This is the last part of DAX to be converted to the XArray so
remove all the old helper functions.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
---
fs/dax.c | 392 ++++++++++++++++---------------------------------------
1 file changed, 111 insertions(+), 281 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 54a01380527a..91f7bce6ce64 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -93,12 +93,6 @@ static unsigned long dax_to_pfn(void *entry)
return xa_to_value(entry) >> DAX_SHIFT;
}
-static void *dax_make_locked(unsigned long pfn, unsigned long flags)
-{
- return xa_mk_value(flags | ((unsigned long)pfn << DAX_SHIFT) |
- DAX_LOCKED);
-}
-
static unsigned long dax_is_pmd_entry(void *entry)
{
return xa_to_value(entry) & DAX_PMD;
@@ -155,10 +149,11 @@ struct wait_exceptional_entry_queue {
struct exceptional_entry_key key;
};
-static wait_queue_head_t *dax_entry_waitqueue(struct xarray *xa,
- pgoff_t index, void *entry, struct exceptional_entry_key *key)
+static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas,
+ void *entry, struct exceptional_entry_key *key)
{
unsigned long hash;
+ unsigned long index = xas->xa_index;
/*
* If 'entry' is a PMD, align the 'index' that we use for the wait
@@ -167,11 +162,10 @@ static wait_queue_head_t *dax_entry_waitqueue(struct xarray *xa,
*/
if (dax_is_pmd_entry(entry))
index &= ~PG_PMD_COLOUR;
-
- key->xa = xa;
+ key->xa = xas->xa;
key->entry_start = index;
- hash = hash_long((unsigned long)xa ^ index, DAX_WAIT_TABLE_BITS);
+ hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS);
return wait_table + hash;
}
@@ -193,13 +187,12 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait,
* The important information it's conveying is whether the entry at
* this index used to be a PMD entry.
*/
-static void dax_wake_mapping_entry_waiter(struct xarray *xa,
- pgoff_t index, void *entry, bool wake_all)
+static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all)
{
struct exceptional_entry_key key;
wait_queue_head_t *wq;
- wq = dax_entry_waitqueue(xa, index, entry, &key);
+ wq = dax_entry_waitqueue(xas, entry, &key);
/*
* Checking for locked entry and prepare_to_wait_exclusive() happens
@@ -211,12 +204,6 @@ static void dax_wake_mapping_entry_waiter(struct xarray *xa,
__wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key);
}
-static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all)
-{
- return dax_wake_mapping_entry_waiter(xas->xa, xas->xa_index, entry,
- wake_all);
-}
-
/*
* Look up entry in page cache, wait for it to become unlocked if it
* is a DAX entry and return it. The caller must subsequently call
@@ -240,8 +227,7 @@ static void *get_unlocked_entry(struct xa_state *xas)
!dax_is_locked(entry))
return entry;
- wq = dax_entry_waitqueue(xas->xa, xas->xa_index, entry,
- &ewait.key);
+ wq = dax_entry_waitqueue(xas, entry, &ewait.key);
prepare_to_wait_exclusive(wq, &ewait.wait,
TASK_UNINTERRUPTIBLE);
xas_unlock_irq(xas);
@@ -282,119 +268,6 @@ static void dax_lock_entry(struct xa_state *xas, void *entry)
xas_store(xas, xa_mk_value(v | DAX_LOCKED));
}
-/*
- * Check whether the given slot is locked. Must be called with the i_pages
- * lock held.
- */
-static inline int slot_locked(struct address_space *mapping, void **slot)
-{
- unsigned long entry = xa_to_value(
- radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock));
- return entry & DAX_LOCKED;
-}
-
-/*
- * Mark the given slot as locked. Must be called with the i_pages lock held.
- */
-static inline void *lock_slot(struct address_space *mapping, void **slot)
-{
- unsigned long v = xa_to_value(
- radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock));
- void *entry = xa_mk_value(v | DAX_LOCKED);
- radix_tree_replace_slot(&mapping->i_pages, slot, entry);
- return entry;
-}
-
-/*
- * Mark the given slot as unlocked. Must be called with the i_pages lock held.
- */
-static inline void *unlock_slot(struct address_space *mapping, void **slot)
-{
- unsigned long v = xa_to_value(
- radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock));
- void *entry = xa_mk_value(v & ~DAX_LOCKED);
- radix_tree_replace_slot(&mapping->i_pages, slot, entry);
- return entry;
-}
-
-/*
- * Lookup entry in page cache, wait for it to become unlocked if it is
- * a DAX entry and return it. The caller must call
- * put_unlocked_mapping_entry() when he decided not to lock the entry or
- * put_locked_mapping_entry() when he locked the entry and now wants to
- * unlock it.
