Patch "scsi: cxlflash: Scan host only after the port is ready for I/O" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

scsi: cxlflash: Scan host only after the port is ready for I/O

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
scsi-cxlflash-scan-host-only-after-the-port-is-ready-for-i-o.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Uma Krishnan <[email protected]>
Date: Fri, 2 Sep 2016 15:38:48 -0500
Subject: scsi: cxlflash: Scan host only after the port is ready for I/O

From: Uma Krishnan <[email protected]>

commit bbbfae962b7c221237c0f92547ee0c83f7204747 upstream.

When a port link is established, the AFU sends a 'link up' interrupt. After the link is up, corresponding initialization steps are performed on the card. Following that, when the card is ready for I/O, the AFU sends 'login succeeded' interrupt. Today, cxlflash invokes scsi_scan_host() upon receipt of both interrupts.

SCSI commands sent to the port prior to the 'login succeeded' interrupt will fail with 'port not available' error. This is not desirable. Moreover, when async_scan is active for the host, subsequent scan calls are terminated with error. Due to this, the scsi_scan_host() call performed after 'login succeeded' interrupt could portentially return error and the devices may not be scanned properly.

To avoid this problem, scsi_scan_host() should be called only after the 'login succeeded' interrupt.

---
 drivers/scsi/cxlflash/main.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -1137,7 +1137,7 @@ static const struct asyc_intr_info ainfo
 	{SISL_ASTATUS_FC0_LOGI_F, "login failed", 0, CLR_FC_ERROR},
 	{SISL_ASTATUS_FC0_LOGI_S, "login succeeded", 0, SCAN_HOST},
 	{SISL_ASTATUS_FC0_LINK_DN, "link down", 0, 0},
-	{SISL_ASTATUS_FC0_LINK_UP, "link up", 0, SCAN_HOST},
+	{SISL_ASTATUS_FC0_LINK_UP, "link up", 0, 0},
 	{SISL_ASTATUS_FC1_OTHER, "other error", 1, CLR_FC_ERROR | LINK_RESET},
 	{SISL_ASTATUS_FC1_LOGO, "target initiated LOGO", 1, 0},
 	{SISL_ASTATUS_FC1_CRC_T, "CRC threshold exceeded", 1, LINK_RESET},

@@ -1145,7 +1145,7 @@ static const struct asyc_intr_info ainfo
 	{SISL_ASTATUS_FC1_LOGI_F, "login failed", 1, CLR_FC_ERROR},
 	{SISL_ASTATUS_FC1_LOGI_S, "login succeeded", 1, SCAN_HOST},
 	{SISL_ASTATUS_FC1_LINK_DN, "link down", 1, 0},
-	{SISL_ASTATUS_FC1_LINK_UP, "link up", 1, SCAN_HOST},
+	{SISL_ASTATUS_FC1_LINK_UP, "link up", 1, 0},
 	{0x0, "", 0, 0}		/* terminator */
 };
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/scsi-cxlflash-fix-to-avoid-eeh-and-host-reset-collisions.patch queue-4.4/scsi-cxlflash-scan-host-only-after-the-port-is-ready-for-i-o.patch queue-4.4/scsi-cxlflash-improve-eeh-recovery-time.patch