Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg...

[deliverable/linux.git] / drivers / scsi / scsi_lib.c

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 36521a0ac54ba50a7bfe3745f3bf1452293141d0..ffd77739ae3e2bc4bf793fe7b4bb0ed37c3ca8f4 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -68,6 +68,23 @@ static struct scsi_host_sg_pool scsi_sg_pools[] = {
 
 struct kmem_cache *scsi_sdb_cache;
 
+#ifdef CONFIG_ACPI
+#include <acpi/acpi_bus.h>
+
+int scsi_register_acpi_bus_type(struct acpi_bus_type *bus)
+{
+        bus->bus = &scsi_bus_type;
+        return register_acpi_bus_type(bus);
+}
+EXPORT_SYMBOL_GPL(scsi_register_acpi_bus_type);
+
+void scsi_unregister_acpi_bus_type(struct acpi_bus_type *bus)
+{
+       unregister_acpi_bus_type(bus);
+}
+EXPORT_SYMBOL_GPL(scsi_unregister_acpi_bus_type);
+#endif
+
 /*
  * When to reinvoke queueing after a resource shortage. It's 3 msecs to
  * not change behaviour from the previous unplug mechanism, experimentation
@@ -109,7 +126,7 @@ static void scsi_unprep_request(struct request *req)
  * for a requeue after completion, which should only occur in this
  * file.
  */
-static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
+static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
 {
        struct Scsi_Host *host = cmd->device->host;
        struct scsi_device *device = cmd->device;
@@ -155,15 +172,14 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
 
        /*
         * Requeue this command.  It will go before all other commands
-        * that are already in the queue.
+        * that are already in the queue. Schedule requeue work under
+        * lock such that the kblockd_schedule_work() call happens
+        * before blk_cleanup_queue() finishes.
         */
        spin_lock_irqsave(q->queue_lock, flags);
        blk_requeue_request(q, cmd->request);
-       spin_unlock_irqrestore(q->queue_lock, flags);
-
        kblockd_schedule_work(q, &device->requeue_work);
-
-       return 0;
+       spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 /*
@@ -185,9 +201,9 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
  * Notes:       This could be called either from an interrupt context or a
  *              normal process context.
  */
-int scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
+void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
 {
-       return __scsi_queue_insert(cmd, reason, 1);
+       __scsi_queue_insert(cmd, reason, 1);
 }
 /**
  * scsi_execute - insert request and wait for the result
@@ -406,10 +422,6 @@ static void scsi_run_queue(struct request_queue *q)
        LIST_HEAD(starved_list);
        unsigned long flags;
 
-       /* if the device is dead, sdev will be NULL, so no queue to run */
-       if (!sdev)
-               return;
-
        shost = sdev->host;
        if (scsi_target(sdev)->single_lun)
                scsi_single_lun_run(sdev);
@@ -483,15 +495,26 @@ void scsi_requeue_run_queue(struct work_struct *work)
  */
 static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
 {
+       struct scsi_device *sdev = cmd->device;
        struct request *req = cmd->request;
        unsigned long flags;
 
+       /*
+        * We need to hold a reference on the device to avoid the queue being
+        * killed after the unlock and before scsi_run_queue is invoked which
+        * may happen because scsi_unprep_request() puts the command which
+        * releases its reference on the device.
+        */
+       get_device(&sdev->sdev_gendev);
+
        spin_lock_irqsave(q->queue_lock, flags);
        scsi_unprep_request(req);
        blk_requeue_request(q, req);
        spin_unlock_irqrestore(q->queue_lock, flags);
 
        scsi_run_queue(q);
+
+       put_device(&sdev->sdev_gendev);
 }
 
 void scsi_next_command(struct scsi_cmnd *cmd)
@@ -1371,16 +1394,16 @@ static inline int scsi_host_queue_ready(struct request_queue *q,
  * may be changed after request stacking drivers call the function,
  * regardless of taking lock or not.
  *
- * When scsi can't dispatch I/Os anymore and needs to kill I/Os
- * (e.g. !sdev), scsi needs to return 'not busy'.
- * Otherwise, request stacking drivers may hold requests forever.
+ * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
+ * needs to return 'not busy'. Otherwise, request stacking drivers
+ * may hold requests forever.
  */
 static int scsi_lld_busy(struct request_queue *q)
 {
        struct scsi_device *sdev = q->queuedata;
        struct Scsi_Host *shost;
 
-       if (!sdev)
+       if (blk_queue_dead(q))
                return 0;
 
        shost = sdev->host;
@@ -1491,12 +1514,6 @@ static void scsi_request_fn(struct request_queue *q)
        struct scsi_cmnd *cmd;
        struct request *req;
 
-       if (!sdev) {
-               while ((req = blk_peek_request(q)) != NULL)
-                       scsi_kill_request(req, q);
-               return;
-       }
-
        if(!get_device(&sdev->sdev_gendev))
                /* We must be tearing the block queue down already */
                return;
@@ -1698,20 +1715,6 @@ struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
        return q;
 }
 
-void scsi_free_queue(struct request_queue *q)
-{
-       unsigned long flags;
-
-       WARN_ON(q->queuedata);
-
-       /* cause scsi_request_fn() to kill all non-finished requests */
-       spin_lock_irqsave(q->queue_lock, flags);
-       q->request_fn(q);
-       spin_unlock_irqrestore(q->queue_lock, flags);
-
-       blk_cleanup_queue(q);
-}
-
 /*
  * Function:    scsi_block_requests()
  *
@@ -2411,7 +2414,6 @@ EXPORT_SYMBOL(scsi_target_resume);
  *     (which must be a legal transition).  When the device is in this
  *     state, all commands are deferred until the scsi lld reenables
  *     the device with scsi_device_unblock or device_block_tmo fires.
- *     This routine assumes the host_lock is held on entry.
  */
 int
 scsi_internal_device_block(struct scsi_device *sdev)
@@ -2455,8 +2457,7 @@ EXPORT_SYMBOL_GPL(scsi_internal_device_block);
  * Notes:       
  *     This routine transitions the device to the SDEV_RUNNING state
  *     or to one of the offline states (which must be a legal transition)
- *     allowing the midlayer to goose the queue for this device. This
- *     routine assumes the host_lock is held upon entry.
+ *     allowing the midlayer to goose the queue for this device.
  */
 int
 scsi_internal_device_unblock(struct scsi_device *sdev,