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21e6ba3f0e
As explained during the 2018 LSF/MM session about increasing SCSI disk
probing concurrency, the problems with the current probing approach are as
follows:
- The driver core is unaware of asynchronous SCSI LUN probing.
wait_for_device_probe() waits for all asynchronous probes except
asynchronous SCSI disk probes.
- There is unnecessary serialization between sd_probe() and sd_remove().
This can lead to a deadlock.
Hence this patch that modifies the sd driver such that it uses the driver
core framework for asynchronous probing. The async domains and
get_device()/put_device() pairs that became superfluous due to this change
are removed.
This patch does not affect the time needed for loading the scsi_debug
kernel module with parameters delay=0 and max_luns=256.
This patch depends on commit ef0ff68351 ("driver core: Probe devices
asynchronously instead of the driver") that went upstream in kernel version
v5.1-rc1.
Cc: Lee Duncan <lduncan@suse.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
342 lines
7.5 KiB
C
342 lines
7.5 KiB
C
/*
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* scsi_pm.c Copyright (C) 2010 Alan Stern
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*
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* SCSI dynamic Power Management
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* Initial version: Alan Stern <stern@rowland.harvard.edu>
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*/
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#include <linux/pm_runtime.h>
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#include <linux/export.h>
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#include <linux/async.h>
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#include <linux/blk-pm.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_device.h>
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#include <scsi/scsi_driver.h>
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#include <scsi/scsi_host.h>
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#include "scsi_priv.h"
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#ifdef CONFIG_PM_SLEEP
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static int do_scsi_suspend(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->suspend ? pm->suspend(dev) : 0;
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}
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static int do_scsi_freeze(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->freeze ? pm->freeze(dev) : 0;
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}
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static int do_scsi_poweroff(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->poweroff ? pm->poweroff(dev) : 0;
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}
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static int do_scsi_resume(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->resume ? pm->resume(dev) : 0;
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}
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static int do_scsi_thaw(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->thaw ? pm->thaw(dev) : 0;
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}
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static int do_scsi_restore(struct device *dev, const struct dev_pm_ops *pm)
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{
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return pm && pm->restore ? pm->restore(dev) : 0;
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}
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static int scsi_dev_type_suspend(struct device *dev,
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int (*cb)(struct device *, const struct dev_pm_ops *))
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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int err;
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err = scsi_device_quiesce(to_scsi_device(dev));
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if (err == 0) {
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err = cb(dev, pm);
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if (err)
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scsi_device_resume(to_scsi_device(dev));
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}
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dev_dbg(dev, "scsi suspend: %d\n", err);
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return err;
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}
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static int scsi_dev_type_resume(struct device *dev,
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int (*cb)(struct device *, const struct dev_pm_ops *))
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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int err = 0;
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err = cb(dev, pm);
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scsi_device_resume(to_scsi_device(dev));
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dev_dbg(dev, "scsi resume: %d\n", err);
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if (err == 0) {
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pm_runtime_disable(dev);
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err = pm_runtime_set_active(dev);
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pm_runtime_enable(dev);
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/*
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* Forcibly set runtime PM status of request queue to "active"
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* to make sure we can again get requests from the queue
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* (see also blk_pm_peek_request()).
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*
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* The resume hook will correct runtime PM status of the disk.
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*/
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if (!err && scsi_is_sdev_device(dev)) {
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struct scsi_device *sdev = to_scsi_device(dev);
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if (sdev->request_queue->dev)
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blk_set_runtime_active(sdev->request_queue);
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}
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}
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return err;
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}
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static int
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scsi_bus_suspend_common(struct device *dev,
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int (*cb)(struct device *, const struct dev_pm_ops *))
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{
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int err = 0;
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if (scsi_is_sdev_device(dev)) {
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/*
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* All the high-level SCSI drivers that implement runtime
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* PM treat runtime suspend, system suspend, and system
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* hibernate nearly identically. In all cases the requirements
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* for runtime suspension are stricter.
