diff options
Diffstat (limited to 'drivers/scsi/device_handler/scsi_dh_alua.c')
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh_alua.c | 66 |
1 files changed, 44 insertions, 22 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 610a51538f03..29a2865b8e2e 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -354,6 +354,8 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, "%s: port group %x rel port %x\n", ALUA_DH_NAME, group_id, rel_port); + kref_get(&pg->kref); + /* Check for existing port group references */ spin_lock(&h->pg_lock); old_pg = rcu_dereference_protected(h->pg, lockdep_is_held(&h->pg_lock)); @@ -373,11 +375,11 @@ static int alua_check_vpd(struct scsi_device *sdev, struct alua_dh_data *h, list_add_rcu(&h->node, &pg->dh_list); spin_unlock_irqrestore(&pg->lock, flags); - alua_rtpg_queue(rcu_dereference_protected(h->pg, - lockdep_is_held(&h->pg_lock)), - sdev, NULL, true); spin_unlock(&h->pg_lock); + alua_rtpg_queue(pg, sdev, NULL, true); + kref_put(&pg->kref, release_port_group); + if (old_pg) kref_put(&old_pg->kref, release_port_group); @@ -811,14 +813,19 @@ static unsigned alua_stpg(struct scsi_device *sdev, struct alua_port_group *pg) return SCSI_DH_RETRY; } -static bool alua_rtpg_select_sdev(struct alua_port_group *pg) +/* + * The caller must call scsi_device_put() on the returned pointer if it is not + * NULL. + */ +static struct scsi_device * __must_check +alua_rtpg_select_sdev(struct alua_port_group *pg) { struct alua_dh_data *h; - struct scsi_device *sdev = NULL; + struct scsi_device *sdev = NULL, *prev_sdev; lockdep_assert_held(&pg->lock); if (WARN_ON(!pg->rtpg_sdev)) - return false; + return NULL; /* * RCU protection isn't necessary for dh_list here @@ -845,22 +852,22 @@ static bool alua_rtpg_select_sdev(struct alua_port_group *pg) pr_warn("%s: no device found for rtpg\n", (pg->device_id_len ? (char *)pg->device_id_str : "(nameless PG)")); - return false; + return NULL; } sdev_printk(KERN_INFO, sdev, "rtpg retry on different device\n"); - scsi_device_put(pg->rtpg_sdev); + prev_sdev = pg->rtpg_sdev; pg->rtpg_sdev = sdev; - return true; + return prev_sdev; } static void alua_rtpg_work(struct work_struct *work) { struct alua_port_group *pg = container_of(work, struct alua_port_group, rtpg_work.work); - struct scsi_device *sdev; + struct scsi_device *sdev, *prev_sdev = NULL; LIST_HEAD(qdata_list); int err = SCSI_DH_OK; struct alua_queue_data *qdata, *tmp; @@ -901,7 +908,7 @@ static void alua_rtpg_work(struct work_struct *work) /* If RTPG failed on the current device, try using another */ if (err == SCSI_DH_RES_TEMP_UNAVAIL && - alua_rtpg_select_sdev(pg)) + (prev_sdev = alua_rtpg_select_sdev(pg))) err = SCSI_DH_IMM_RETRY; if (err == SCSI_DH_RETRY || err == SCSI_DH_IMM_RETRY || @@ -913,9 +920,7 @@ static void alua_rtpg_work(struct work_struct *work) pg->interval = ALUA_RTPG_RETRY_DELAY; pg->flags |= ALUA_PG_RUN_RTPG; spin_unlock_irqrestore(&pg->lock, flags); - queue_delayed_work(kaluad_wq, &pg->rtpg_work, - pg->interval * HZ); - return; + goto queue_rtpg; } if (err != SCSI_DH_OK) pg->flags &= ~ALUA_PG_RUN_STPG; @@ -930,9 +935,7 @@ static void alua_rtpg_work(struct work_struct *work) pg->interval = 0; pg->flags &= ~ALUA_PG_RUNNING; spin_unlock_irqrestore(&pg->lock, flags); - queue_delayed_work(kaluad_wq, &pg->rtpg_work, - pg->interval * HZ); - return; + goto queue_rtpg; } } @@ -946,6 +949,9 @@ static void alua_rtpg_work(struct work_struct *work) pg->rtpg_sdev = NULL; spin_unlock_irqrestore(&pg->lock, flags); + if (prev_sdev) + scsi_device_put(prev_sdev); + list_for_each_entry_safe(qdata, tmp, &qdata_list, entry) { list_del(&qdata->entry); if (qdata->callback_fn) @@ -957,6 +963,12 @@ static void alua_rtpg_work(struct work_struct *work) spin_unlock_irqrestore(&pg->lock, flags); scsi_device_put(sdev); kref_put(&pg->kref, release_port_group); + return; + +queue_rtpg: + if (prev_sdev) + scsi_device_put(prev_sdev); + queue_delayed_work(kaluad_wq, &pg->rtpg_work, pg->interval * HZ); } /** @@ -969,6 +981,9 @@ static void alua_rtpg_work(struct work_struct *work) * * Returns true if and only if alua_rtpg_work() will be called asynchronously. * That function is responsible for calling @qdata->fn(). + * + * Context: may be called from atomic context (alua_check()) only if the caller + * holds an sdev reference. */ static bool alua_rtpg_queue(struct alua_port_group *pg, struct scsi_device *sdev, @@ -976,6 +991,7 @@ static bool alua_rtpg_queue(struct alua_port_group *pg, { int start_queue = 0; unsigned long flags; + if (WARN_ON_ONCE(!pg) || scsi_device_get(sdev)) return false; @@ -986,11 +1002,17 @@ static bool alua_rtpg_queue(struct alua_port_group *pg, force = true; } if (pg->rtpg_sdev == NULL) { - pg->interval = 0; - pg->flags |= ALUA_PG_RUN_RTPG; - kref_get(&pg->kref); - pg->rtpg_sdev = sdev; - start_queue = 1; + struct alua_dh_data *h = sdev->handler_data; + + rcu_read_lock(); + if (h && rcu_dereference(h->pg) == pg) { + pg->interval = 0; + pg->flags |= ALUA_PG_RUN_RTPG; + kref_get(&pg->kref); + pg->rtpg_sdev = sdev; + start_queue = 1; + } + rcu_read_unlock(); } else if (!(pg->flags & ALUA_PG_RUN_RTPG) && force) { pg->flags |= ALUA_PG_RUN_RTPG; /* Do not queue if the worker is already running */ |