From: Christof Schmitt Date: Tue, 24 Nov 2009 15:54:07 +0000 (+0100) Subject: [SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8830271c4819d86d8e87202a1fe8da0bb58912a2;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git [SCSI] zfcp: Dont fail SCSI commands when transitioning to blocked fc_rport If an error occurs that triggers the call to fc_remote_port_delete, ideally this call would happen before any I/O is passed back to the SCSI midlayer through scsi_done. The SCSI midlayer will retry the commands and fc_remote_port_chkready will return the correct status code. But with the delay between calling scsi_done in softirq context and the call to fc_remote_port_delete from the workqueue, there is a window where zfcp returns DID_ERROR. This leads to SCSI error recovery which then leads to offline SCSI devices since all recovery actions will fail with the rport now being blocked. In this window, zfcp has to return DID_IMM_RETRY just as the FC transport class would do in fc_remote_port_chkready for the blocked fc_rport. As soon as the fc_rport is BLOCKED, fc_remote_port_chkready will do the right thing. Additionally, there are two more cases to catch in zfcp_scsi_queuecommand: - After the port has been opened, the unit has to be opened. During this period I/O has to be retried. This can also be handled with DID_IMM_RETRY. - If the access to the unit fails, but the port is good, then this single unit cannot be accessed and I/O to this unit has to fail without involving the FC transport class. Reviewed-by: Swen Schillig Signed-off-by: Christof Schmitt Signed-off-by: James Bottomley --- diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c index 39a621d729e9..0ecec9c1b490 100644 --- a/drivers/s390/scsi/zfcp_scsi.c +++ b/drivers/s390/scsi/zfcp_scsi.c @@ -112,12 +112,26 @@ static int zfcp_scsi_queuecommand(struct scsi_cmnd *scpnt, } status = atomic_read(&unit->status); - if (unlikely((status & ZFCP_STATUS_COMMON_ERP_FAILED) || - !(status & ZFCP_STATUS_COMMON_RUNNING))) { + if (unlikely(status & ZFCP_STATUS_COMMON_ERP_FAILED) && + !(atomic_read(&unit->port->status) & + ZFCP_STATUS_COMMON_ERP_FAILED)) { + /* only unit access denied, but port is good + * not covered by FC transport, have to fail here */ zfcp_scsi_command_fail(scpnt, DID_ERROR); return 0; } + if (unlikely(!(status & ZFCP_STATUS_COMMON_UNBLOCKED))) { + /* This could be either + * open unit pending: this is temporary, will result in + * open unit or ERP_FAILED, so retry command + * call to rport_delete pending: mimic retry from + * fc_remote_port_chkready until rport is BLOCKED + */ + zfcp_scsi_command_fail(scpnt, DID_IMM_RETRY); + return 0; + } + ret = zfcp_fsf_send_fcp_command_task(unit, scpnt); if (unlikely(ret == -EBUSY)) return SCSI_MLQUEUE_DEVICE_BUSY;