submit_bio() may be called recursively. To limit the stack depth, recursive calls result in bios being added to a list (current->bio_list). __submit_bio_noacct() sets up that list and maintains two lists with requests: * bio_list_on_stack[0] is the list with bios submitted by recursive submit_bio() calls from inside the latest __submit_bio() call. * bio_list_on_stack[1] is the list with bios submitted by recursive submit_bio() calls from inside previous __submit_bio() calls. Make sure that bios are submitted to lower devices in the order these have been submitted by submit_bio() by adding new bios at the end of the list instead of at the front. This patch fixes unaligned write errors that I encountered with F2FS submitting zoned writes to a dm driver stacked on top of a zoned UFS device. Cc: Christoph Hellwig <hch@xxxxxx> Cc: Damien Le Moal <dlemoal@xxxxxxxxxx> Cc: Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> Cc: Ming Lei <ming.lei@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-core.c b/block/blk-core.c index b862c66018f2..4b728fa1c138 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -704,9 +704,9 @@ static void __submit_bio_noacct(struct bio *bio) /* * Now assemble so we handle the lowest level first. */ + bio_list_on_stack[0] = bio_list_on_stack[1]; bio_list_merge(&bio_list_on_stack[0], &lower); bio_list_merge(&bio_list_on_stack[0], &same); - bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); current->bio_list = NULL;
