| Message ID | 1463748974-31315-1-git-send-email-emilne@redhat.com (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
----- Original Message ----- > From: "Ewan D. Milne" <emilne@redhat.com> > To: linux-scsi@vger.kernel.org > Sent: Friday, May 20, 2016 8:56:14 AM > Subject: [PATCH] scsi: use spinlock instead of mutex for RCU-protected VPD inquiry data > > From: "Ewan D. Milne" <emilne@redhat.com> > > A spinlock is sufficient for this purpose, and much smaller. > > Signed-off-by: Ewan D. Milne <emilne@redhat.com> > --- > drivers/scsi/scsi.c | 8 ++++---- > drivers/scsi/scsi_scan.c | 2 +- > include/scsi/scsi_device.h | 2 +- > 3 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index 1deb6ad..330d807 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -829,11 +829,11 @@ retry_pg80: > kfree(vpd_buf); > goto retry_pg80; > } > - mutex_lock(&sdev->inquiry_mutex); > + spin_lock(&sdev->inquiry_lock); > orig_vpd_buf = sdev->vpd_pg80; > sdev->vpd_pg80_len = result; > rcu_assign_pointer(sdev->vpd_pg80, vpd_buf); > - mutex_unlock(&sdev->inquiry_mutex); > + spin_unlock(&sdev->inquiry_lock); > synchronize_rcu(); > if (orig_vpd_buf) { > kfree(orig_vpd_buf); > @@ -858,11 +858,11 @@ retry_pg83: > kfree(vpd_buf); > goto retry_pg83; > } > - mutex_lock(&sdev->inquiry_mutex); > + spin_lock(&sdev->inquiry_lock); > orig_vpd_buf = sdev->vpd_pg83; > sdev->vpd_pg83_len = result; > rcu_assign_pointer(sdev->vpd_pg83, vpd_buf); > - mutex_unlock(&sdev->inquiry_mutex); > + spin_unlock(&sdev->inquiry_lock); > synchronize_rcu(); > if (orig_vpd_buf) > kfree(orig_vpd_buf); > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c > index e0a78f5..f445615 100644 > --- a/drivers/scsi/scsi_scan.c > +++ b/drivers/scsi/scsi_scan.c > @@ -240,7 +240,7 @@ static struct scsi_device *scsi_alloc_sdev(struct > scsi_target *starget, > INIT_LIST_HEAD(&sdev->starved_entry); > INIT_LIST_HEAD(&sdev->event_list); > spin_lock_init(&sdev->list_lock); > - mutex_init(&sdev->inquiry_mutex); > + spin_lock_init(&sdev->inquiry_lock); > INIT_WORK(&sdev->event_work, scsi_evt_thread); > INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue); > > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index a6c346d..0410ed8 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -115,7 +115,7 @@ struct scsi_device { > char type; > char scsi_level; > char inq_periph_qual; /* PQ from INQUIRY data */ > - struct mutex inquiry_mutex; > + spinlock_t inquiry_lock; > unsigned char inquiry_len; /* valid bytes in 'inquiry' */ > unsigned char * inquiry; /* INQUIRY response data */ > const char * vendor; /* [back_compat] point into 'inquiry' ... */ > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Look fine to me: Reviewed by: Laurence Oberman <loberman@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 20, 2016 at 08:56:14AM -0400, Ewan D. Milne wrote: > From: "Ewan D. Milne" <emilne@redhat.com> > > A spinlock is sufficient for this purpose, and much smaller. > > Signed-off-by: Ewan D. Milne <emilne@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 1deb6ad..330d807 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -829,11 +829,11 @@ retry_pg80: kfree(vpd_buf); goto retry_pg80; } - mutex_lock(&sdev->inquiry_mutex); + spin_lock(&sdev->inquiry_lock); orig_vpd_buf = sdev->vpd_pg80; sdev->vpd_pg80_len = result; rcu_assign_pointer(sdev->vpd_pg80, vpd_buf); - mutex_unlock(&sdev->inquiry_mutex); + spin_unlock(&sdev->inquiry_lock); synchronize_rcu(); if (orig_vpd_buf) { kfree(orig_vpd_buf); @@ -858,11 +858,11 @@ retry_pg83: kfree(vpd_buf); goto retry_pg83; } - mutex_lock(&sdev->inquiry_mutex); + spin_lock(&sdev->inquiry_lock); orig_vpd_buf = sdev->vpd_pg83; sdev->vpd_pg83_len = result; rcu_assign_pointer(sdev->vpd_pg83, vpd_buf); - mutex_unlock(&sdev->inquiry_mutex); + spin_unlock(&sdev->inquiry_lock); synchronize_rcu(); if (orig_vpd_buf) kfree(orig_vpd_buf); diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index e0a78f5..f445615 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -240,7 +240,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, INIT_LIST_HEAD(&sdev->starved_entry); INIT_LIST_HEAD(&sdev->event_list); spin_lock_init(&sdev->list_lock); - mutex_init(&sdev->inquiry_mutex); + spin_lock_init(&sdev->inquiry_lock); INIT_WORK(&sdev->event_work, scsi_evt_thread); INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue); diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index a6c346d..0410ed8 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -115,7 +115,7 @@ struct scsi_device { char type; char scsi_level; char inq_periph_qual; /* PQ from INQUIRY data */ - struct mutex inquiry_mutex; + spinlock_t inquiry_lock; unsigned char inquiry_len; /* valid bytes in 'inquiry' */ unsigned char * inquiry; /* INQUIRY response data */ const char * vendor; /* [back_compat] point into 'inquiry' ... */