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

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 <>
Signed-off-by: default avatarJens Axboe <>
parent 2b8393b4
......@@ -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);
......@@ -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)
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