| Message ID | 1454942086-128704-23-git-send-email-hare@suse.de (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Mon, Feb 08, 2016 at 03:34:45PM +0100, Hannes Reinecke wrote: > Track attached SCSI devices and update the 'access_state' field > whenever an ALUA state change has been detected. > > Signed-off-by: Hannes Reinecke <hare@suse.de> Looks fine, Reviewed-by: Christoph Hellwig <hch@lst.de> -- 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 Mon, 2016-02-08 at 15:34 +0100, Hannes Reinecke wrote: > Track attached SCSI devices and update the 'access_state' field > whenever an ALUA state change has been detected. > > Signed-off-by: Hannes Reinecke <hare@suse.de> > --- > drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++++++++++++-- > 1 file changed, 43 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c > index 51126b78..7bcc075 100644 > --- a/drivers/scsi/device_handler/scsi_dh_alua.c > +++ b/drivers/scsi/device_handler/scsi_dh_alua.c > @@ -24,6 +24,7 @@ > #include <linux/module.h> > #include <asm/unaligned.h> > #include <scsi/scsi.h> > +#include <scsi/scsi_proto.h> > #include <scsi/scsi_dbg.h> > #include <scsi/scsi_eh.h> > #include <scsi/scsi_dh.h> > @@ -75,6 +76,7 @@ struct alua_port_group { > struct kref kref; > struct rcu_head rcu; > struct list_head node; > + struct list_head dh_list; > unsigned char device_id_str[256]; > int device_id_len; > int group_id; > @@ -92,6 +94,7 @@ struct alua_port_group { > }; > > struct alua_dh_data { > + struct list_head node; > struct alua_port_group *pg; > int group_id; > spinlock_t pg_lock; > @@ -247,6 +250,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, > INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); > INIT_LIST_HEAD(&pg->rtpg_list); > INIT_LIST_HEAD(&pg->node); > + INIT_LIST_HEAD(&pg->dh_list); > spin_lock_init(&pg->lock); > > spin_lock(&port_group_lock); > @@ -328,6 +332,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, > { > int rel_port = -1, group_id; > struct alua_port_group *pg, *old_pg = NULL; > + bool pg_updated; > + unsigned long flags; > > group_id = scsi_vpd_tpg_id(sdev, &rel_port); > if (group_id < 0) { > @@ -357,13 +363,25 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, > old_pg = h->pg; > if (old_pg != pg) { > /* port group has changed. Update to new port group */ > + if (h->pg) { > + spin_lock_irqsave(&old_pg->lock, flags); > + list_del_rcu(&h->node); > + spin_unlock_irqrestore(&old_pg->lock, flags); > + } > rcu_assign_pointer(h->pg, pg); > + pg_updated = true; > } > if (sdev->synchronous_alua) > pg->flags |= ALUA_SYNC_STPG; > alua_rtpg_queue(h->pg, sdev, NULL, true); > spin_unlock(&h->pg_lock); > > + if (pg_updated) { > + spin_lock_irqsave(&pg->lock, flags); > + list_add_rcu(&h->node, &pg->dh_list); > + spin_unlock_irqrestore(&pg->lock, flags); > + } > + > if (old_pg) > kref_put(&old_pg->kref, release_port_group); > > @@ -613,8 +631,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) > if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { > if ((tmp_pg == pg) || > !