scsi: ipr: System hung while dlpar adding primary ipr adapter back

While dlpar adding primary ipr adapter back, driver goes through adapter
initialization then schedule ipr_worker_thread to start te disk scan by
dropping the host lock, calling scsi_add_device.  Then get the adapter reset
request again, so driver does scsi_block_requests, this will cause the
scsi_add_device get hung until we unblock. But we can't run ipr_worker_thread
to do the unblock because its stuck in scsi_add_device.

This patch fixes the issue.

[mkp: typo and whitespace fixes]

Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c
index f2ec80b0ffc080d614909dab1040b34342769930..271990bc065b924dda965bc8ee777aface7a5b47 100644 (file)
--- a/drivers/scsi/ipr.c
+++ b/drivers/scsi/ipr.c
@@ -3335,6 +3335,65 @@ static void ipr_release_dump(struct kref *kref)
        LEAVE;
 }
 
+static void ipr_add_remove_thread(struct work_struct *work)
+{
+       unsigned long lock_flags;
+       struct ipr_resource_entry *res;
+       struct scsi_device *sdev;
+       struct ipr_ioa_cfg *ioa_cfg =
+               container_of(work, struct ipr_ioa_cfg, scsi_add_work_q);
+       u8 bus, target, lun;
+       int did_work;
+
+       ENTER;
+       spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+
+restart:
+       do {
+               did_work = 0;
+               if (!ioa_cfg->hrrq[IPR_INIT_HRRQ].allow_cmds) {
+                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+                       return;
+               }
+
+               list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {
+                       if (res->del_from_ml && res->sdev) {
+                               did_work = 1;
+                               sdev = res->sdev;
+                               if (!scsi_device_get(sdev)) {
+                                       if (!res->add_to_ml)
+                                               list_move_tail(&res->queue, &ioa_cfg->free_res_q);
+                                       else
+                                               res->del_from_ml = 0;
+                                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+                                       scsi_remove_device(sdev);
+                                       scsi_device_put(sdev);
+                                       spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+                               }
+                               break;
+                       }
+               }
+       } while (did_work);
+
+       list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {
+               if (res->add_to_ml) {
+                       bus = res->bus;
+                       target = res->target;
+                       lun = res->lun;
+                       res->add_to_ml = 0;
+                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+                       scsi_add_device(ioa_cfg->host, bus, target, lun);
+                       spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
+                       goto restart;
+               }
+       }
+
+       ioa_cfg->scan_done = 1;
+       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
+       kobject_uevent(&ioa_cfg->host->shost_dev.kobj, KOBJ_CHANGE);
+       LEAVE;
+}
+
 /**
  * ipr_worker_thread - Worker thread
  * @work:              ioa config struct
@@ -3349,13 +3408,9 @@ static void ipr_release_dump(struct kref *kref)
 static void ipr_worker_thread(struct work_struct *work)
 {
        unsigned long lock_flags;
-       struct ipr_resource_entry *res;
-       struct scsi_device *sdev;
        struct ipr_dump *dump;
        struct ipr_ioa_cfg *ioa_cfg =
                container_of(work, struct ipr_ioa_cfg, work_q);
-       u8 bus, target, lun;
-       int did_work;
 
        ENTER;
        spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
@@ -3393,49 +3448,9 @@ static void ipr_worker_thread(struct work_struct *work)
                return;
        }
 
-restart:
-       do {
-               did_work = 0;
-               if (!ioa_cfg->hrrq[IPR_INIT_HRRQ].allow_cmds) {
-                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
-                       return;
-               }
+       schedule_work(&ioa_cfg->scsi_add_work_q);
 
-               list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {
-                       if (res->del_from_ml && res->sdev) {
-                               did_work = 1;
-                               sdev = res->sdev;
-                               if (!scsi_device_get(sdev)) {
-                                       if (!res->add_to_ml)
-                                               list_move_tail(&res->queue, &ioa_cfg->free_res_q);
-                                       else
-                                               res->del_from_ml = 0;
-                                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
-                                       scsi_remove_device(sdev);
-                                       scsi_device_put(sdev);
-                                       spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
-                               }
-                               break;
-                       }
-               }
-       } while (did_work);
-
-       list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {
-               if (res->add_to_ml) {
-                       bus = res->bus;
-                       target = res->target;
-                       lun = res->lun;
-                       res->add_to_ml = 0;
-                       spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
-                       scsi_add_device(ioa_cfg->host, bus, target, lun);
-                       spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
-                       goto restart;
-               }
-       }
-
-       ioa_cfg->scan_done = 1;
        spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);
-       kobject_uevent(&ioa_cfg->host->shost_dev.kobj, KOBJ_CHANGE);
        LEAVE;
 }
 
@@ -9933,6 +9948,7 @@ static void ipr_init_ioa_cfg(struct ipr_ioa_cfg *ioa_cfg,
        INIT_LIST_HEAD(&ioa_cfg->free_res_q);
        INIT_LIST_HEAD(&ioa_cfg->used_res_q);
        INIT_WORK(&ioa_cfg->work_q, ipr_worker_thread);
+       INIT_WORK(&ioa_cfg->scsi_add_work_q, ipr_add_remove_thread);
        init_waitqueue_head(&ioa_cfg->reset_wait_q);
        init_waitqueue_head(&ioa_cfg->msi_wait_q);
        init_waitqueue_head(&ioa_cfg->eeh_wait_q);

diff --git a/drivers/scsi/ipr.h b/drivers/scsi/ipr.h
index 68afbbde54d352f4c88cb4a3b5695ad3bd713ba0..f6baa23513139a53676b3f5005474cd419818098 100644 (file)
--- a/drivers/scsi/ipr.h
+++ b/drivers/scsi/ipr.h
@@ -1575,6 +1575,7 @@ struct ipr_ioa_cfg {
        u8 saved_mode_page_len;
 
        struct work_struct work_q;
+       struct work_struct scsi_add_work_q;
        struct workqueue_struct *reset_work_q;
 
        wait_queue_head_t reset_wait_q;