[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1315593060-20031-3-git-send-email-konrad.wilk@oracle.com>
Date: Fri, 9 Sep 2011 14:31:00 -0400
From: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To: linux-kernel@...r.kernel.org
Cc: xen-devel@...ts.xensource.com, JBeulich@...ell.com,
jeremy.fitzhardinge@...rix.com, axboe@...nel.dk,
Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
stable@...nel.org
Subject: [PATCH 3/3] xen-blkfront: If no barrier or flush is supported, use invalid operation.
By default we would set the info->flush_op=0, and zero maps
to BLKIF_OP_READ request code. So if the backend did not support
either barrier ('feature-barrier') or flush ('feature-flush-cache')
we would end up using that opcode for the flush/barrier request, meaning
we actually do a READ request. Fortunatly for us, __generic_make_request
checks q->flush_flags and realizes that we don't do FLUSH and removes
the REQ_FLUSH | REQ_FUA so we never end up issuing a READ request
for a flush request. However, other third party implementations of
__make_request might not be so smart, so lets fix this up.
CC: stable@...nel.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
---
drivers/block/xen-blkfront.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index e205d91..c4aa9da 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -97,7 +97,7 @@ struct blkfront_info
struct blk_shadow shadow[BLK_RING_SIZE];
unsigned long shadow_free;
unsigned int feature_flush;
- unsigned int flush_op;
+ int flush_op;
unsigned int feature_discard;
unsigned int discard_granularity;
unsigned int discard_alignment;
@@ -774,7 +774,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
if (error == -EOPNOTSUPP)
error = 0;
info->feature_flush = 0;
- info->flush_op = 0;
+ info->flush_op = -1; /* 0 is BLKIF_OP_READ */
xlvbd_flush(info);
}
/* fall through */
@@ -1207,7 +1207,7 @@ static void blkfront_connect(struct blkfront_info *info)
}
info->feature_flush = 0;
- info->flush_op = 0;
+ info->flush_op = -1; /* 0 is BLKIF_OP_READ */
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"feature-barrier", "%d", &barrier,
@@ -1234,7 +1234,7 @@ static void blkfront_connect(struct blkfront_info *info)
if (!err && flush)
info->flush_op = BLKIF_OP_FLUSH_DISKCACHE;
- if (info->flush_op)
+ if (info->flush_op > 0)
info->feature_flush = REQ_FLUSH | REQ_FUA;
err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
--
1.7.4.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists