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

With commit 762380ad93 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: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2014-06-10 12:53:56 -06:00
parent 2b8393b43e
commit 58a4915ad2
2 changed files with 10 additions and 2 deletions

View file

@ -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);

View file

@ -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)
{