[PATCH] splice: LRU fixups
Nick says that the current construct isn't safe. This goes back to the
original, but sets PIPE_BUF_FLAG_LRU on user pages as well as they all
seem to be on the LRU in the first place.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index 27f5e37..0b20242 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -78,6 +78,7 @@
return 1;
}
+ buf->flags |= PIPE_BUF_FLAG_LRU;
return 0;
}
@@ -85,6 +86,7 @@
struct pipe_buffer *buf)
{
page_cache_release(buf->page);
+ buf->flags &= ~PIPE_BUF_FLAG_LRU;
}
static int page_cache_pipe_buf_pin(struct pipe_inode_info *info,
@@ -141,6 +143,7 @@
if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
return 1;
+ buf->flags |= PIPE_BUF_FLAG_LRU;
return generic_pipe_buf_steal(pipe, buf);
}
@@ -566,37 +569,23 @@
*/
if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) {
/*
- * If steal succeeds, buf->page is now pruned from the vm
- * side (page cache) and we can reuse it. The page will also
- * be locked on successful return.
+ * If steal succeeds, buf->page is now pruned from the
+ * pagecache and we can reuse it. The page will also be
+ * locked on successful return.
*/
if (buf->ops->steal(info, buf))
goto find_page;
page = buf->page;
- page_cache_get(page);
-
- /*
- * page must be on the LRU for adding to the pagecache.
- * Check this without grabbing the zone lock, if it isn't
- * the do grab the zone lock, recheck, and add if necessary.
- */
- if (!PageLRU(page)) {
- struct zone *zone = page_zone(page);
-
- spin_lock_irq(&zone->lru_lock);
- if (!PageLRU(page)) {
- SetPageLRU(page);
- add_page_to_inactive_list(zone, page);
- }
- spin_unlock_irq(&zone->lru_lock);
- }
-
if (add_to_page_cache(page, mapping, index, gfp_mask)) {
- page_cache_release(page);
unlock_page(page);
goto find_page;
}
+
+ page_cache_get(page);
+
+ if (!(buf->flags & PIPE_BUF_FLAG_LRU))
+ lru_cache_add(page);
} else {
find_page:
page = find_lock_page(mapping, index);