[v7,02/10] block: copy back bounce buffer to user-space correctly in case of split

Commit Message

Anuj Gupta Nov. 4, 2024, 2:05 p.m. UTC

From: Christoph Hellwig <[e-mail]>

Copy back the bounce buffer to user-space in entirety when the parent
bio completes. The existing code uses bip_iter.bi_size for sizing the
copy, which can be modified. So move away from that and fetch it from
the vector passed to the block layer. While at it, switch to using
better variable names.

Fixes: 492c5d455969f ("block: bio-integrity: directly map user buffers")
Signed-off-by: Anuj Gupta <[e-mail]>
[hch: better names for variables]
Signed-off-by: Christoph Hellwig <[e-mail]>
Reviewed-by: Keith Busch <[e-mail]>
---
 block/bio-integrity.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Comments

Christoph Hellwig Nov. 5, 2024, 10:03 a.m. UTC | #1

On Mon, Nov 04, 2024 at 07:35:53PM +0530, Anuj Gupta wrote:
> From: Christoph Hellwig <[e-mail]>
> 
> Copy back the bounce buffer to user-space in entirety when the parent
> bio completes. The existing code uses bip_iter.bi_size for sizing the
> copy, which can be modified. So move away from that and fetch it from
> the vector passed to the block layer. While at it, switch to using
> better variable names.
> 
> Fixes: 492c5d455969f ("block: bio-integrity: directly map user buffers")
> Signed-off-by: Anuj Gupta <[e-mail]>
> [hch: better names for variables]
> Signed-off-by: Christoph Hellwig <[e-mail]>

This shouldn't really have a from for me as it wasn't my patch
originally.  But if you insist to re-attribute it, my signoff should
be the first as signoffs are supposed to be a chain starting from
the original author to the submitter.

Anuj gupta Nov. 5, 2024, 1:15 p.m. UTC | #2

> This shouldn't really have a from for me as it wasn't my patch
> originally.  But if you insist to re-attribute it, my signoff should
> be the first as signoffs are supposed to be a chain starting from
> the original author to the submitter.
>
Will change the sign-off order if I have to iterate.

Patch

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index a448a25d13de..4341b0d4efa1 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -118,17 +118,18 @@  static void bio_integrity_unpin_bvec(struct bio_vec *bv, int nr_vecs,
 
 static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
 {
-	unsigned short nr_vecs = bip->bip_max_vcnt - 1;
-	struct bio_vec *copy = &bip->bip_vec[1];
-	size_t bytes = bip->bip_iter.bi_size;
-	struct iov_iter iter;
+	unsigned short orig_nr_vecs = bip->bip_max_vcnt - 1;
+	struct bio_vec *orig_bvecs = &bip->bip_vec[1];
+	struct bio_vec *bounce_bvec = &bip->bip_vec[0];
+	size_t bytes = bounce_bvec->bv_len;
+	struct iov_iter orig_iter;
 	int ret;
 
-	iov_iter_bvec(&iter, ITER_DEST, copy, nr_vecs, bytes);
-	ret = copy_to_iter(bvec_virt(bip->bip_vec), bytes, &iter);
+	iov_iter_bvec(&orig_iter, ITER_DEST, orig_bvecs, orig_nr_vecs, bytes);
+	ret = copy_to_iter(bvec_virt(bounce_bvec), bytes, &orig_iter);
 	WARN_ON_ONCE(ret != bytes);
 
-	bio_integrity_unpin_bvec(copy, nr_vecs, true);
+	bio_integrity_unpin_bvec(orig_bvecs, orig_nr_vecs, true);
 }
 
 /**