpage->zone_device_data;
- mdevice->calloc++;
- spin_unlock(&mdevice->lock);
- } else {
- spin_unlock(&mdevice->lock);
- if (dmirror_allocate_chunk(mdevice, &dpage))
- goto error;
- }
- zone_device_page_init(dpage);
- dpage->zone_device_data = rpage;
- return dpage;
- error:
- if (rpage)
- __free_page(rpage);
- return NULL;
- }
- static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
- {
- struct dmirror_device *mdevice = dmirror->mdevice;
- const unsigned long *src = args->src;
- unsigned long *dst = args->dst;
- unsigned long addr;
- for (addr = args->start; addr < args->end; addr += PAGE_SIZE,
- src++, dst++) {
- struct page *spage;
- struct page *dpage;
- struct page *rpage;
- if (!(*src & MIGRATE_PFN_MIGRATE))
- continue;
- /*
- * Note that spage might be NULL which is OK since it is an
- * unallocated pte_none() or read-only zero page.
- */
- spage = migrate_pfn_to_page(*src);
- if (WARN(spage && is_zone_device_page(spage),
- "page already in device spage pfn: 0x%lx\n",
- page_to_pfn(spage)))
- continue;
- dpage = dmirror_devmem_alloc_page(mdevice);
- if (!dpage)
- continue;
- rpage = BACKING_PAGE(dpage);
- if (spage)
- copy_highpage(rpage, spage);
- else
- clear_highpage(rpage);
- /*
- * Normally, a device would use the page->zone_device_data to
- * point to the mirror but here we use it to hold the page for
- * the simulated device memory and that page holds the pointer
- * to the mirror.
- */
- rpage->zone_device_data = dmirror;
- pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
- page_to_pfn(spage), page_to_pfn(dpage));
- *dst = migrate_pfn(page_to_pfn(dpage));
- if ((*src & MIGRATE_PFN_WRITE) ||
- (!spage && args->vma->vm_flags & VM_WRITE))
- *dst |= MIGRATE_PFN_WRITE;
- }
- }
- static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start,
- unsigned long end)
- {
- unsigned long pfn;
- for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
- void *entry;
- entry = xa_load(&dmirror->pt, pfn);
- if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC)
- return -EPERM;
- }
- return 0;
- }
- static int dmirror_atomic_map(unsigned long start, unsigned long end,
- struct page **pages, struct dmirror *dmirror)
- {
- unsigned long pfn, mapped = 0;
- int i;
- /* Map the migrated pages into the device's page tables. */
- mutex_lock(&dmirror->mutex);
- for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) {
- void *entry;
- if (!pages[i])
- continue;
- entry = pages[i];
- entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC);
- entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
- if (xa_is_err(entry)) {
- mutex_unlock(&dmirror->mutex);
- return xa_err(entry);
- }
- mapped++;
- }
- mutex_unlock(&dmirror->mutex);
- return mapped;
- }
- static int dmirror_migrate_finalize_and_map(struct migrate_vma *args,
- struct dmirror *dmirror)
- {
- unsigned long start = args->start;
- unsigned long end = args->end;
- const unsigned long *src = args->src;
- const unsigned long *dst = args->dst;
- unsigned long pfn;
- /* Map the migrated pages into the device's page tables. */
- mutex_lock(&dmirror->mutex);
- for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++,
- src++, dst++) {
- struct page *dpage;
- void *entry;
- if (!(*src & MIGRATE_PFN_MIGRATE))
- continue;
- dpage = migrate_pfn_to_page(*dst);
- if (!dpage)
- continue;
- entry = BACKING_PAGE(dpage);
- if (*dst & MIGRATE_PFN_WRITE)
- entry = xa_tag_pointer(entry, DPT_XA_TAG_WRITE);
- entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC);
- if (xa_is_err(entry)) {
- mutex_unlock(&dmirror->mutex);
- return xa_err(entry);
- }
- }
- mutex_unlock(&dmirror->mutex);
- return 0;
- }
- static int dmirror_exclusive(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
- {
- unsigned long start, end, addr;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- struct mm_struct *mm = dmirror->notifier.mm;
- struct page *pages[64];
- struct dmirror_bounce bounce;
- unsigned long next;
- int ret;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- /* Since the mm is for the mirrored process, get a reference first. */
- if (!mmget_not_zero(mm))
- return -EINVAL;
- mmap_read_lock(mm);
- for (addr = start; addr < end; addr = next) {
- unsigned long mapped = 0;
- int i;
- if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT))
- next = end;
- else
- next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT);
- ret = make_device_exclusive_range(mm, addr, next, pages, NULL);
- /*
- * Do dmirror_atomic_map() iff all pages are marked for
- * exclusive access to avoid accessing uninitialized
- * fields of pages.
