From c829c394165f981d49f05a9be228404d7a9398d4 Mon Sep 17 00:00:00 2001 From: James Smart Date: Mon, 13 Mar 2006 08:28:57 -0500 Subject: [SCSI] FC transport : Avoid device offline cases by stalling aborts until device unblocked This moves the eh_timed_out functionality from the scsi_host_template to the transport_template. Given that this is now a transport function, the EH_RESET_TIMER case no longer caps the timer reschedulings. The transport guarantees that this is not an infinite condition. Signed-off-by: James Bottomley --- drivers/scsi/scsi_error.c | 9 +++------ drivers/scsi/scsi_transport_fc.c | 37 +++++++++++++++++++++++++++++++++++++ include/scsi/scsi_host.h | 14 -------------- include/scsi/scsi_transport.h | 11 +++++++++++ 4 files changed, 51 insertions(+), 20 deletions(-) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 5cc97b72166..9cf02062213 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -163,16 +164,12 @@ void scsi_times_out(struct scsi_cmnd *scmd) { scsi_log_completion(scmd, TIMEOUT_ERROR); - if (scmd->device->host->hostt->eh_timed_out) - switch (scmd->device->host->hostt->eh_timed_out(scmd)) { + if (scmd->device->host->transportt->eh_timed_out) + switch (scmd->device->host->transportt->eh_timed_out(scmd)) { case EH_HANDLED: __scsi_done(scmd); return; case EH_RESET_TIMER: - /* This allows a single retry even of a command - * with allowed == 0 */ - if (scmd->retries++ > scmd->allowed) - break; scsi_add_timer(scmd, scmd->timeout_per_command, scsi_times_out); return; diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 56012b2694d..3c3baa9f5f2 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "scsi_priv.h" /* @@ -1090,6 +1091,40 @@ static int fc_rport_match(struct attribute_container *cont, } +/** + * fc_timed_out - FC Transport I/O timeout intercept handler + * + * @scmd: The SCSI command which timed out + * + * This routine protects against error handlers getting invoked while a + * rport is in a blocked state, typically due to a temporarily loss of + * connectivity. If the error handlers are allowed to proceed, requests + * to abort i/o, reset the target, etc will likely fail as there is no way + * to communicate with the device to perform the requested function. These + * failures may result in the midlayer taking the device offline, requiring + * manual intervention to restore operation. + * + * This routine, called whenever an i/o times out, validates the state of + * the underlying rport. If the rport is blocked, it returns + * EH_RESET_TIMER, which will continue to reschedule the timeout. + * Eventually, either the device will return, or devloss_tmo will fire, + * and when the timeout then fires, it will be handled normally. + * If the rport is not blocked, normal error handling continues. + * + * Notes: + * This routine assumes no locks are held on entry. + **/ +static enum scsi_eh_timer_return +fc_timed_out(struct scsi_cmnd *scmd) +{ + struct fc_rport *rport = starget_to_rport(scsi_target(scmd->device)); + + if (rport->port_state == FC_PORTSTATE_BLOCKED) + return EH_RESET_TIMER; + + return EH_NOT_HANDLED; +} + /* * Must be called with shost->host_lock held */ @@ -1146,6 +1181,8 @@ fc_attach_transport(struct fc_function_template *ft) /* Transport uses the shost workq for scsi scanning */ i->t.create_work_queue = 1; + i->t.eh_timed_out = fc_timed_out; + i->t.user_scan = fc_user_scan; /* diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 827992949c4..a6cf3e535c0 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -146,20 +146,6 @@ struct scsi_host_template { int (* eh_bus_reset_handler)(struct scsi_cmnd *); int (* eh_host_reset_handler)(struct scsi_cmnd *); - /* - * This is an optional routine to notify the host that the scsi - * timer just fired. The returns tell the timer routine what to - * do about this: - * - * EH_HANDLED: I fixed the error, please complete the command - * EH_RESET_TIMER: I need more time, reset the timer and - * begin counting again - * EH_NOT_HANDLED Begin normal error recovery - * - * Status: OPTIONAL - */ - enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); - /* * Before the mid layer attempts to scan for a new device where none * currently exists, it will call this entry in your driver. Should diff --git a/include/scsi/scsi_transport.h b/include/scsi/scsi_transport.h index e7b1054adf8..b3657f11193 100644 --- a/include/scsi/scsi_transport.h +++ b/include/scsi/scsi_transport.h @@ -48,6 +48,17 @@ struct scsi_transport_template { * True if the transport wants to use a host-based work-queue */ unsigned int create_work_queue : 1; + + /* + * This is an optional routine that allows the transport to become + * involved when a scsi io timer fires. The return value tells the + * timer routine how to finish the io timeout handling: + * EH_HANDLED: I fixed the error, please complete the command + * EH_RESET_TIMER: I need more time, reset the timer and + * begin counting again + * EH_NOT_HANDLED Begin normal error recovery + */ + enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *); }; #define transport_class_to_shost(tc) \ -- cgit v1.2.3-70-g09d2