Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull HMM updates from Jason Gunthorpe:
"Improvements and bug fixes for the hmm interface in the kernel:
- Improve clarity, locking and APIs related to the 'hmm mirror'
feature merged last cycle. In linux-next we now see AMDGPU and
nouveau to be using this API.
- Remove old or transitional hmm APIs. These are hold overs from the
past with no users, or APIs that existed only to manage cross tree
conflicts. There are still a few more of these cleanups that didn't
make the merge window cut off.
- Improve some core mm APIs:
- export alloc_pages_vma() for driver use
- refactor into devm_request_free_mem_region() to manage
DEVICE_PRIVATE resource reservations
- refactor duplicative driver code into the core dev_pagemap
struct
- Remove hmm wrappers of improved core mm APIs, instead have drivers
use the simplified API directly
- Remove DEVICE_PUBLIC
- Simplify the kconfig flow for the hmm users and core code"
* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (42 commits)
mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
mm: remove the HMM config option
mm: sort out the DEVICE_PRIVATE Kconfig mess
mm: simplify ZONE_DEVICE page private data
mm: remove hmm_devmem_add
mm: remove hmm_vma_alloc_locked_page
nouveau: use devm_memremap_pages directly
nouveau: use alloc_page_vma directly
PCI/P2PDMA: use the dev_pagemap internal refcount
device-dax: use the dev_pagemap internal refcount
memremap: provide an optional internal refcount in struct dev_pagemap
memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
memremap: remove the data field in struct dev_pagemap
memremap: add a migrate_to_ram method to struct dev_pagemap_ops
memremap: lift the devmap_enable manipulation into devm_memremap_pages
memremap: pass a struct dev_pagemap to ->kill and ->cleanup
memremap: move dev_pagemap callbacks into a separate structure
memremap: validate the pagemap type passed to devm_memremap_pages
mm: factor out a devm_request_free_mem_region helper
mm: export alloc_pages_vma
...
diff --git a/mm/hmm.c b/mm/hmm.c
index f702a38..e1eedef 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -20,26 +20,14 @@
#include <linux/swapops.h>
#include <linux/hugetlb.h>
#include <linux/memremap.h>
+#include <linux/sched/mm.h>
#include <linux/jump_label.h>
#include <linux/dma-mapping.h>
#include <linux/mmu_notifier.h>
#include <linux/memory_hotplug.h>
-#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
-
-#if IS_ENABLED(CONFIG_HMM_MIRROR)
static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
-static inline struct hmm *mm_get_hmm(struct mm_struct *mm)
-{
- struct hmm *hmm = READ_ONCE(mm->hmm);
-
- if (hmm && kref_get_unless_zero(&hmm->kref))
- return hmm;
-
- return NULL;
-}
-
/**
* hmm_get_or_create - register HMM against an mm (HMM internal)
*
@@ -54,11 +42,16 @@ static inline struct hmm *mm_get_hmm(struct mm_struct *mm)
*/
static struct hmm *hmm_get_or_create(struct mm_struct *mm)
{
- struct hmm *hmm = mm_get_hmm(mm);
- bool cleanup = false;
+ struct hmm *hmm;
- if (hmm)
- return hmm;
+ lockdep_assert_held_write(&mm->mmap_sem);
+
+ /* Abuse the page_table_lock to also protect mm->hmm. */
+ spin_lock(&mm->page_table_lock);
+ hmm = mm->hmm;
+ if (mm->hmm && kref_get_unless_zero(&mm->hmm->kref))
+ goto out_unlock;
+ spin_unlock(&mm->page_table_lock);
hmm = kmalloc(sizeof(*hmm), GFP_KERNEL);
if (!hmm)
@@ -68,55 +61,50 @@ static struct hmm *hmm_get_or_create(struct mm_struct *mm)
init_rwsem(&hmm->mirrors_sem);
hmm->mmu_notifier.ops = NULL;
INIT_LIST_HEAD(&hmm->ranges);
- mutex_init(&hmm->lock);
+ spin_lock_init(&hmm->ranges_lock);
kref_init(&hmm->kref);
hmm->notifiers = 0;
- hmm->dead = false;
hmm->mm = mm;
- spin_lock(&mm->page_table_lock);
- if (!mm->hmm)
- mm->hmm = hmm;
- else
- cleanup = true;
- spin_unlock(&mm->page_table_lock);
+ hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops;
+ if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) {
+ kfree(hmm);
+ return NULL;
+ }
- if (cleanup)
- goto error;
+ mmgrab(hmm->mm);
/*
- * We should only get here if hold the mmap_sem in write mode ie on
- * registration of first mirror through hmm_mirror_register()
+ * We hold the exclusive mmap_sem here so we know that mm->hmm is
+ * still NULL or 0 kref, and is safe to update.
