diff mbox series

[v4,1/6] block: Rework bio_split() return value

Message ID 20241111112150.3756529-2-john.g.garry@oracle.com (mailing list archive)
State Handled Elsewhere
Headers show
Series bio_split() error handling rework | expand

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mdraidci/vmtest-md-6_13-PR success PR summary
mdraidci/vmtest-md-6_13-VM_Test-0 success Logs for per-patch-testing

Commit Message

John Garry Nov. 11, 2024, 11:21 a.m. UTC 
Instead of returning an inconclusive value of NULL for an error in calling
bio_split(), return a ERR_PTR() always.

Also remove the BUG_ON() calls, and WARN_ON_ONCE() instead. Indeed, since
almost all callers don't check the return code from bio_split(), we'll
crash anyway (for those failures).

Fix up the only user which checks bio_split() return code today (directly
or indirectly), blk_crypto_fallback_split_bio_if_needed(). The md/bcache
code does check the return code in cached_dev_cache_miss() ->
bio_next_split() -> bio_split(), but only to see if there was a split, so
there would be no change in behaviour here (when returning a ERR_PTR()).

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 block/bio.c                 | 10 ++++++----
 block/blk-crypto-fallback.c |  2 +-
 2 files changed, 7 insertions(+), 5 deletions(-)

Comments

Hannes Reinecke Nov. 12, 2024, 6:58 a.m. UTC | #1 
On 11/11/24 12:21, John Garry wrote:
> Instead of returning an inconclusive value of NULL for an error in calling
> bio_split(), return a ERR_PTR() always.
> 
> Also remove the BUG_ON() calls, and WARN_ON_ONCE() instead. Indeed, since
> almost all callers don't check the return code from bio_split(), we'll
> crash anyway (for those failures).
> 
> Fix up the only user which checks bio_split() return code today (directly
> or indirectly), blk_crypto_fallback_split_bio_if_needed(). The md/bcache
> code does check the return code in cached_dev_cache_miss() ->
> bio_next_split() -> bio_split(), but only to see if there was a split, so
> there would be no change in behaviour here (when returning a ERR_PTR()).
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> Signed-off-by: John Garry <john.g.garry@oracle.com>
> ---
>   block/bio.c                 | 10 ++++++----
>   block/blk-crypto-fallback.c |  2 +-
>   2 files changed, 7 insertions(+), 5 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
diff mbox series

Patch

diff --git a/block/bio.c b/block/bio.c
index daceb0a5c1d7..948b22825510 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1665,16 +1665,18 @@  struct bio *bio_split(struct bio *bio, int sectors,
 {
 	struct bio *split;
 
-	BUG_ON(sectors <= 0);
-	BUG_ON(sectors >= bio_sectors(bio));
+	if (WARN_ON_ONCE(sectors <= 0))
+		return ERR_PTR(-EINVAL);
+	if (WARN_ON_ONCE(sectors >= bio_sectors(bio)))
+		return ERR_PTR(-EINVAL);
 
 	/* Zone append commands cannot be split */
 	if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);
 	if (!split)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	split->bi_iter.bi_size = sectors << 9;
 
diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
index b1e7415f8439..29a205482617 100644
--- a/block/blk-crypto-fallback.c
+++ b/block/blk-crypto-fallback.c
@@ -226,7 +226,7 @@  static bool blk_crypto_fallback_split_bio_if_needed(struct bio **bio_ptr)
 
 		split_bio = bio_split(bio, num_sectors, GFP_NOIO,
 				      &crypto_bio_split);
-		if (!split_bio) {
+		if (IS_ERR(split_bio)) {
 			bio->bi_status = BLK_STS_RESOURCE;
 			return false;
 		}