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From: Paul Durrant <pdurrant@amazon.com>
To: <linux-kernel@vger.kernel.org>, <xen-devel@lists.xenproject.org>
Cc: Juergen Gross <jgross@suse.com>,
	Paul Durrant <pdurrant@amazon.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: [Xen-devel] [PATCH 3/4] xen/interface: don't discard pending work in FRONT/BACK_RING_ATTACH
Date: Thu, 5 Dec 2019 14:01:22 +0000	[thread overview]
Message-ID: <20191205140123.3817-4-pdurrant@amazon.com> (raw)
In-Reply-To: <20191205140123.3817-1-pdurrant@amazon.com>

Currently these macros will skip over any requests/responses that are
added to the shared ring whilst it is detached. This, in general, is not
a desirable semantic since most frontend implementations will eventually
block waiting for a response which would either never appear or never be
processed.

NOTE: These macros are currently unused. BACK_RING_ATTACH(), however, will
      be used in a subsequent patch.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
---
 include/xen/interface/io/ring.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
index 3f40501fc60b..405adfed87e6 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h
@@ -143,14 +143,14 @@ struct __name##_back_ring {						\
 #define FRONT_RING_ATTACH(_r, _s, __size) do {				\
     (_r)->sring = (_s);							\
     (_r)->req_prod_pvt = (_s)->req_prod;				\
-    (_r)->rsp_cons = (_s)->rsp_prod;					\
+    (_r)->rsp_cons = (_s)->req_prod;					\
     (_r)->nr_ents = __RING_SIZE(_s, __size);				\
 } while (0)
 
 #define BACK_RING_ATTACH(_r, _s, __size) do {				\
     (_r)->sring = (_s);							\
     (_r)->rsp_prod_pvt = (_s)->rsp_prod;				\
-    (_r)->req_cons = (_s)->req_prod;					\
+    (_r)->req_cons = (_s)->rsp_prod;					\
     (_r)->nr_ents = __RING_SIZE(_s, __size);				\
 } while (0)
 
-- 
2.20.1


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WARNING: multiple messages have this Message-ID (diff)
From: Paul Durrant <pdurrant@amazon.com>
To: <linux-kernel@vger.kernel.org>, <xen-devel@lists.xenproject.org>
Cc: Paul Durrant <pdurrant@amazon.com>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	"Stefano Stabellini" <sstabellini@kernel.org>
Subject: [PATCH 3/4] xen/interface: don't discard pending work in FRONT/BACK_RING_ATTACH
Date: Thu, 5 Dec 2019 14:01:22 +0000	[thread overview]
Message-ID: <20191205140123.3817-4-pdurrant@amazon.com> (raw)
In-Reply-To: <20191205140123.3817-1-pdurrant@amazon.com>

Currently these macros will skip over any requests/responses that are
added to the shared ring whilst it is detached. This, in general, is not
a desirable semantic since most frontend implementations will eventually
block waiting for a response which would either never appear or never be
processed.

NOTE: These macros are currently unused. BACK_RING_ATTACH(), however, will
      be used in a subsequent patch.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
---
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
---
 include/xen/interface/io/ring.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/xen/interface/io/ring.h b/include/xen/interface/io/ring.h
index 3f40501fc60b..405adfed87e6 100644
--- a/include/xen/interface/io/ring.h
+++ b/include/xen/interface/io/ring.h
@@ -143,14 +143,14 @@ struct __name##_back_ring {						\
 #define FRONT_RING_ATTACH(_r, _s, __size) do {				\
     (_r)->sring = (_s);							\
     (_r)->req_prod_pvt = (_s)->req_prod;				\
-    (_r)->rsp_cons = (_s)->rsp_prod;					\
+    (_r)->rsp_cons = (_s)->req_prod;					\
     (_r)->nr_ents = __RING_SIZE(_s, __size);				\
 } while (0)
 
 #define BACK_RING_ATTACH(_r, _s, __size) do {				\
     (_r)->sring = (_s);							\
     (_r)->rsp_prod_pvt = (_s)->rsp_prod;				\
-    (_r)->req_cons = (_s)->req_prod;					\
+    (_r)->req_cons = (_s)->rsp_prod;					\
     (_r)->nr_ents = __RING_SIZE(_s, __size);				\
 } while (0)
 
