8 files changed, 201 insertions, 11 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index a2b1414da288..8a8f803439e1 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -32,6 +32,7 @@
 #include <linux/completion.h>
 #include <linux/transport_class.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
@@ -156,6 +157,7 @@ EXPORT_SYMBOL(scsi_host_set_state);
 void scsi_remove_host(struct Scsi_Host *shost)
 {
         unsigned long flags;
+
         mutex_lock(&shost->scan_mutex);
         spin_lock_irqsave(shost->host_lock, flags);
         if (scsi_host_set_state(shost, SHOST_CANCEL))
@@ -165,6 +167,8 @@ void scsi_remove_host(struct Scsi_Host *shost)
                         return;
                 }
         spin_unlock_irqrestore(shost->host_lock, flags);
+
+        scsi_autopm_get_host(shost);
         scsi_forget_host(shost);
         mutex_unlock(&shost->scan_mutex);
         scsi_proc_host_rm(shost);
@@ -216,12 +220,14 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
         shost->dma_dev = dma_dev;
 
-        device_enable_async_suspend(&shost->shost_gendev);
-
         error = device_add(&shost->shost_gendev);
         if (error)
                 goto out;
 
+        pm_runtime_set_active(&shost->shost_gendev);
+        pm_runtime_enable(&shost->shost_gendev);
+        device_enable_async_suspend(&shost->shost_gendev);
+
         scsi_host_set_state(shost, SHOST_RUNNING);
         get_device(shost->shost_gendev.parent);
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c60cffbefa3c..2bf98469dc4c 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -1775,6 +1775,14 @@ int scsi_error_handler(void *data)
                  * what we need to do to get it up and online again (if we can).
                  * If we fail, we end up taking the thing offline.
                  */
+                if (scsi_autopm_get_host(shost) != 0) {
+                        SCSI_LOG_ERROR_RECOVERY(1,
+                                printk(KERN_ERR "Error handler scsi_eh_%d "
+                                                "unable to autoresume\n",
+                                                shost->host_no));
+                        continue;
+                }
+
                 if (shost->transportt->eh_strategy_handler)
                         shost->transportt->eh_strategy_handler(shost);
                 else
@@ -1788,6 +1796,7 @@ int scsi_error_handler(void *data)
                  * which are still online.
                  */
                 scsi_restart_operations(shost);
+                scsi_autopm_put_host(shost);
                 set_current_state(TASK_INTERRUPTIBLE);
         }
         __set_current_state(TASK_RUNNING);
@@ -1885,12 +1894,16 @@ scsi_reset_provider_done_command(struct scsi_cmnd *scmd)
 int
 scsi_reset_provider(struct scsi_device *dev, int flag)
 {
-        struct scsi_cmnd *scmd = scsi_get_command(dev, GFP_KERNEL);
+        struct scsi_cmnd *scmd;
         struct Scsi_Host *shost = dev->host;
         struct request req;
         unsigned long flags;
         int rtn;
 
+        if (scsi_autopm_get_host(shost) < 0)
+                return FAILED;
+
+        scmd = scsi_get_command(dev, GFP_KERNEL);
         blk_rq_init(NULL, &req);
         scmd->request = &req;
 
@@ -1947,6 +1960,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
         scsi_run_host_queues(shost);
 
         scsi_next_command(scmd);
+        scsi_autopm_put_host(shost);
         return rtn;
 }
 EXPORT_SYMBOL(scsi_reset_provider);
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index cd83758ce0a2..d70e91ae60af 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -59,6 +59,12 @@ static int scsi_bus_resume_common(struct device *dev)
 
         if (scsi_is_sdev_device(dev))
                 err = scsi_dev_type_resume(dev);
+
+        if (err == 0) {
+                pm_runtime_disable(dev);
+                pm_runtime_set_active(dev);
+                pm_runtime_enable(dev);
+        }
         return err;
 }
 
@@ -86,6 +92,107 @@ static int scsi_bus_poweroff(struct device *dev)
 
