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path: root/drivers/scsi/scsi_pm.c
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2020-07-24scsi: block: pm: Simplify resume handlingAlan Stern
Commit 05d18ae1cc8a ("scsi: pm: Balance pm_only counter of request queue during system resume") fixed a problem in the block layer's runtime-PM code: blk_set_runtime_active() failed to call blk_clear_pm_only(). However, the commit's implementation was awkward; it forced the SCSI system-resume handler to choose whether to call blk_post_runtime_resume() or blk_set_runtime_active(), depending on whether or not the SCSI device had previously been runtime suspended. This patch simplifies the situation considerably by adding the missing function call directly into blk_set_runtime_active() (under the condition that the queue is not already in the RPM_ACTIVE state). This allows the SCSI routine to revert back to its original form. Furthermore, making this change reveals that blk_post_runtime_resume() (in its success pathway) does exactly the same thing as blk_set_runtime_active(). The duplicate code is easily removed by making one routine call the other. No functional changes are intended. Link: https://lore.kernel.org/r/20200706151436.GA702867@rowland.harvard.edu CC: Can Guo <cang@codeaurora.org> CC: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2020-05-11scsi: pm: Balance pm_only counter of request queue during system resumeCan Guo
During system resume, scsi_resume_device() decreases a request queue's pm_only counter if the scsi device was quiesced before. But after that, if the scsi device's RPM status is RPM_SUSPENDED, the pm_only counter is still held (non-zero). Current SCSI resume hook only sets the RPM status of the scsi_device and its request queue to RPM_ACTIVE, but leaves the pm_only counter unchanged. This may make the request queue's pm_only counter remain non-zero after resume hook returns, hence those who are waiting on the mq_freeze_wq would never be woken up. Fix this by calling blk_post_runtime_resume() if a sdev's RPM status was RPM_SUSPENDED. (struct request_queue)0xFFFFFF815B69E938 pm_only = (counter = 2), rpm_status = 0, dev = 0xFFFFFF815B0511A0, ((struct device)0xFFFFFF815B0511A0)).power is_suspended = FALSE, runtime_status = RPM_ACTIVE, (struct scsi_device)0xffffff815b051000 request_queue = 0xFFFFFF815B69E938, sdev_state = SDEV_RUNNING, quiesced_by = 0x0, B::v.f_/task_0xFFFFFF810C246940 -000|__switch_to(prev = 0xFFFFFF810C246940, next = 0xFFFFFF80A49357C0) -001|context_switch(inline) -001|__schedule(?) -002|schedule() -003|blk_queue_enter(q = 0xFFFFFF815B69E938, flags = 0) -004|generic_make_request(?) -005|submit_bio(bio = 0xFFFFFF80A8195B80) Link: https://lore.kernel.org/r/1588740936-28846-1-git-send-email-cang@codeaurora.org Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Can Guo <cang@codeaurora.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-09-12scsi: core: remove dummy q->dev checkStanley Chu
Currently blk_set_runtime_active() is checking if q->dev is null by itself, thus remove the same checking in its user: scsi_dev_type_resume(). Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-07-11Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds
Pull SCSI updates from James Bottomley: "This is mostly update of the usual drivers: qla2xxx, hpsa, lpfc, ufs, mpt3sas, ibmvscsi, megaraid_sas, bnx2fc and hisi_sas as well as the removal of the osst driver (I heard from Willem privately that he would like the driver removed because all his test hardware has failed). Plus number of minor changes, spelling fixes and other trivia. The big merge conflict this time around is the SPDX licence tags. Following discussion on linux-next, we believe our version to be more accurate than the one in the tree, so the resolution is to take our version for all the SPDX conflicts" Note on the SPDX license tag conversion conflicts: the SCSI tree had done its own SPDX conversion, which in some cases conflicted with the treewide ones done by Thomas & co. In almost all cases, the conflicts were purely syntactic: the SCSI tree used the old-style SPDX tags ("GPL-2.0" and "GPL-2.0+") while the treewide conversion had used the new-style ones ("GPL-2.0-only" and "GPL-2.0-or-later"). In these cases I picked the new-style one. In a few cases, the SPDX conversion was actually different, though. As explained by James above, and in more detail in a pre-pull-request thread: "The other problem is actually substantive: In the libsas code Luben Tuikov originally specified gpl 2.0 only by dint of stating: * This file is licensed under GPLv2. In all the libsas files, but then muddied the water by quoting GPLv2 verbatim (which includes the or later than language). So for these files Christoph did the conversion to v2 only SPDX tags and Thomas converted to v2 or later tags" So in those cases, where the spdx tag substantially mattered, I took the SCSI tree conversion of it, but then also took the opportunity to turn the old-style "GPL-2.0" into a new-style "GPL-2.0-only" tag. Similarly, when there were whitespace differences or other differences to the comments around the copyright notices, I took the version from the SCSI tree as being the more specific conversion. Finally, in the spdx conversions that had no conflicts (because the treewide