(tmp_pg->flags & ALUA_PG_RUNNING)) { > + struct alua_dh_data *h; > + > tmp_pg->state = desc[0] & 0x0f; > tmp_pg->pref = desc[0] >> 7; > + rcu_read_lock(); > + list_for_each_entry_rcu(h, > + &tmp_pg->dh_list, node) { > + /* h->sdev should always be valid */ > + BUG_ON(!h->sdev); > + h->sdev->access_state = desc[0]; Here you did not mask desc[0] with 0x0f like you did in other places in the code. > + } > + rcu_read_unlock(); > } > if (tmp_pg == pg) > valid_states = desc[1]; > @@ -646,10 +674,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) > pg->interval = 2; > err = SCSI_DH_RETRY; > } else { > + struct alua_dh_data *h; > + > /* Transitioning time exceeded, set port to standby */ > err = SCSI_DH_IO; > pg->state = SCSI_ACCESS_STATE_STANDBY; > pg->expiry = 0; > + rcu_read_lock(); > + list_for_each_entry_rcu(h, &pg->dh_list, node) { > + BUG_ON(!h->sdev); > + h->sdev->access_state = (pg->state & 0x0f) | > + (pg->pref << 7); Since SCSI_ACCESS_STATE_PREFERRED is #defined as 0x80 in scsi_proto.h you should use | (pg->pref ? SCSI_ACCESS_STATE_PREFERRED : 0) here rather than just shifting, otherwise you will have a hard to find bug if somebody changes the constant. (But I would prefer keeping them separate anyway.) > + } > + rcu_read_unlock(); > } > break; > case SCSI_ACCESS_STATE_OFFLINE: > @@ -1053,6 +1090,7 @@ static int alua_bus_attach(struct scsi_device *sdev) > rcu_assign_pointer(h->pg, NULL); > h->init_error = SCSI_DH_OK; > h->sdev = sdev; > + INIT_LIST_HEAD(&h->node); > > mutex_init(&h->init_mutex); > err = alua_initialize(sdev, h); > @@ -1082,9 +1120,12 @@ static void alua_bus_detach(struct scsi_device *sdev) > rcu_assign_pointer(h->pg, NULL); > h->sdev = NULL; > spin_unlock(&h->pg_lock); > - if (pg) > + if (pg) { > + spin_lock(&pg->lock); > + list_del_rcu(&h->node); > + spin_unlock(&pg->lock); > kref_put(&pg->kref, release_port_group); > - > + } > sdev->handler_data = NULL; > kfree(h); > } Reviewed-by: Ewan D. Milne <emilne@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 02/11/2016 09:37 PM, Ewan Milne wrote: > On Mon, 2016-02-08 at 15:34 +0100, Hannes Reinecke wrote: >> Track attached SCSI devices and update the 'access_state' field >> whenever an ALUA state change has been detected. >> >> Signed-off-by: Hannes Reinecke <hare@suse.de> >> --- >> drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++++++++++++-- >> 1 file changed, 43 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c >> index 51126b78..7bcc075 100644 >> --- a/drivers/scsi/device_handler/scsi_dh_alua.c >> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c >> @@ -24,6 +24,7 @@ >> #include <linux/module.h> >> #include <asm/unaligned.h> >> #include <scsi/scsi.h> >> +#include <scsi/scsi_proto.h> >> #include <scsi/scsi_dbg.h> >> #include <scsi/scsi_eh.h> >> #include <scsi/scsi_dh.h> >> @@ -75,6 +76,7 @@ struct alua_port_group { >> struct kref kref; >> struct rcu_head rcu; >> struct list_head node; >> + struct list_head dh_list; >> unsigned char device_id_str[256]; >> int device_id_len; >> int group_id; >> @@ -92,6 +94,7 @@ struct alua_port_group { >> }; >> >> struct alua_dh_data { >> + struct list_head node; >> struct alua_port_group *pg; >> int group_id; >> spinlock_t pg_lock; >> @@ -247,6 +250,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, >> INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); >> INIT_LIST_HEAD(&pg->rtpg_list); >> INIT_LIST_HEAD(&pg->node); >> + INIT_LIST_HEAD(&pg->dh_list); >> spin_lock_init(&pg->lock); >> >> spin_lock(&port_group_lock); >> @@ -328,6 +332,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, >> { >> int