[PATCH v9 59/61] dax: Convert to XArray

From: Matthew Wilcox
Date: Tue Mar 13 2018 - 09:28:41 EST

From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>

The DAX code (by its nature) is deeply interwoven with the radix tree
infrastructure, doing operations directly on the radix tree slots.
Convert the whole file to use XArray concepts; mostly passing around
xa_state instead of address_space, index or slot.

Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
fs/dax.c | 369 +++++++++++++++++++++++++--------------------------------------
1 file changed, 143 insertions(+), 226 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index ae70bebdb835..d14c2d931377 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -45,6 +45,7 @@
/* The 'colour' (ie low bits) within a PMD of a page offset. */
#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1)
#define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT)
+#define PMD_ORDER (PMD_SHIFT - PAGE_SHIFT)

static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES];

@@ -74,21 +75,26 @@ fs_initcall(init_dax_wait_table);
#define DAX_ZERO_PAGE (1UL << 2)
#define DAX_EMPTY (1UL << 3)

-static unsigned long dax_radix_sector(void *entry)
+static bool xa_is_dax_locked(void *entry)
+{
+ return xa_to_value(entry) & DAX_ENTRY_LOCK;
+}
+
+static unsigned long xa_to_dax_sector(void *entry)
{
return xa_to_value(entry) >> DAX_SHIFT;
}

-static void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
+static void *xa_mk_dax_locked(sector_t sector, unsigned long flags)
{
return xa_mk_value(flags | ((unsigned long)sector << DAX_SHIFT) |
DAX_ENTRY_LOCK);
}

-static unsigned int dax_radix_order(void *entry)
+static unsigned int dax_entry_order(void *entry)
{
if (xa_to_value(entry) & DAX_PMD)
- return PMD_SHIFT - PAGE_SHIFT;
+ return PMD_ORDER;
return 0;
}

@@ -113,10 +119,10 @@ static int dax_is_empty_entry(void *entry)
}

/*
- * DAX radix tree locking
+ * DAX page cache entry locking
*/
struct exceptional_entry_key {
- struct address_space *mapping;
+ struct xarray *xa;
pgoff_t entry_start;
};

@@ -125,9 +131,10 @@ struct wait_exceptional_entry_queue {
struct exceptional_entry_key key;
};

-static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping,
- 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 index = xas->xa_index;
unsigned long hash;

/*
@@ -138,10 +145,10 @@ static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping,
if (dax_is_pmd_entry(entry))
index &= ~PG_PMD_COLOUR;

- key->mapping = mapping;
+ key->xa = xas->xa;
key->entry_start = index;

- hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS);
+ hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS);
return wait_table + hash;
}

@@ -152,7 +159,7 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
struct wait_exceptional_entry_queue *ewait =
container_of(wait, struct wait_exceptional_entry_queue, wait);

- if (key->mapping != ewait->key.mapping ||
+ if (key->xa != ewait->key.xa ||
key->entry_start != ewait->key.entry_start)
return 0;
return autoremove_wake_function(wait, mode, sync, NULL);
@@ -163,13 +170,12 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
* 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 address_space *mapping,
- 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(mapping, index, entry, &key);
+ wq = dax_entry_waitqueue(xas, entry, &key);

/*
* Checking for locked entry and prepare_to_wait_exclusive() happens
@@ -182,53 +188,27 @@ static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
}

/*
- * 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_ENTRY_LOCK;
-}
-
-/*
- * Mark the given slot as locked. Must be called with the i_pages lock held.
+ * Mark the given entry as locked. Must be called with the i_pages lock held.
*/
-static inline void *lock_slot(struct address_space *mapping, void **slot)
+static inline void *lock_entry(struct xa_state *xas)
{
- unsigned long v = xa_to_value(
- radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock));
+ unsigned long v = xa_to_value(xas_load(xas));
void *entry = xa_mk_value(v | DAX_ENTRY_LOCK);
- radix_tree_replace_slot(&mapping->i_pages, slot, entry);
+ xas_store(xas, 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_ENTRY_LOCK);
- radix_tree_replace_slot(&mapping->i_pages, slot, entry);
- return entry;
-}
-
-/*
- * Lookup entry in radix tree, 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.
+ * Lookup entry in page cache, wait for it to become unlocked if it
+ * is a DAX entry and return it. The caller must subsequently call
+ * put_unlocked_entry() if it did not lock the entry or
+ * put_locked_entry() if it did lock the entry.
*
* Must be called with the i_pages lock held.
*/
-static void *get_unlocked_mapping_entry(struct address_space *mapping,
- pgoff_t index, void ***slotp)
+static void *get_unlocked_entry(struct xa_state *xas)
{
- void *entry, **slot;
+ void *entry;
struct wait_exceptional_entry_queue ewait;
wait_queue_head_t *wq;

