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* scsi: async sd resumeDan Williams2014-04-101-29/+99
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* [SCSI] sr: use block layer runtime PMAaron Lu2013-12-161-46/+16
| | | | | | | | | | | | | | | Migrate sr to make use of block layer runtime PM. Accordingly, the SCSI bus layer runtime PM callback is simplified as all SCSI drivers implementing runtime PM now use the block layer's request-based mechanism. Note that due to the device will be polled by kernel at a constant interval, if the autosuspend delay is set longer than the polling interval then the device will never suspend. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] sd: Add error handling during flushing cachesOliver Neukum2013-10-251-1/+2
| | | | | | | | | | | | | | It makes no sense to flush the cache of a device without medium. Errors during suspend must be handled according to their causes. Errors due to missing media or unplugged devices must be ignored. Errors due to devices being offlined must also be ignored. The error returns must be modified so that the generic layer understands them. [jejb: fix up whitespace and other formatting problems] Signed-off-by: Oliver Neukum <oneukum@suse.de> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* PM / Runtime: Rework the "runtime idle" helper routineRafael J. Wysocki2013-06-031-8/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | The "runtime idle" helper routine, rpm_idle(), currently ignores return values from .runtime_idle() callbacks executed by it. However, it turns out that many subsystems use pm_generic_runtime_idle() which checks the return value of the driver's callback and executes pm_runtime_suspend() for the device unless that value is not 0. If that logic is moved to rpm_idle() instead, pm_generic_runtime_idle() can be dropped and its users will not need any .runtime_idle() callbacks any more. Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle() routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and ata_port_runtime_idle(), respectively, as well as a few drivers' ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has been returned by the .runtime_idle() callback executed by it. To reduce overall code bloat, make the changes described above. Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Tested-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Kevin Hilman <khilman@linaro.org> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Acked-by: Alan Stern <stern@rowland.harvard.edu>
* [SCSI] sd: change to auto suspend modeLin Ming2013-05-061-13/+71
| | | | | | | | | | | | Uses block layer runtime pm helper functions in scsi_runtime_suspend/resume for devices that take advantage of it. Remove scsi_autopm_* from sd open/release path and check_events path. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] scsi_pm: use callbacks from dev_pm_ops for scsi devicesAaron Lu2012-11-301-33/+53
| | | | | | | | | | | | | | | | | | | | | | | | | | Use of pm_message_t is deprecated and device driver is not supposed to use that. This patch migrates the SCSI bus level pm callbacks to call device's pm callbacks defined in its driver's dev_pm_ops. This is achieved by finding out which device pm callback should be used in bus callback function, and then pass that callback function pointer as a param to the scsi_bus_{suspend,resume}_common routine, which will further pass that callback to scsi_dev_type_{suspend,resume} after proper handling. The special case for freeze in scsi_bus_suspend_common is not necessary since there is no high level SCSI driver has implemented freeze, so no need to runtime resume the device if it is in runtime suspended state for system freeze, just return like the system suspend/hibernate case. Since only sd has implemented drv->suspend/drv->resume, and I'll update sd driver to use the new callbacks in the following patch, there is no need to fallback to call drv->suspend/drv->resume if dev_pm_ops is NULL. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] Revert "[SCSI] runtime resume parent for child's system-resume"Aaron Lu2012-11-301-10/+1
| | | | | | | | | | | | This reverts commit 28fd00d42cca178638f51c08efa986a777c24a4b. With commit 88d26136a256576e444db312179e17af6dd0ea87 (PM: Prevent runtime suspend during system resume), this patch is no longer needed. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] Revert "[SCSI] scsi_pm: set device runtime state before parent suspended"Aaron Lu2012-11-301-12/+11
| | | | | | | | | | | | This reverts commit 33a2285d96b5e7b9500612ec623bf4313397bb53. With commit 88d26136a256576e444db312179e17af6dd0ea87 (PM: Prevent runtime suspend during system resume), this patch is no longer needed. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] scsi_pm: set device runtime state before parent suspendedLin Ming2012-07-201-11/+12
| | | | | | | | | | | | There is a race in scsi_bus_resume_common when set device's runtime state to active after pm_runtime_put_sync(dev->parent). Parent device may have been suspended so pm_runtime_set_active(dev) will fail with -EBUSY. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] scsi_pm: resume device if suspend failedAaron Lu2012-05-221-1/+4
