[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 <James.Bottomley@SteelEye.com>
This commit is contained in:
James Smart
James Bottomley
parent
ce313db240
commit
c829c39416
4 changed files with 51 additions and 20 deletions
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@ -29,6 +29,7 @@
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#include <scsi/scsi_dbg.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_eh.h>
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#include <scsi/scsi_transport.h>
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#include <scsi/scsi_host.h>
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#include <scsi/scsi_ioctl.h>
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#include <scsi/scsi_request.h>
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@ -163,16 +164,12 @@ void scsi_times_out(struct scsi_cmnd *scmd)
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{
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scsi_log_completion(scmd, TIMEOUT_ERROR);
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if (scmd->device->host->hostt->eh_timed_out)
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switch (scmd->device->host->hostt->eh_timed_out(scmd)) {
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if (scmd->device->host->transportt->eh_timed_out)
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switch (scmd->device->host->transportt->eh_timed_out(scmd)) {
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case EH_HANDLED:
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__scsi_done(scmd);
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return;
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case EH_RESET_TIMER:
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/* This allows a single retry even of a command
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* with allowed == 0 */
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if (scmd->retries++ > scmd->allowed)
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break;
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scsi_add_timer(scmd, scmd->timeout_per_command,
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scsi_times_out);
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return;
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@ -31,6 +31,7 @@
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#include <scsi/scsi_host.h>
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#include <scsi/scsi_transport.h>
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#include <scsi/scsi_transport_fc.h>
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#include <scsi/scsi_cmnd.h>
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#include "scsi_priv.h"
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/*
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@ -1090,6 +1091,40 @@ static int fc_rport_match(struct attribute_container *cont,
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}
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/**
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* fc_timed_out - FC Transport I/O timeout intercept handler
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*
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* @scmd: The SCSI command which timed out
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*
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* This routine protects against error handlers getting invoked while a
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* rport is in a blocked state, typically due to a temporarily loss of
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* connectivity. If the error handlers are allowed to proceed, requests
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* to abort i/o, reset the target, etc will likely fail as there is no way
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* to communicate with the device to perform the requested function. These
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* failures may result in the midlayer taking the device offline, requiring
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* manual intervention to restore operation.
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*
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* This routine, called whenever an i/o times out, validates the state of
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* the underlying rport. If the rport is blocked, it returns
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* EH_RESET_TIMER, which will continue to reschedule the timeout.
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* Eventually, either the device will return, or devloss_tmo will fire,
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* and when the timeout then fires, it will be handled normally.
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* If the rport is not blocked, normal error handling continues.
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*
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* Notes:
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* This routine assumes no locks are held on entry.
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**/
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static enum scsi_eh_timer_return
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fc_timed_out(struct scsi_cmnd *scmd)
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{
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struct fc_rport *rport = starget_to_rport(scsi_target(scmd->device));
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if (rport->port_state == FC_PORTSTATE_BLOCKED)
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return EH_RESET_TIMER;
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return EH_NOT_HANDLED;
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}
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/*
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* Must be called with shost->host_lock held
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*/
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@ -1146,6 +1181,8 @@ fc_attach_transport(struct fc_function_template *ft)
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/* Transport uses the shost workq for scsi scanning */
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i->t.create_work_queue = 1;
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i->t.eh_timed_out = fc_timed_out;
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i->t.user_scan = fc_user_scan;
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/*
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@ -146,20 +146,6 @@ struct scsi_host_template {
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int (* eh_bus_reset_handler)(struct scsi_cmnd *);
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int (* eh_host_reset_handler)(struct scsi_cmnd *);
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/*
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* This is an optional routine to notify the host that the scsi
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* timer just fired. The returns tell the timer routine what to
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* do about this:
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*
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* EH_HANDLED: I fixed the error, please complete the command
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* EH_RESET_TIMER: I need more time, reset the timer and
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* begin counting again
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* EH_NOT_HANDLED Begin normal error recovery
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*
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* Status: OPTIONAL
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*/
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enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
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/*
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* Before the mid layer attempts to scan for a new device where none
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* currently exists, it will call this entry in your driver. Should
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@ -48,6 +48,17 @@ struct scsi_transport_template {
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* True if the transport wants to use a host-based work-queue
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*/
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unsigned int create_work_queue : 1;
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/*
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* This is an optional routine that allows the transport to become
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* involved when a scsi io timer fires. The return value tells the
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* timer routine how to finish the io timeout handling:
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* EH_HANDLED: I fixed the error, please complete the command
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* EH_RESET_TIMER: I need more time, reset the timer and
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* begin counting again
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* EH_NOT_HANDLED Begin normal error recovery
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*/
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enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);
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};
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#define transport_class_to_shost(tc) \
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