From 54b2b50c20a61b51199bedb6e5d2f8ec2568fb43 Mon Sep 17 00:00:00 2001
From: "Martin K. Petersen" <martin.petersen@oracle.com>
Date: Wed, 23 Oct 2013 06:25:40 -0400
Subject: [SCSI] Disable WRITE SAME for RAID and virtual host adapter drivers
Some host adapters do not pass commands through to the target disk
directly. Instead they provide an emulated target which may or may not
accurately report its capabilities. In some cases the physical device
characteristics are reported even when the host adapter is processing
commands on the device's behalf. This can lead to adapter firmware hangs
or excessive I/O errors.
This patch disables WRITE SAME for devices connected to host adapters
that provide an emulated target. Driver writers can disable WRITE SAME
by setting the no_write_same flag in the host adapter template.
[jejb: fix up rejections due to eh_deadline patch]
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: stable@kernel.org
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
---
drivers/scsi/megaraid/megaraid_sas_base.c | 1 +
1 file changed, 1 insertion(+)
(limited to 'drivers/scsi/megaraid/megaraid_sas_base.c')
diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 0a743a5d164..c99812bf2a7 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -2148,6 +2148,7 @@ static struct scsi_host_template megasas_template = {
.bios_param = megasas_bios_param,
.use_clustering = ENABLE_CLUSTERING,
.change_queue_depth = megasas_change_queue_depth,
+ .no_write_same = 1,
};
/**
--
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