- *
- * Must be called with the i_pages lock held.
- */
-static void *get_unlocked_mapping_entry(struct address_space *mapping,
- pgoff_t index, void ***slotp)
-{
- void *entry, **slot;
- struct wait_exceptional_entry_queue ewait;
- wait_queue_head_t *wq;
-
- init_wait(&ewait.wait);
- ewait.wait.func = wake_exceptional_entry_func;
-
- for (;;) {
- entry = __radix_tree_lookup(&mapping->i_pages, index, NULL,
- &slot);
- if (!entry ||
- WARN_ON_ONCE(!xa_is_value(entry)) ||
- !slot_locked(mapping, slot)) {
- if (slotp)
- *slotp = slot;
- return entry;
- }
-
- wq = dax_entry_waitqueue(&mapping->i_pages, index, entry,
- &ewait.key);
- prepare_to_wait_exclusive(wq, &ewait.wait,
- TASK_UNINTERRUPTIBLE);
- xa_unlock_irq(&mapping->i_pages);
- schedule();
- finish_wait(wq, &ewait.wait);
- xa_lock_irq(&mapping->i_pages);
- }
-}
-
-static void dax_unlock_mapping_entry(struct address_space *mapping,
- pgoff_t index)
-{
- void *entry, **slot;
-
- xa_lock_irq(&mapping->i_pages);
- entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot);
- if (WARN_ON_ONCE(!entry || !xa_is_value(entry) ||
- !slot_locked(mapping, slot))) {
- xa_unlock_irq(&mapping->i_pages);
- return;
- }
- unlock_slot(mapping, slot);
- xa_unlock_irq(&mapping->i_pages);
- dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false);
-}
-
-static void put_locked_mapping_entry(struct address_space *mapping,
- pgoff_t index)
-{
- dax_unlock_mapping_entry(mapping, index);
-}
-
-/*
- * Called when we are done with page cache entry we looked up via
- * get_unlocked_mapping_entry() and which we didn't lock in the end.
- */
-static void put_unlocked_mapping_entry(struct address_space *mapping,
- pgoff_t index, void *entry)
-{
- if (!entry)
- return;
-
- /* We have to wake up next waiter for the page cache entry lock */
- dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false);
-}
-
static unsigned long dax_entry_size(void *entry)
{
if (dax_is_zero_entry(entry))
@@ -550,9 +423,9 @@ void dax_unlock_page(struct page *page)
* that index, add a locked empty entry.
*
* When requesting an entry with size DAX_PMD, grab_mapping_entry() will
- * either return that locked entry or will return an error. This error will
- * happen if there are any 4k entries within the 2MiB range that we are
- * requesting.
+ * either return that locked entry or will return VM_FAULT_FALLBACK.
+ * This will happen if there are any 4k entries within the 2MiB range
+ * that we are requesting.
*
* We always favor 4k entries over 2MiB entries. There isn't a flow where we
* evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB
@@ -568,29 +441,31 @@ void dax_unlock_page(struct page *page)
* Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For
* persistent memory the benefit is doubtful. We can add that later if we can
* show it helps.
+ *
+ * On error, this function does not return an ERR_PTR. Instead it returns
+ * a VM_FAULT code, encoded as an xarray internal entry. The ERR_PTR values
+ * overlap with xarray value entries.
*/
-static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
- unsigned long size_flag)
+static
+void *grab_mapping_entry(struct xa_state *xas, struct address_space *mapping)
{
bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */
- void *entry, **slot;
-
-restart:
- xa_lock_irq(&mapping->i_pages);
- entry = get_unlocked_mapping_entry(mapping, index, &slot);
-
- if (WARN_ON_ONCE(entry && !xa_is_value(entry))) {
- entry = ERR_PTR(-EIO);
- goto out_unlock;
- }
+ void *locked = dax_make_entry(pfn_to_pfn_t(0),
+ DAX_EMPTY | DAX_LOCKED);
+ void *unlocked = dax_make_entry(pfn_to_pfn_t(0), DAX_EMPTY);
+ void *entry;
- if (entry) {
- if (size_flag & DAX_PMD) {
+retry:
+ xas_lock_irq(xas);
+ xas_for_each_conflict(xas, entry) {
+ if (dax_is_locked(entry))
+ entry = get_unlocked_entry(xas);
+ if (!xa_is_value(entry))
+ goto error;
+ if (xas->xa_shift) {
if (dax_is_pte_entry(entry)) {
- put_unlocked_mapping_entry(mapping, index,
- entry);
- entry = ERR_PTR(-EEXIST);
- goto out_unlock;
+ put_unlocked_entry(xas, entry);
+ goto fallback;
}
} else { /* trying to grab a PTE entry */
if (dax_is_pmd_entry(entry) &&
@@ -599,89 +474,56 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
pmd_downgrade = true;
}
}
+ dax_lock_entry(xas, entry);
+ break; /* We don't want to overwrite an existing entry */
}
- /* No entry for given index? Make sure radix tree is big enough. */
- if (!entry || pmd_downgrade) {
- int err;
-
- if (pmd_downgrade) {
- /*
- * Make sure 'entry' remains valid while we drop
- * the i_pages lock.
