]> git.itanic.dy.fi Git - linux-stable/commitdiff
xen-blkfront: Apply 'feature_persistent' parameter when connect
authorSeongJae Park <sj@kernel.org>
Fri, 15 Jul 2022 22:51:08 +0000 (22:51 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 21 Aug 2022 13:16:22 +0000 (15:16 +0200)
commit 402c43ea6b34a1b371ffeed9adf907402569eaf5 upstream.

In some use cases[1], the backend is created while the frontend doesn't
support the persistent grants feature, but later the frontend can be
changed to support the feature and reconnect.  In the past, 'blkback'
enabled the persistent grants feature since it unconditionally checked
if frontend supports the persistent grants feature for every connect
('connect_ring()') and decided whether it should use persistent grans or
not.

However, commit aac8a70db24b ("xen-blkback: add a parameter for
disabling of persistent grants") has mistakenly changed the behavior.
It made the frontend feature support check to not be repeated once it
shown the 'feature_persistent' as 'false', or the frontend doesn't
support persistent grants.

Similar behavioral change has made on 'blkfront' by commit 74a852479c68
("xen-blkfront: add a parameter for disabling of persistent grants").
This commit changes the behavior of the parameter to make effect for
every connect, so that the previous behavior of 'blkfront' can be
restored.

[1] https://lore.kernel.org/xen-devel/CAJwUmVB6H3iTs-C+U=v-pwJB7-_ZRHPxHzKRJZ22xEPW7z8a=g@mail.gmail.com/

Fixes: 74a852479c68 ("xen-blkfront: add a parameter for disabling of persistent grants")
Cc: <stable@vger.kernel.org> # 5.10.x
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Maximilian Heyne <mheyne@amazon.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220715225108.193398-4-sj@kernel.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/ABI/testing/sysfs-driver-xen-blkfront
drivers/block/xen-blkfront.c

index 28008905615f052f047c91d4c9190893334724e5..1f7659aa085c26a40a01a443295f2f2137bd890a 100644 (file)
@@ -15,5 +15,5 @@ KernelVersion:  5.10
 Contact:        SeongJae Park <sjpark@amazon.de>
 Description:
                 Whether to enable the persistent grants feature or not.  Note
-                that this option only takes effect on newly created frontends.
+                that this option only takes effect on newly connected frontends.
                 The default is Y (enable).
index abbb68b6d9bd53b5428c9ba3f4ee5173f576739e..03e079a6f0721fe1bd3af67b0e3be63d868f803e 100644 (file)
@@ -2088,8 +2088,6 @@ static int blkfront_probe(struct xenbus_device *dev,
        info->vdevice = vdevice;
        info->connected = BLKIF_STATE_DISCONNECTED;
 
-       info->feature_persistent = feature_persistent;
-
        /* Front end dir is a number, which is used as the id. */
        info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
        dev_set_drvdata(&dev->dev, info);
@@ -2393,7 +2391,7 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
        if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0))
                blkfront_setup_discard(info);
 
-       if (info->feature_persistent)
+       if (feature_persistent)
                info->feature_persistent =
                        !!xenbus_read_unsigned(info->xbdev->otherend,
                                               "feature-persistent", 0);