diff options
authorJens Axboe <>2021-08-13 07:53:09 -0600
committerJens Axboe <>2021-08-23 13:45:40 -0600
commit3d5b3fbedad65088ec079a4c4d1a2f47e11ae1e7 (patch)
parent270a1c913ebd745ebee716af5f7215e1c2b30cc0 (diff)
bio: improve kerneldoc documentation for bio_alloc_kiocb()io_uring-bio-cache.5-2021-08-30io_uring-bio-cache.5
We're missing a description for the 'nr_vecs' parameter. While in there, clarify that freeing a bio allocated through this function must be done from process context. Fixes: 1cbbd31c4ada ("bio: add allocation cache abstraction") Reported-by: Stephen Rothwell <> Signed-off-by: Jens Axboe <>
1 files changed, 4 insertions, 1 deletions
diff --git a/block/bio.c b/block/bio.c
index dbb0bc8e1ef7..ef88fa3afe4c 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1692,12 +1692,15 @@ EXPORT_SYMBOL(bioset_init_from_src);
* bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
* @kiocb: kiocb describing the IO
+ * @nr_iovecs: number of iovecs to pre-allocate
* @bs: bio_set to allocate from
* Description:
* Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
* used to check if we should dip into the per-cpu bio_set allocation
- * cache. The allocation uses GFP_KERNEL internally.
+ * cache. The allocation uses GFP_KERNEL internally. On return, the
+ * bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
+ * MUST be done from process context, not hard/soft IRQ.
struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,