Commit c829c394 authored by James Smart's avatar James Smart Committed by James Bottomley

[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: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent ce313db2
......@@ -29,6 +29,7 @@
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_request.h>
......@@ -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;
......
......@@ -31,6 +31,7 @@
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_fc.h>
#include <scsi/scsi_cmnd.h>
#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;
/*
......
......@@ -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
......
......@@ -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) \
......
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