- */
- if (ret == (next - addr) >> PAGE_SHIFT)
- mapped = dmirror_atomic_map(addr, next, pages, dmirror);
- for (i = 0; i < ret; i++) {
- if (pages[i]) {
- unlock_page(pages[i]);
- put_page(pages[i]);
- }
- }
- if (addr + (mapped << PAGE_SHIFT) < next) {
- mmap_read_unlock(mm);
- mmput(mm);
- return -EBUSY;
- }
- }
- mmap_read_unlock(mm);
- mmput(mm);
- /* Return the migrated data for verification. */
- ret = dmirror_bounce_init(&bounce, start, size);
- if (ret)
- return ret;
- mutex_lock(&dmirror->mutex);
- ret = dmirror_do_read(dmirror, start, end, &bounce);
- mutex_unlock(&dmirror->mutex);
- if (ret == 0) {
- if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr,
- bounce.size))
- ret = -EFAULT;
- }
- cmd->cpages = bounce.cpages;
- dmirror_bounce_fini(&bounce);
- return ret;
- }
- static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
- struct dmirror *dmirror)
- {
- const unsigned long *src = args->src;
- unsigned long *dst = args->dst;
- unsigned long start = args->start;
- unsigned long end = args->end;
- unsigned long addr;
- for (addr = start; addr < end; addr += PAGE_SIZE,
- src++, dst++) {
- struct page *dpage, *spage;
- spage = migrate_pfn_to_page(*src);
- if (!spage || !(*src & MIGRATE_PFN_MIGRATE))
- continue;
- if (WARN_ON(!is_device_private_page(spage) &&
- !is_device_coherent_page(spage)))
- continue;
- spage = BACKING_PAGE(spage);
- dpage = alloc_page_vma(GFP_HIGHUSER_MOVABLE, args->vma, addr);
- if (!dpage)
- continue;
- pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
- page_to_pfn(spage), page_to_pfn(dpage));
- lock_page(dpage);
- xa_erase(&dmirror->pt, addr >> PAGE_SHIFT);
- copy_highpage(dpage, spage);
- *dst = migrate_pfn(page_to_pfn(dpage));
- if (*src & MIGRATE_PFN_WRITE)
- *dst |= MIGRATE_PFN_WRITE;
- }
- return 0;
- }
- static unsigned long
- dmirror_successful_migrated_pages(struct migrate_vma *migrate)
- {
- unsigned long cpages = 0;
- unsigned long i;
- for (i = 0; i < migrate->npages; i++) {
- if (migrate->src[i] & MIGRATE_PFN_VALID &&
- migrate->src[i] & MIGRATE_PFN_MIGRATE)
- cpages++;
- }
- return cpages;
- }
- static int dmirror_migrate_to_system(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
- {
- unsigned long start, end, addr;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- struct mm_struct *mm = dmirror->notifier.mm;
- struct vm_area_struct *vma;
- unsigned long src_pfns[64] = { 0 };
- unsigned long dst_pfns[64] = { 0 };
- struct migrate_vma args = { 0 };
- unsigned long next;
- int ret;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- /* Since the mm is for the mirrored process, get a reference first. */
- if (!mmget_not_zero(mm))
- return -EINVAL;
- cmd->cpages = 0;
- mmap_read_lock(mm);
- for (addr = start; addr < end; addr = next) {
- vma = vma_lookup(mm, addr);
- if (!vma || !(vma->vm_flags & VM_READ)) {
- ret = -EINVAL;
- goto out;
- }
- next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
- if (next > vma->vm_end)
- next = vma->vm_end;
- args.vma = vma;
- args.src = src_pfns;
- args.dst = dst_pfns;
- args.start = addr;
- args.end = next;
- args.pgmap_owner = dmirror->mdevice;
- args.flags = dmirror_select_device(dmirror);
