The patch titled
mm: improve find_lock_page
has been added to the -mm tree. Its filename is
mm-improve-find_lock_page.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
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
remove-zero_page.patch
mm-use-lockless-radix-tree-probe.patch
mm-improve-find_lock_page.patch
mm-clarify-__add_to_swap_cache-locking.patch
radix-tree-use-indirect-bit.patch
mm-revert-kernel_ds-buffered-write-optimisation.patch
revert-81b0c8713385ce1b1b9058e916edcf9561ad76d6.patch
revert-6527c2bdf1f833cc18e8f42bd97973d583e4aa83.patch
mm-clean-up-buffered-write-code.patch
mm-debug-write-deadlocks.patch
mm-trim-more-holes.patch
mm-buffered-write-cleanup.patch
mm-write-iovec-cleanup.patch
mm-fix-pagecache-write-deadlocks.patch
mm-buffered-write-iterator.patch
fs-fix-data-loss-on-error.patch
fs-introduce-write_begin-write_end-and-perform_write-aops.patch
introduce-write_begin-write_end-aops-important-fix.patch
mm-restore-kernel_ds-optimisations.patch
implement-simple-fs-aops.patch
block_dev-convert-to-new-aops.patch
ext2-convert-to-new-aops.patch
ext2-convert-to-new-aops-fix.patch
ext3-convert-to-new-aops.patch
ext3-convert-to-new-aops-fix.patch
ext4-convert-to-new-aops.patch
ext4-convert-to-new-aops-fix.patch
xfs-convert-to-new-aops.patch
fs-new-cont-helpers.patch
fat-convert-to-new-aops.patch
hfs-convert-to-new-aops.patch
hfsplus-convert-to-new-aops.patch
hpfs-convert-to-new-aops.patch
bfs-convert-to-new-aops.patch
qnx4-convert-to-new-aops.patch
reiserfs-use-generic-write.patch
reiserfs-convert-to-new-aops.patch
reiserfs-convert-to-new-aops-fix.patch
reiserfs-use-generic_cont_expand_simple.patch
with-reiserfs-no-longer-using-the-weird-generic_cont_expand-remove-it-completely.patch
nfs-convert-to-new-aops.patch
smb-convert-to-new-aops.patch
fuse-convert-to-new-aops.patch
hostfs-convert-to-new-aops.patch
hostfs-convert-to-new-aops-fix.patch
jffs2-convert-to-new-aops.patch
ufs-convert-to-new-aops.patch
ufs-convert-to-new-aops-fix.patch
udf-convert-to-new-aops.patch
udf-convert-to-new-aops-fix.patch
sysv-convert-to-new-aops.patch
sysv-convert-to-new-aops-fix.patch
minix-convert-to-new-aops.patch
minix-convert-to-new-aops-fix.patch
jfs-convert-to-new-aops.patch
fs-adfs-convert-to-new-aops.patch
fs-affs-convert-to-new-aops.patch
affs-convert-to-new-aops-fix.patch
ocfs2-convert-to-new-aops.patch
fs-remove-some-aop_truncated_page.patch
fs-remove-some-aop_truncated_page-fix.patch
fs-reiserfs-cleanups.patch
fs-introduce-write_begin-write_end-and-perform_write-aops-revoke.patch
reiser4-fix-for-new-aops-patches.patch
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