ones hadn't been done for those files), I just took the SCSI tree version as-is, even if it was old-style. The old-style conversions are perfectly valid, even if the "-only" and "-or-later" versions are perhaps more descriptive. * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (185 commits) scsi: qla2xxx: move IO flush to the front of NVME rport unregistration scsi: qla2xxx: Fix NVME cmd and LS cmd timeout race condition scsi: qla2xxx: on session delete, return nvme cmd scsi: qla2xxx: Fix kernel crash after disconnecting NVMe devices scsi: megaraid_sas: Update driver version to 07.710.06.00-rc1 scsi: megaraid_sas: Introduce various Aero performance modes scsi: megaraid_sas: Use high IOPS queues based on IO workload scsi: megaraid_sas: Set affinity for high IOPS reply queues scsi: megaraid_sas: Enable coalescing for high IOPS queues scsi: megaraid_sas: Add support for High IOPS queues scsi: megaraid_sas: Add support for MPI toolbox commands scsi: megaraid_sas: Offload Aero RAID5/6 division calculations to driver scsi: megaraid_sas: RAID1 PCI bandwidth limit algorithm is applicable for only Ventura scsi: megaraid_sas: megaraid_sas: Add check for count returned by HOST_DEVICE_LIST DCMD scsi: megaraid_sas: Handle sequence JBOD map failure at driver level scsi: megaraid_sas: Don't send FPIO to RL Bypass queue scsi: megaraid_sas: In probe context, retry IOC INIT once if firmware is in fault scsi: megaraid_sas: Release Mutex lock before OCR in case of DCMD timeout scsi: megaraid_sas: Call disable_irq from process IRQ poll scsi: megaraid_sas: Remove few debug counters from IO path ...
2019-06-18scsi: sd: Rely on the driver core for asynchronous probingBart Van Assche
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 domain 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 ef0ff68351be ("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: Pavel Machek <pavel@ucw.cz> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-05-21scsi: core: add SPDX tags to scsi midlayer files missing licensing informationChristoph Hellwig
Add the default kernel GPLv2 annotation to SCSI midlayer files missing any licensing information. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2019-05-21treewide: Add SPDX license identifier for missed filesThomas Gleixner
Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-08scsi: core: Synchronize request queue PM status only on successful resumeStanley Chu
The commit 356fd2663cff ("scsi: Set request queue runtime PM status back to active on resume") fixed up the inconsistent RPM status between request queue and device. However changing request queue RPM status shall be done only on successful resume, otherwise status may be still inconsistent as below, Request queue: RPM_ACTIVE Device: RPM_SUSPENDED This ends up soft lockup because requests can be submitted to underlying devices but those devices and their required resource are not resumed. For example, After above inconsistent status happens, IO request can be submitted to UFS device driver but required resource (like clock) is not resumed yet thus lead to warning as below call stack, WARN_ON(hba->clk_gating.state != CLKS_ON); ufshcd_queuecommand scsi_dispatch_cmd scsi_request_fn __blk_run_queue cfq_insert_request __elv_add_request blk_flush_plug_list blk_finish_plug jbd2_journal_commit_transaction kjournald2 We may see all behind IO requests hang because of no response from storage host or device and then soft lockup happens in system. In the end, system may crash in many ways. Fixes: 356fd2663cff (scsi: Set request queue runtime PM status back to active on resume) Cc: stable@vger.kernel.org Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-09-26block: Move power management code into a new source fileBart Van Assche
Move the code for runtime power management from blk-core.c into the new source file blk-pm.c. Move the corresponding declarations from <linux/blkdev.h> into <linux/blk-pm.h>. For CONFIG_PM=n, leave out the declarations of the functions that are not used in that mode. This patch not only reduces the number of #ifdefs in the block layer core code but also reduces the size of header file <linux/blkdev.h> and hence should help to reduce the build time of the Linux kernel if CONFIG_PM is not defined. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2016-02-19scsi: Set request queue runtime PM status back to active on resumeMika Westerberg
We treat system suspend of SCSI devices pretty much the same as runtime suspend. If the device is already runtime suspended we leave it to that state during system suspend. On resume from system sleep we then resume the device and correct the runtime PM status back to "active". There is a problem with this because runtime PM status of the request queue in question is not changed (it will be in "suspended" state). When SCSI disk driver (sd.c) resumes the disk it sends START message to the device and because the request queue is still in "suspended" state blk_pm_peek_request() returns NULL preventing resume of the disk. The issue can be reproduced with following commands: # echo auto > /sys/block/sda/device/power/control # echo 15000 > /sys/block/sda/device/power/autosuspend_delay_ms [ 57.191706] sd 0:0:0:0: [sda] Synchronizing SCSI cache [ 57.380015] sd 0:0:0:0: [sda] Stopping disk Now suspend the machine: # rtcwake -s10 -mmem This ends up in soft lockup because resume is not proceeding accordingly and userspace is never restarted. Also there is nothing printed to the console. Fix this by forcing request queue status to "active" before the disk is resumed. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2015-12-10Revert "SCSI: Fix NULL pointer dereference in runtime PM"Ken Xue