- */
- entry = lock_slot(mapping, slot);
- }
+ if (!entry) {
+ xas_store(xas, locked);
+ if (xas_error(xas))
+ goto error;
+ entry = unlocked;
+ mapping->nrexceptional++;
+ }
- xa_unlock_irq(&mapping->i_pages);
+ if (pmd_downgrade) {
/*
* Besides huge zero pages the only other thing that gets
* downgraded are empty entries which don't need to be
* unmapped.
*/
- if (pmd_downgrade && dax_is_zero_entry(entry))
- unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
+ if (dax_is_zero_entry(entry)) {
+ xas_unlock_irq(xas);
+ unmap_mapping_pages(mapping, xas->xa_index,
PG_PMD_NR, false);
-
- err = radix_tree_preload(
- mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM);
- if (err) {
- if (pmd_downgrade)
- put_locked_mapping_entry(mapping, index);
- return ERR_PTR(err);
- }
- xa_lock_irq(&mapping->i_pages);
-
- if (!entry) {
- /*
- * We needed to drop the i_pages lock while calling
- * radix_tree_preload() and we didn't have an entry to
- * lock. See if another thread inserted an entry at
- * our index during this time.
- */
- entry = __radix_tree_lookup(&mapping->i_pages, index,
- NULL, &slot);
- if (entry) {
- radix_tree_preload_end();
- xa_unlock_irq(&mapping->i_pages);
- goto restart;
- }
+ xas_reset(xas);
+ xas_lock_irq(xas);
}
- if (pmd_downgrade) {
- dax_disassociate_entry(entry, mapping, false);
- radix_tree_delete(&mapping->i_pages, index);
+ dax_disassociate_entry(entry, mapping, false);
+ xas_store(xas, NULL); /* undo the PMD join */
+ xas_store(xas, locked); /* may fail with ENOMEM */
+ dax_wake_entry(xas, entry, true);
+ if (xas_error(xas)) {
mapping->nrexceptional--;
- dax_wake_mapping_entry_waiter(&mapping->i_pages,
- index, entry, true);
+ goto error;
}
-
- entry = dax_make_locked(0, size_flag | DAX_EMPTY);
-
- err = __radix_tree_insert(&mapping->i_pages, index,
- dax_entry_order(entry), entry);
- radix_tree_preload_end();
- if (err) {
- xa_unlock_irq(&mapping->i_pages);
- /*
- * Our insertion of a DAX entry failed, most likely
- * because we were inserting a PMD entry and it
- * collided with a PTE sized entry at a different
- * index in the PMD range. We haven't inserted
- * anything into the radix tree and have no waiters to
- * wake.
- */
- return ERR_PTR(err);
- }
- /* Good, we have inserted empty locked entry into the tree. */
- mapping->nrexceptional++;
- xa_unlock_irq(&mapping->i_pages);
- return entry;
+ entry = unlocked;
}
- entry = lock_slot(mapping, slot);
- out_unlock:
- xa_unlock_irq(&mapping->i_pages);
+
+ xas_unlock_irq(xas);
return entry;
+
+fallback:
+ xas_unlock_irq(xas);
+ return xa_mk_internal(VM_FAULT_FALLBACK);
+error:
+ xas_unlock_irq(xas);
+ if (xas_nomem(xas, GFP_NOIO))
+ goto retry;
+ if (xas->xa_node == XA_ERROR(-ENOMEM))
+ return xa_mk_internal(VM_FAULT_OOM);
+ return xa_mk_internal(VM_FAULT_SIGBUS);
}
/**
@@ -840,29 +682,25 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
* already in the tree, we will skip the insertion and just dirty the PMD as
* appropriate.