*/
- hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops;
- if (__mmu_notifier_register(&hmm->mmu_notifier, mm))
- goto error_mm;
-
- return hmm;
-
-error_mm:
spin_lock(&mm->page_table_lock);
- if (mm->hmm == hmm)
- mm->hmm = NULL;
+ mm->hmm = hmm;
+
+out_unlock:
spin_unlock(&mm->page_table_lock);
-error:
+ return hmm;
+}
+
+static void hmm_free_rcu(struct rcu_head *rcu)
+{
+ struct hmm *hmm = container_of(rcu, struct hmm, rcu);
+
+ mmdrop(hmm->mm);
kfree(hmm);
- return NULL;
}
static void hmm_free(struct kref *kref)
{
struct hmm *hmm = container_of(kref, struct hmm, kref);
- struct mm_struct *mm = hmm->mm;
- mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm);
+ spin_lock(&hmm->mm->page_table_lock);
+ if (hmm->mm->hmm == hmm)
+ hmm->mm->hmm = NULL;
+ spin_unlock(&hmm->mm->page_table_lock);
- spin_lock(&mm->page_table_lock);
- if (mm->hmm == hmm)
- mm->hmm = NULL;
- spin_unlock(&mm->page_table_lock);
-
- kfree(hmm);
+ mmu_notifier_unregister_no_release(&hmm->mmu_notifier, hmm->mm);
+ mmu_notifier_call_srcu(&hmm->rcu, hmm_free_rcu);
}
static inline void hmm_put(struct hmm *hmm)
@@ -124,126 +112,40 @@ static inline void hmm_put(struct hmm *hmm)
kref_put(&hmm->kref, hmm_free);
}
-void hmm_mm_destroy(struct mm_struct *mm)
-{
- struct hmm *hmm;
-
- spin_lock(&mm->page_table_lock);
- hmm = mm_get_hmm(mm);
- mm->hmm = NULL;
- if (hmm) {
- hmm->mm = NULL;
- hmm->dead = true;
- spin_unlock(&mm->page_table_lock);
- hmm_put(hmm);
- return;
- }
-
- spin_unlock(&mm->page_table_lock);
-}
-
static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm)
{
- struct hmm *hmm = mm_get_hmm(mm);
+ struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
struct hmm_mirror *mirror;
- struct hmm_range *range;
- /* Report this HMM as dying. */
- hmm->dead = true;
+ /* Bail out if hmm is in the process of being freed */
+ if (!kref_get_unless_zero(&hmm->kref))
+ return;
- /* Wake-up everyone waiting on any range. */
- mutex_lock(&hmm->lock);
- list_for_each_entry(range, &hmm->ranges, list) {
- range->valid = false;
- }
- wake_up_all(&hmm->wq);
- mutex_unlock(&hmm->lock);
+ /*
+ * Since hmm_range_register() holds the mmget() lock hmm_release() is
+ * prevented as long as a range exists.
