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From: "K. Y. Srinivasan" <kys@microsoft.com>
To: gregkh@suse.de, linux-kernel@vger.kernel.org,
	devel@linuxdriverproject.org, virtualization@lists.osdl.org,
	ohering@suse.com, jbottomley@parallels.com, hch@infradead.org,
	linux-scsi@vger.kernel.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Subject: [PATCH 07/15] Staging: hv: storvsc: Add a comment to explain life-cycle management
Date: Thu, 12 Jan 2012 12:38:00 -0800	[thread overview]
Message-ID: <1326400688-13544-7-git-send-email-kys@microsoft.com> (raw)
In-Reply-To: <1326400688-13544-1-git-send-email-kys@microsoft.com>

Add a comment to explain life-cycle management and fix format issue.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/staging/hv/storvsc_drv.c |   17 ++++++++++++++++-
 1 files changed, 16 insertions(+), 1 deletions(-)

diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
index e0e471c..204b3ca 100644
--- a/drivers/staging/hv/storvsc_drv.c
+++ b/drivers/staging/hv/storvsc_drv.c
@@ -375,6 +375,21 @@ done:
 	kfree(wrk);
 }
 
+/*
+ * We can get incoming messages from the host that are not in response to
+ * messages that we have sent out. An example of this would be messages
+ * received by the guest to notify dynamic addition/removal of LUNs. To
+ * deal with potential race conditions where the driver may be in the
+ * midst of being unloaded when we might receive an unsolicited message
+ * from the host, we have implemented a mechanism to gurantee sequential
+ * consistency:
+ *
+ * 1) Once the device is marked as being destroyed, we will fail all
+ *    outgoing messages.
+ * 2) We permit incoming messages when the device is being destroyed,
+ *    only to properly account for messages already sent out.
+ */
+
 static inline struct storvsc_device *get_out_stor_device(
 					struct hv_device *device)
 {
@@ -569,7 +584,7 @@ static void storvsc_on_io_completion(struct hv_device *device,
 	 */
 
 	if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) ||
-		(stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
+	   (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) {
 		vstor_packet->vm_srb.scsi_status = 0;
 		vstor_packet->vm_srb.srb_status = SRB_STATUS_SUCCESS;
 	}
-- 
1.7.4.1

  parent reply	other threads:[~2012-01-12 20:38 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-12 20:37 [PATCH 0000/0015] Staging: hv: storvsc cleanup K. Y. Srinivasan
2012-01-12 20:37 ` [PATCH 01/15] Staging: hv: storvsc: Cleanup some comments K. Y. Srinivasan
2012-01-12 20:37   ` [PATCH 02/15] Staging: hv: storvsc: Cleanup storvsc_probe() K. Y. Srinivasan
2012-01-12 20:37   ` [PATCH 03/15] Staging: hv: storvsc: Cleanup storvsc_queuecommand() K. Y. Srinivasan
2012-01-12 20:37   ` [PATCH 04/15] Staging: hv: storvsc: Introduce defines for srb status codes K. Y. Srinivasan
2012-01-12 20:37   ` [PATCH 05/15] Staging:hv: storvsc: Cleanup storvsc_host_reset_handler() K. Y. Srinivasan
2012-01-12 20:37   ` [PATCH 06/15] Staging: hv: storvsc: Move and cleanup storvsc_remove() K. Y. Srinivasan
2012-01-12 20:38   ` K. Y. Srinivasan [this message]
2012-01-12 20:38   ` [PATCH 08/15] Staging: hv: storvsc: Get rid of the on_io_completion in hv_storvsc_request K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 09/15] Staging: hv: storvsc: Rename the context field " K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 10/15] Staging: hv: storvsc: Miscellaneous cleanup of storvsc driver K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 11/15] Staging: hv: storvsc: Cleanup the code for generating protocol version K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 12/15] Staging: hv: storvsc: Cleanup some protocol related constants K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 13/15] Staging: hv: storvsc: Get rid of some unused defines K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 14/15] Staging: hv: storvsc: Consolidate the request structure K. Y. Srinivasan
2012-01-12 20:38   ` [PATCH 15/15] Staging: hv: storvsc: Consolidate all the wire protocol definitions K. Y. Srinivasan

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