- ret = migrate_vma_setup(&args);
- if (ret)
- goto out;
- pr_debug("Migrating from device mem to sys mem\n");
- dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
- migrate_vma_pages(&args);
- cmd->cpages += dmirror_successful_migrated_pages(&args);
- migrate_vma_finalize(&args);
- }
- out:
- mmap_read_unlock(mm);
- mmput(mm);
- return ret;
- }
- static int dmirror_migrate_to_device(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
- {
- unsigned long start, end, addr;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- struct mm_struct *mm = dmirror->notifier.mm;
- struct vm_area_struct *vma;
- unsigned long src_pfns[64] = { 0 };
- unsigned long dst_pfns[64] = { 0 };
- struct dmirror_bounce bounce;
- struct migrate_vma args = { 0 };
- unsigned long next;
- int ret;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- /* Since the mm is for the mirrored process, get a reference first. */
- if (!mmget_not_zero(mm))
- return -EINVAL;
- mmap_read_lock(mm);
- for (addr = start; addr < end; addr = next) {
- vma = vma_lookup(mm, addr);
- if (!vma || !(vma->vm_flags & VM_READ)) {
- ret = -EINVAL;
- goto out;
- }
- next = min(end, addr + (ARRAY_SIZE(src_pfns) << PAGE_SHIFT));
- if (next > vma->vm_end)
- next = vma->vm_end;
- args.vma = vma;
- args.src = src_pfns;
- args.dst = dst_pfns;
- args.start = addr;
- args.end = next;
- args.pgmap_owner = dmirror->mdevice;
- args.flags = MIGRATE_VMA_SELECT_SYSTEM;
- ret = migrate_vma_setup(&args);
- if (ret)
- goto out;
- pr_debug("Migrating from sys mem to device mem\n");
- dmirror_migrate_alloc_and_copy(&args, dmirror);
- migrate_vma_pages(&args);
- dmirror_migrate_finalize_and_map(&args, dmirror);
- migrate_vma_finalize(&args);
- }
- mmap_read_unlock(mm);
- mmput(mm);
- /*
- * Return the migrated data for verification.
- * Only for pages in device zone
- */
- ret = dmirror_bounce_init(&bounce, start, size);
- if (ret)
- return ret;
- mutex_lock(&dmirror->mutex);
- ret = dmirror_do_read(dmirror, start, end, &bounce);
- mutex_unlock(&dmirror->mutex);
- if (ret == 0) {
- if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr,
- bounce.size))
- ret = -EFAULT;
- }
- cmd->cpages = bounce.cpages;
- dmirror_bounce_fini(&bounce);
- return ret;
- out:
- mmap_read_unlock(mm);
- mmput(mm);
- return ret;
- }
- static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
- unsigned char *perm, unsigned long entry)
- {
- struct page *page;
- if (entry & HMM_PFN_ERROR) {
- *perm = HMM_DMIRROR_PROT_ERROR;
- return;
- }
- if (!(entry & HMM_PFN_VALID)) {
- *perm = HMM_DMIRROR_PROT_NONE;
- return;
- }
- page = hmm_pfn_to_page(entry);
- if (is_device_private_page(page)) {
- /* Is the page migrated to this device or some other? */
- if (dmirror->mdevice == dmirror_page_to_device(page))
- *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL;
- else
- *perm = HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE;
- } else if (is_device_coherent_page(page)) {
- /* Is the page migrated to this device or some other? */
- if (dmirror->mdevice == dmirror_page_to_device(page))
- *perm = HMM_DMIRROR_PROT_DEV_COHERENT_LOCAL;
- else
- *perm = HMM_DMIRROR_PROT_DEV_COHERENT_REMOTE;