+ */
+ WARN_ON(!list_empty_careful(&hmm->ranges));
- down_write(&hmm->mirrors_sem);
- mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror,
- list);
- while (mirror) {
- list_del_init(&mirror->list);
- if (mirror->ops->release) {
- /*
- * Drop mirrors_sem so callback can wait on any pending
- * work that might itself trigger mmu_notifier callback
- * and thus would deadlock with us.
- */
- up_write(&hmm->mirrors_sem);
- mirror->ops->release(mirror);
- down_write(&hmm->mirrors_sem);
- }
- mirror = list_first_entry_or_null(&hmm->mirrors,
- struct hmm_mirror, list);
- }
- up_write(&hmm->mirrors_sem);
-
- hmm_put(hmm);
-}
-
-static int hmm_invalidate_range_start(struct mmu_notifier *mn,
- const struct mmu_notifier_range *nrange)
-{
- struct hmm *hmm = mm_get_hmm(nrange->mm);
- struct hmm_mirror *mirror;
- struct hmm_update update;
- struct hmm_range *range;
- int ret = 0;
-
- VM_BUG_ON(!hmm);
-
- update.start = nrange->start;
- update.end = nrange->end;
- update.event = HMM_UPDATE_INVALIDATE;
- update.blockable = mmu_notifier_range_blockable(nrange);
-
- if (mmu_notifier_range_blockable(nrange))
- mutex_lock(&hmm->lock);
- else if (!mutex_trylock(&hmm->lock)) {
- ret = -EAGAIN;
- goto out;
- }
- hmm->notifiers++;
- list_for_each_entry(range, &hmm->ranges, list) {
- if (update.end < range->start || update.start >= range->end)
- continue;
-
- range->valid = false;
- }
- mutex_unlock(&hmm->lock);
-
- if (mmu_notifier_range_blockable(nrange))
- down_read(&hmm->mirrors_sem);
- else if (!down_read_trylock(&hmm->mirrors_sem)) {
- ret = -EAGAIN;
- goto out;
- }
+ down_read(&hmm->mirrors_sem);
list_for_each_entry(mirror, &hmm->mirrors, list) {
- int ret;
-
- ret = mirror->ops->sync_cpu_device_pagetables(mirror, &update);
- if (!update.blockable && ret == -EAGAIN) {
- up_read(&hmm->mirrors_sem);
- ret = -EAGAIN;
- goto out;
- }
+ /*
+ * Note: The driver is not allowed to trigger
+ * hmm_mirror_unregister() from this thread.
+ */
+ if (mirror->ops->release)
+ mirror->ops->release(mirror);
}
up_read(&hmm->mirrors_sem);
-out:
hmm_put(hmm);
- return ret;
}
-static void hmm_invalidate_range_end(struct mmu_notifier *mn,
- const struct mmu_notifier_range *nrange)
+static void notifiers_decrement(struct hmm *hmm)
{
- struct hmm *hmm = mm_get_hmm(nrange->mm);
+ unsigned long flags;
- VM_BUG_ON(!hmm);
-
- mutex_lock(&hmm->lock);
+ spin_lock_irqsave(&hmm->ranges_lock, flags);
hmm->notifiers--;
if (!hmm->notifiers) {
struct hmm_range *range;
@@ -255,8 +157,73 @@ static void hmm_invalidate_range_end(struct mmu_notifier *mn,
}
wake_up_all(&hmm->wq);
}
- mutex_unlock(&hmm->lock);
+ spin_unlock_irqrestore(&hmm->ranges_lock, flags);
+}
+static int hmm_invalidate_range_start(struct mmu_notifier *mn,
+ const struct mmu_notifier_range *nrange)
+{
+ struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
+ struct hmm_mirror *mirror;
+ struct hmm_update update;
+ struct hmm_range *range;
+ unsigned long flags;
+ int ret = 0;
+
+ if (!kref_get_unless_zero(&hmm->kref))
+ return 0;
+
+ update.start = nrange->start;
+ update.end = nrange->end;
+ update.event = HMM_UPDATE_INVALIDATE;