rel_port = -1, group_id; >> struct alua_port_group *pg, *old_pg = NULL; >> + bool pg_updated; >> + unsigned long flags; >> >> group_id = scsi_vpd_tpg_id(sdev, &rel_port); >> if (group_id < 0) { >> @@ -357,13 +363,25 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, >> old_pg = h->pg; >> if (old_pg != pg) { >> /* port group has changed. Update to new port group */ >> + if (h->pg) { >> + spin_lock_irqsave(&old_pg->lock, flags); >> + list_del_rcu(&h->node); >> + spin_unlock_irqrestore(&old_pg->lock, flags); >> + } >> rcu_assign_pointer(h->pg, pg); >> + pg_updated = true; >> } >> if (sdev->synchronous_alua) >> pg->flags |= ALUA_SYNC_STPG; >> alua_rtpg_queue(h->pg, sdev, NULL, true); >> spin_unlock(&h->pg_lock); >> >> + if (pg_updated) { >> + spin_lock_irqsave(&pg->lock, flags); >> + list_add_rcu(&h->node, &pg->dh_list); >> + spin_unlock_irqrestore(&pg->lock, flags); >> + } >> + >> if (old_pg) >> kref_put(&old_pg->kref, release_port_group); >> >> @@ -613,8 +631,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) >> if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { >> if ((tmp_pg == pg) || >> !(tmp_pg->flags & ALUA_PG_RUNNING)) { >> + struct alua_dh_data *h; >> + >> tmp_pg->state = desc[0] & 0x0f; >> tmp_pg->pref = desc[0] >> 7; >> + rcu_read_lock(); >> + list_for_each_entry_rcu(h, >> + &tmp_pg->dh_list, node) { >> + /* h->sdev should always be valid */ >> + BUG_ON(!h->sdev); >> + h->sdev->access_state = desc[0]; > > Here you did not mask desc[0] with 0x0f like you did in other places in the code. > Because the access_state field is a 1:1 copy of the 'desc[0]' field, containing both the value and the pref bit. >> + } >> + rcu_read_unlock(); >> } >> if (tmp_pg == pg) >> valid_states = desc[1]; >> @@ -646,10 +674,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) >> pg->interval = 2; >> err = SCSI_DH_RETRY; >> } else { >> + struct alua_dh_data *h; >> + >> /* Transitioning time exceeded, set port to standby */ >> err = SCSI_DH_IO; >> pg->state = SCSI_ACCESS_STATE_STANDBY; >> pg->expiry = 0; >> + rcu_read_lock(); >> + list_for_each_entry_rcu(h, &pg->dh_list, node) { >> + BUG_ON(!h->sdev); >> + h->sdev->access_state = (pg->state & 0x0f) | >> + (pg->pref << 7); > > Since SCSI_ACCESS_STATE_PREFERRED is #defined as 0x80 in scsi_proto.h you > should use | (pg->pref ? SCSI_ACCESS_STATE_PREFERRED : 0) here rather than > just shifting, otherwise you will have a hard to find bug if somebody > changes the constant. (But I would prefer keeping them separate anyway.) > _Actually_ I was pondering to make it the other way around, namely shifting pg->pref on top of pg->state, then this whole thing would become a simple assignment. But I didn't as I wanted to keep the original code as-is. So yeah, there is an inconsistency, but some I would like to resolve in exactly the other direction :-) Cheers, Hannes
