[Xen-devel] [PATCH] xen-blkback: prefer xenbus_scanf() over xenbus_gather()

["Jan Beulich" <JBeulich@xxxxxxxx>]

... for single items being collected: It is more typesafe (as the
compiler can check format string and to-be-written-to variable match)
and requires one less parameter to be passed.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 drivers/block/xen-blkback/xenbus.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

--- 4.7-rc6-prefer-xenbus_scanf.orig/drivers/block/xen-blkback/xenbus.c
+++ 4.7-rc6-prefer-xenbus_scanf/drivers/block/xen-blkback/xenbus.c
@@ -1022,9 +1022,9 @@ static int connect_ring(struct backend_i
        pr_debug("%s %s\n", __func__, dev->otherend);
 
        be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
-       err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
-                           "%63s", protocol, NULL);
-       if (err)
+       err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol",
+                          "%63s", protocol);
+       if (err <= 0)
                strcpy(protocol, "unspecified, assuming default");
        else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
                be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
@@ -1036,10 +1036,9 @@ static int connect_ring(struct backend_i
                xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
                return -ENOSYS;
        }
-       err = xenbus_gather(XBT_NIL, dev->otherend,
-                           "feature-persistent", "%u",
-                           &pers_grants, NULL);
-       if (err)
+       err = xenbus_scanf(XBT_NIL, dev->otherend,
+                          "feature-persistent", "%u", &pers_grants);
+       if (err <= 0)
                pers_grants = 0;
 
        be->blkif->vbd.feature_gnt_persistent = pers_grants;




_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel