[PATCH 4.4 08/20] scsi: cxlflash: Scan host only after the port is ready for I/O

From: Greg Kroah-Hartman
Date: Fri May 05 2017 - 14:38:05 EST

4.4-stable review patch. If anyone has any objections, please let me know.


From: Uma Krishnan <ukrishn@xxxxxxxxxxxxxxxxxx>

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.

Signed-off-by: Uma Krishnan <ukrishn@xxxxxxxxxxxxxxxxxx>
Acked-by: Matthew R. Ochs <mrochs@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -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_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 */