Branch data     Line data    Source code

       1                 :            : // SPDX-License-Identifier: GPL-2.0
       2                 :            : 
       3                 :            : #include <linux/blk-mq.h>
       4                 :            : #include <linux/blk-pm.h>
       5                 :            : #include <linux/blkdev.h>
       6                 :            : #include <linux/pm_runtime.h>
       7                 :            : #include "blk-mq.h"
       8                 :            : #include "blk-mq-tag.h"
       9                 :            : 
      10                 :            : /**
      11                 :            :  * blk_pm_runtime_init - Block layer runtime PM initialization routine
      12                 :            :  * @q: the queue of the device
      13                 :            :  * @dev: the device the queue belongs to
      14                 :            :  *
      15                 :            :  * Description:
      16                 :            :  *    Initialize runtime-PM-related fields for @q and start auto suspend for
      17                 :            :  *    @dev. Drivers that want to take advantage of request-based runtime PM
      18                 :            :  *    should call this function after @dev has been initialized, and its
      19                 :            :  *    request queue @q has been allocated, and runtime PM for it can not happen
      20                 :            :  *    yet(either due to disabled/forbidden or its usage_count > 0). In most
      21                 :            :  *    cases, driver should call this function before any I/O has taken place.
      22                 :            :  *
      23                 :            :  *    This function takes care of setting up using auto suspend for the device,
      24                 :            :  *    the autosuspend delay is set to -1 to make runtime suspend impossible
      25                 :            :  *    until an updated value is either set by user or by driver. Drivers do
      26                 :            :  *    not need to touch other autosuspend settings.
      27                 :            :  *
      28                 :            :  *    The block layer runtime PM is request based, so only works for drivers
      29                 :            :  *    that use request as their IO unit instead of those directly use bio's.
      30                 :            :  */
      31                 :          0 : void blk_pm_runtime_init(struct request_queue *q, struct device *dev)
      32                 :            : {
      33                 :          0 :         q->dev = dev;
      34                 :          0 :         q->rpm_status = RPM_ACTIVE;
      35                 :          0 :         pm_runtime_set_autosuspend_delay(q->dev, -1);
      36                 :          0 :         pm_runtime_use_autosuspend(q->dev);
      37                 :          0 : }
      38                 :            : EXPORT_SYMBOL(blk_pm_runtime_init);
      39                 :            : 
      40                 :            : /**
      41                 :            :  * blk_pre_runtime_suspend - Pre runtime suspend check
      42                 :            :  * @q: the queue of the device
      43                 :            :  *
      44                 :            :  * Description:
      45                 :            :  *    This function will check if runtime suspend is allowed for the device
      46                 :            :  *    by examining if there are any requests pending in the queue. If there
      47                 :            :  *    are requests pending, the device can not be runtime suspended; otherwise,
      48                 :            :  *    the queue's status will be updated to SUSPENDING and the driver can
      49                 :            :  *    proceed to suspend the device.
      50                 :            :  *
      51                 :            :  *    For the not allowed case, we mark last busy for the device so that
      52                 :            :  *    runtime PM core will try to autosuspend it some time later.
      53                 :            :  *
      54                 :            :  *    This function should be called near the start of the device's
      55                 :            :  *    runtime_suspend callback.
      56                 :            :  *
      57                 :            :  * Return:
      58                 :            :  *    0         - OK to runtime suspend the device
      59                 :            :  *    -EBUSY    - Device should not be runtime suspended
      60                 :            :  */
      61                 :          0 : int blk_pre_runtime_suspend(struct request_queue *q)
      62                 :            : {
      63                 :            :         int ret = 0;
      64                 :            : 
      65                 :          0 :         if (!q->dev)
      66                 :            :                 return ret;
      67                 :            : 
      68                 :          0 :         WARN_ON_ONCE(q->rpm_status != RPM_ACTIVE);
      69                 :            : 
      70                 :            :         /*
      71                 :            :          * Increase the pm_only counter before checking whether any
      72                 :            :          * non-PM blk_queue_enter() calls are in progress to avoid that any
      73                 :            :          * new non-PM blk_queue_enter() calls succeed before the pm_only
      74                 :            :          * counter is decreased again.
