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 'int
(*cb)(struct device *)' parameter is never NULL. With this in place the
type of resume operation is encoded in the async function identifier.
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 <[email protected]>
Cc: Phillip Susi <[email protected]>
Cc: Alan Stern <[email protected]>
Suggested-by: Todd Brandt <[email protected]>
[djbw: kick all resume work to the async queue]
Signed-off-by: Dan Williams <[email protected]>
---
drivers/scsi/scsi.c | 3 +
drivers/scsi/scsi_pm.c | 115 ++++++++++++++++++++++++++++++++++++----------
drivers/scsi/scsi_priv.h | 1
drivers/scsi/sd.c | 1
4 files changed, 95 insertions(+), 25 deletions(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index d8afec8317cf..990d4a302788 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -91,6 +91,9 @@ EXPORT_SYMBOL(scsi_logging_level);
ASYNC_DOMAIN(scsi_sd_probe_domain);
EXPORT_SYMBOL(scsi_sd_probe_domain);
+ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
+EXPORT_SYMBOL(scsi_sd_pm_domain);
+
/* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
* You may not alter any existing entry (although adding new ones is
* encouraged once assigned by ANSI/INCITS T10
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index 001e9ceda4c3..1cb211bf0383 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -18,17 +18,52 @@
#ifdef CONFIG_PM_SLEEP
+#define do_pm_op(dev, op) \
+ dev->driver ? dev->driver->pm ? \
+ dev->driver->pm->op(dev) : 0 : 0
+
+static int do_scsi_suspend(struct device *dev)
+{
+ return do_pm_op(dev, suspend);
+}
+
+static int do_scsi_freeze(struct device *dev)
+{
+ return do_pm_op(dev, freeze);
+}
+
+static int do_scsi_poweroff(struct device *dev)
+{
+ return do_pm_op(dev, poweroff);
+}
+
+static int do_scsi_resume(struct device *dev)
+{
+ return do_pm_op(dev, resume);
+}
+
+static int do_scsi_thaw(struct device *dev)
+{
+ return do_pm_op(dev, thaw);
+}
+
+static int do_scsi_restore(struct device *dev)
+{
+ return do_pm_op(dev, restore);
+}
+
static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device
*))
{
int err;
+ /* flush pending in-flight resume operations, suspend is synchronous */
+ async_synchronize_full_domain(&scsi_sd_pm_domain);
+
err = scsi_device_quiesce(to_scsi_device(dev));
if (err == 0) {
- if (cb) {
- err = cb(dev);
- if (err)
- scsi_device_resume(to_scsi_device(dev));
- }
+ err = cb(dev);
+ if (err)
+ scsi_device_resume(to_scsi_device(dev));
}
dev_dbg(dev, "scsi suspend: %d\n", err);
return err;
@@ -38,10 +73,16 @@ static int scsi_dev_type_resume(struct device *dev, int
(*cb)(struct device *))
{
int err = 0;
- if (cb)
- err = cb(dev);
+ err = cb(dev);
scsi_device_resume(to_scsi_device(dev));
dev_dbg(dev, "scsi resume: %d\n", err);
+
+ if (err == 0) {
+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+ }
+
return err;
}
@@ -66,20 +107,50 @@ scsi_bus_suspend_common(struct device *dev, int
(*cb)(struct device *))
return err;
}
+static void async_sdev_resume(void *dev, async_cookie_t cookie)
+{
+ scsi_dev_type_resume(dev, do_scsi_resume);
+}
+
+static void async_sdev_thaw(void *dev, async_cookie_t cookie)
+{
+ scsi_dev_type_resume(dev, do_scsi_thaw);
+}
+
+static void async_sdev_restore(void *dev, async_cookie_t cookie)
+{
+ scsi_dev_type_resume(dev, do_scsi_restore);
+}
+
+static async_func_t to_async_sdev_resume_fn(struct device *dev,
+ int (*cb)(struct device *))
+{
+ if (!scsi_is_sdev_device(dev))
+ return NULL;
+
+ if (cb == do_scsi_resume)
+ return async_sdev_resume;
+ else if (cb == do_scsi_thaw)
+ return async_sdev_thaw;
+ else if (cb == do_scsi_restore)
+ return async_sdev_restore;
+ else
+ return NULL;
+}
+
static int
scsi_bus_resume_common(struct device *dev, int (*cb)(struct device *))
{
- int err = 0;
-
- if (scsi_is_sdev_device(dev))
- err = scsi_dev_type_resume(dev, cb);
+ async_func_t fn = to_async_sdev_resume_fn(dev, cb);
- if (err == 0) {
+ if (fn)
+ async_schedule_domain(fn, dev, &scsi_sd_pm_domain);
+ else {
pm_runtime_disable(dev);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
}
- return err;
+ return 0;
}
static int scsi_bus_prepare(struct device *dev)
@@ -97,38 +168,32 @@ static int scsi_bus_prepare(struct device *dev)
static int scsi_bus_suspend(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_suspend_common(dev, pm ? pm->suspend : NULL);
+ return scsi_bus_suspend_common(dev, do_scsi_suspend);
}
static int scsi_bus_resume(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_resume_common(dev, pm ? pm->resume : NULL);
+ return scsi_bus_resume_common(dev, do_scsi_resume);
}
static int scsi_bus_freeze(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_suspend_common(dev, pm ? pm->freeze : NULL);
+ return scsi_bus_suspend_common(dev, do_scsi_freeze);
}
static int scsi_bus_thaw(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_resume_common(dev, pm ? pm->thaw : NULL);
+ return scsi_bus_resume_common(dev, do_scsi_thaw);
}
static int scsi_bus_poweroff(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_suspend_common(dev, pm ? pm->poweroff : NULL);
+ return scsi_bus_suspend_common(dev, do_scsi_poweroff);
}
static int scsi_bus_restore(struct device *dev)
{
- const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
- return scsi_bus_resume_common(dev, pm ? pm->restore : NULL);
+ return scsi_bus_resume_common(dev, do_scsi_restore);
}
#else /* CONFIG_PM_SLEEP */
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index f079a598bed4..a26fd44c7738 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -166,6 +166,7 @@ static inline int scsi_autopm_get_host(struct Scsi_Host *h)
{ return 0; }
static inline void scsi_autopm_put_host(struct Scsi_Host *h) {}
#endif /* CONFIG_PM_RUNTIME */
+extern struct async_domain scsi_sd_pm_domain;
extern struct async_domain scsi_sd_probe_domain;
/*
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 470954aba728..700c595c603e 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3020,6 +3020,7 @@ static int sd_remove(struct device *dev)
devt = disk_devt(sdkp->disk);
scsi_autopm_get_device(sdkp->device);
+ async_synchronize_full_domain(&scsi_sd_pm_domain);
async_synchronize_full_domain(&scsi_sd_probe_domain);
blk_queue_prep_rq(sdkp->device->request_queue, scsi_prep_fn);
blk_queue_unprep_rq(sdkp->device->request_queue, NULL);
--
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