| | | | | | | | | | | | | For scsi devices which use scsi bus runtime callback, runtime suspend will call scsi_dev_type_suspend, and if the drv->suspend failed, the device will still be in active state. But since scsi_device_quiesce is called, the device will not be able to respond any more commands. So add a check here to see if err occured, if so, bring the device back to normal state with scsi_device_resume. Signed-off-by: Aaron Lu <aaron.lu@amd.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] sd: limit the scope of the async probe domainDan Williams2012-05-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sd injects and synchronizes probe work on the global kernel-wide domain. This runs into conflict with PM that wants to perform resume actions in async context: [ 494.237079] INFO: task kworker/u:3:554 blocked for more than 120 seconds. [ 494.294396] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 494.360809] kworker/u:3 D 0000000000000000 0 554 2 0x00000000 [ 494.420739] ffff88012e4d3af0 0000000000000046 ffff88013200c160 ffff88012e4d3fd8 [ 494.484392] ffff88012e4d3fd8 0000000000012500 ffff8801394ea0b0 ffff88013200c160 [ 494.548038] ffff88012e4d3ae0 00000000000001e3 ffffffff81a249e0 ffff8801321c5398 [ 494.611685] Call Trace: [ 494.632649] [<ffffffff8149dd25>] schedule+0x5a/0x5c [ 494.674687] [<ffffffff8104b968>] async_synchronize_cookie_domain+0xb6/0x112 [ 494.734177] [<ffffffff810461ff>] ? __init_waitqueue_head+0x50/0x50 [ 494.787134] [<ffffffff8131a224>] ? scsi_remove_target+0x48/0x48 [ 494.837900] [<ffffffff8104b9d9>] async_synchronize_cookie+0x15/0x17 [ 494.891567] [<ffffffff8104ba49>] async_synchronize_full+0x54/0x70 <-- here we wait for async contexts to complete [ 494.943783] [<ffffffff8104b9f5>] ? async_synchronize_full_domain+0x1a/0x1a [ 495.002547] [<ffffffffa00114b1>] sd_remove+0x2c/0xa2 [sd_mod] [ 495.051861] [<ffffffff812fe94f>] __device_release_driver+0x86/0xcf [ 495.104807] [<ffffffff812fe9bd>] device_release_driver+0x25/0x32 <-- here we take device_lock() [ 853.511341] INFO: task kworker/u:4:549 blocked for more than 120 seconds. [ 853.568693] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 853.635119] kworker/u:4 D ffff88013097b5d0 0 549 2 0x00000000 [ 853.695129] ffff880132773c40 0000000000000046 ffff880130790000 ffff880132773fd8 [ 853.758990] ffff880132773fd8 0000000000012500 ffff88013288a0b0 ffff880130790000 [ 853.822796] 0000000000000246 0000000000000040 ffff88013097b5c8 ffff880130790000 [ 853.886633] Call Trace: [ 853.907631] [<ffffffff8149dd25>] schedule+0x5a/0x5c [ 853.949670] [<ffffffff8149cc44>] __mutex_lock_common+0x220/0x351 [ 854.001225] [<ffffffff81304bd7>] ? device_resume+0x58/0x1c4 [ 854.049082] [<ffffffff81304bd7>] ? device_resume+0x58/0x1c4 [ 854.097011] [<ffffffff8149ce48>] mutex_lock_nested+0x2f/0x36 <-- here we wait for device_lock() [ 854.145591] [<ffffffff81304bd7>] device_resume+0x58/0x1c4 [ 854.192066] [<ffffffff81304d61>] async_resume+0x1e/0x45 [ 854.237019] [<ffffffff8104bc93>] async_run_entry_fn+0xc6/0x173 <-- ...while running in async context Provide a 'scsi_sd_probe_domain' so that async probe actions actions can be flushed without regard for the state of PM, and allow for the resume path to handle devices that have transitioned from SDEV_QUIESCE to SDEV_DEL prior to resume. Acked-by: Alan Stern <stern@rowland.harvard.edu> [alan: uplevel scsi_sd_probe_domain, clarify scsi_device_resume] Signed-off-by: Dan Williams <dan.j.williams@intel.com> [jejb: remove unneeded config guards in include file] Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] scsi_pm: Fix bug in the SCSI power management handlerAlan Stern2012-02-181-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch (as1520) fixes a bug in the SCSI layer's power management implementation. LUN scanning can be carried out asynchronously in do_scan_async(), and sd uses an asynchronous thread for the time-consuming parts of disk probing in sd_probe_async(). Currently nothing coordinates these async threads with system sleep transitions; they can and do attempt to continue scanning/probing SCSI devices even after the host adapter has been suspended. As one might expect, the outcome is not ideal. This is what the "prepare" stage of system suspend was created for. After the prepare callback has been called for a host, target, or device, drivers are not allowed to register any children underneath them. Currently the SCSI prepare callback is not implemented; this patch rectifies that omission. For SCSI hosts, the prepare routine calls scsi_complete_async_scans() to wait until async scanning is finished. It might be slightly more efficient to wait only until the host in question has been scanned, but there's currently no way to do that. Besides, during a sleep transition we will ultimately have to wait until all the host scanning has finished anyway. For SCSI devices, the prepare routine calls async_synchronize_full() to wait until sd probing is finished. The routine does nothing for SCSI targets, because asynchronous target scanning is done only as part of host scanning. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> CC: <stable@kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
