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Commit 58a4915a authored by Jens Axboe's avatar Jens Axboe
Browse files

block: ensure that bio_add_page() always accepts a page for an empty bio 



With commit 762380ad added support for chunk sizes and no merging
across them, it broke the rule of always allowing adding of a single
page to an empty bio. So relax the restriction a bit to allow for that,
similarly to what we have always done.

This fixes a crash with mkfs.xfs and 512b sector sizes on NVMe.

Reported-by: default avatarKeith Busch <keith.busch@intel.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 2b8393b4

block/bio.c

+6 −1
Original line number Diff line number Diff line
@@ -849,8 +849,13 @@ int bio_add_page(struct bio *bio, struct page *page, unsigned int len, 
		 unsigned int offset)

{

	struct request_queue *q = bdev_get_queue(bio->bi_bdev);

	unsigned int max_sectors;



	return __bio_add_page(q, bio, page, len, offset, blk_max_size_offset(q, bio->bi_iter.bi_sector));

	max_sectors = blk_max_size_offset(q, bio->bi_iter.bi_sector);

	if ((max_sectors < (len >> 9)) && !bio->bi_iter.bi_size)

		max_sectors = len >> 9;



	return __bio_add_page(q, bio, page, len, offset, max_sectors);

}

EXPORT_SYMBOL(bio_add_page);

block/blk-settings.c

+4 −1
Original line number Diff line number Diff line
@@ -285,7 +285,10 @@ EXPORT_SYMBOL(blk_queue_max_hw_sectors); 
 * Description:

 *    If a driver doesn't want IOs to cross a given chunk size, it can set

 *    this limit and prevent merging across chunks. Note that the chunk size

 *    must currently be a power-of-2 in sectors.

 *    must currently be a power-of-2 in sectors. Also note that the block

 *    layer must accept a page worth of data at any offset. So if the

 *    crossing of chunks is a hard limitation in the driver, it must still be

 *    prepared to split single page bios.

 **/

void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)

{