From: Dongli Zhang <dongli.zhang@oracle.com>
To: xen-devel@lists.xenproject.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: konrad.wilk@oracle.com, roger.pau@citrix.com, axboe@kernel.dk,
royger@freebsd.org, Paul.Durrant@citrix.com
Subject: [PATCH v6 1/2] xen/blkback: add stack variable 'blkif' in connect_ring()
Date: Tue, 15 Jan 2019 00:41:43 +0800 [thread overview]
Message-ID: <1547484104-20625-1-git-send-email-dongli.zhang@oracle.com> (raw)
As 'be->blkif' is used for many times in connect_ring(), the stack variable
'blkif' is added to substitute 'be-blkif'.
Suggested-by: Paul Durrant <paul.durrant@citrix.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
---
drivers/block/xen-blkback/xenbus.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index a4bc74e..a4aadac 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -1023,6 +1023,7 @@ static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
static int connect_ring(struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
+ struct xen_blkif *blkif = be->blkif;
unsigned int pers_grants;
char protocol[64] = "";
int err, i;
@@ -1033,25 +1034,25 @@ static int connect_ring(struct backend_info *be)
pr_debug("%s %s\n", __func__, dev->otherend);
- be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
+ blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
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;
+ blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
+ blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
- be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
+ blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
else {
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
return -ENOSYS;
}
pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
0);
- be->blkif->vbd.feature_gnt_persistent = pers_grants;
- be->blkif->vbd.overflow_max_grants = 0;
+ blkif->vbd.feature_gnt_persistent = pers_grants;
+ blkif->vbd.overflow_max_grants = 0;
/*
* Read the number of hardware queues from frontend.
@@ -1067,16 +1068,16 @@ static int connect_ring(struct backend_info *be)
requested_num_queues, xenblk_max_queues);
return -ENOSYS;
}
- be->blkif->nr_rings = requested_num_queues;
- if (xen_blkif_alloc_rings(be->blkif))
+ blkif->nr_rings = requested_num_queues;
+ if (xen_blkif_alloc_rings(blkif))
return -ENOMEM;
pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
- be->blkif->nr_rings, be->blkif->blk_protocol, protocol,
+ blkif->nr_rings, blkif->blk_protocol, protocol,
pers_grants ? "persistent grants" : "");
- if (be->blkif->nr_rings == 1)
- return read_per_ring_refs(&be->blkif->rings[0], dev->otherend);
+ if (blkif->nr_rings == 1)
+ return read_per_ring_refs(&blkif->rings[0], dev->otherend);
else {
xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
xspath = kmalloc(xspathsize, GFP_KERNEL);
@@ -1085,10 +1086,10 @@ static int connect_ring(struct backend_info *be)
return -ENOMEM;
}
- for (i = 0; i < be->blkif->nr_rings; i++) {
+ for (i = 0; i < blkif->nr_rings; i++) {
memset(xspath, 0, xspathsize);
snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i);
- err = read_per_ring_refs(&be->blkif->rings[i], xspath);
+ err = read_per_ring_refs(&blkif->rings[i], xspath);
if (err) {
kfree(xspath);
return err;
--
2.7.4
next reply other threads:[~2019-01-14 16:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-14 16:41 Dongli Zhang [this message]
2019-01-14 16:41 ` [PATCH v6 2/2] xen/blkback: rework connect_ring() to avoid inconsistent xenstore 'ring-page-order' set by malicious blkfront Dongli Zhang
2019-01-15 8:20 ` [Xen-devel] " Roger Pau Monné
2019-01-17 15:29 ` Konrad Rzeszutek Wilk
2019-02-18 8:04 ` Dongli Zhang
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