kernel.git/drivers/scsi/scsi_pm.c, branch linux-3.8.y

[SCSI] scsi_pm: use callbacks from dev_pm_ops for scsi devices

2012-11-30T09:26:48Z

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 Acked-by: Alan Stern Acked-by: Rafael J. Wysocki Signed-off-by: James Bottomley

[SCSI] Revert "[SCSI] runtime resume parent for child's system-resume"

2012-11-30T09:25:37Z

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 Acked-by: Alan Stern Acked-by: Rafael J. Wysocki Signed-off-by: James Bottomley

[SCSI] Revert "[SCSI] scsi_pm: set device runtime state before parent suspended"

2012-11-30T09:24:43Z

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 Acked-by: Alan Stern Acked-by: Rafael J. Wysocki Signed-off-by: James Bottomley

[SCSI] scsi_pm: set device runtime state before parent suspended

2012-07-20T07:58:55Z

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 Acked-by: Alan Stern Signed-off-by: James Bottomley

[SCSI] scsi_pm: resume device if suspend failed

2012-05-22T10:09:50Z

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 Acked-by: Alan Stern Signed-off-by: James Bottomley

[SCSI] sd: limit the scope of the async probe domain

2012-05-17T08:10:46Z

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] [] schedule+0x5a/0x5c [ 494.674687] [] async_synchronize_cookie_domain+0xb6/0x112 [ 494.734177] [] ? __init_waitqueue_head+0x50/0x50 [ 494.787134] [] ? scsi_remove_target+0x48/0x48 [ 494.837900] [] async_synchronize_cookie+0x15/0x17 [ 494.891567] [] async_synchronize_full+0x54/0x70 <-- here we wait for async contexts to complete [ 494.943783] [] ? async_synchronize_full_domain+0x1a/0x1a [ 495.002547] [] sd_remove+0x2c/0xa2 [sd_mod] [ 495.051861] [] __device_release_driver+0x86/0xcf [ 495.104807] [] 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] [] schedule+0x5a/0x5c [ 853.949670] [] __mutex_lock_common+0x220/0x351 [ 854.001225] [] ? device_resume+0x58/0x1c4 [ 854.049082] [] ? device_resume+0x58/0x1c4 [ 854.097011] [] mutex_lock_nested+0x2f/0x36 <-- here we wait for device_lock() [ 854.145591] [] device_resume+0x58/0x1c4 [ 854.192066] [] async_resume+0x1e/0x45 [ 854.237019] [] 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 [alan: uplevel scsi_sd_probe_domain, clarify scsi_device_resume] Signed-off-by: Dan Williams [jejb: remove unneeded config guards in include file] Signed-off-by: James Bottomley

[SCSI] scsi_pm: Fix bug in the SCSI power management handler

2012-02-18T14:54:19Z

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 CC: Signed-off-by: James Bottomley

[SCSI] runtime resume parent for child's system-resume

2012-01-09T00:14:59Z

[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 Signed-off-by: Lin Ming Signed-off-by: Jeff Garzik

[SCSI] check runtime PM status in system PM

2012-01-09T00:14:57Z

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 Signed-off-by: Alan Stern Signed-off-by: Jeff Garzik

scsi: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required

2011-10-31T23:31:23Z

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