+ update.blockable = mmu_notifier_range_blockable(nrange);
+
+ spin_lock_irqsave(&hmm->ranges_lock, flags);
+ hmm->notifiers++;
+ list_for_each_entry(range, &hmm->ranges, list) {
+ if (update.end < range->start || update.start >= range->end)
+ continue;
+
+ range->valid = false;
+ }
+ spin_unlock_irqrestore(&hmm->ranges_lock, flags);
+
+ if (mmu_notifier_range_blockable(nrange))
+ down_read(&hmm->mirrors_sem);
+ else if (!down_read_trylock(&hmm->mirrors_sem)) {
+ ret = -EAGAIN;
+ goto out;
+ }
+
+ list_for_each_entry(mirror, &hmm->mirrors, list) {
+ int rc;
+
+ rc = mirror->ops->sync_cpu_device_pagetables(mirror, &update);
+ if (rc) {
+ if (WARN_ON(update.blockable || rc != -EAGAIN))
+ continue;
+ ret = -EAGAIN;
+ break;
+ }
+ }
+ up_read(&hmm->mirrors_sem);
+
+out:
+ if (ret)
+ notifiers_decrement(hmm);
+ hmm_put(hmm);
+ return ret;
+}
+
+static void hmm_invalidate_range_end(struct mmu_notifier *mn,
+ const struct mmu_notifier_range *nrange)
+{
+ struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
+
+ if (!kref_get_unless_zero(&hmm->kref))
+ return;
+
+ notifiers_decrement(hmm);
hmm_put(hmm);
}
@@ -271,14 +238,15 @@ static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
*
* @mirror: new mirror struct to register
* @mm: mm to register against
+ * Return: 0 on success, -ENOMEM if no memory, -EINVAL if invalid arguments
*
* To start mirroring a process address space, the device driver must register
* an HMM mirror struct.
- *
- * THE mm->mmap_sem MUST BE HELD IN WRITE MODE !
*/
int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
{
+ lockdep_assert_held_write(&mm->mmap_sem);
+
/* Sanity check */
if (!mm || !mirror || !mirror->ops)
return -EINVAL;
@@ -298,23 +266,17 @@ EXPORT_SYMBOL(hmm_mirror_register);
/*
* hmm_mirror_unregister() - unregister a mirror
*
- * @mirror: new mirror struct to register
+ * @mirror: mirror struct to unregister
*
* Stop mirroring a process address space, and cleanup.
*/
void hmm_mirror_unregister(struct hmm_mirror *mirror)
{
- struct hmm *hmm = READ_ONCE(mirror->hmm);
-
- if (hmm == NULL)
- return;
+ struct hmm *hmm = mirror->hmm;
down_write(&hmm->mirrors_sem);
- list_del_init(&mirror->list);
- /* To protect us against double unregister ... */
- mirror->hmm = NULL;
+ list_del(&mirror->list);
up_write(&hmm->mirrors_sem);
-
hmm_put(hmm);
}
EXPORT_SYMBOL(hmm_mirror_unregister);
@@ -330,7 +292,7 @@ struct hmm_vma_walk {
static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr,
bool write_fault, uint64_t *pfn)
{
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
+ unsigned int flags = FAULT_FLAG_REMOTE;
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
struct vm_area_struct *vma = walk->vma;
@@ -372,7 +334,7 @@ static int hmm_pfns_bad(unsigned long addr,
* @fault: should we fault or not ?
* @write_fault: write fault ?
* @walk: mm_walk structure
- * Returns: 0 on success, -EBUSY after page fault, or page fault error
+ * Return: 0 on success, -EBUSY after page fault, or page fault error
*
* This function will be called whenever pmd_none() or pte_none() returns true,
* or whenever there is no page directory covering the virtual address range.