@@ -236,67 +216,59 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping,
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;
+ entry = xas_load(xas);
+ if (!entry || WARN_ON_ONCE(!xa_is_value(entry)) ||
+ !xa_is_dax_locked(entry))
return entry;
- }

- wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key);
+ wq = dax_entry_waitqueue(xas, entry, &ewait.key);
prepare_to_wait_exclusive(wq, &ewait.wait,
TASK_UNINTERRUPTIBLE);
- xa_unlock_irq(&mapping->i_pages);
+ xas_unlock_irq(xas);
schedule();
finish_wait(wq, &ewait.wait);
- xa_lock_irq(&mapping->i_pages);
+ xas_reset(xas);
+ xas_lock_irq(xas);
}
}

-static void dax_unlock_mapping_entry(struct address_space *mapping,
- pgoff_t index)
+static void put_locked_entry(struct xa_state *xas, void *entry)
{
- 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, index, entry, false);
+ entry = xa_mk_value(xa_to_value(entry) & ~DAX_ENTRY_LOCK);
+ xas_reset(xas);
+ xas_lock_irq(xas);
+ xas_store(xas, entry);
+ xas_unlock_irq(xas);
+ dax_wake_entry(xas, entry, false);
}

-static void put_locked_mapping_entry(struct address_space *mapping,
- pgoff_t index)
+static void dax_unlock_entry(struct address_space *mapping, pgoff_t index)
{
- dax_unlock_mapping_entry(mapping, index);
+ XA_STATE(xas, &mapping->i_pages, index);
+ void *entry = xas_load(&xas);
+
+ if (WARN_ON_ONCE(!xa_is_value(entry) || !xa_is_dax_locked(entry)))
+ return;
+ put_locked_entry(&xas, entry);
}

/*
- * Called when we are done with radix tree entry we looked up via
- * get_unlocked_mapping_entry() and which we didn't lock in the end.
+ * Called when we are done with page cache entry we looked up via
+ * get_unlocked_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)
+static void put_unlocked_entry(struct xa_state *xas, void *entry)
{
if (!entry)
return;

- /* We have to wake up next waiter for the radix tree entry lock */
- dax_wake_mapping_entry_waiter(mapping, index, entry, false);
+ /* We have to wake up next waiter for the page cache entry lock */
+ dax_wake_entry(xas, entry, false);
}

/*
- * Find radix tree entry at given index. If it is a DAX entry, return it
- * with the radix tree entry locked. If the radix tree doesn't contain the
- * given index, create an empty entry for the index and return with it locked.
+ * Find page cache entry at given index. If it is a DAX entry, return it
+ * with the entry locked. If the page cache doesn't contain the given
+ * index, create an empty entry for the index and return with it locked.
*
* 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
@@ -321,12 +293,14 @@ static void put_unlocked_mapping_entry(struct address_space *mapping,
static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
unsigned long size_flag)
{
+ XA_STATE(xas, &mapping->i_pages, index);
bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */
- void *entry, **slot;
+ void *entry;

+ xas_set_order(&xas, index, size_flag ? PMD_ORDER : 0);
restart:
- xa_lock_irq(&mapping->i_pages);
- entry = get_unlocked_mapping_entry(mapping, index, &slot);
+ xas_lock_irq(&xas);
+ entry = get_unlocked_entry(&xas);

if (WARN_ON_ONCE(entry && !xa_is_value(entry))) {
entry = ERR_PTR(-EIO);
@@ -336,8 +310,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
if (entry) {
if (size_flag & DAX_PMD) {
if (dax_is_pte_entry(entry)) {
- put_unlocked_mapping_entry(mapping, index,
- entry);
+ put_unlocked_entry(&xas, entry);
entry = ERR_PTR(-EEXIST);
goto out_unlock;
}
@@ -350,123 +323,75 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index,
}
}

