[Devel] [PATCH RHEL10 COMMIT] drivers/vhost/blk: fix sector alignment calculation

[Konstantin Khorenko <khorenko@virtuozzo.com>]

The commit is pushed to "branch-rh10-6.12.0-211.39.1.16.x.vz10-ovz" and will appear at git at bitbucket.org:openvz/vzkernel.git
after rh10-6.12.0-211.39.1.16.9.vz10
------>
commit 0aeb1139bbf38fa05d4b1f48df906c502f99c121
Author: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
Date:   Tue Aug 25 15:51:51 2026 +0300

    drivers/vhost/blk: fix sector alignment calculation
    
    SECTOR_MASK is actually a number 7, not some bitmask. Hence
    the code actually checked 8 byte alignment.
    Use IS_ALIGNED to correctly check sector alignment.
    
    https://virtuozzo.atlassian.net/browse/VSTOR-138640
    Fixes: a0d3b8956fb0 ("vhost-blk: rework iov and bio handling")
    Fixes: ca8ed3fe5da5 ("vhost-blk: add bounce-buffer for non-aligned requests")
    Feature: vhost-blk: in-kernel accelerator for virtio-blk guests
    Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko@virtuozzo.com>
    Reviewed-by: Vasileios Almpanis <vasileios.almpanis@virtuozzo.com>
    Reviewed-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 drivers/vhost/blk.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/blk.c b/drivers/vhost/blk.c
index 5c8d5b210c315..b2cf111bbb455 100644
--- a/drivers/vhost/blk.c
+++ b/drivers/vhost/blk.c
@@ -209,13 +209,13 @@ inline static bool vhost_blk_iov_need_bb(struct vhost_blk_req *req)
 {
 	int i;
 
-	if (req->len & SECTOR_MASK)
+	if (!IS_ALIGNED(req->len, SECTOR_SIZE))
 		return true;
 
 	for (i = 0; i < req->iov_nr; i++) {
-		if (((size_t)req->iov[i].iov_base) & SECTOR_MASK)
+		if (!IS_ALIGNED((size_t)req->iov[i].iov_base, SECTOR_SIZE))
 			return true;
-		if (req->iov[i].iov_len & SECTOR_MASK)
+		if (!IS_ALIGNED(req->iov[i].iov_len, SECTOR_SIZE))
 			return true;
 	}
 
@@ -277,7 +277,7 @@ static int vhost_blk_bio_make(struct vhost_blk_req *req,
 	if (unlikely(req->bi_opf & REQ_PREFLUSH))
 		return vhost_blk_bio_make_simple(req, bdev);
 
-	if (req->bi_opf == REQ_OP_WRITE && req->len & SECTOR_MASK) {
+	if (req->bi_opf == REQ_OP_WRITE && !IS_ALIGNED(req->len, SECTOR_SIZE)) {
 		WARN_ONCE(1, "vhost-blk: write requests with unaligned len"
 			  " are not supported, len = %zu", req->len);
 		return -EINVAL;
@@ -339,7 +339,7 @@ static int vhost_blk_bio_make(struct vhost_blk_req *req,
 	nr_pages = bio_iov_vecs_to_alloc(&iter, BIO_MAX_VECS);
 	do {
 		/* We can't handle next bio if it's start is not sector aligned */
-		if (pos & SECTOR_MASK) {
+		if (!IS_ALIGNED(pos, SECTOR_SIZE)) {
 			WARN_ONCE(1, "vhost-blk: guest provided unaligned buffers");
 			ret = -EINVAL;
 			goto err_bio;