@@ -550,7 +512,7 @@ static int hmm_vma_handle_pmd(struct mm_walk *walk,
static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte)
{
- if (pte_none(pte) || !pte_present(pte))
+ if (pte_none(pte) || !pte_present(pte) || pte_protnone(pte))
return 0;
return pte_write(pte) ? range->flags[HMM_PFN_VALID] |
range->flags[HMM_PFN_WRITE] :
@@ -788,7 +750,6 @@ static int hmm_vma_walk_pud(pud_t *pudp,
return hmm_vma_walk_hole_(addr, end, fault,
write_fault, walk);
-#ifdef CONFIG_HUGETLB_PAGE
pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT);
for (i = 0; i < npages; ++i, ++pfn) {
hmm_vma_walk->pgmap = get_dev_pagemap(pfn,
@@ -804,9 +765,6 @@ static int hmm_vma_walk_pud(pud_t *pudp,
}
hmm_vma_walk->last = end;
return 0;
-#else
- return -EINVAL;
-#endif
}
split_huge_pud(walk->vma, pudp, addr);
@@ -909,12 +867,14 @@ static void hmm_pfns_clear(struct hmm_range *range,
* Track updates to the CPU page table see include/linux/hmm.h
*/
int hmm_range_register(struct hmm_range *range,
- struct mm_struct *mm,
+ struct hmm_mirror *mirror,
unsigned long start,
unsigned long end,
unsigned page_shift)
{
unsigned long mask = ((1UL << page_shift) - 1UL);
+ struct hmm *hmm = mirror->hmm;
+ unsigned long flags;
range->valid = false;
range->hmm = NULL;
@@ -928,28 +888,24 @@ int hmm_range_register(struct hmm_range *range,
range->start = start;
range->end = end;
- range->hmm = hmm_get_or_create(mm);
- if (!range->hmm)
+ /* Prevent hmm_release() from running while the range is valid */
+ if (!mmget_not_zero(hmm->mm))
return -EFAULT;
- /* Check if hmm_mm_destroy() was call. */
- if (range->hmm->mm == NULL || range->hmm->dead) {
- hmm_put(range->hmm);
- return -EFAULT;
- }
+ /* Initialize range to track CPU page table updates. */
+ spin_lock_irqsave(&hmm->ranges_lock, flags);
- /* Initialize range to track CPU page table update */
- mutex_lock(&range->hmm->lock);
-
- list_add_rcu(&range->list, &range->hmm->ranges);
+ range->hmm = hmm;
+ kref_get(&hmm->kref);
+ list_add(&range->list, &hmm->ranges);
/*
* If there are any concurrent notifiers we have to wait for them for
* the range to be valid (see hmm_range_wait_until_valid()).
*/
- if (!range->hmm->notifiers)
+ if (!hmm->notifiers)
range->valid = true;
- mutex_unlock(&range->hmm->lock);
+ spin_unlock_irqrestore(&hmm->ranges_lock, flags);
return 0;
}
@@ -964,25 +920,31 @@ EXPORT_SYMBOL(hmm_range_register);
*/
void hmm_range_unregister(struct hmm_range *range)
{
- /* Sanity check this really should not happen. */
- if (range->hmm == NULL || range->end <= range->start)
- return;
+ struct hmm *hmm = range->hmm;
+ unsigned long flags;
- mutex_lock(&range->hmm->lock);
- list_del_rcu(&range->list);
- mutex_unlock(&range->hmm->lock);
+ spin_lock_irqsave(&hmm->ranges_lock, flags);
+ list_del_init(&range->list);
+ spin_unlock_irqrestore(&hmm->ranges_lock, flags);
/* Drop reference taken by hmm_range_register() */
+ mmput(hmm->mm);
+ hmm_put(hmm);
+
+ /*
+ * The range is now invalid and the ref on the hmm is dropped, so
+ * poison the pointer. Leave other fields in place, for the caller's
+ * use.