- /* 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);
- }
-
- xa_unlock_irq(&mapping->i_pages);
+ if (pmd_downgrade) {
+ entry = lock_entry(&xas);
/*
* 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))
+ if (dax_is_zero_entry(entry)) {
+ xas_unlock_irq(&xas);
unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
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) {
- radix_tree_delete(&mapping->i_pages, index);
- mapping->nrexceptional--;
- dax_wake_mapping_entry_waiter(mapping, index, entry,
- true);
- }
-
- entry = dax_radix_locked_entry(0, size_flag | DAX_EMPTY);
-
- err = __radix_tree_insert(&mapping->i_pages, index,
- dax_radix_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;
+ xas_store(&xas, NULL);
+ mapping->nrexceptional--;
+ dax_wake_entry(&xas, entry, true);
+ }
+ if (!entry || pmd_downgrade) {
+ entry = xa_mk_dax_locked(0, size_flag | DAX_EMPTY);
+ xas_store(&xas, entry);
+ if (!xas_error(&xas))
+ mapping->nrexceptional++;
+ } else {
+ entry = lock_entry(&xas);
}
- entry = lock_slot(mapping, slot);
out_unlock:
- xa_unlock_irq(&mapping->i_pages);
+ xas_unlock_irq(&xas);
+ if (xas_nomem(&xas, GFP_NOIO))
+ goto restart;
return entry;
}

-static int __dax_invalidate_mapping_entry(struct address_space *mapping,
+static int __dax_invalidate_entry(struct address_space *mapping,
pgoff_t index, bool trunc)
{
+ XA_STATE(xas, &mapping->i_pages, index);
int ret = 0;
void *entry;
- struct radix_tree_root *pages = &mapping->i_pages;

- xa_lock_irq(pages);
- entry = get_unlocked_mapping_entry(mapping, index, NULL);
+ xas_lock_irq(&xas);
+ entry = get_unlocked_entry(&xas);
if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
goto out;
if (!trunc &&
- (radix_tree_tag_get(pages, index, PAGECACHE_TAG_DIRTY) ||
- radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE)))
+ (xas_get_tag(&xas, PAGECACHE_TAG_DIRTY) ||
+ xas_get_tag(&xas, PAGECACHE_TAG_TOWRITE)))
goto out;
- radix_tree_delete(pages, index);
+ xas_store(&xas, NULL);
mapping->nrexceptional--;
ret = 1;
out:
- put_unlocked_mapping_entry(mapping, index, entry);
- xa_unlock_irq(pages);
+ put_unlocked_entry(&xas, entry);
+ xas_unlock_irq(&xas);
return ret;
}
+
/*
* Delete DAX entry at @index from @mapping. Wait for it
* to be unlocked before deleting it.
*/
int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
{
- int ret = __dax_invalidate_mapping_entry(mapping, index, true);
+ int ret = __dax_invalidate_entry(mapping, index, true);

/*
* This gets called from truncate / punch_hole path. As such, the caller
* must hold locks protecting against concurrent modifications of the
- * radix tree (usually fs-private i_mmap_sem for writing). Since the
+ * page cache (usually fs-private i_mmap_sem for writing). Since the
* caller has seen a DAX entry for this index, we better find it
* at that index as well...
*/
@@ -480,7 +405,7 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index)
int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
pgoff_t index)
{
- return __dax_invalidate_mapping_entry(mapping, index, false);
+ return __dax_invalidate_entry(mapping, index, false);
}

static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev,
@@ -517,14 +442,14 @@ 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_mapping_entry(struct address_space *mapping,
+static void *dax_insert_entry(struct address_space *mapping,
struct vm_fault *vmf,
void *entry, sector_t sector,
unsigned long flags, bool dirty)
{
- struct radix_tree_root *pages = &mapping->i_pages;
void *new_entry;
pgoff_t index = vmf->pgoff;
+ XA_STATE(xas, &mapping->i_pages, index);

if (dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -538,33 +463,27 @@ static void *dax_insert_mapping_entry(struct address_space *mapping,
unmap_mapping_pages(mapping, vmf->pgoff, 1, false);
}

- xa_lock_irq(pages);
- new_entry = dax_radix_locked_entry(sector, flags);
+ xas_lock_irq(&xas);
+ new_entry = xa_mk_dax_locked(sector, flags);

if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
/*
- * Only swap our new entry into the radix tree if the current
+ * Only swap our new entry into the page cache if the current
* entry is a zero page or an empty entry. If a normal PTE or
* PMD entry is already in the tree, we leave it alone. This
* means that if we are trying to insert a PTE and the
* 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);
+ void *prev = xas_store(&xas, new_entry);
+ WARN_ON_ONCE(prev != entry);
entry = new_entry;
}

if (dirty)
- radix_tree_tag_set(pages, index, PAGECACHE_TAG_DIRTY);
+ xas_set_tag(&xas, PAGECACHE_TAG_DIRTY);