-- 
2.20.1


  parent reply	other threads:[~2019-12-05 14:02 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-05 14:01 [Xen-devel] [PATCH 0/4] xen-blkback: support live update Paul Durrant
2019-12-05 14:01 ` Paul Durrant
2019-12-05 14:01 ` [Xen-devel] [PATCH 1/4] xenbus: move xenbus_dev_shutdown() into frontend code Paul Durrant
2019-12-05 14:01   ` Paul Durrant
2019-12-09 11:33   ` [Xen-devel] " Jürgen Groß
2019-12-09 11:33     ` Jürgen Groß
2019-12-09 11:55     ` [Xen-devel] " Durrant, Paul
2019-12-09 11:55       ` Durrant, Paul
2019-12-09 11:57       ` [Xen-devel] " Jürgen Groß
2019-12-09 11:57         ` Jürgen Groß
2019-12-05 14:01 ` [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to closed Paul Durrant
2019-12-05 14:01   ` Paul Durrant
2019-12-09 11:39   ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:39     ` Roger Pau Monné
2019-12-09 11:55     ` Jürgen Groß
2019-12-09 11:55       ` Jürgen Groß
2019-12-09 12:03       ` Durrant, Paul
2019-12-09 12:03         ` Durrant, Paul
2019-12-09 12:08         ` Jürgen Groß
2019-12-09 12:08           ` Jürgen Groß
2019-12-09 12:19           ` Durrant, Paul
2019-12-09 12:19             ` Durrant, Paul
2019-12-09 13:38             ` Jürgen Groß
2019-12-09 13:38               ` Jürgen Groß
2019-12-09 14:06               ` Durrant, Paul
2019-12-09 14:06                 ` Durrant, Paul
2019-12-09 14:09                 ` Jürgen Groß
2019-12-09 14:09                   ` Jürgen Groß
2019-12-09 14:23                   ` Durrant, Paul
2019-12-09 14:23                     ` Durrant, Paul
2019-12-09 14:41                     ` Jürgen Groß
2019-12-09 14:41                       ` Jürgen Groß
2019-12-09 14:43                       ` Durrant, Paul
2019-12-09 14:43                         ` Durrant, Paul
2019-12-09 12:01     ` Durrant, Paul
2019-12-09 12:01       ` Durrant, Paul
2019-12-09 12:25       ` Roger Pau Monné
2019-12-09 12:25         ` Roger Pau Monné
2019-12-09 12:40         ` Durrant, Paul
2019-12-09 12:40           ` Durrant, Paul
2019-12-09 14:28           ` Roger Pau Monné
2019-12-09 14:28             ` Roger Pau Monné
2019-12-09 14:41             ` Durrant, Paul
2019-12-09 14:41               ` Durrant, Paul
2019-12-09 15:13               ` Roger Pau Monné
2019-12-09 15:13                 ` Roger Pau Monné
2019-12-09 16:26                 ` Durrant, Paul
2019-12-09 16:26                   ` Durrant, Paul
2019-12-09 17:17                   ` Roger Pau Monné
2019-12-09 17:17                     ` Roger Pau Monné
2019-12-09 17:23                     ` Durrant, Paul
2019-12-09 17:23                       ` Durrant, Paul
2019-12-05 14:01 ` Paul Durrant [this message]
2019-12-05 14:01   ` [PATCH 3/4] xen/interface: don't discard pending work in FRONT/BACK_RING_ATTACH Paul Durrant
2019-12-09 11:41   ` [Xen-devel] " Roger Pau Monné
2019-12-09 11:41     ` Roger Pau Monné
2019-12-09 11:52     ` Jürgen Groß
2019-12-09 11:52       ` Jürgen Groß
2019-12-09 12:50       ` Durrant, Paul
2019-12-09 12:50         ` Durrant, Paul
2019-12-09 13:55   ` Jürgen Groß
2019-12-09 13:55     ` Jürgen Groß
2019-12-09 16:38     ` [Xen-devel] " Durrant, Paul
2019-12-09 16:38       ` Durrant, Paul
2019-12-10 11:42       ` [Xen-devel] " Jürgen Groß
2019-12-10 11:42         ` Jürgen Groß
2019-12-05 14:01 ` [Xen-devel] [PATCH 4/4] xen-blkback: support dynamic unbind/bind Paul Durrant
2019-12-05 14:01   ` Paul Durrant
2019-12-09 12:17   ` [Xen-devel] " Roger Pau Monné
2019-12-09 12:17     ` Roger Pau Monné
2019-12-09 12:24     ` [Xen-devel] " Durrant, Paul
2019-12-09 12:24       ` Durrant, Paul
2019-12-09 13:57   ` [Xen-devel] " Jürgen Groß
2019-12-09 13:57     ` Jürgen Groß
2019-12-09 14:01     ` [Xen-devel] " Durrant, Paul
2019-12-09 14:01       ` Durrant, Paul

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