@@ -263,6 +263,9 @@ config SCSI_SCAN_ASYNC
You can override this choice by specifying "scsi_mod.scan=sync"
or async on the kernel's command line.
+ Note that this setting also affects whether resuming from
+ system suspend will be performed asynchronously.
+
menu "SCSI Transports"
depends on SCSI
@@ -91,6 +91,15 @@ EXPORT_SYMBOL(scsi_logging_level);
ASYNC_DOMAIN(scsi_sd_probe_domain);
EXPORT_SYMBOL(scsi_sd_probe_domain);
+/*
+ * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
+ * asynchronous system resume operations. It is marked 'exclusive' to avoid
+ * being included in the async_synchronize_full() that is invoked by
+ * dpm_resume()
+ */
+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
@@ -18,35 +18,77 @@
#ifdef CONFIG_PM_SLEEP
-static int scsi_dev_type_suspend(struct device *dev, int (*cb)(struct device *))
+static int do_scsi_suspend(struct device *dev, const struct dev_pm_ops *pm)
{
+ return pm && pm->suspend ? pm->suspend(dev) : 0;
+}
+
+static int do_scsi_freeze(struct device *dev, const struct dev_pm_ops *pm)
+{
+ return pm && pm->freeze ? pm->freeze(dev) : 0;
+}
+
+static int do_scsi_poweroff(struct device *dev, const struct dev_pm_ops *pm)
+{
+ return pm && pm->poweroff ? pm->poweroff(dev) : 0;
+}
+
+static int do_scsi_resume(struct device *dev, const struct dev_pm_ops *pm)
+{
+ return pm && pm->resume ? pm->resume(dev) : 0;
+}
+
+static int do_scsi_thaw(struct device *dev, const struct dev_pm_ops *pm)
+{
+ return pm && pm->thaw ? pm->thaw(dev) : 0;
+}
+
+static int do_scsi_restore(struct device *dev, const struct dev_pm_ops *pm)
+{
+ return pm && pm->restore ? pm->restore(dev) : 0;
+}
+
+static int scsi_dev_type_suspend(struct device *dev,
+ int (*cb)(struct device *, const struct dev_pm_ops *))
+{
+ const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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, pm);
+ if (err)
+ scsi_device_resume(to_scsi_device(dev));
}
dev_dbg(dev, "scsi suspend: %d\n", err);
return err;
}
-static int scsi_dev_type_resume(struct device *dev, int (*cb)(struct device *))
+static int scsi_dev_type_resume(struct device *dev,
+ int (*cb)(struct device *, const struct dev_pm_ops *))
{
+ const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int err = 0;
- if (cb)
- err = cb(dev);
+ err = cb(dev, pm);
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;
}
static int
-scsi_bus_suspend_common(struct device *dev, int (*cb)(struct device *))
+scsi_bus_suspend_common(struct device *dev,
+ int (*cb)(struct device *, const struct dev_pm_ops *))
{
int err = 0;
@@ -66,20 +108,54 @@ scsi_bus_suspend_common(struct device *dev, int (*cb)(struct device *))
return err;
}
-static int
-scsi_bus_resume_common(struct device *dev, int (*cb)(struct device *))
+static void async_sdev_resume(void *dev, async_cookie_t cookie)
{
- int err = 0;
+ scsi_dev_type_resume(dev, do_scsi_resume);
+}
- if (scsi_is_sdev_device(dev))
- err = scsi_dev_type_resume(dev, cb);
+static void async_sdev_thaw(void *dev, async_cookie_t cookie)
+{
+ scsi_dev_type_resume(dev, do_scsi_thaw);
+}
- if (err == 0) {
+static void async_sdev_restore(void *dev, async_cookie_t cookie)
+{
+ scsi_dev_type_resume(dev, do_scsi_restore);
+}
+
+static int scsi_bus_resume_common(struct device *dev,
+ int (*cb)(struct device *, const struct dev_pm_ops *))
+{
+ async_func_t fn;
+
+ if (!scsi_is_sdev_device(dev))
+ fn = NULL;
+ else if (cb == do_scsi_resume)
+ fn = async_sdev_resume;
+ else if (cb == do_scsi_thaw)
+ fn = async_sdev_thaw;
+ else if (cb == do_scsi_restore)
+ fn = async_sdev_restore;
+ else
+ fn = NULL;
+
+ if (fn) {
+ async_schedule_domain(fn, dev, &scsi_sd_pm_domain);
+
+ /*
+ * If a user has disabled async probing a likely reason
+ * is due to a storage enclosure that does not inject
+ * staggered spin-ups. For safety, make resume
+ * synchronous as well in that case.