- } else if (is_zero_pfn(page_to_pfn(page)))
- *perm = HMM_DMIRROR_PROT_ZERO;
- else
- *perm = HMM_DMIRROR_PROT_NONE;
- if (entry & HMM_PFN_WRITE)
- *perm |= HMM_DMIRROR_PROT_WRITE;
- else
- *perm |= HMM_DMIRROR_PROT_READ;
- if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT)
- *perm |= HMM_DMIRROR_PROT_PMD;
- else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT)
- *perm |= HMM_DMIRROR_PROT_PUD;
- }
- static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni,
- const struct mmu_notifier_range *range,
- unsigned long cur_seq)
- {
- struct dmirror_interval *dmi =
- container_of(mni, struct dmirror_interval, notifier);
- struct dmirror *dmirror = dmi->dmirror;
- if (mmu_notifier_range_blockable(range))
- mutex_lock(&dmirror->mutex);
- else if (!mutex_trylock(&dmirror->mutex))
- return false;
- /*
- * Snapshots only need to set the sequence number since any
- * invalidation in the interval invalidates the whole snapshot.
- */
- mmu_interval_set_seq(mni, cur_seq);
- mutex_unlock(&dmirror->mutex);
- return true;
- }
- static const struct mmu_interval_notifier_ops dmirror_mrn_ops = {
- .invalidate = dmirror_snapshot_invalidate,
- };
- static int dmirror_range_snapshot(struct dmirror *dmirror,
- struct hmm_range *range,
- unsigned char *perm)
- {
- struct mm_struct *mm = dmirror->notifier.mm;
- struct dmirror_interval notifier;
- unsigned long timeout =
- jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
- unsigned long i;
- unsigned long n;
- int ret = 0;
- notifier.dmirror = dmirror;
- range->notifier = ¬ifier.notifier;
- ret = mmu_interval_notifier_insert(range->notifier, mm,
- range->start, range->end - range->start,
- &dmirror_mrn_ops);
- if (ret)
- return ret;
- while (true) {
- if (time_after(jiffies, timeout)) {
- ret = -EBUSY;
- goto out;
- }
- range->notifier_seq = mmu_interval_read_begin(range->notifier);
- mmap_read_lock(mm);
- ret = hmm_range_fault(range);
- mmap_read_unlock(mm);
- if (ret) {
- if (ret == -EBUSY)
- continue;
- goto out;
- }
- mutex_lock(&dmirror->mutex);
- if (mmu_interval_read_retry(range->notifier,
- range->notifier_seq)) {
- mutex_unlock(&dmirror->mutex);
- continue;
- }
- break;
- }
- n = (range->end - range->start) >> PAGE_SHIFT;
- for (i = 0; i < n; i++)
- dmirror_mkentry(dmirror, range, perm + i, range->hmm_pfns[i]);
- mutex_unlock(&dmirror->mutex);
- out:
- mmu_interval_notifier_remove(range->notifier);
- return ret;
- }
- static int dmirror_snapshot(struct dmirror *dmirror,
- struct hmm_dmirror_cmd *cmd)
- {
- struct mm_struct *mm = dmirror->notifier.mm;
- unsigned long start, end;
- unsigned long size = cmd->npages << PAGE_SHIFT;
- unsigned long addr;
- unsigned long next;
- unsigned long pfns[64];
- unsigned char perm[64];
- char __user *uptr;
- struct hmm_range range = {
- .hmm_pfns = pfns,
- .dev_private_owner = dmirror->mdevice,
- };
- int ret = 0;
- start = cmd->addr;
- end = start + size;
- if (end < start)
- return -EINVAL;
- /* Since the mm is for the mirrored process, get a reference first. */
- if (!mmget_not_zero(mm))
- return -EINVAL;
- /*
- * Register a temporary notifier to detect invalidations even if it
- * overlaps with other mmu_interval_notifiers.