* [SCSI] runtime resume parent for child's system-resumeLin Ming2012-01-081-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | [Patch description from Alan Stern] If a child device was runtime-suspended when a system suspend began, then there will be nothing to prevent its parent from runtime-suspending as soon as it is woken up during the system resume. Then when the time comes to resume the child, the resume will fail because the parent is already back at low power. On the other hand, there are some devices which should remain at low power across an entire suspend-resume cycle. The details depend on the device and the platform. This suggests that the PM core is not the right place to solve the problem. One possible solution is for the subsystem or device driver to call pm_runtime_get_sync(dev->parent) at the start of the system-resume procedure and pm_runtime_put_sync(dev->parent) at the end. Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
* [SCSI] check runtime PM status in system PMLin Ming2012-01-081-1/+15
| | | | | | | | | | | | | | | | | The only high-level SCSI driver that currently implements runtime PM is sd, and sd treats runtime suspend exactly the same as the SUSPEND and HIBERNATE stages of system sleep, but not the same as the FREEZE stage. Therefore, when entering the SUSPEND or HIBERNATE stages of system sleep, we can skip the callback to the driver if the device is already in runtime suspend. When entering the FREEZE stage, however, we should first issue a runtime resume. The overhead of doing this is negligible, because a suspended drive would be spun up during the THAW stage of hibernation anyway. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
* scsi: Add export.h for EXPORT_SYMBOL/THIS_MODULE as requiredPaul Gortmaker2011-10-311-0/+1
| | | | | | | | For the basic SCSI infrastructure files that are exporting symbols but not modules themselves, add in the basic export.h header file to allow the exports. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
* PM / Runtime: Return special error code if runtime PM is disabledRafael J. Wysocki2011-07-021-4/+4
| | | | | | | | | | | | | | | Some callers of pm_runtime_get_sync() and other runtime PM helper functions, scsi_autopm_get_host() and scsi_autopm_get_device() in particular, need to distinguish error codes returned when runtime PM is disabled (i.e. power.disable_depth is nonzero for the given device) from error codes returned in other situations. For this reason, make the runtime PM helper functions return -EACCES when power.disable_depth is nonzero and ensure that this error code won't be returned by them in any other circumstances. Modify scsi_autopm_get_host() and scsi_autopm_get_device() to check the error code returned by pm_runtime_get_sync() and ignore -EACCES. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* [SCSI] implement runtime Power ManagementAlan Stern2010-07-281-0/+110
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch (as1398b) adds runtime PM support to the SCSI layer. Only the machanism is provided; use of it is up to the various high-level drivers, and the patch doesn't change any of them. Except for sg -- the patch expicitly prevents a device from being runtime-suspended while its sg device file is open. The implementation is simplistic. In general, hosts and targets are automatically suspended when all their children are asleep, but for them the runtime-suspend code doesn't actually do anything. (A host's runtime PM status is propagated up the device tree, though, so a runtime-PM-aware lower-level driver could power down the host adapter hardware at the appropriate times.) There are comments indicating where a transport class might be notified or some other hooks added. LUNs are runtime-suspended by calling the drivers' existing suspend handlers (and likewise for runtime-resume). Somewhat arbitrarily, the implementation delays for 100 ms before suspending an eligible LUN. This is because there typically are occasions during bootup when the same device file is opened and closed several times in quick succession. The way this all works is that the SCSI core increments a device's PM-usage count when it is registered. If a high-level driver does nothing then the device will not be eligible for runtime-suspend because of the elevated usage count. If a high-level driver wants to use runtime PM then it can call scsi_autopm_put_device() in its probe routine to decrement the usage count and scsi_autopm_get_device() in its remove routine to restore the original count. Hosts, targets, and LUNs are not suspended while they are being probed or removed, or while the error handler is running. In fact, a fairly large part of the patch consists of code to make sure that things aren't suspended at such times. [jejb: fix up compile issues in PM config variations] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
* [SCSI] convert to the new PM frameworkAlan Stern2010-07-281-0/+96
This patch (as1397b) converts the SCSI midlayer to use the new PM callbacks (struct dev_pm_ops). A new source file, scsi_pm.c, is created to hold the new callback routines, and the existing suspend/resume code is moved there. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
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