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authorJason Gunthorpe <jgg@mellanox.com>2019-11-12 16:22:30 -0400
committerJason Gunthorpe <jgg@mellanox.com>2019-11-23 19:56:45 -0400
commita22dd506400d0f4784ad596f073b9eb5ed7c6a2a (patch)
tree55e0716e1e78ff34c4ce515671a6ae9de80741a0 /mm
parent81fa1af31b5d79047821def6abdcb97a735d8a52 (diff)
mm/hmm: remove hmm_mirror and related
The only two users of this are now converted to use mmu_interval_notifier, delete all the code and update hmm.rst. Link: https://lore.kernel.org/r/20191112202231.3856-14-jgg@ziepe.ca Reviewed-by: Jérôme Glisse <jglisse@redhat.com> Tested-by: Ralph Campbell <rcampbell@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'mm')
-rw-r--r--mm/Kconfig1
-rw-r--r--mm/hmm.c285
2 files changed, 8 insertions, 278 deletions
diff --git a/mm/Kconfig b/mm/Kconfig
index d0b5046d9aef..e38ff1d5968d 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -675,7 +675,6 @@ config DEV_PAGEMAP_OPS
config HMM_MIRROR
bool
depends on MMU
- depends on MMU_NOTIFIER
config DEVICE_PRIVATE
bool "Unaddressable device memory (GPU memory, ...)"
diff --git a/mm/hmm.c b/mm/hmm.c
index 8d060c5dabe3..aed2f39d1a98 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -26,193 +26,6 @@
#include <linux/mmu_notifier.h>
#include <linux/memory_hotplug.h>
-static struct mmu_notifier *hmm_alloc_notifier(struct mm_struct *mm)
-{
- struct hmm *hmm;
-
- hmm = kzalloc(sizeof(*hmm), GFP_KERNEL);
- if (!hmm)
- return ERR_PTR(-ENOMEM);
-
- init_waitqueue_head(&hmm->wq);
- INIT_LIST_HEAD(&hmm->mirrors);
- init_rwsem(&hmm->mirrors_sem);
- INIT_LIST_HEAD(&hmm->ranges);
- spin_lock_init(&hmm->ranges_lock);
- hmm->notifiers = 0;
- return &hmm->mmu_notifier;
-}
-
-static void hmm_free_notifier(struct mmu_notifier *mn)
-{
- struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
-
- WARN_ON(!list_empty(&hmm->ranges));
- WARN_ON(!list_empty(&hmm->mirrors));
- kfree(hmm);
-}
-
-static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm)
-{
- struct hmm *hmm = container_of(mn, struct hmm, mmu_notifier);
- struct hmm_mirror *mirror;
-
- /*
- * 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_read(&hmm->mirrors_sem);
- list_for_each_entry(mirror, &hmm->mirrors, list) {
- /*
- * 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);
-}
-
-static void notifiers_decrement(struct hmm *hmm)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&hmm->ranges_lock, flags);
- hmm->notifiers--;
- if (!hmm->notifiers) {
- struct hmm_range *range;
-
- list_for_each_entry(range, &hmm->ranges, list) {
- if (range->valid)
- continue;
- range->valid = true;
- }
- wake_up_all(&hmm->wq);
- }
- 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_range *range;
- unsigned long flags;
- int ret = 0;
-
- spin_lock_irqsave(&hmm->ranges_lock, flags);
- hmm->notifiers++;
- list_for_each_entry(range, &hmm->ranges, list) {
- if (nrange->end < range->start || nrange->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, nrange);
- if (rc) {
- if (WARN_ON(mmu_notifier_range_blockable(nrange) ||
- rc != -EAGAIN))
- continue;
- ret = -EAGAIN;
- break;
- }
- }
- up_read(&hmm->mirrors_sem);
-
-out:
- if (ret)
- notifiers_decrement(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);
-
- notifiers_decrement(hmm);
-}
-
-static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
- .release = hmm_release,
- .invalidate_range_start = hmm_invalidate_range_start,
- .invalidate_range_end = hmm_invalidate_range_end,
- .alloc_notifier = hmm_alloc_notifier,
- .free_notifier = hmm_free_notifier,
-};
-
-/*
- * hmm_mirror_register() - register a mirror against an mm
- *
- * @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 caller cannot unregister the hmm_mirror while any ranges are
- * registered.
- *
- * Callers using this function must put a call to mmu_notifier_synchronize()
- * in their module exit functions.
