dm-ebs: fix prefetch-vs-suspend race

JIRA: https://issues.redhat.com/browse/RHEL-92762
Upstream Status: kernel/git/torvalds/linux.git

commit 9c56542
Author: Mikulas Patocka <[email protected]>
Date:   Fri Mar 28 16:19:07 2025 +0100

    dm-ebs: fix prefetch-vs-suspend race

    There's a possible race condition in dm-ebs - dm bufio prefetch may be in
    progress while the device is suspended. Fix this by calling
    dm_bufio_client_reset in the postsuspend hook.

    Signed-off-by: Mikulas Patocka <[email protected]>
    Cc: [email protected]

Signed-off-by: Benjamin Marzinski <[email protected]>

Author: bmarzins

drivers/md/dm-ebs-target.c

@@ -390,6 +390,12 @@ static int ebs_map(struct dm_target *ti, struct bio *bio)
 	return DM_MAPIO_REMAPPED;
 }
 
+static void ebs_postsuspend(struct dm_target *ti)
+{
+	struct ebs_c *ec = ti->private;
+	dm_bufio_client_reset(ec->bufio);
+}
+
 static void ebs_status(struct dm_target *ti, status_type_t type,
 		       unsigned int status_flags, char *result, unsigned int maxlen)
 {
@@ -447,6 +453,7 @@ static struct target_type ebs_target = {
 	.ctr		 = ebs_ctr,
 	.dtr		 = ebs_dtr,
 	.map		 = ebs_map,
+	.postsuspend	 = ebs_postsuspend,
 	.status		 = ebs_status,
 	.io_hints	 = ebs_io_hints,
 	.prepare_ioctl	 = ebs_prepare_ioctl,