This reverts commit 49718f0fb8c9 ("SCSI: Fix NULL pointer dereference in runtime PM") The old commit may lead to a issue that blk_{pre|post}_runtime_suspend and blk_{pre|post}_runtime_resume may not be called in pairs. Take sr device as example, when sr device goes to runtime suspend, blk_{pre|post}_runtime_suspend will be called since sr device defined pm->runtime_suspend. But blk_{pre|post}_runtime_resume will not be called since sr device doesn't have pm->runtime_resume. so, sr device can not resume correctly anymore. More discussion can be found from below link. http://marc.info/?l=linux-scsi&m=144163730531875&w=2 Signed-off-by: Ken Xue <Ken.Xue@amd.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: Xiangliang Yu <Xiangliang.Yu@amd.com> Cc: James E.J. Bottomley <JBottomley@odin.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Michael Terry <Michael.terry@canonical.com> Cc: stable@vger.kernel.org Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2015-08-18SCSI: Fix NULL pointer dereference in runtime PMAlan Stern
The routines in scsi_rpm.c assume that if a runtime-PM callback is invoked for a SCSI device, it can only mean that the device's driver has asked the block layer to handle the runtime power management (by calling blk_pm_runtime_init(), which among other things sets q->dev). However, this assumption turns out to be wrong for things like the ses driver. Normally ses devices are not allowed to do runtime PM, but userspace can override this setting. If this happens, the kernel gets a NULL pointer dereference when blk_post_runtime_resume() tries to use the uninitialized q->dev pointer. This patch fixes the problem by calling the block layer's runtime-PM routines only if the device's driver really does have a runtime-PM callback routine. Since ses doesn't define any such callbacks, the crash won't occur. This fixes Bugzilla #101371. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Stanisław Pitucha <viraptor@gmail.com> Reported-by: Ilan Cohen <ilanco@gmail.com> Tested-by: Ilan Cohen <ilanco@gmail.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Odin.com>
2014-12-15SCSI / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PMRafael J. Wysocki
After commit b2b49ccbdd54 (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is selected) PM_RUNTIME is always set if PM is set, so #ifdef blocks depending on CONFIG_PM_RUNTIME may now be changed to depend on CONFIG_PM. Replace CONFIG_PM_RUNTIME with CONFIG_PM everywhere under drivers/scsi/ and in include/scsi/scsi_device.h. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Christoph Hellwig <hch@lst.de>
2014-04-10scsi: async sd resumeDan Williams
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>
2013-12-16[SCSI] sr: use block layer runtime PMAaron Lu
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>
2013-10-25[SCSI] sd: Add error handling during flushing cachesOliver Neukum
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>
2013-06-03PM / Runtime: Rework the "runtime idle" helper routineRafael J. Wysocki
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>
2013-05-06[SCSI] sd: change to auto suspend modeLin Ming
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>
2012-11-30[SCSI] scsi_pm: use callbacks from dev_pm_ops for scsi devicesAaron Lu
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>
2012-11-30[SCSI] Revert "[SCSI] runtime resume parent for child's system-resume"Aaron Lu
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>
2012-11-30[SCSI] Revert "[SCSI] scsi_pm: set device runtime state before parent suspended"Aaron Lu
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>
2012-07-20[SCSI] scsi_pm: set device runtime state before parent suspendedLin Ming
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>
2012-05-22[SCSI] scsi_pm: resume device if suspend failedAaron Lu
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>
2012-05-17[SCSI] sd: limit the scope of the async probe domainDan Williams
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>
2012-02-18[SCSI] scsi_pm: Fix bug in the SCSI power management handlerAlan Stern
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>
2012-01-08[SCSI] runtime resume parent for child's system-resumeLin Ming
[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>
2012-01-08[SCSI] check runtime PM status in system PMLin Ming
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>
2011-10-31scsi: Add export.h for EXPORT_SYMBOL/THIS_MODULE as requiredPaul Gortmaker
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>
2011-07-02PM / Runtime: Return special error code if runtime PM is disabledRafael J. Wysocki
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>
2010-07-28[SCSI] implement runtime Power ManagementAlan Stern
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>
2010-07-28[SCSI] convert to the new PM frameworkAlan Stern
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>