- */
-int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
-{
- struct mmu_notifier *mn;
-
- lockdep_assert_held_write(&mm->mmap_sem);
-
- /* Sanity check */
- if (!mm || !mirror || !mirror->ops)
- return -EINVAL;
-
- mn = mmu_notifier_get_locked(&hmm_mmu_notifier_ops, mm);
- if (IS_ERR(mn))
- return PTR_ERR(mn);
- mirror->hmm = container_of(mn, struct hmm, mmu_notifier);
-
- down_write(&mirror->hmm->mirrors_sem);
- list_add(&mirror->list, &mirror->hmm->mirrors);
- up_write(&mirror->hmm->mirrors_sem);
-
- return 0;
-}
-EXPORT_SYMBOL(hmm_mirror_register);
-
-/*
- * hmm_mirror_unregister() - unregister a mirror
- *
- * @mirror: mirror struct to unregister
- *
- * Stop mirroring a process address space, and cleanup.
- */
-void hmm_mirror_unregister(struct hmm_mirror *mirror)
-{
- struct hmm *hmm = mirror->hmm;
-
- down_write(&hmm->mirrors_sem);
- list_del(&mirror->list);
- up_write(&hmm->mirrors_sem);
- mmu_notifier_put(&hmm->mmu_notifier);
-}
-EXPORT_SYMBOL(hmm_mirror_unregister);
-
struct hmm_vma_walk {
struct hmm_range *range;
struct dev_pagemap *pgmap;
@@ -785,87 +598,6 @@ static void hmm_pfns_clear(struct hmm_range *range,
*pfns = range->values[HMM_PFN_NONE];
}
-/*
- * hmm_range_register() - start tracking change to CPU page table over a range
- * @range: range
- * @mm: the mm struct for the range of virtual address
- *
- * Return: 0 on success, -EFAULT if the address space is no longer valid
- *
- * Track updates to the CPU page table see include/linux/hmm.h
- */
-int hmm_range_register(struct hmm_range *range, struct hmm_mirror *mirror)
-{
- struct hmm *hmm = mirror->hmm;
- unsigned long flags;
-
- range->valid = false;
- range->hmm = NULL;
-
- if ((range->start & (PAGE_SIZE - 1)) || (range->end & (PAGE_SIZE - 1)))
- return -EINVAL;
- if (range->start >= range->end)
- return -EINVAL;
-
- /* Prevent hmm_release() from running while the range is valid */
- if (!mmget_not_zero(hmm->mmu_notifier.mm))
- return -EFAULT;
-
- /* Initialize range to track CPU page table updates. */
- spin_lock_irqsave(&hmm->ranges_lock, flags);
-
- range->hmm = hmm;
- 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 (!hmm->notifiers)
- range->valid = true;
- spin_unlock_irqrestore(&hmm->ranges_lock, flags);
-
- return 0;
-}
-EXPORT_SYMBOL(hmm_range_register);
-
-/*
- * hmm_range_unregister() - stop tracking change to CPU page table over a range
- * @range: range
- *
- * Range struct is used to track updates to the CPU page table after a call to
- * hmm_range_register(). See include/linux/hmm.h for how to use it.
- */
-void hmm_range_unregister(struct hmm_range *range)
-{
- struct hmm *hmm = range->hmm;
- unsigned long flags;
-
- 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->mmu_notifier.mm);
-
- /*
- * 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;
- memset(&range->hmm, POISON_INUSE, sizeof(range->hmm));
-}
-EXPORT_SYMBOL(hmm_range_unregister);
-
-static bool needs_retry(struct hmm_range *range)
-{
- if (range->notifier)
- return mmu_interval_check_retry(range->notifier,
- range->notifier_seq);
- return !range->valid;
-}
-
static const struct mm_walk_ops hmm_walk_ops = {
.pud_entry = hmm_vma_walk_pud,
.pmd_entry = hmm_vma_walk_pmd,
@@ -906,20 +638,16 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP;
unsigned long start = range->start, end;
struct hmm_vma_walk hmm_vma_walk;
- struct mm_struct *mm;
+ struct mm_struct *mm = range->notifier->mm;
struct vm_area_struct *vma;
int ret;
- if (range->notifier)
- mm = range->notifier->mm;
- else
- mm = range->hmm->mmu_notifier.mm;
-
lockdep_assert_held(&mm->mmap_sem);
do {
/* If range is no longer valid force retry. */
- if (needs_retry(range))
+ if (mmu_interval_check_retry(range->notifier,
+ range->notifier_seq))
return -EBUSY;
vma = find_vma(mm, start);
@@ -952,7 +680,9 @@ long hmm_range_fault(struct hmm_range *range, unsigned int flags)
start = hmm_vma_walk.last;
/* Keep trying while the range is valid. */
- } while (ret == -EBUSY && !needs_retry(range));
+ } while (ret == -EBUSY &&
+ !mmu_interval_check_retry(range->notifier,
+ range->notifier_seq));
if (ret) {
unsigned long i;
@@ -1010,7 +740,8 @@ long hmm_range_dma_map(struct hmm_range *range, struct device *device,
continue;
/* Check if range is being invalidated */
- if (needs_retry(range)) {
+ if (mmu_interval_check_retry(range->notifier,
+ range->notifier_seq)) {
ret = -EBUSY;
goto unmap;
}