 #endif /* CONFIG_PM_SLEEP */
 
+#ifdef CONFIG_PM_RUNTIME
+
+static int scsi_runtime_suspend(struct device *dev)
+{
+        int err = 0;
+
+        dev_dbg(dev, "scsi_runtime_suspend\n");
+        if (scsi_is_sdev_device(dev)) {
+                err = scsi_dev_type_suspend(dev, PMSG_AUTO_SUSPEND);
+                if (err == -EAGAIN)
+                        pm_schedule_suspend(dev, jiffies_to_msecs(
+                                round_jiffies_up_relative(HZ/10)));
+        }
+
+        /* Insert hooks here for targets, hosts, and transport classes */
+
+        return err;
+}
+
+static int scsi_runtime_resume(struct device *dev)
+{
+        int err = 0;
+
+        dev_dbg(dev, "scsi_runtime_resume\n");
+        if (scsi_is_sdev_device(dev))
+                err = scsi_dev_type_resume(dev);
+
+        /* Insert hooks here for targets, hosts, and transport classes */
+
+        return err;
+}
+
+static int scsi_runtime_idle(struct device *dev)
+{
+        int err;
+
+        dev_dbg(dev, "scsi_runtime_idle\n");
+
+        /* Insert hooks here for targets, hosts, and transport classes */
+
+        if (scsi_is_sdev_device(dev))
+                err = pm_schedule_suspend(dev, 100);
+        else
+                err = pm_runtime_suspend(dev);
+        return err;
+}
+
+int scsi_autopm_get_device(struct scsi_device *sdev)
+{
+        int     err;
+
+        err = pm_runtime_get_sync(&sdev->sdev_gendev);
+        if (err < 0)
+                pm_runtime_put_sync(&sdev->sdev_gendev);
+        else if (err > 0)
+                err = 0;
+        return err;
+}
+EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
+
+void scsi_autopm_put_device(struct scsi_device *sdev)
+{
+        pm_runtime_put_sync(&sdev->sdev_gendev);
+}
+EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
+
+void scsi_autopm_get_target(struct scsi_target *starget)
+{
+        pm_runtime_get_sync(&starget->dev);
+}
+
+void scsi_autopm_put_target(struct scsi_target *starget)
+{
+        pm_runtime_put_sync(&starget->dev);
+}
+
+int scsi_autopm_get_host(struct Scsi_Host *shost)
+{
+        int     err;
+
+        err = pm_runtime_get_sync(&shost->shost_gendev);
+        if (err < 0)
+                pm_runtime_put_sync(&shost->shost_gendev);
+        else if (err > 0)
+                err = 0;
+        return err;
+}
+
+void scsi_autopm_put_host(struct Scsi_Host *shost)
+{
+        pm_runtime_put_sync(&shost->shost_gendev);
+}
+
+#else
+
+#define scsi_runtime_suspend    NULL
+#define scsi_runtime_resume     NULL
+#define scsi_runtime_idle       NULL
+
+#endif /* CONFIG_PM_RUNTIME */
+
 const struct dev_pm_ops scsi_bus_pm_ops = {
         .suspend =              scsi_bus_suspend,
         .resume =               scsi_bus_resume_common,
@@ -93,4 +200,7 @@ const struct dev_pm_ops scsi_bus_pm_ops = {
         .thaw =                 scsi_bus_resume_common,
         .poweroff =             scsi_bus_poweroff,
         .restore =              scsi_bus_resume_common,
+        .runtime_suspend =      scsi_runtime_suspend,
+        .runtime_resume =       scsi_runtime_resume,
+        .runtime_idle =         scsi_runtime_idle,
 };
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index dddacc732550..026295e2c539 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -7,6 +7,7 @@ struct request_queue;
 struct request;
 struct scsi_cmnd;
 struct scsi_device;
+struct scsi_target;
 struct scsi_host_template;
 struct Scsi_Host;
 struct scsi_nl_hdr;
@@ -147,9 +148,20 @@ static inline void scsi_netlink_exit(void) {}
 /* scsi_pm.c */
 #ifdef CONFIG_PM_OPS
 extern const struct dev_pm_ops scsi_bus_pm_ops;
-#else
+#else /* CONFIG_PM_OPS */
 #define scsi_bus_pm_ops         (*NULL)
 #endif
+#ifdef CONFIG_PM_RUNTIME
+extern void scsi_autopm_get_target(struct scsi_target *);
+extern void scsi_autopm_put_target(struct scsi_target *);
+extern int scsi_autopm_get_host(struct Scsi_Host *);
+extern void scsi_autopm_put_host(struct Scsi_Host *);
+#else
+static inline void scsi_autopm_get_target(struct scsi_target *t) {}
+static inline void scsi_autopm_put_target(struct scsi_target *t) {}
+static inline int scsi_autopm_get_host(struct Scsi_Host *h) { return 0; }
+static inline void scsi_autopm_put_host(struct Scsi_Host *h) {}
+#endif /* CONFIG_PM_RUNTIME */
 