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 51126b78..7bcc075 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -24,6 +24,7 @@ #include <linux/module.h> #include <asm/unaligned.h> #include <scsi/scsi.h> +#include <scsi/scsi_proto.h> #include <scsi/scsi_dbg.h> #include <scsi/scsi_eh.h> #include <scsi/scsi_dh.h> @@ -75,6 +76,7 @@ struct alua_port_group { struct kref kref; struct rcu_head rcu; struct list_head node; + struct list_head dh_list; unsigned char device_id_str[256]; int device_id_len; int group_id; @@ -92,6 +94,7 @@ struct alua_port_group { }; struct alua_dh_data { + struct list_head node; struct alua_port_group *pg; int group_id; spinlock_t pg_lock; @@ -247,6 +250,7 @@ struct alua_port_group *alua_alloc_pg(struct scsi_device *sdev, INIT_DELAYED_WORK(&pg->rtpg_work, alua_rtpg_work); INIT_LIST_HEAD(&pg->rtpg_list); INIT_LIST_HEAD(&pg->node); + INIT_LIST_HEAD(&pg->dh_list); spin_lock_init(&pg->lock); spin_lock(&port_group_lock); @@ -328,6 +332,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, { int rel_port = -1, group_id; struct alua_port_group *pg, *old_pg = NULL; + bool pg_updated; + unsigned long flags; group_id = scsi_vpd_tpg_id(sdev, &rel_port); if (group_id < 0) { @@ -357,13 +363,25 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, old_pg = h->pg; if (old_pg != pg) { /* port group has changed. Update to new port group */ + if (h->pg) { + spin_lock_irqsave(&old_pg->lock, flags); + list_del_rcu(&h->node); + spin_unlock_irqrestore(&old_pg->lock, flags); + } rcu_assign_pointer(h->pg, pg); + pg_updated = true; } if (sdev->synchronous_alua) pg->flags |= ALUA_SYNC_STPG; alua_rtpg_queue(h->pg, sdev, NULL, true); spin_unlock(&h->pg_lock); + if (pg_updated) { + spin_lock_irqsave(&pg->lock, flags); + list_add_rcu(&h->node, &pg->dh_list); + spin_unlock_irqrestore(&pg->lock, flags); + } + if (old_pg) kref_put(&old_pg->kref, release_port_group); @@ -613,8 +631,18 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) if (spin_trylock_irqsave(&tmp_pg->lock, flags)) { if ((tmp_pg == pg) || !(tmp_pg->flags & ALUA_PG_RUNNING)) { + struct alua_dh_data *h; + tmp_pg->state = desc[0] & 0x0f; tmp_pg->pref = desc[0] >> 7; + rcu_read_lock(); + list_for_each_entry_rcu(h, + &tmp_pg->dh_list, node) { + /* h->sdev should always be valid */ + BUG_ON(!h->sdev); + h->sdev->access_state = desc[0]; + } + rcu_read_unlock(); } if (tmp_pg == pg) valid_states = desc[1]; @@ -646,10 +674,19 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg) pg->interval = 2; err = SCSI_DH_RETRY; } else { + struct alua_dh_data *h; + /* Transitioning time exceeded, set port to standby */ err = SCSI_DH_IO; pg->state = SCSI_ACCESS_STATE_STANDBY; pg->expiry = 0; + rcu_read_lock(); + list_for_each_entry_rcu(h, &pg->dh_list, node) { + BUG_ON(!h->sdev); + h->sdev->access_state = (pg->state & 0x0f) | + (pg->pref << 7); + } + rcu_read_unlock(); } break; case SCSI_ACCESS_STATE_OFFLINE: @@ -1053,6 +1090,7 @@ static int alua_bus_attach(struct scsi_device *sdev) rcu_assign_pointer(h->pg, NULL); h->init_error = SCSI_DH_OK; h->sdev = sdev; + INIT_LIST_HEAD(&h->node); mutex_init(&h->init_mutex); err = alua_initialize(sdev, h); @@ -1082,9 +1120,12 @@ static void alua_bus_detach(struct scsi_device *sdev) rcu_assign_pointer(h->pg, NULL); h->sdev = NULL; spin_unlock(&h->pg_lock); - if (pg) + if (pg) { + spin_lock(&pg->lock); + list_del_rcu(&h->node); + spin_unlock(&pg->lock); kref_put(&pg->kref, release_port_group); - + } sdev->handler_data = NULL; kfree(h); }
Track attached SCSI devices and update the 'access_state' field whenever an ALUA state change has been detected. Signed-off-by: Hannes Reinecke <hare@suse.de> --- drivers/scsi/device_handler/scsi_dh_alua.c | 45 ++++++++++++++++++++++++++++-- 1 file changed, 43 insertions(+), 2 deletions(-)