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Diffstat (limited to 'mm/shmem.c')
-rw-r--r--mm/shmem.c122
1 files changed, 31 insertions, 91 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index f0d698ba7d0f..0f1447563f17 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -243,19 +243,17 @@ static int shmem_radix_tree_replace(struct address_space *mapping,
pgoff_t index, void *expected, void *replacement)
{
void **pslot;
- void *item = NULL;
+ void *item;
VM_BUG_ON(!expected);
+ VM_BUG_ON(!replacement);
pslot = radix_tree_lookup_slot(&mapping->page_tree, index);
- if (pslot)
- item = radix_tree_deref_slot_protected(pslot,
- &mapping->tree_lock);
+ if (!pslot)
+ return -ENOENT;
+ item = radix_tree_deref_slot_protected(pslot, &mapping->tree_lock);
if (item != expected)
return -ENOENT;
- if (replacement)
- radix_tree_replace_slot(pslot, replacement);
- else
- radix_tree_delete(&mapping->page_tree, index);
+ radix_tree_replace_slot(pslot, replacement);
return 0;
}
@@ -332,84 +330,20 @@ static void shmem_delete_from_page_cache(struct page *page, void *radswap)
}
/*
- * Like find_get_pages, but collecting swap entries as well as pages.
- */
-static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping,
- pgoff_t start, unsigned int nr_pages,
- struct page **pages, pgoff_t *indices)
-{
- void **slot;
- unsigned int ret = 0;
- struct radix_tree_iter iter;
-
- if (!nr_pages)
- return 0;
-
- rcu_read_lock();
-restart:
- radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) {
- struct page *page;
-repeat:
- page = radix_tree_deref_slot(slot);
- if (unlikely(!page))
- continue;
- if (radix_tree_exception(page)) {
- if (radix_tree_deref_retry(page))
- goto restart;
- /*
- * Otherwise, we must be storing a swap entry
- * here as an exceptional entry: so return it
- * without attempting to raise page count.
- */
- goto export;
- }
- if (!page_cache_get_speculative(page))
- goto repeat;
-
- /* Has the page moved? */
- if (unlikely(page != *slot)) {
- page_cache_release(page);
- goto repeat;
- }
-export:
- indices[ret] = iter.index;
- pages[ret] = page;
- if (++ret == nr_pages)
- break;
- }
- rcu_read_unlock();
- return ret;
-}
-
-/*
* Remove swap entry from radix tree, free the swap and its page cache.
*/
static int shmem_free_swap(struct address_space *mapping,
pgoff_t index, void *radswap)
{
- int error;
+ void *old;
spin_lock_irq(&mapping->tree_lock);
- error = shmem_radix_tree_replace(mapping, index, radswap, NULL);
+ old = radix_tree_delete_item(&mapping->page_tree, index, radswap);
spin_unlock_irq(&mapping->tree_lock);
- if (!error)
- free_swap_and_cache(radix_to_swp_entry(radswap));
- return error;
-}
-
-/*
- * Pagevec may contain swap entries, so shuffle up pages before releasing.
- */
-static void shmem_deswap_pagevec(struct pagevec *pvec)
-{
- int i, j;
-
- for (i = 0, j = 0; i < pagevec_count(pvec); i++) {
- struct page *page = pvec->pages[i];
- if (!radix_tree_exceptional_entry(page))
- pvec->pages[j++] = page;
- }
- pvec->nr = j;
+ if (old != radswap)
+ return -ENOENT;
+ free_swap_and_cache(radix_to_swp_entry(radswap));
+ return 0;
}
/*
@@ -430,12 +364,12 @@ void shmem_unlock_mapping(struct address_space *mapping)
* Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
* has finished, if it hits a row of PAGEVEC_SIZE swap entries.
*/
- pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
- PAGEVEC_SIZE, pvec.pages, indices);
+ pvec.nr = find_get_entries(mapping, index,
+ PAGEVEC_SIZE, pvec.pages, indices);
if (!pvec.nr)
break;
index = indices[pvec.nr - 1] + 1;
- shmem_deswap_pagevec(&pvec);
+ pagevec_remove_exceptionals(&pvec);
check_move_unevictable_pages(pvec.pages, pvec.nr);
pagevec_release(&pvec);
cond_resched();
@@ -467,9 +401,9 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
pagevec_init(&pvec, 0);
index = start;
while (index < end) {
- pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
- min(end - index, (pgoff_t)PAGEVEC_SIZE),
- pvec.pages, indices);
+ pvec.nr = find_get_entries(mapping, index,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE),
+ pvec.pages, indices);
if (!pvec.nr)
break;
mem_cgroup_uncharge_start();
@@ -498,7 +432,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
unlock_page(page);
}
- shmem_deswap_pagevec(&pvec);
+ pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
mem_cgroup_uncharge_end();
cond_resched();
@@ -536,9 +470,10 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
index = start;
while (index < end) {
cond_resched();
- pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
+
+ pvec.nr = find_get_entries(mapping, index,
min(end - index, (pgoff_t)PAGEVEC_SIZE),
- pvec.pages, indices);
+ pvec.pages, indices);
if (!pvec.nr) {
/* If all gone or hole-punch or unfalloc, we're done */
if (index == start || end != -1)
@@ -581,7 +516,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
}
unlock_page(page);
}
- shmem_deswap_pagevec(&pvec);
+ pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
mem_cgroup_uncharge_end();
index++;
@@ -1088,7 +1023,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
return -EFBIG;
repeat:
swap.val = 0;
- page = find_lock_page(mapping, index);
+ page = find_lock_entry(mapping, index);
if (radix_tree_exceptional_entry(page)) {
swap = radix_to_swp_entry(page);
page = NULL;
@@ -1483,6 +1418,11 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
return inode;
}
+bool shmem_mapping(struct address_space *mapping)
+{
+ return mapping->backing_dev_info == &shmem_backing_dev_info;
+}
+
#ifdef CONFIG_TMPFS
static const struct inode_operations shmem_symlink_inode_operations;
static const struct inode_operations shmem_short_symlink_operations;
@@ -1795,7 +1735,7 @@ static pgoff_t shmem_seek_hole_data(struct address_space *mapping,
pagevec_init(&pvec, 0);
pvec.nr = 1; /* start small: we may be there already */
while (!done) {
- pvec.nr = shmem_find_get_pages_and_swap(mapping, index,
+ pvec.nr = find_get_entries(mapping, index,
pvec.nr, pvec.pages, indices);
if (!pvec.nr) {
if (whence == SEEK_DATA)
@@ -1822,7 +1762,7 @@ static pgoff_t shmem_seek_hole_data(struct address_space *mapping,
break;
}
}
- shmem_deswap_pagevec(&pvec);
+ pagevec_remove_exceptionals(&pvec);
pagevec_release(&pvec);
pvec.nr = PAGEVEC_SIZE;
cond_resched();
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-05 01:39:17 +0000