Adding Hannes to the Cc list as he's been looking into EH improvements in this area.
On Wed, May 25, 2016 at 02:55:02AM -0500, [email protected] wrote: > From: Mike Christie <[email protected]> > > Currently, if the SCSI eh runs then before we do a LUN_RESET > we stop the host. This patch and the block layer one before it > begin to add infrastructure to be able to do a LUN_RESET and > eventually do a transport level recovery without having to stop the > host. > > For LUn-reset, this patch adds a new callout, eh_async_device_reset_handler, > which works similar to how LLDs handle SG_SCSI_RESET_DEVICE where the > LLD manages the commands that are affected. > > eh_async_device_reset_handler: > > The LLD should perform a LUN RESET that affects all commands > that have been accepted by its queuecommand callout for the > device passed in to the callout. While the reset handler is running, > queuecommand will not be running or called for the device. > > Unlike eh_device_reset_handler, queuecommand may still be > called for other devices, and the LLD must call scsi_done for the > commands that have been affected by the reset. > > If SUCCESS or FAST_IO_FAIL is returned, the scsi_cmnds cleaned up > must be failed with DID_ABORT. > > Signed-off-by: Mike Christie <[email protected]> > --- > drivers/scsi/scsi_error.c | 31 ++++++++++++++++++++++++++++--- > drivers/scsi/scsi_lib.c | 6 ++++++ > drivers/scsi/scsi_priv.h | 1 + > include/scsi/scsi_host.h | 17 +++++++++++++++++ > 4 files changed, 52 insertions(+), 3 deletions(-) > > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c > index 984ddcb..cec2dfb 100644 > --- a/drivers/scsi/scsi_error.c > +++ b/drivers/scsi/scsi_error.c > @@ -853,16 +853,41 @@ static int scsi_try_bus_device_reset(struct scsi_cmnd > *scmd) > { > int rtn; > struct scsi_host_template *hostt = scmd->device->host->hostt; > + struct scsi_device *sdev = scmd->device; > > - if (!hostt->eh_device_reset_handler) > + if (!hostt->eh_device_reset_handler && > + !hostt->eh_async_device_reset_handler) > return FAILED; > > - rtn = hostt->eh_device_reset_handler(scmd); > + if (hostt->eh_device_reset_handler) { > + rtn = hostt->eh_device_reset_handler(scmd); > + } else { > + if (!blk_reset_queue(sdev->request_queue)) > + rtn = SUCCESS; > + else > + rtn = FAILED; > + } > if (rtn == SUCCESS) > - __scsi_report_device_reset(scmd->device, NULL); > + __scsi_report_device_reset(sdev, NULL); > return rtn; > } > > +enum blk_eh_timer_return scsi_reset_queue(struct request_queue *q) > +{ > + struct scsi_device *sdev = q->queuedata; > + struct scsi_host_template *hostt = sdev->host->hostt; > + int rtn; > + > + if (!hostt->eh_async_device_reset_handler) > + return -EOPNOTSUPP; > + > + rtn = hostt->eh_async_device_reset_handler(sdev); > + if (rtn == SUCCESS || rtn == FAST_IO_FAIL) > + return BLK_EH_HANDLED; > + > + return BLK_EH_NOT_HANDLED; > +} > + > /** > * scsi_try_to_abort_cmd - Ask host to abort a SCSI command > * @hostt: SCSI driver host template > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 8106515..11374dd 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -779,6 +779,10 @@ static int __scsi_error_from_host_byte(struct scsi_cmnd > *cmd, int result) > set_host_byte(cmd, DID_OK); > error = -ENODATA; > break; > + case DID_ABORT: > + set_host_byte(cmd, DID_OK); > + error = -EINTR; > + break; > default: > error = -EIO; > break; > @@ -2159,6 +2163,7 @@ struct request_queue *scsi_alloc_queue(struct > scsi_device *sdev) > blk_queue_softirq_done(q, scsi_softirq_done); > blk_queue_rq_timed_out(q, scsi_times_out); > blk_queue_lld_busy(q, scsi_lld_busy); > + blk_queue_reset(q, scsi_reset_queue); > return q; > } > > @@ -2167,6 +2172,7 @@ static struct blk_mq_ops scsi_mq_ops = { > .queue_rq = scsi_queue_rq, > .complete = scsi_softirq_done, > .timeout = scsi_timeout, > + .reset = scsi_reset_queue, > .init_request = scsi_init_request, > .exit_request = scsi_exit_request, > }; > diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h > index 27b4d0a..2e03168 100644 > --- a/drivers/scsi/scsi_priv.h > +++ b/drivers/scsi/scsi_priv.h > @@ -67,6 +67,7 @@ extern void scsi_exit_devinfo(void); > > /* scsi_error.c */ > extern void scmd_eh_abort_handler(struct work_struct *work); > +extern enum blk_eh_timer_return scsi_reset_queue(struct request_queue *q); > extern enum blk_eh_timer_return scsi_times_out(struct request *req); > extern int scsi_error_handler(void *host); > extern int scsi_decide_disposition(struct scsi_cmnd *cmd); > diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h > index fcfa3d7..532deb5 100644 > --- a/include/scsi/scsi_host.h > +++ b/include/scsi/scsi_host.h > @@ -146,6 +146,23 @@ struct scsi_host_template { > */ > int (* eh_abort_handler)(struct scsi_cmnd *); > int (* eh_device_reset_handler)(struct scsi_cmnd *); > + /* > + * eh_async_device_reset_handler - Perform LUN RESET > + * @scsi_device: scsi device to reset > + * > + * The LLD should perform a LUN RESET that affects all commands > + * that have been accepted by its queuecommand callout for the > + * device passed in. While the reset handler is running, queuecommand > + * will not be called for the device. > + * > + * Unlike eh_device_reset_handler, queuecommand may still be called > + * for other devices, and the LLD must call scsi_done for the commands > + * that have been affected by the reset. > + * > + * If SUCCESS or FAST_IO_FAIL is returned, the scsi_cmnds for > + * scsi_device must be failed with DID_ABORT. > + */ > + int (* eh_async_device_reset_handler)(struct scsi_device *); > int (* eh_target_reset_handler)(struct scsi_cmnd *); > int (* eh_bus_reset_handler)(struct scsi_cmnd *); > int (* eh_host_reset_handler)(struct scsi_cmnd *); > -- > 2.7.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html ---end quoted text--- -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