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*/
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if (pm_runtime_suspended(dev))
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return 0;
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err = scsi_dev_type_suspend(dev, cb);
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}
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return err;
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}
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static void async_sdev_resume(void *dev, async_cookie_t cookie)
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{
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scsi_dev_type_resume(dev, do_scsi_resume);
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}
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static void async_sdev_thaw(void *dev, async_cookie_t cookie)
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{
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scsi_dev_type_resume(dev, do_scsi_thaw);
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}
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static void async_sdev_restore(void *dev, async_cookie_t cookie)
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{
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scsi_dev_type_resume(dev, do_scsi_restore);
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}
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static int scsi_bus_resume_common(struct device *dev,
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int (*cb)(struct device *, const struct dev_pm_ops *))
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{
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async_func_t fn;
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if (!scsi_is_sdev_device(dev))
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fn = NULL;
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else if (cb == do_scsi_resume)
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fn = async_sdev_resume;
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else if (cb == do_scsi_thaw)
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fn = async_sdev_thaw;
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else if (cb == do_scsi_restore)
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fn = async_sdev_restore;
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else
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fn = NULL;
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if (!fn) {
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pm_runtime_disable(dev);
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pm_runtime_set_active(dev);
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pm_runtime_enable(dev);
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}
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return 0;
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}
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static int scsi_bus_prepare(struct device *dev)
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{
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if (scsi_is_host_device(dev)) {
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/* Wait until async scanning is finished */
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scsi_complete_async_scans();
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}
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return 0;
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}
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static int scsi_bus_suspend(struct device *dev)
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{
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return scsi_bus_suspend_common(dev, do_scsi_suspend);
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}
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static int scsi_bus_resume(struct device *dev)
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{
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return scsi_bus_resume_common(dev, do_scsi_resume);
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}
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static int scsi_bus_freeze(struct device *dev)
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{
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return scsi_bus_suspend_common(dev, do_scsi_freeze);
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}
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static int scsi_bus_thaw(struct device *dev)
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{
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return scsi_bus_resume_common(dev, do_scsi_thaw);
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}
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static int scsi_bus_poweroff(struct device *dev)
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{
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return scsi_bus_suspend_common(dev, do_scsi_poweroff);
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}
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static int scsi_bus_restore(struct device *dev)
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{
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return scsi_bus_resume_common(dev, do_scsi_restore);
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}
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#else /* CONFIG_PM_SLEEP */
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#define scsi_bus_prepare NULL
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#define scsi_bus_suspend NULL
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#define scsi_bus_resume NULL
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#define scsi_bus_freeze NULL
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#define scsi_bus_thaw NULL
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#define scsi_bus_poweroff NULL
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#define scsi_bus_restore NULL
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#endif /* CONFIG_PM_SLEEP */
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static int sdev_runtime_suspend(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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struct scsi_device *sdev = to_scsi_device(dev);
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int err = 0;
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err = blk_pre_runtime_suspend(sdev->request_queue);
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if (err)
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return err;
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if (pm && pm->runtime_suspend)
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err = pm->runtime_suspend(dev);
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blk_post_runtime_suspend(sdev->request_queue, err);
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return err;
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}
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static int scsi_runtime_suspend(struct device *dev)
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{
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int err = 0;
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dev_dbg(dev, "scsi_runtime_suspend\n");
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if (scsi_is_sdev_device(dev))
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err = sdev_runtime_suspend(dev);
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/* Insert hooks here for targets, hosts, and transport classes */
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return err;
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}
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static int sdev_runtime_resume(struct device *dev)
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{
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struct scsi_device *sdev = to_scsi_device(dev);
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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int err = 0;
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blk_pre_runtime_resume(sdev->request_queue);
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if (pm && pm->runtime_resume)
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err = pm->runtime_resume(dev);
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blk_post_runtime_resume(sdev->request_queue, err);
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return err;
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}
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static int scsi_runtime_resume(struct device *dev)
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{
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int err = 0;
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dev_dbg(dev, "scsi_runtime_resume\n");
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if (scsi_is_sdev_device(dev))
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err = sdev_runtime_resume(dev);
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/* Insert hooks here for targets, hosts, and transport classes */
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return err;
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}
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static int scsi_runtime_idle(struct device *dev)
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{
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dev_dbg(dev, "scsi_runtime_idle\n");
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/* Insert hooks here for targets, hosts, and transport classes */
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if (scsi_is_sdev_device(dev)) {
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pm_runtime_mark_last_busy(dev);
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pm_runtime_autosuspend(dev);
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return -EBUSY;
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}
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return 0;
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}
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int scsi_autopm_get_device(struct scsi_device *sdev)
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{
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int err;
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err = pm_runtime_get_sync(&sdev->sdev_gendev);
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if (err < 0 && err !=-EACCES)
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pm_runtime_put_sync(&sdev->sdev_gendev);
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else
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err = 0;
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return err;
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}
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EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
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void scsi_autopm_put_device(struct scsi_device *sdev)
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{
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pm_runtime_put_sync(&sdev->sdev_gendev);
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}
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EXPORT_SYMBOL_GPL(scsi_autopm_put_device);
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void scsi_autopm_get_target(struct scsi_target *starget)
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{
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pm_runtime_get_sync(&starget->dev);
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}
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void scsi_autopm_put_target(struct scsi_target *starget)
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{
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pm_runtime_put_sync(&starget->dev);
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}
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int scsi_autopm_get_host(struct Scsi_Host *shost)
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{
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int err;
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err = pm_runtime_get_sync(&shost->shost_gendev);
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if (err < 0 && err !=-EACCES)
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pm_runtime_put_sync(&shost->shost_gendev);
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else
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err = 0;
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return err;
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}
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void scsi_autopm_put_host(struct Scsi_Host *shost)
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{
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pm_runtime_put_sync(&shost->shost_gendev);
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}
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const struct dev_pm_ops scsi_bus_pm_ops = {
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.prepare = scsi_bus_prepare,
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.suspend = scsi_bus_suspend,
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.resume = scsi_bus_resume,
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.freeze = scsi_bus_freeze,
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.thaw = scsi_bus_thaw,
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.poweroff = scsi_bus_poweroff,
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.restore = scsi_bus_restore,
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.runtime_suspend = scsi_runtime_suspend,
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.runtime_resume = scsi_runtime_resume,
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.runtime_idle = scsi_runtime_idle,
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};
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