+ */
+ if (strncmp(scsi_scan_type, "async", 5) != 0)
+ async_synchronize_full_domain(&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 +173,32 @@ 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 */
@@ -112,6 +112,7 @@ extern void scsi_exit_procfs(void);
#endif /* CONFIG_PROC_FS */
/* scsi_scan.c */
+extern char scsi_scan_type[];
extern int scsi_complete_async_scans(void);
extern int scsi_scan_host_selected(struct Scsi_Host *, unsigned int,
unsigned int, unsigned int, int);
@@ -166,6 +167,7 @@ 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;
/*
@@ -97,7 +97,7 @@ MODULE_PARM_DESC(max_luns,
#define SCSI_SCAN_TYPE_DEFAULT "sync"
#endif
-static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT;
+char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT;
module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO);
MODULE_PARM_DESC(scan, "sync, async or none");
@@ -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);
Hi Linus, James might still be in the process of sending this your way. However, given the proximity to -rc1, my reasoning for sending this directly is: 1/ It provides a tangible speed up for a non-esoteric use case (laptop resume): https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach 2/ You already pulled the first half of this enabling from Tejun. Quoting Tejun's ATA pull request: "Dan finishes the patchset to make libata PM operations asynchronous. Combined with one patch being routed through scsi, this should speed resume measurably." 3/ As far as I can tell it is acceptable to James: http://marc.info/?l=linux-scsi&m=139499409510791&w=2 http://marc.info/?l=linux-scsi&m=139508044602605&w=2 http://marc.info/?l=linux-scsi&m=139536062515216&w=2 4/ I promised Todd I would get it upstream before he returns from vacation. Please pull, thank you. -- Dan The following changes since commit 455c6fdbd219161bd09b1165f11699d6d73de11c: Linux 3.14 (2014-03-30 20:40:15 -0700) are available in the git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/djbw/isci async-scsi-resume for you to fetch changes up to 3c31b52f96f7b559d950b16113c0f68c72a1985e: scsi: async sd resume (2014-04-10 15:30:35 -0700) ---------------------------------------------------------------- Dan Williams (1): scsi: async sd resume drivers/scsi/Kconfig | 3 ++ drivers/scsi/scsi.c | 9 ++++ drivers/scsi/scsi_pm.c | 128 ++++++++++++++++++++++++++++++++++++----------- drivers/scsi/scsi_priv.h | 2 + drivers/scsi/scsi_scan.c | 2 +- drivers/scsi/sd.c | 1 + 6 files changed, 115 insertions(+), 30 deletions(-) 8<------------- From 3c31b52f96f7b559d950b16113c0f68c72a1985e Mon Sep 17 00:00:00 2001 From: Dan Williams <dan.j.williams@intel.com> Date: Thu, 10 Apr 2014 15:30:35 -0700 Subject: [PATCH] scsi: async sd resume 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> --- drivers/scsi/Kconfig | 3 ++ drivers/scsi/scsi.c | 9 ++++ drivers/scsi/scsi_pm.c | 128 ++++++++++++++++++++++++++++++++++++----------- drivers/scsi/scsi_priv.h | 2 + drivers/scsi/scsi_scan.c | 2 +- drivers/scsi/sd.c | 1 + 6 files changed, 115 insertions(+), 30 deletions(-)