*/
-static void *dax_insert_entry(struct address_space *mapping,
- struct vm_fault *vmf,
+static void *dax_insert_entry(struct xa_state *xas,
+ struct address_space *mapping, struct vm_fault *vmf,
void *entry, pfn_t pfn_t, unsigned long flags, bool dirty)
{
- struct radix_tree_root *pages = &mapping->i_pages;
- unsigned long pfn = pfn_t_to_pfn(pfn_t);
- pgoff_t index = vmf->pgoff;
- void *new_entry;
-
+ void *new_entry = dax_make_entry(pfn_t, flags);
if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
if (dax_is_zero_entry(entry) && !(flags & DAX_ZERO_PAGE)) {
+ unsigned long index = xas->xa_index;
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
- unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
- PG_PMD_NR, false);
+ unmap_mapping_pages(mapping, index, PG_PMD_NR, false);
else /* pte entry */
- unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
+ unmap_mapping_pages(mapping, index, 1, false);
}
- xa_lock_irq(pages);
- new_entry = dax_make_locked(pfn, flags);
+ xas_reset(xas);
+ xas_lock_irq(xas);
if (dax_entry_size(entry) != dax_entry_size(new_entry)) {
dax_disassociate_entry(entry, mapping, false);
dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address);
@@ -877,21 +715,16 @@ static void *dax_insert_entry(struct address_space *mapping,
* existing entry is a PMD, we will just leave the PMD in the
* tree and dirty it if necessary.
*/
- struct radix_tree_node *node;
- void **slot;
- void *ret;
-
- ret = __radix_tree_lookup(pages, index, &node, &slot);
- WARN_ON_ONCE(ret != entry);
- __radix_tree_replace(pages, node, slot,
- new_entry, NULL);
+ dax_lock_entry(xas, new_entry);
entry = new_entry;
}
- if (dirty)
- radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY);
+ if (dirty) {
+ xas_load(xas); /* Walk the xa_state */
+ xas_set_tag(xas, PAGECACHE_TAG_DIRTY);
+ }
- xa_unlock_irq(pages);
+ xas_unlock_irq(xas);
return entry;
}
@@ -1160,15 +993,16 @@ static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size,
* If this page is ever written to we will re-fault and change the mapping to
* point to real DAX storage instead.
*/
-static vm_fault_t dax_load_hole(struct address_space *mapping, void *entry,
- struct vm_fault *vmf)
+static vm_fault_t dax_load_hole(struct xa_state *xas,
+ struct address_space *mapping, void **entry,
+ struct vm_fault *vmf)
{
struct inode *inode = mapping->host;
unsigned long vaddr = vmf->address;
pfn_t pfn = pfn_to_pfn_t(my_zero_pfn(vaddr));
vm_fault_t ret;
- dax_insert_entry(mapping, vmf, entry, pfn,
+ *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
DAX_ZERO_PAGE, false);
ret = vmf_insert_mixed(vmf->vma, vaddr, pfn);
@@ -1381,6 +1215,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
{
struct vm_area_struct *vma = vmf->vma;
struct address_space *mapping = vma->vm_file->f_mapping;
+ XA_STATE(xas, &mapping->i_pages, vmf->pgoff);
struct inode *inode = mapping->host;
unsigned long vaddr = vmf->address;
loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
@@ -1407,9 +1242,9 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (write && !vmf->cow_page)
flags |= IOMAP_WRITE;
- entry = grab_mapping_entry(mapping, vmf->pgoff, 0);
- if (IS_ERR(entry)) {
- ret = dax_fault_return(PTR_ERR(entry));
+ entry = grab_mapping_entry(&xas, mapping);
+ if (xa_is_internal(entry)) {
+ ret = xa_to_internal(entry);
goto out;
}
@@ -1482,7 +1317,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0)
goto error_finish_iomap;
- entry = dax_insert_entry(mapping, vmf, entry, pfn,
+ entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
0, write && !sync);
/*
@@ -1510,7 +1345,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
case IOMAP_UNWRITTEN:
case IOMAP_HOLE:
if (!write) {
- ret = dax_load_hole(mapping, entry, vmf);
+ ret = dax_load_hole(&xas, mapping, &entry, vmf);
goto finish_iomap;
}
/*FALLTHRU*/
@@ -1537,21 +1372,20 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap);
}
unlock_entry:
- put_locked_mapping_entry(mapping, vmf->pgoff);
+ put_locked_entry(&xas, entry);
out:
trace_dax_pte_fault_done(inode, vmf, ret);
return ret | major;
}
#ifdef CONFIG_FS_DAX_PMD
-static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
- void *entry)
+static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf,
+ struct iomap *iomap, void **entry)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
