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6e1fcab00a
John Garry reported a deadlock that occurs when trying to access a
runtime-suspended SATA device. For obscure reasons, the rescan procedure
causes the link to be hard-reset, which disconnects the device.
The rescan tries to carry out a runtime resume when accessing the device.
scsi_rescan_device() holds the SCSI device lock and won't release it until
it can put commands onto the device's block queue. This can't happen until
the queue is successfully runtime-resumed or the device is unregistered.
But the runtime resume fails because the device is disconnected, and
__scsi_remove_device() can't do the unregistration because it can't get the
device lock.
The best way to resolve this deadlock appears to be to allow the block
queue to start running again even after an unsuccessful runtime resume.
The idea is that the driver or the SCSI error handler will need to be able
to use the queue to resolve the runtime resume failure.
This patch removes the err argument to blk_post_runtime_resume() and makes
the routine act as though the resume was successful always. This fixes the
deadlock.
Link: https://lore.kernel.org/r/1639999298-244569-4-git-send-email-chenxiang66@hisilicon.com
Fixes: e27829dc92 ("scsi: serialize ->rescan against ->remove")
Reported-and-tested-by: John Garry <john.garry@huawei.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
274 lines
6.0 KiB
C
274 lines
6.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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/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
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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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if (!scsi_is_sdev_device(dev))
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return 0;
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return scsi_dev_type_suspend(dev, cb);
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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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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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int err;
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if (!scsi_is_sdev_device(dev))
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return 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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return err;
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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);
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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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