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3c31b52f96
async_schedule() sd resume work to allow disks and other devices to
resume in parallel.
This moves the entirety of scsi_device resume to an async context to
ensure that scsi_device_resume() remains ordered with respect to the
completion of the start/stop command. For the duration of the resume,
new command submissions (that do not originate from the scsi-core) will
be deferred (BLKPREP_DEFER).
It adds a new ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain) as a container
of these operations. Like scsi_sd_probe_domain it is flushed at
sd_remove() time to ensure async ops do not continue past the
end-of-life of the sdev. The implementation explicitly refrains from
reusing scsi_sd_probe_domain directly for this purpose as it is flushed
at the end of dpm_resume(), potentially defeating some of the benefit.
Given sdevs are quiesced it is permissible for these resume operations
to bleed past the async_synchronize_full() calls made by the driver
core.
We defer the resolution of which pm callback to call until
scsi_dev_type_{suspend|resume} time and guarantee that the callback
parameter is never NULL. With this in place the type of resume
operation is encoded in the async function identifier.
There is a concern that async resume could trigger PSU overload. In the
enterprise, storage enclosures enforce staggered spin-up regardless of
what the kernel does making async scanning safe by default. Outside of
that context a user can disable asynchronous scanning via a kernel
command line or CONFIG_SCSI_SCAN_ASYNC. Honor that setting when
deciding whether to do resume asynchronously.
Inspired by Todd's analysis and initial proposal [2]:
https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach
Cc: Len Brown <len.brown@intel.com>
Cc: Phillip Susi <psusi@ubuntu.com>
[alan: bug fix and clean up suggestion]
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Suggested-by: Todd Brandt <todd.e.brandt@linux.intel.com>
[djbw: kick all resume work to the async queue]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
355 lines
7.9 KiB
C
355 lines
7.9 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 <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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/* flush pending in-flight resume operations, suspend is synchronous */
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async_synchronize_full_domain(&scsi_sd_pm_domain);
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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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pm_runtime_set_active(dev);
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pm_runtime_enable(dev);
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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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async_schedule_domain(fn, dev, &scsi_sd_pm_domain);
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/*
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* If a user has disabled async probing a likely reason
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* is due to a storage enclosure that does not inject
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* staggered spin-ups. For safety, make resume
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* synchronous as well in that case.
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*/
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if (strncmp(scsi_scan_type, "async", 5) != 0)
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async_synchronize_full_domain(&scsi_sd_pm_domain);
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} else {
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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_sdev_device(dev)) {
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/* sd probing uses async_schedule. Wait until it finishes. */
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async_synchronize_full_domain(&scsi_sd_probe_domain);
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} else 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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#ifdef CONFIG_PM_RUNTIME
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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;
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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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#else
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#define scsi_runtime_suspend NULL
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#define scsi_runtime_resume NULL
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#define scsi_runtime_idle NULL
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#endif /* CONFIG_PM_RUNTIME */
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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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