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Commit 1432873a authored by Jens Axboe's avatar Jens Axboe Committed by Jens Axboe
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[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: default avatarJens Axboe <axboe@suse.de>
parent bfc4ee39

fs/splice.c

+11 −22
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, 
		return 1;

	}



	buf->flags |= PIPE_BUF_FLAG_LRU;

	return 0;

}
@@ -85,6 +86,7 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info, 
					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 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, 
	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 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, 
	 */

	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);

include/linux/pipe_fs_i.h

+3 −2
Original line number Diff line number Diff line
@@ -5,8 +5,9 @@ 


#define PIPE_BUFFERS (16)



#define PIPE_BUF_FLAG_ATOMIC	0x01	/* was atomically mapped */

#define PIPE_BUF_FLAG_GIFT	0x02	/* page is a gift */

#define PIPE_BUF_FLAG_LRU	0x01	/* page is on the LRU */

#define PIPE_BUF_FLAG_ATOMIC	0x02	/* was atomically mapped */

#define PIPE_BUF_FLAG_GIFT	0x04	/* page is a gift */



struct pipe_buffer {

	struct page *page;