- */
- uptr = u64_to_user_ptr(cmd->ptr);
- for (addr = start; addr < end; addr = next) {
- unsigned long n;
- next = min(addr + (ARRAY_SIZE(pfns) << PAGE_SHIFT), end);
- range.start = addr;
- range.end = next;
- ret = dmirror_range_snapshot(dmirror, &range, perm);
- if (ret)
- break;
- n = (range.end - range.start) >> PAGE_SHIFT;
- if (copy_to_user(uptr, perm, n)) {
- ret = -EFAULT;
- break;
- }
- cmd->cpages += n;
- uptr += n;
- }
- mmput(mm);
- return ret;
- }
- static void dmirror_device_evict_chunk(struct dmirror_chunk *chunk)
- {
- unsigned long start_pfn = chunk->pagemap.range.start >> PAGE_SHIFT;
- unsigned long end_pfn = chunk->pagemap.range.end >> PAGE_SHIFT;
- unsigned long npages = end_pfn - start_pfn + 1;
- unsigned long i;
- unsigned long *src_pfns;
- unsigned long *dst_pfns;
- src_pfns = kcalloc(npages, sizeof(*src_pfns), GFP_KERNEL);
- dst_pfns = kcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL);
- migrate_device_range(src_pfns, start_pfn, npages);
- for (i = 0; i < npages; i++) {
- struct page *dpage, *spage;
- spage = migrate_pfn_to_page(src_pfns[i]);
- if (!spage || !(src_pfns[i] & MIGRATE_PFN_MIGRATE))
- continue;
- if (WARN_ON(!is_device_private_page(spage) &&
- !is_device_coherent_page(spage)))
- continue;
- spage = BACKING_PAGE(spage);
- dpage = alloc_page(GFP_HIGHUSER_MOVABLE | __GFP_NOFAIL);
- lock_page(dpage);
- copy_highpage(dpage, spage);
- dst_pfns[i] = migrate_pfn(page_to_pfn(dpage));
- if (src_pfns[i] & MIGRATE_PFN_WRITE)
- dst_pfns[i] |= MIGRATE_PFN_WRITE;
- }
- migrate_device_pages(src_pfns, dst_pfns, npages);
- migrate_device_finalize(src_pfns, dst_pfns, npages);
- kfree(src_pfns);
- kfree(dst_pfns);
- }
- /* Removes free pages from the free list so they can't be re-allocated */
- static void dmirror_remove_free_pages(struct dmirror_chunk *devmem)
- {
- struct dmirror_device *mdevice = devmem->mdevice;
- struct page *page;
- for (page = mdevice->free_pages; page; page = page->zone_device_data)
- if (dmirror_page_to_chunk(page) == devmem)
- mdevice->free_pages = page->zone_device_data;
- }
- static void dmirror_device_remove_chunks(struct dmirror_device *mdevice)
- {
- unsigned int i;
- mutex_lock(&mdevice->devmem_lock);
- if (mdevice->devmem_chunks) {
- for (i = 0; i < mdevice->devmem_count; i++) {
- struct dmirror_chunk *devmem =
- mdevice->devmem_chunks[i];
- spin_lock(&mdevice->lock);
- devmem->remove = true;
- dmirror_remove_free_pages(devmem);
- spin_unlock(&mdevice->lock);
- dmirror_device_evict_chunk(devmem);
- memunmap_pages(&devmem->pagemap);
- if (devmem->pagemap.type == MEMORY_DEVICE_PRIVATE)
- release_mem_region(devmem->pagemap.range.start,
- range_len(&devmem->pagemap.range));
- kfree(devmem);
- }
- mdevice->devmem_count = 0;
- mdevice->devmem_capacity = 0;
- mdevice->free_pages = NULL;
- kfree(mdevice->devmem_chunks);
- mdevice->devmem_chunks = NULL;
- }
- mutex_unlock(&mdevice->devmem_lock);
- }
- static long dmirror_fops_unlocked_ioctl(struct file *filp,