- xa_unlock_irq(pages);
+ xas_unlock_irq(&xas);
return entry;
}

@@ -579,7 +498,7 @@ pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma)
}

/* Walk all mappings of a given index of a file and writeprotect them */
-static void dax_mapping_entry_mkclean(struct address_space *mapping,
+static void dax_entry_mkclean(struct address_space *mapping,
pgoff_t index, unsigned long pfn)
{
struct vm_area_struct *vma;
@@ -654,8 +573,8 @@ static int dax_writeback_one(struct block_device *bdev,
struct dax_device *dax_dev, struct address_space *mapping,
pgoff_t index, void *entry)
{
- struct radix_tree_root *pages = &mapping->i_pages;
- void *entry2, **slot, *kaddr;
+ XA_STATE(xas, &mapping->i_pages, index);
+ void *entry2, *kaddr;
long ret = 0, id;
sector_t sector;
pgoff_t pgoff;
@@ -669,8 +588,8 @@ static int dax_writeback_one(struct block_device *bdev,
if (WARN_ON(!xa_is_value(entry)))
return -EIO;

- xa_lock_irq(pages);
- entry2 = get_unlocked_mapping_entry(mapping, index, &slot);
+ xas_lock_irq(&xas);
+ entry2 = get_unlocked_entry(&xas);
/* Entry got punched out / reallocated? */
if (!entry2 || WARN_ON_ONCE(!xa_is_value(entry2)))
goto put_unlocked;
@@ -679,7 +598,7 @@ static int dax_writeback_one(struct block_device *bdev,
* compare sectors as we must not bail out due to difference in lockbit
* or entry type.
*/
- if (dax_radix_sector(entry2) != dax_radix_sector(entry))
+ if (xa_to_dax_sector(entry2) != xa_to_dax_sector(entry))
goto put_unlocked;
if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
dax_is_zero_entry(entry))) {
@@ -688,10 +607,10 @@ static int dax_writeback_one(struct block_device *bdev,
}

/* Another fsync thread may have already written back this entry */
- if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))
+ if (!xas_get_tag(&xas, PAGECACHE_TAG_TOWRITE))
goto put_unlocked;
/* Lock the entry to serialize with page faults */
- entry = lock_slot(mapping, slot);
+ entry = lock_entry(&xas);
/*
* We can clear the tag now but we have to be careful so that concurrent
* dax_writeback_one() calls for the same index cannot finish before we
@@ -699,8 +618,8 @@ static int dax_writeback_one(struct block_device *bdev,
* at the entry only under the i_pages lock and once they do that
* they will see the entry locked and wait for it to unlock.
*/
- radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE);
- xa_unlock_irq(pages);
+ xas_clear_tag(&xas, PAGECACHE_TAG_TOWRITE);
+ xas_unlock_irq(&xas);

/*
* Even if dax_writeback_mapping_range() was given a wbc->range_start
@@ -709,8 +628,8 @@ static int dax_writeback_one(struct block_device *bdev,
* 'entry'. This allows us to flush for PMD_SIZE and not have to
* worry about partial PMD writebacks.
*/
- sector = dax_radix_sector(entry);
- size = PAGE_SIZE << dax_radix_order(entry);
+ sector = xa_to_dax_sector(entry);
+ size = PAGE_SIZE << dax_entry_order(entry);

id = dax_read_lock();
ret = bdev_dax_pgoff(bdev, sector, size, &pgoff);
@@ -730,7 +649,7 @@ static int dax_writeback_one(struct block_device *bdev,
goto dax_unlock;
}

- dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
+ dax_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn));
dax_flush(dax_dev, kaddr, size);
/*
* After we have flushed the cache, we can clear the dirty tag. There
@@ -738,18 +657,16 @@ static int dax_writeback_one(struct block_device *bdev,
* the pfn mappings are writeprotected and fault waits for mapping
* entry lock.
*/
- xa_lock_irq(pages);
- radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY);
- xa_unlock_irq(pages);
+ xa_clear_tag(&mapping->i_pages, index, PAGECACHE_TAG_DIRTY);
trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
dax_unlock:
dax_read_unlock(id);
- put_locked_mapping_entry(mapping, index);
+ put_locked_entry(&xas, entry2);
return ret;

put_unlocked:
- put_unlocked_mapping_entry(mapping, index, entry2);
- xa_unlock_irq(pages);
+ put_unlocked_entry(&xas, entry2);
+ xas_unlock_irq(&xas);
return ret;
}