      75                 :            :          */
      76                 :          0 :         blk_set_pm_only(q);
      77                 :            :         ret = -EBUSY;
      78                 :            :         /* Switch q_usage_counter from per-cpu to atomic mode. */
      79                 :          0 :         blk_freeze_queue_start(q);
      80                 :            :         /*
      81                 :            :          * Wait until atomic mode has been reached. Since that
      82                 :            :          * involves calling call_rcu(), it is guaranteed that later
      83                 :            :          * blk_queue_enter() calls see the pm-only state. See also
      84                 :            :          * http://lwn.net/Articles/573497/.
      85                 :            :          */
      86                 :          0 :         percpu_ref_switch_to_atomic_sync(&q->q_usage_counter);
      87                 :          0 :         if (percpu_ref_is_zero(&q->q_usage_counter))
      88                 :            :                 ret = 0;
      89                 :            :         /* Switch q_usage_counter back to per-cpu mode. */
      90                 :          0 :         blk_mq_unfreeze_queue(q);
      91                 :            : 
      92                 :            :         spin_lock_irq(&q->queue_lock);
      93                 :          0 :         if (ret < 0)
      94                 :          0 :                 pm_runtime_mark_last_busy(q->dev);
      95                 :            :         else
      96                 :          0 :                 q->rpm_status = RPM_SUSPENDING;
      97                 :            :         spin_unlock_irq(&q->queue_lock);
      98                 :            : 
      99                 :          0 :         if (ret)
     100                 :          0 :                 blk_clear_pm_only(q);
     101                 :            : 
     102                 :          0 :         return ret;
     103                 :            : }
     104                 :            : EXPORT_SYMBOL(blk_pre_runtime_suspend);
     105                 :            : 
     106                 :            : /**
     107                 :            :  * blk_post_runtime_suspend - Post runtime suspend processing
     108                 :            :  * @q: the queue of the device
     109                 :            :  * @err: return value of the device's runtime_suspend function
     110                 :            :  *
     111                 :            :  * Description:
     112                 :            :  *    Update the queue's runtime status according to the return value of the
     113                 :            :  *    device's runtime suspend function and mark last busy for the device so
     114                 :            :  *    that PM core will try to auto suspend the device at a later time.
     115                 :            :  *
     116                 :            :  *    This function should be called near the end of the device's
     117                 :            :  *    runtime_suspend callback.
     118                 :            :  */
     119                 :          0 : void blk_post_runtime_suspend(struct request_queue *q, int err)
     120                 :            : {
     121                 :          0 :         if (!q->dev)
     122                 :          0 :                 return;
     123                 :            : 
     124                 :            :         spin_lock_irq(&q->queue_lock);
     125                 :          0 :         if (!err) {
     126                 :          0 :                 q->rpm_status = RPM_SUSPENDED;
     127                 :            :         } else {
     128                 :          0 :                 q->rpm_status = RPM_ACTIVE;
     129                 :          0 :                 pm_runtime_mark_last_busy(q->dev);
     130                 :            :         }
     131                 :            :         spin_unlock_irq(&q->queue_lock);
     132                 :            : 
     133                 :          0 :         if (err)
     134                 :          0 :                 blk_clear_pm_only(q);
     135                 :            : }
     136                 :            : EXPORT_SYMBOL(blk_post_runtime_suspend);
     137                 :            : 
     138                 :            : /**
     139                 :            :  * blk_pre_runtime_resume - Pre runtime resume processing
     140                 :            :  * @q: the queue of the device
     141                 :            :  *
     142                 :            :  * Description:
     143                 :            :  *    Update the queue's runtime status to RESUMING in preparation for the
     144                 :            :  *    runtime resume of the device.
