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| author | Shaohua Li <shaohua.li@intel.com> | 2011-09-15 02:45:19 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-09-15 03:17:56 +0200 |
| commit | cc39c6a9bbdebfcf1a7dee64d83bf302bc38d941 (patch) | |
| tree | 5c8c8b127e8bd31300fba1f5aa155c6463c4c78f | |
| parent | drivers/gpio/gpio-generic.c: fix build errors (diff) | |
| download | linux-cc39c6a9bbdebfcf1a7dee64d83bf302bc38d941.tar.xz linux-cc39c6a9bbdebfcf1a7dee64d83bf302bc38d941.zip | |
mm: account skipped entries to avoid looping in find_get_pages
The found entries by find_get_pages() could be all swap entries. In
this case we skip the entries, but make sure the skipped entries are
accounted, so we don't keep looping.
Using nr_found > nr_skip to simplify code as suggested by Eric.
Reported-and-tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/filemap.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 645a080ba4df..7771871fa353 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -827,13 +827,14 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, { unsigned int i; unsigned int ret; - unsigned int nr_found; + unsigned int nr_found, nr_skip; rcu_read_lock(); restart: nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, (void ***)pages, NULL, start, nr_pages); ret = 0; + nr_skip = 0; for (i = 0; i < nr_found; i++) { struct page *page; repeat: @@ -856,6 +857,7 @@ repeat: * here as an exceptional entry: so skip over it - * we only reach this from invalidate_mapping_pages(). */ + nr_skip++; continue; } @@ -876,7 +878,7 @@ repeat: * If all entries were removed before we could secure them, * try again, because callers stop trying once 0 is returned. */ - if (unlikely(!ret && nr_found)) + if (unlikely(!ret && nr_found > nr_skip)) goto restart; rcu_read_unlock(); return ret; |