diff options
authorJens Axboe <>2021-08-13 07:53:09 -0600
committerJens Axboe <>2021-08-13 07:53:09 -0600
commit13b17703b0be19f2054ce51022a2b34da759ab73 (patch)
parent6e2e645a2467fe43bb76a2cb6f5702f39b9e6334 (diff)
bio: improve kerneldoc documentation for bio_alloc_kiocb()
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 bb16e556bc68..44c328db4390 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1691,12 +1691,15 @@ 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,