+ */
range->valid = false;
- hmm_put(range->hmm);
- range->hmm = NULL;
+ memset(&range->hmm, POISON_INUSE, sizeof(range->hmm));
}
EXPORT_SYMBOL(hmm_range_unregister);
/*
* hmm_range_snapshot() - snapshot CPU page table for a range
* @range: range
- * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
+ * Return: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid
* permission (for instance asking for write and range is read only),
* -EAGAIN if you need to retry, -EFAULT invalid (ie either no valid
* vma or it is illegal to access that range), number of valid pages
@@ -1001,10 +963,7 @@ long hmm_range_snapshot(struct hmm_range *range)
struct vm_area_struct *vma;
struct mm_walk mm_walk;
- /* Check if hmm_mm_destroy() was call. */
- if (hmm->mm == NULL || hmm->dead)
- return -EFAULT;
-
+ lockdep_assert_held(&hmm->mm->mmap_sem);
do {
/* If range is no longer valid force retry. */
if (!range->valid)
@@ -1015,9 +974,8 @@ long hmm_range_snapshot(struct hmm_range *range)
return -EFAULT;
if (is_vm_hugetlb_page(vma)) {
- struct hstate *h = hstate_vma(vma);
-
- if (huge_page_shift(h) != range->page_shift &&
+ if (huge_page_shift(hstate_vma(vma)) !=
+ range->page_shift &&
range->page_shift != PAGE_SHIFT)
return -EINVAL;
} else {
@@ -1066,7 +1024,7 @@ EXPORT_SYMBOL(hmm_range_snapshot);
* hmm_range_fault() - try to fault some address in a virtual address range
* @range: range being faulted
* @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
- * Returns: number of valid pages in range->pfns[] (from range start
+ * Return: number of valid pages in range->pfns[] (from range start
* address). This may be zero. If the return value is negative,
* then one of the following values may be returned:
*
@@ -1100,9 +1058,7 @@ long hmm_range_fault(struct hmm_range *range, bool block)
struct mm_walk mm_walk;
int ret;
- /* Check if hmm_mm_destroy() was call. */
- if (hmm->mm == NULL || hmm->dead)
- return -EFAULT;
+ lockdep_assert_held(&hmm->mm->mmap_sem);
do {
/* If range is no longer valid force retry. */
@@ -1184,7 +1140,7 @@ EXPORT_SYMBOL(hmm_range_fault);
* @device: device against to dma map page to
* @daddrs: dma address of mapped pages
* @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
- * Returns: number of pages mapped on success, -EAGAIN if mmap_sem have been
+ * Return: number of pages mapped on success, -EAGAIN if mmap_sem have been
* drop and you need to try again, some other error value otherwise
*
* Note same usage pattern as hmm_range_fault().