- unsigned int command,
- unsigned long arg)
- {
- void __user *uarg = (void __user *)arg;
- struct hmm_dmirror_cmd cmd;
- struct dmirror *dmirror;
- int ret;
- dmirror = filp->private_data;
- if (!dmirror)
- return -EINVAL;
- if (copy_from_user(&cmd, uarg, sizeof(cmd)))
- return -EFAULT;
- if (cmd.addr & ~PAGE_MASK)
- return -EINVAL;
- if (cmd.addr >= (cmd.addr + (cmd.npages << PAGE_SHIFT)))
- return -EINVAL;
- cmd.cpages = 0;
- cmd.faults = 0;
- switch (command) {
- case HMM_DMIRROR_READ:
- ret = dmirror_read(dmirror, &cmd);
- break;
- case HMM_DMIRROR_WRITE:
- ret = dmirror_write(dmirror, &cmd);
- break;
- case HMM_DMIRROR_MIGRATE_TO_DEV:
- ret = dmirror_migrate_to_device(dmirror, &cmd);
- break;
- case HMM_DMIRROR_MIGRATE_TO_SYS:
- ret = dmirror_migrate_to_system(dmirror, &cmd);
- break;
- case HMM_DMIRROR_EXCLUSIVE:
- ret = dmirror_exclusive(dmirror, &cmd);
- break;
- case HMM_DMIRROR_CHECK_EXCLUSIVE:
- ret = dmirror_check_atomic(dmirror, cmd.addr,
- cmd.addr + (cmd.npages << PAGE_SHIFT));
- break;
- case HMM_DMIRROR_SNAPSHOT:
- ret = dmirror_snapshot(dmirror, &cmd);
- break;
- case HMM_DMIRROR_RELEASE:
- dmirror_device_remove_chunks(dmirror->mdevice);
- ret = 0;
- break;
- default:
- return -EINVAL;
- }
- if (ret)
- return ret;
- if (copy_to_user(uarg, &cmd, sizeof(cmd)))
- return -EFAULT;
- return 0;
- }
- static int dmirror_fops_mmap(struct file *file, struct vm_area_struct *vma)
- {
- unsigned long addr;
- for (addr = vma->vm_start; addr < vma->vm_end; addr += PAGE_SIZE) {
- struct page *page;
- int ret;
- page = alloc_page(GFP_KERNEL | __GFP_ZERO);
- if (!page)
- return -ENOMEM;
- ret = vm_insert_page(vma, addr, page);
- if (ret) {
- __free_page(page);
- return ret;
- }
- put_page(page);
- }
- return 0;
- }
- static const struct file_operations dmirror_fops = {
- .open = dmirror_fops_open,
- .release = dmirror_fops_release,
- .mmap = dmirror_fops_mmap,
- .unlocked_ioctl = dmirror_fops_unlocked_ioctl,
- .llseek = default_llseek,
- .owner = THIS_MODULE,
- };
- static void dmirror_devmem_free(struct page *page)
- {
- struct page *rpage = BACKING_PAGE(page);
- struct dmirror_device *mdevice;
- if (rpage != page)
- __free_page(rpage);
- mdevice = dmirror_page_to_device(page);
- spin_lock(&mdevice->lock);
- /* Return page to our allocator if not freeing the chunk */
- if (!dmirror_page_to_chunk(page)->remove) {
- mdevice->cfree++;
- page->zone_device_data = mdevice->free_pages;
- mdevice->free_pages = page;
- }
- spin_unlock(&mdevice->lock);
- }
- static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
- {
- struct migrate_vma args = { 0 };
- unsigned long src_pfns = 0;
- unsigned long dst_pfns = 0;
- struct page *rpage;
- struct dmirror *dmirror;
- vm_fault_t ret;
- /*
- * Normally, a device would use the page->zone_device_data to point to
- * the mirror but here we use it to hold the page for the simulated
- * device memory and that page holds the pointer to the mirror.