unsigned long pmd_addr = vmf->address & PMD_MASK;
struct inode *inode = mapping->host;
struct page *zero_page;
- void *ret = NULL;
spinlock_t *ptl;
pmd_t pmd_entry;
pfn_t pfn;
@@ -1562,7 +1396,7 @@ static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
goto fallback;
pfn = page_to_pfn_t(zero_page);
- ret = dax_insert_entry(mapping, vmf, entry, pfn,
+ *entry = dax_insert_entry(xas, mapping, vmf, *entry, pfn,
DAX_PMD | DAX_ZERO_PAGE, false);
ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
@@ -1575,11 +1409,11 @@ static vm_fault_t dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
pmd_entry = pmd_mkhuge(pmd_entry);
set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry);
spin_unlock(ptl);
- trace_dax_pmd_load_hole(inode, vmf, zero_page, ret);
+ trace_dax_pmd_load_hole(inode, vmf, zero_page, *entry);
return VM_FAULT_NOPAGE;
fallback:
- trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret);
+ trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, *entry);
return VM_FAULT_FALLBACK;
}
@@ -1588,6 +1422,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
{
struct vm_area_struct *vma = vmf->vma;
struct address_space *mapping = vma->vm_file->f_mapping;
+ XA_STATE_ORDER(xas, &mapping->i_pages, vmf->pgoff, PMD_ORDER);
unsigned long pmd_addr = vmf->address & PMD_MASK;
bool write = vmf->flags & FAULT_FLAG_WRITE;
bool sync;
@@ -1595,7 +1430,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
struct inode *inode = mapping->host;
vm_fault_t result = VM_FAULT_FALLBACK;
struct iomap iomap = { 0 };
- pgoff_t max_pgoff, pgoff;
+ pgoff_t max_pgoff;
void *entry;
loff_t pos;
int error;
@@ -1606,7 +1441,6 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
* supposed to hold locks serializing us with truncate / punch hole so
* this is a reliable test.
*/
- pgoff = linear_page_index(vma, pmd_addr);
max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
trace_dax_pmd_fault(inode, vmf, max_pgoff, 0);
@@ -1631,24 +1465,21 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
if ((pmd_addr + PMD_SIZE) > vma->vm_end)
goto fallback;
- if (pgoff >= max_pgoff) {
- result = VM_FAULT_SIGBUS;
- goto out;
- }
-
/* If the PMD would extend beyond the file size */
- if ((pgoff | PG_PMD_COLOUR) >= max_pgoff)
+ if ((xas.xa_index | PG_PMD_COLOUR) >= max_pgoff)
goto fallback;
/*
- * grab_mapping_entry() will make sure we get a 2MiB empty entry, a
- * 2MiB zero page entry or a DAX PMD. If it can't (because a 4k page
- * is already in the tree, for instance), it will return -EEXIST and
- * we just fall back to 4k entries.
+ * grab_mapping_entry() will make sure we get a 2MiB empty entry,
+ * a 2MiB zero page entry or a DAX PMD. If it can't (because a 4k
+ * page is already in the tree, for instance), it will return
+ * VM_FAULT_FALLBACK.
*/
- entry = grab_mapping_entry(mapping, pgoff, DAX_PMD);
- if (IS_ERR(entry))
+ entry = grab_mapping_entry(&xas, mapping);
+ if (xa_is_internal(entry)) {
+ result = xa_to_internal(entry);
goto fallback;
+ }
/*
* It is possible, particularly with mixed reads & writes to private
@@ -1667,7 +1498,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
* setting up a mapping, so really we're using iomap_begin() as a way
* to look up our filesystem block.
*/
- pos = (loff_t)pgoff << PAGE_SHIFT;
+ pos = (loff_t)xas.xa_index << PAGE_SHIFT;
error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap);
if (error)
goto unlock_entry;
@@ -1683,7 +1514,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0)
goto finish_iomap;
- entry = dax_insert_entry(mapping, vmf, entry, pfn,
+ entry = dax_insert_entry(&xas, mapping, vmf, entry, pfn,
DAX_PMD, write && !sync);
/*
@@ -1708,7 +1539,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
case IOMAP_HOLE:
if (WARN_ON_ONCE(write))
break;
- result = dax_pmd_load_hole(vmf, &iomap, entry);
+ result = dax_pmd_load_hole(&xas, vmf, &iomap, &entry);
break;
default:
WARN_ON_ONCE(1);
@@ -1731,13 +1562,12 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
&iomap);
}
unlock_entry:
- put_locked_mapping_entry(mapping, pgoff);
+ put_locked_entry(&xas, entry);
fallback:
if (result == VM_FAULT_FALLBACK) {
split_huge_pmd(vma, vmf->pmd, vmf->address);
count_vm_event(THP_FAULT_FALLBACK);
}
-out:
trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result);
return result;
}
--
2.17.1