     145                 :            :  *
     146                 :            :  *    This function should be called near the start of the device's
     147                 :            :  *    runtime_resume callback.
     148                 :            :  */
     149                 :          0 : void blk_pre_runtime_resume(struct request_queue *q)
     150                 :            : {
     151                 :          0 :         if (!q->dev)
     152                 :          0 :                 return;
     153                 :            : 
     154                 :            :         spin_lock_irq(&q->queue_lock);
     155                 :          0 :         q->rpm_status = RPM_RESUMING;
     156                 :            :         spin_unlock_irq(&q->queue_lock);
     157                 :            : }
     158                 :            : EXPORT_SYMBOL(blk_pre_runtime_resume);
     159                 :            : 
     160                 :            : /**
     161                 :            :  * blk_post_runtime_resume - Post runtime resume processing
     162                 :            :  * @q: the queue of the device
     163                 :            :  * @err: return value of the device's runtime_resume function
     164                 :            :  *
     165                 :            :  * Description:
     166                 :            :  *    Update the queue's runtime status according to the return value of the
     167                 :            :  *    device's runtime_resume function. If it is successfully resumed, process
     168                 :            :  *    the requests that are queued into the device's queue when it is resuming
     169                 :            :  *    and then mark last busy and initiate autosuspend for it.
     170                 :            :  *
     171                 :            :  *    This function should be called near the end of the device's
     172                 :            :  *    runtime_resume callback.
     173                 :            :  */
     174                 :          0 : void blk_post_runtime_resume(struct request_queue *q, int err)
     175                 :            : {
     176                 :          0 :         if (!q->dev)
     177                 :          0 :                 return;
     178                 :            : 
     179                 :            :         spin_lock_irq(&q->queue_lock);
     180                 :          0 :         if (!err) {
     181                 :          0 :                 q->rpm_status = RPM_ACTIVE;
     182                 :          0 :                 pm_runtime_mark_last_busy(q->dev);
     183                 :          0 :                 pm_request_autosuspend(q->dev);
     184                 :            :         } else {
     185                 :          0 :                 q->rpm_status = RPM_SUSPENDED;
     186                 :            :         }
     187                 :            :         spin_unlock_irq(&q->queue_lock);
     188                 :            : 
     189                 :          0 :         if (!err)
     190                 :          0 :                 blk_clear_pm_only(q);
     191                 :            : }
     192                 :            : EXPORT_SYMBOL(blk_post_runtime_resume);
     193                 :            : 
     194                 :            : /**
     195                 :            :  * blk_set_runtime_active - Force runtime status of the queue to be active
     196                 :            :  * @q: the queue of the device
     197                 :            :  *
     198                 :            :  * If the device is left runtime suspended during system suspend the resume
     199                 :            :  * hook typically resumes the device and corrects runtime status
     200                 :            :  * accordingly. However, that does not affect the queue runtime PM status
     201                 :            :  * which is still "suspended". This prevents processing requests from the
     202                 :            :  * queue.
     203                 :            :  *
     204                 :            :  * This function can be used in driver's resume hook to correct queue
     205                 :            :  * runtime PM status and re-enable peeking requests from the queue. It
     206                 :            :  * should be called before first request is added to the queue.
     207                 :            :  */
     208                 :          0 : void blk_set_runtime_active(struct request_queue *q)
     209                 :            : {
     210                 :          0 :         if (q->dev) {
     211                 :            :                 spin_lock_irq(&q->queue_lock);
     212                 :          0 :                 q->rpm_status = RPM_ACTIVE;
     213                 :          0 :                 pm_runtime_mark_last_busy(q->dev);
     214                 :          0 :                 pm_request_autosuspend(q->dev);
     215                 :            :                 spin_unlock_irq(&q->queue_lock);
     216                 :            :         }
     217                 :          0 : }
     218                 :            : EXPORT_SYMBOL(blk_set_runtime_active);