@@ -1272,7 +1228,7 @@ EXPORT_SYMBOL(hmm_range_dma_map);
* @device: device against which dma map was done
* @daddrs: dma address of mapped pages
* @dirty: dirty page if it had the write flag set
- * Returns: number of page unmapped on success, -EINVAL otherwise
+ * Return: number of page unmapped on success, -EINVAL otherwise
*
* Note that caller MUST abide by mmu notifier or use HMM mirror and abide
* to the sync_cpu_device_pagetables() callback so that it is safe here to
@@ -1328,284 +1284,3 @@ long hmm_range_dma_unmap(struct hmm_range *range,
return cpages;
}
EXPORT_SYMBOL(hmm_range_dma_unmap);
-#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
-
-
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
-struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
- unsigned long addr)
-{
- struct page *page;
-
- page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
- if (!page)
- return NULL;
- lock_page(page);
- return page;
-}
-EXPORT_SYMBOL(hmm_vma_alloc_locked_page);
-
-
-static void hmm_devmem_ref_release(struct percpu_ref *ref)
-{
- struct hmm_devmem *devmem;
-
- devmem = container_of(ref, struct hmm_devmem, ref);
- complete(&devmem->completion);
-}
-
-static void hmm_devmem_ref_exit(struct percpu_ref *ref)
-{
- struct hmm_devmem *devmem;
-
- devmem = container_of(ref, struct hmm_devmem, ref);
- wait_for_completion(&devmem->completion);
- percpu_ref_exit(ref);
-}
-
-static void hmm_devmem_ref_kill(struct percpu_ref *ref)
-{
- percpu_ref_kill(ref);
-}
-
-static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma,
- unsigned long addr,
- const struct page *page,
- unsigned int flags,
- pmd_t *pmdp)
-{
- struct hmm_devmem *devmem = page->pgmap->data;
-
- return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp);
-}
-
-static void hmm_devmem_free(struct page *page, void *data)
-{
- struct hmm_devmem *devmem = data;
-
- page->mapping = NULL;
-
- devmem->ops->free(devmem, page);
-}
-
-/*
- * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory
- *
- * @ops: memory event device driver callback (see struct hmm_devmem_ops)
- * @device: device struct to bind the resource too
- * @size: size in bytes of the device memory to add
- * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise
- *
- * This function first finds an empty range of physical address big enough to
- * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which
- * in turn allocates struct pages. It does not do anything beyond that; all
- * events affecting the memory will go through the various callbacks provided
- * by hmm_devmem_ops struct.
- *
- * Device driver should call this function during device initialization and
- * is then responsible of memory management. HMM only provides helpers.
- */
-struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
- struct device *device,
- unsigned long size)
-{
- struct hmm_devmem *devmem;
- resource_size_t addr;
- void *result;
- int ret;
-
- dev_pagemap_get_ops();
-
- devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
- if (!devmem)
- return ERR_PTR(-ENOMEM);
-
- init_completion(&devmem->completion);
- devmem->pfn_first = -1UL;
- devmem->pfn_last = -1UL;
- devmem->resource = NULL;
- devmem->device = device;
- devmem->ops = ops;
-
- ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
- 0, GFP_KERNEL);
- if (ret)
- return ERR_PTR(ret);
-
- size = ALIGN(size, PA_SECTION_SIZE);
- addr = min((unsigned long)iomem_resource.end,
- (1UL << MAX_PHYSMEM_BITS) - 1);
- addr = addr - size + 1UL;
-
- /*
- * FIXME add a new helper to quickly walk resource tree and find free
- * range
- *
- * FIXME what about ioport_resource resource ?
- */
- for (; addr > size && addr >= iomem_resource.start; addr -= size) {
- ret = region_intersects(addr, size, 0, IORES_DESC_NONE);
- if (ret != REGION_DISJOINT)
- continue;
-
- devmem->resource = devm_request_mem_region(device, addr, size,
- dev_name(device));
- if (!devmem->resource)
- return ERR_PTR(-ENOMEM);
- break;
- }
- if (!devmem->resource)
- return ERR_PTR(-ERANGE);
-
- devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY;
- devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
- devmem->pfn_last = devmem->pfn_first +
- (resource_size(devmem->resource) >> PAGE_SHIFT);