 /* 
  * internal scsi timeout functions: for use by mid-layer and transport
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 1c027a97d8b9..3d0a1e6e9c48 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -1513,14 +1513,18 @@ struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
         starget = scsi_alloc_target(parent, channel, id);
         if (!starget)
                 return ERR_PTR(-ENOMEM);
+        scsi_autopm_get_target(starget);
 
         mutex_lock(&shost->scan_mutex);
         if (!shost->async_scan)
                 scsi_complete_async_scans();
 
-        if (scsi_host_scan_allowed(shost))
+        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
                 scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
+                scsi_autopm_put_host(shost);
+        }
         mutex_unlock(&shost->scan_mutex);
+        scsi_autopm_put_target(starget);
         scsi_target_reap(starget);
         put_device(&starget->dev);
 
@@ -1574,6 +1578,7 @@ static void __scsi_scan_target(struct device *parent, unsigned int channel,
         starget = scsi_alloc_target(parent, channel, id);
         if (!starget)
                 return;
+        scsi_autopm_get_target(starget);
 
         if (lun != SCAN_WILD_CARD) {
                 /*
@@ -1599,6 +1604,7 @@ static void __scsi_scan_target(struct device *parent, unsigned int channel,
         }
 
  out_reap:
+        scsi_autopm_put_target(starget);
         /* now determine if the target has any children at all
          * and if not, nuke it */
         scsi_target_reap(starget);
@@ -1633,8 +1639,10 @@ void scsi_scan_target(struct device *parent, unsigned int channel,
         if (!shost->async_scan)
                 scsi_complete_async_scans();
 
-        if (scsi_host_scan_allowed(shost))
+        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
                 __scsi_scan_target(parent, channel, id, lun, rescan);
+                scsi_autopm_put_host(shost);
+        }
         mutex_unlock(&shost->scan_mutex);
 }
 EXPORT_SYMBOL(scsi_scan_target);
@@ -1686,7 +1694,7 @@ int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
         if (!shost->async_scan)
                 scsi_complete_async_scans();
 
-        if (scsi_host_scan_allowed(shost)) {
+        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
                 if (channel == SCAN_WILD_CARD)
                         for (channel = 0; channel <= shost->max_channel;
                              channel++)
@@ -1694,6 +1702,7 @@ int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
                                                   rescan);
                 else
                         scsi_scan_channel(shost, channel, id, lun, rescan);
+                scsi_autopm_put_host(shost);
         }
         mutex_unlock(&shost->scan_mutex);
 
@@ -1831,8 +1840,11 @@ static void do_scsi_scan_host(struct Scsi_Host *shost)
 static int do_scan_async(void *_data)
 {
         struct async_scan_data *data = _data;
-        do_scsi_scan_host(data->shost);
+        struct Scsi_Host *shost = data->shost;
+
+        do_scsi_scan_host(shost);
         scsi_finish_async_scan(data);
+        scsi_autopm_put_host(shost);
         return 0;
 }
 
