From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [PATCH] delay transition requeues for 2 seconds - alua Date: Tue, 20 Dec 2011 16:41:04 +0100 Message-ID: <4EF0AC90.5010109@suse.de> References: <1323816041-25557-1-git-send-email-revers@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from cantor2.suse.de ([195.135.220.15]:59577 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751414Ab1LTPlF (ORCPT ); Tue, 20 Dec 2011 10:41:05 -0500 In-Reply-To: <1323816041-25557-1-git-send-email-revers@redhat.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Rob Evers Cc: linux-scsi@vger.kernel.org On 12/13/2011 11:40 PM, Rob Evers wrote: > When alua targets are transitioning, the scsi midlayer retry mechanis= m > continuously retries the scsi commands that are returning with not re= ady > transitioning status. The target is not capable of handling the > commands for time on the order of several seconds during these transi= stions. >=20 > This patch delays the device queue for 2 seconds, which is in the sam= e > order of aas transition time. >=20 > Also, handle all other cases where ADD_TO_MLQUEUE_DELAY could be retu= rned > instead of ADD_TO_MLQUEUE as if ADD_TO_MLQUEUE were being returned. >=20 > Problem found by array partner testing >=20 > Signed-off-by: Rob Evers > --- > drivers/scsi/device_handler/scsi_dh_alua.c | 7 ++++--- > drivers/scsi/scsi.c | 3 +++ > drivers/scsi/scsi_error.c | 1 + > drivers/scsi/scsi_lib.c | 9 ++++++++- > include/scsi/scsi.h | 4 +++- > 5 files changed, 19 insertions(+), 5 deletions(-) >=20 > diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scs= i/device_handler/scsi_dh_alua.c > index 4ef0212..33b8df7 100644 > --- a/drivers/scsi/device_handler/scsi_dh_alua.c > +++ b/drivers/scsi/device_handler/scsi_dh_alua.c > @@ -233,7 +233,7 @@ static void stpg_endio(struct request *req, int e= rror) > goto done; > } > err =3D alua_check_sense(h->sdev, &sense_hdr); > - if (err =3D=3D ADD_TO_MLQUEUE) { > + if (err =3D=3D ADD_TO_MLQUEUE || err =3D=3D ADD_TO_MLQUEUE_DELAY) = { > err =3D SCSI_DH_RETRY; > goto done; > } > @@ -443,7 +443,7 @@ static int alua_check_sense(struct scsi_device *s= dev, > /* > * LUN Not Accessible - ALUA state transition > */ > - return ADD_TO_MLQUEUE; > + return ADD_TO_MLQUEUE_DELAY; > if (sense_hdr->asc =3D=3D 0x04 && sense_hdr->ascq =3D=3D 0x0b) > /* > * LUN Not Accessible -- Target port in standby state > @@ -521,7 +521,8 @@ static int alua_rtpg(struct scsi_device *sdev, st= ruct alua_dh_data *h) > return SCSI_DH_IO; > =20 > err =3D alua_check_sense(sdev, &sense_hdr); > - if (err =3D=3D ADD_TO_MLQUEUE && time_before(jiffies, expiry)) > + if ((err =3D=3D ADD_TO_MLQUEUE || err =3D=3D ADD_TO_MLQUEUE_DELAY)= && > + time_before(jiffies, expiry)) > goto retry; > sdev_printk(KERN_INFO, sdev, > "%s: rtpg sense code %02x/%02x/%02x\n", > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index 2aeb2e9..ced0085 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -600,6 +600,9 @@ void scsi_log_completion(struct scsi_cmnd *cmd, i= nt disposition) > case ADD_TO_MLQUEUE: > printk("MLQUEUE\n"); > break; > + case ADD_TO_MLQUEUE_DELAY: > + printk("MLQUEUE_DELAY\n"); > + break; > case FAILED: > printk("FAILED\n"); > break; > diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c > index dc6131e..775f822 100644 > --- a/drivers/scsi/scsi_error.c > +++ b/drivers/scsi/scsi_error.c > @@ -812,6 +812,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *sc= md, unsigned char *cmnd, > case TARGET_ERROR: > break; > case ADD_TO_MLQUEUE: > + case ADD_TO_MLQUEUE_DELAY: > rtn =3D NEEDS_RETRY; > break; > default: > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 06bc265..fb35a76 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -139,6 +139,7 @@ static int __scsi_queue_insert(struct scsi_cmnd *= cmd, int reason, int unbusy) > break; > case SCSI_MLQUEUE_DEVICE_BUSY: > case SCSI_MLQUEUE_EH_RETRY: > + case SCSI_MLQUEUE_DEV_DLY_RTY: > device->device_blocked =3D device->max_device_blocked; > break; > case SCSI_MLQUEUE_TARGET_BUSY: > @@ -161,7 +162,10 @@ static int __scsi_queue_insert(struct scsi_cmnd = *cmd, int reason, int unbusy) > blk_requeue_request(q, cmd->request); > spin_unlock_irqrestore(q->queue_lock, flags); > =20 > - kblockd_schedule_work(q, &device->requeue_work); > + if (reason =3D=3D SCSI_MLQUEUE_DEV_DLY_RTY) > + blk_delay_queue(q, 2000); > + else > + kblockd_schedule_work(q, &device->requeue_work); > =20 > return 0; > } > @@ -1465,6 +1469,9 @@ static void scsi_softirq_done(struct request *r= q) > case ADD_TO_MLQUEUE: > scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); > break; > + case ADD_TO_MLQUEUE_DELAY: > + scsi_queue_insert(cmd, SCSI_MLQUEUE_DEV_DLY_RTY); > + break; > default: > if (!scsi_eh_scmd_add(cmd, 0)) > scsi_finish_command(cmd); > diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h > index 8001ae4..df0e353 100644 > --- a/include/scsi/scsi.h > +++ b/include/scsi/scsi.h > @@ -466,9 +466,10 @@ static inline int scsi_is_wlun(unsigned int lun) > #define SOFT_ERROR 0x2005 > #define ADD_TO_MLQUEUE 0x2006 > #define TIMEOUT_ERROR 0x2007 > -#define SCSI_RETURN_NOT_HANDLED 0x2008 > +#define SCSI_RETURN_NOT_HANDLED 0x2008 > #define FAST_IO_FAIL 0x2009 > #define TARGET_ERROR 0x200A > +#define ADD_TO_MLQUEUE_DELAY 0x200B > =20 > /* > * Midlevel queue return values. > @@ -477,6 +478,7 @@ static inline int scsi_is_wlun(unsigned int lun) > #define SCSI_MLQUEUE_DEVICE_BUSY 0x1056 > #define SCSI_MLQUEUE_EH_RETRY 0x1057 > #define SCSI_MLQUEUE_TARGET_BUSY 0x1058 > +#define SCSI_MLQUEUE_DEV_DLY_RTY 0x1059 > =20 Can't we just name it 'MLQUEUE_DELAYED_RETRY'? 'MLQUEUE_DEV_DLY_RTY' is a bit unwieldy ... Other than that: Looks good. Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: J. Hawn, J. Guild, F. Imend=F6rffer, HRB 16746 (AG N=FCrnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html