The patch titled
mm: improve find_lock_page
has been removed from the -mm tree. Its filename was
mm-improve-find_lock_page.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: mm: improve find_lock_page
From: Nick Piggin <npiggin@xxxxxxx>
find_lock_page does not need to recheck ->index because if the page is in the
right mapping then the index must be the same. Also, tree_lock does not need
to be retaken after the page is locked in order to test that ->mapping has not
changed, because holding the page lock pins its mapping.
Signed-off-by: Nick Piggin <npiggin@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff -puN mm/filemap.c~mm-improve-find_lock_page mm/filemap.c
--- a/mm/filemap.c~mm-improve-find_lock_page
+++ a/mm/filemap.c
@@ -621,26 +621,27 @@ struct page *find_lock_page(struct addre
{
struct page *page;
- read_lock_irq(&mapping->tree_lock);
repeat:
+ read_lock_irq(&mapping->tree_lock);
page = radix_tree_lookup(&mapping->page_tree, offset);
if (page) {
page_cache_get(page);
if (TestSetPageLocked(page)) {
read_unlock_irq(&mapping->tree_lock);
__lock_page(page);
- read_lock_irq(&mapping->tree_lock);
/* Has the page been truncated while we slept? */
- if (unlikely(page->mapping != mapping ||
- page->index != offset)) {
+ if (unlikely(page->mapping != mapping)) {
unlock_page(page);
page_cache_release(page);
goto repeat;
}
+ VM_BUG_ON(page->index != offset);
+ goto out;
}
}
read_unlock_irq(&mapping->tree_lock);
+out:
return page;
}
EXPORT_SYMBOL(find_lock_page);
_
Patches currently in -mm which might be from npiggin@xxxxxxx are
origin.patch
mm-document-tree_lock-zonelock-lockorder.patch
fs-reiserfs-cleanups.patch
atomic_opstxt-has-incorrect-misleading-and-insufficient-information.patch
fs-introduce-write_begin-write_end-and-perform_write-aops-revoke.patch
fs-introduce-write_begin-write_end-and-perform_write-aops-revoke-fix.patch
bitops-introduce-lock-ops.patch
alpha-fix-bitops.patch
alpha-lock-bitops.patch
alpha-lock-bitops-fix.patch
ia64-lock-bitops.patch
mips-fix-bitops.patch
mips-lock-bitops.patch
powerpc-lock-bitops.patch
powerpc-lock-bitops-fix.patch
bit_spin_lock-use-lock-bitops.patch
reiser4-fix-for-new-aops-patches.patch
-
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