xen-blkback: prefer xenbus_scanf() over xenbus_gather() (6694389a) · Commits · 戴 / test

... 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@suse.com> Signed-off-by:

Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Acked-by:

Roger Pau Monné <roger.pau@citrix.com> Acked-by:

Jens Axboe <axboe@kernel.dk>

drivers/block/xen-blkback/xenbus.c

+6 −7

Original line number	Diff line number	Diff line
		@@ -1022,9 +1022,9 @@ static int connect_ring(struct backend_info *be)
		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_info *be)
		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;

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