@@ -877,7 +794,7 @@ static int dax_load_hole(struct address_space *mapping, void *entry,
goto out;
}

- entry2 = dax_insert_mapping_entry(mapping, vmf, entry, 0,
+ entry2 = dax_insert_entry(mapping, vmf, entry, 0,
DAX_ZERO_PAGE, false);
if (IS_ERR(entry2)) {
ret = VM_FAULT_SIGBUS;
@@ -1193,7 +1110,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0)
goto error_finish_iomap;

- entry = dax_insert_mapping_entry(mapping, vmf, entry,
+ entry = dax_insert_entry(mapping, vmf, entry,
dax_iomap_sector(&iomap, pos),
0, write && !sync);
if (IS_ERR(entry)) {
@@ -1256,7 +1173,7 @@ static int 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);
+ dax_unlock_entry(mapping, vmf->pgoff);
out:
trace_dax_pte_fault_done(inode, vmf, vmf_ret);
return vmf_ret;
@@ -1279,7 +1196,7 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap,
if (unlikely(!zero_page))
goto fallback;

- ret = dax_insert_mapping_entry(mapping, vmf, entry, 0,
+ ret = dax_insert_entry(mapping, vmf, entry, 0,
DAX_PMD | DAX_ZERO_PAGE, false);
if (IS_ERR(ret))
goto fallback;
@@ -1334,7 +1251,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
* Make sure that the faulting address's PMD offset (color) matches
* the PMD offset from the start of the file. This is necessary so
* that a PMD range in the page table overlaps exactly with a PMD
- * range in the radix tree.
+ * range in the page cache.
*/
if ((vmf->pgoff & PG_PMD_COLOUR) !=
((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR))
@@ -1402,7 +1319,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
if (error < 0)
goto finish_iomap;

- entry = dax_insert_mapping_entry(mapping, vmf, entry,
+ entry = dax_insert_entry(mapping, vmf, entry,
dax_iomap_sector(&iomap, pos),
DAX_PMD, write && !sync);
if (IS_ERR(entry))
@@ -1453,7 +1370,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
&iomap);
}
unlock_entry:
- put_locked_mapping_entry(mapping, pgoff);
+ dax_unlock_entry(mapping, pgoff);
fallback:
if (result == VM_FAULT_FALLBACK) {
split_huge_pmd(vma, vmf->pmd, vmf->address);
@@ -1504,34 +1421,34 @@ EXPORT_SYMBOL_GPL(dax_iomap_fault);
* @pe_size: Size of entry to be inserted
* @pfn: PFN to insert
*
- * This function inserts writeable PTE or PMD entry into page tables for mmaped
- * DAX file. It takes care of marking corresponding radix tree entry as dirty
- * as well.
+ * This function inserts a writeable PTE or PMD entry into the page tables
+ * for an mmaped DAX file. It also marks the page cache entry as dirty.
*/
static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
enum page_entry_size pe_size,
pfn_t pfn)
{
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
- void *entry, **slot;
pgoff_t index = vmf->pgoff;
+ XA_STATE(xas, &mapping->i_pages, index);
+ void *entry;
int vmf_ret, error;

- xa_lock_irq(&mapping->i_pages);
- entry = get_unlocked_mapping_entry(mapping, index, &slot);
+ xas_lock_irq(&xas);
+ entry = get_unlocked_entry(&xas);
/* Did we race with someone splitting entry or so? */
if (!entry ||
(pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) ||
(pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) {
- put_unlocked_mapping_entry(mapping, index, entry);
- xa_unlock_irq(&mapping->i_pages);
+ put_unlocked_entry(&xas, entry);
+ xas_unlock_irq(&xas);
trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf,
VM_FAULT_NOPAGE);
return VM_FAULT_NOPAGE;
}
- radix_tree_tag_set(&mapping->i_pages, index, PAGECACHE_TAG_DIRTY);
- entry = lock_slot(mapping, slot);
- xa_unlock_irq(&mapping->i_pages);
+ xas_set_tag(&xas, PAGECACHE_TAG_DIRTY);
+ entry = lock_entry(&xas);
+ xas_unlock_irq(&xas);
switch (pe_size) {
case PE_SIZE_PTE:
error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn);
@@ -1546,7 +1463,7 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf,
default:
vmf_ret = VM_FAULT_FALLBACK;
}
- put_locked_mapping_entry(mapping, index);
+ put_locked_entry(&xas, entry);
trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret);
return vmf_ret;
}
--
2.16.1