- */
- rpage = vmf->page->zone_device_data;
- dmirror = rpage->zone_device_data;
- /* FIXME demonstrate how we can adjust migrate range */
- args.vma = vmf->vma;
- args.start = vmf->address;
- args.end = args.start + PAGE_SIZE;
- args.src = &src_pfns;
- args.dst = &dst_pfns;
- args.pgmap_owner = dmirror->mdevice;
- args.flags = dmirror_select_device(dmirror);
- args.fault_page = vmf->page;
- if (migrate_vma_setup(&args))
- return VM_FAULT_SIGBUS;
- ret = dmirror_devmem_fault_alloc_and_copy(&args, dmirror);
- if (ret)
- return ret;
- migrate_vma_pages(&args);
- /*
- * No device finalize step is needed since
- * dmirror_devmem_fault_alloc_and_copy() will have already
- * invalidated the device page table.
- */
- migrate_vma_finalize(&args);
- return 0;
- }
- static const struct dev_pagemap_ops dmirror_devmem_ops = {
- .page_free = dmirror_devmem_free,
- .migrate_to_ram = dmirror_devmem_fault,
- };
- static int dmirror_device_init(struct dmirror_device *mdevice, int id)
- {
- dev_t dev;
- int ret;
- dev = MKDEV(MAJOR(dmirror_dev), id);
- mutex_init(&mdevice->devmem_lock);
- spin_lock_init(&mdevice->lock);
- cdev_init(&mdevice->cdevice, &dmirror_fops);
- mdevice->cdevice.owner = THIS_MODULE;
- device_initialize(&mdevice->device);
- mdevice->device.devt = dev;
- ret = dev_set_name(&mdevice->device, "hmm_dmirror%u", id);
- if (ret)
- return ret;
- ret = cdev_device_add(&mdevice->cdevice, &mdevice->device);
- if (ret)
- return ret;
- /* Build a list of free ZONE_DEVICE struct pages */
- return dmirror_allocate_chunk(mdevice, NULL);
- }
- static void dmirror_device_remove(struct dmirror_device *mdevice)
- {
- dmirror_device_remove_chunks(mdevice);
- cdev_device_del(&mdevice->cdevice, &mdevice->device);
- }
- static int __init hmm_dmirror_init(void)
- {
- int ret;
- int id = 0;
- int ndevices = 0;
- ret = alloc_chrdev_region(&dmirror_dev, 0, DMIRROR_NDEVICES,
- "HMM_DMIRROR");
- if (ret)
- goto err_unreg;
- memset(dmirror_devices, 0, DMIRROR_NDEVICES * sizeof(dmirror_devices[0]));
- dmirror_devices[ndevices++].zone_device_type =
- HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
- dmirror_devices[ndevices++].zone_device_type =
- HMM_DMIRROR_MEMORY_DEVICE_PRIVATE;
- if (spm_addr_dev0 && spm_addr_dev1) {
- dmirror_devices[ndevices++].zone_device_type =
- HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
- dmirror_devices[ndevices++].zone_device_type =
- HMM_DMIRROR_MEMORY_DEVICE_COHERENT;
- }
- for (id = 0; id < ndevices; id++) {
- ret = dmirror_device_init(dmirror_devices + id, id);
- if (ret)
- goto err_chrdev;
- }
- pr_info("HMM test module loaded. This is only for testing HMM.\n");
- return 0;
- err_chrdev:
- while (--id >= 0)
- dmirror_device_remove(dmirror_devices + id);
- unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
- err_unreg:
- return ret;
- }
- static void __exit hmm_dmirror_exit(void)
- {
- int id;
- for (id = 0; id < DMIRROR_NDEVICES; id++)
- if (dmirror_devices[id].zone_device_type)
- dmirror_device_remove(dmirror_devices + id);
- unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES);
- }
- module_init(hmm_dmirror_init);
- module_exit(hmm_dmirror_exit);
- MODULE_LICENSE("GPL");
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