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authorSteffen Maier <maier@linux.ibm.com>2018-05-17 19:14:55 +0200
committerMartin K. Petersen <martin.petersen@oracle.com>2018-05-18 11:22:11 -0400
commit42afc6527d43fdb8c74a170de9735b07019b104c (patch)
treebb0838c7d2838fc31dae0bfd8a7e9d14eec8bfaf /drivers/s390/scsi
parent26f5fa9d47c12661f282f8009c4a64e449dd36c5 (diff)
scsi: zfcp: decouple TMFs from scsi_cmnd by using fc_block_rport
Intentionally retrieve the rport by walking SCSI common code objects rather than zfcp_sdev->port->rport. The latter is used for pairing the calls to fc_remote_port_add() and fc_remote_port_delete(). [see v2.6.31 commit 379d6bf6573e ("[SCSI] zfcp: Add port only once to FC transport class")] zfcp_scsi_rport_register() sets zfcp_port.rport to what fc_remote_port_add() returned. zfcp_scsi_rport_block() sets zfcp_port.rport = NULL after having called fc_remote_port_delete(). Hence, while an rport is blocked (or in any subsequent state due to scsi_transport_fc timeouts such as fast_io_fail_tmo or dev_loss_tmo), zfcp_port.rport is NULL and cannot serve as argument to fc_block_rport(). During zfcp recovery, a just recovered zfcp_port can have the UNBLOCKED status flag, but an async rport unblocking has only started via zfcp_scsi_schedule_rport_register() in zfcp_erp_try_rport_unblock() [see v4.10 commit 6f2ce1c6af37 ("scsi: zfcp: fix rport unblock race with LUN recovery")] in zfcp_erp_action_cleanup(). Now zfcp_erp_wait() can return. This would be sufficient to successfully send a TMF. But the rport can still be blocked and zfcp_port.rport can still be NULL until zfcp_port.rport_work was scheduled and has actually called fc_remote_port_add() and assigned its return value to zfcp_port.rport. We need an unblocked rport for a successful scsi_eh TUR. Similarly, for a zfcp_port which has just lost its UNBLOCKED status flag, the return of zfcp_erp_wait() can race with zfcp_port.rport_work queued by zfcp_scsi_schedule_rport_block(). Therefore we cannot reliably access zfcp_port.rport. However, we'd like to get fc_rport_block()'s opinion on when fast_io_fail_tmo triggered. While we might use flush_work(&port->rport_work) to sync with the work item, we can simply use the other way to get an rport pointer. Signed-off-by: Steffen Maier <maier@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/s390/scsi')
-rw-r--r--drivers/s390/scsi/zfcp_scsi.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c
index e77e43a0630a..e0c5735cf3db 100644
--- a/drivers/s390/scsi/zfcp_scsi.c
+++ b/drivers/s390/scsi/zfcp_scsi.c
@@ -270,6 +270,7 @@ static int zfcp_task_mgmt_function(struct scsi_cmnd *scpnt, u8 tm_flags)
struct scsi_device *sdev = scpnt->device;
struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev);
struct zfcp_adapter *adapter = zfcp_sdev->port->adapter;
+ struct fc_rport *rport = starget_to_rport(scsi_target(sdev));
struct zfcp_fsf_req *fsf_req = NULL;
int retval = SUCCESS, ret;
int retry = 3;
@@ -281,7 +282,7 @@ static int zfcp_task_mgmt_function(struct scsi_cmnd *scpnt, u8 tm_flags)
zfcp_dbf_scsi_devreset("wait", sdev, tm_flags, NULL);
zfcp_erp_wait(adapter);
- ret = fc_block_scsi_eh(scpnt);
+ ret = fc_block_rport(rport);
if (ret) {
zfcp_dbf_scsi_devreset("fiof", sdev, tm_flags, NULL);
return ret;