@@ -1847,16 +1859,20 @@ void scsi_scan_host(struct Scsi_Host *shost)
 
         if (strncmp(scsi_scan_type, "none", 4) == 0)
                 return;
+        if (scsi_autopm_get_host(shost) < 0)
+                return;
 
         data = scsi_prep_async_scan(shost);
         if (!data) {
                 do_scsi_scan_host(shost);
+                scsi_autopm_put_host(shost);
                 return;
         }
 
         p = kthread_run(do_scan_async, data, "scsi_scan_%d", shost->host_no);
         if (IS_ERR(p))
                 do_scan_async(data);
+        /* scsi_autopm_put_host(shost) is called in do_scan_async() */
 }
 EXPORT_SYMBOL(scsi_scan_host);
 
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 5f85f8e831f3..562fb3bce261 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -11,6 +11,7 @@
 #include <linux/init.h>
 #include <linux/blkdev.h>
 #include <linux/device.h>
+#include <linux/pm_runtime.h>
 
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
@@ -802,8 +803,6 @@ static int scsi_target_add(struct scsi_target *starget)
         if (starget->state != STARGET_CREATED)
                 return 0;
 
-        device_enable_async_suspend(&starget->dev);
-
         error = device_add(&starget->dev);
         if (error) {
                 dev_err(&starget->dev, "target device_add failed, error %d\n", error);
@@ -812,6 +811,10 @@ static int scsi_target_add(struct scsi_target *starget)
         transport_add_device(&starget->dev);
         starget->state = STARGET_RUNNING;
 
+        pm_runtime_set_active(&starget->dev);
+        pm_runtime_enable(&starget->dev);
+        device_enable_async_suspend(&starget->dev);
+
         return 0;
 }
 
@@ -841,7 +844,20 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
                 return error;
 
         transport_configure_device(&starget->dev);
+
         device_enable_async_suspend(&sdev->sdev_gendev);
+        scsi_autopm_get_target(starget);
+        pm_runtime_set_active(&sdev->sdev_gendev);
+        pm_runtime_forbid(&sdev->sdev_gendev);
+        pm_runtime_enable(&sdev->sdev_gendev);
+        scsi_autopm_put_target(starget);
+
+        /* The following call will keep sdev active indefinitely, until
+         * its driver does a corresponding scsi_autopm_pm_device().  Only
+         * drivers supporting autosuspend will do this.
+         */
+        scsi_autopm_get_device(sdev);
+
         error = device_add(&sdev->sdev_gendev);
         if (error) {
                 printk(KERN_INFO "error 1\n");
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index d4549092400c..2968c6b83ddb 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -245,6 +245,10 @@ sg_open(struct inode *inode, struct file *filp)
         if (retval)
                 goto sg_put;
 
+        retval = scsi_autopm_get_device(sdp->device);
+        if (retval)
+                goto sdp_put;
+
         if (!((flags & O_NONBLOCK) ||
               scsi_block_when_processing_errors(sdp->device))) {
                 retval = -ENXIO;
@@ -302,8 +306,11 @@ sg_open(struct inode *inode, struct file *filp)
         }
         retval = 0;
 error_out:
-        if (retval)
+        if (retval) {
+                scsi_autopm_put_device(sdp->device);
+sdp_put:
                 scsi_device_put(sdp->device);
+        }
 sg_put:
         if (sdp)
                 sg_put_dev(sdp);
@@ -327,6 +334,7 @@ sg_release(struct inode *inode, struct file *filp)
         sdp->exclude = 0;
         wake_up_interruptible(&sdp->o_excl_wait);
 
+        scsi_autopm_put_device(sdp->device);
         kref_put(&sfp->f_ref, sg_remove_sfp);
         return 0;
 }
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index d80b6dbed1ca..50cb34ffef11 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -381,6 +381,14 @@ extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
                             struct scsi_sense_hdr *, int timeout, int retries,
                             int *resid);
 
+#ifdef CONFIG_PM_RUNTIME
+extern int scsi_autopm_get_device(struct scsi_device *);
+extern void scsi_autopm_put_device(struct scsi_device *);
+#else
+static inline int scsi_autopm_get_device(struct scsi_device *d) { return 0; }
+static inline void scsi_autopm_put_device(struct scsi_device *d) {}
+#endif /* CONFIG_PM_RUNTIME */
+
 static inline int __must_check scsi_device_reprobe(struct scsi_device *sdev)
 {
         return device_reprobe(&sdev->sdev_gendev);