- devmem->page_fault = hmm_devmem_fault;
-
- devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
- devmem->pagemap.res = *devmem->resource;
- devmem->pagemap.page_free = hmm_devmem_free;
- devmem->pagemap.altmap_valid = false;
- devmem->pagemap.ref = &devmem->ref;
- devmem->pagemap.data = devmem;
- devmem->pagemap.kill = hmm_devmem_ref_kill;
- devmem->pagemap.cleanup = hmm_devmem_ref_exit;
-
- result = devm_memremap_pages(devmem->device, &devmem->pagemap);
- if (IS_ERR(result))
- return result;
- return devmem;
-}
-EXPORT_SYMBOL_GPL(hmm_devmem_add);
-
-struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
- struct device *device,
- struct resource *res)
-{
- struct hmm_devmem *devmem;
- void *result;
- int ret;
-
- if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
- return ERR_PTR(-EINVAL);
-
- dev_pagemap_get_ops();
-
- devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL);
- if (!devmem)
- return ERR_PTR(-ENOMEM);
-
- init_completion(&devmem->completion);
- devmem->pfn_first = -1UL;
- devmem->pfn_last = -1UL;
- devmem->resource = res;
- devmem->device = device;
- devmem->ops = ops;
-
- ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release,
- 0, GFP_KERNEL);
- if (ret)
- return ERR_PTR(ret);
-
- devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT;
- devmem->pfn_last = devmem->pfn_first +
- (resource_size(devmem->resource) >> PAGE_SHIFT);
- devmem->page_fault = hmm_devmem_fault;
-
- devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
- devmem->pagemap.res = *devmem->resource;
- devmem->pagemap.page_free = hmm_devmem_free;
- devmem->pagemap.altmap_valid = false;
- devmem->pagemap.ref = &devmem->ref;
- devmem->pagemap.data = devmem;
- devmem->pagemap.kill = hmm_devmem_ref_kill;
- devmem->pagemap.cleanup = hmm_devmem_ref_exit;
-
- result = devm_memremap_pages(devmem->device, &devmem->pagemap);
- if (IS_ERR(result))
- return result;
- return devmem;
-}
-EXPORT_SYMBOL_GPL(hmm_devmem_add_resource);
-
-/*
- * A device driver that wants to handle multiple devices memory through a
- * single fake device can use hmm_device to do so. This is purely a helper
- * and it is not needed to make use of any HMM functionality.
- */
-#define HMM_DEVICE_MAX 256
-
-static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX);
-static DEFINE_SPINLOCK(hmm_device_lock);
-static struct class *hmm_device_class;
-static dev_t hmm_device_devt;
-
-static void hmm_device_release(struct device *device)
-{
- struct hmm_device *hmm_device;
-
- hmm_device = container_of(device, struct hmm_device, device);
- spin_lock(&hmm_device_lock);
- clear_bit(hmm_device->minor, hmm_device_mask);
- spin_unlock(&hmm_device_lock);
-
- kfree(hmm_device);
-}
-
-struct hmm_device *hmm_device_new(void *drvdata)
-{
- struct hmm_device *hmm_device;
-
- hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL);
- if (!hmm_device)
- return ERR_PTR(-ENOMEM);
-
- spin_lock(&hmm_device_lock);
- hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX);
- if (hmm_device->minor >= HMM_DEVICE_MAX) {
- spin_unlock(&hmm_device_lock);
- kfree(hmm_device);
- return ERR_PTR(-EBUSY);
- }
- set_bit(hmm_device->minor, hmm_device_mask);
- spin_unlock(&hmm_device_lock);
-
- dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor);
- hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt),
- hmm_device->minor);
- hmm_device->device.release = hmm_device_release;
- dev_set_drvdata(&hmm_device->device, drvdata);
- hmm_device->device.class = hmm_device_class;
- device_initialize(&hmm_device->device);
-
- return hmm_device;
-}
-EXPORT_SYMBOL(hmm_device_new);
-
-void hmm_device_put(struct hmm_device *hmm_device)
-{
- put_device(&hmm_device->device);
-}
-EXPORT_SYMBOL(hmm_device_put);
-
-static int __init hmm_init(void)
-{
- int ret;
-
- ret = alloc_chrdev_region(&hmm_device_devt, 0,
- HMM_DEVICE_MAX,
- "hmm_device");
- if (ret)
- return ret;
-
- hmm_device_class = class_create(THIS_MODULE, "hmm_device");
- if (IS_ERR(hmm_device_class)) {
- unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX);
- return PTR_ERR(hmm_device_class);
- }
- return 0;
-}
-
-device_initcall(hmm_init);
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
