Re: [PATCH 7/8] PM: Use the new device_to_pm() helper to access struct dev_pm_ops

Rafael J. Wysocki
2020-05-26T08:33:50Z

On Mon, May 25, 2020 at 8:26 PM Krzysztof Wilczyński <kw@linux.com> wrote:
>
> Use the new device_to_pm() helper to access Power Management callbacs
> (struct dev_pm_ops) for a particular device (struct device_driver).
>
> No functional change intended.
>
> This change builds on top of the previous commit 6da2f2ccfd2d ("PCI/PM:
> Make power management op coding style consistent").
>
> Links:
> https://lore.kernel.org/driverdev-devel/20191014230016.240912-6-helgaas@kernel.org/
> https://lore.kernel.org/driverdev-devel/8592302.r4xC6RIy69@kreacher/
> https://lore.kernel.org/driverdev-devel/20191016135002.GA24678@kadam/
>
> Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
> ---
> drivers/base/power/domain.c | 12 ++++--
> drivers/base/power/generic_ops.c | 65 ++++++++++++++------------------
> drivers/base/power/main.c | 48 +++++++++++++++--------
> drivers/base/power/runtime.c | 7 ++--
> 4 files changed, 73 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> index 0a01df608849..92a96fcb2717 100644
> --- a/drivers/base/power/domain.c
> +++ b/drivers/base/power/domain.c
> @@ -703,6 +703,7 @@ static void genpd_power_off_work_fn(struct work_struct *work)
> static int __genpd_runtime_suspend(struct device *dev)
> {
> int (*cb)(struct device *__dev);
> + const struct dev_pm_ops *pm;
>
> if (dev->type && dev->type->pm)
> cb = dev->type->pm->runtime_suspend;
> @@ -713,8 +714,9 @@ static int __genpd_runtime_suspend(struct device *dev)
> else
> cb = NULL;
>
> - if (!cb && dev->driver && dev->driver->pm)
> - cb = dev->driver->pm->runtime_suspend;
> + pm = driver_to_pm(dev->driver);
> + if (!cb && pm)
> + cb = pm->runtime_suspend;

So why exactly is the new version better?

1. It adds lines of code.
2. It adds checks.
3. It adds function calls.
4. It makes one need to see the extra driver_to_pm() function to find
out what's going on.

Which of the above is an improvement?

> return cb ? cb(dev) : 0;
> }
> @@ -726,6 +728,7 @@ static int __genpd_runtime_suspend(struct device *dev)
> static int __genpd_runtime_resume(struct device *dev)
> {
> int (*cb)(struct device *__dev);
> + const struct dev_pm_ops *pm;
>
> if (dev->type && dev->type->pm)
> cb = dev->type->pm->runtime_resume;
> @@ -736,8 +739,9 @@ static int __genpd_runtime_resume(struct device *dev)
> else
> cb = NULL;
>
> - if (!cb && dev->driver && dev->driver->pm)
> - cb = dev->driver->pm->runtime_resume;
> + pm = driver_to_pm(dev->driver);
> + if (!cb && pm)
> + cb = pm->runtime_resume;
>
> return cb ? cb(dev) : 0;
> }
> diff --git a/drivers/base/power/generic_ops.c b/drivers/base/power/generic_ops.c
> index 4fa525668cb7..fbd2edef0201 100644
> --- a/drivers/base/power/generic_ops.c
> +++ b/drivers/base/power/generic_ops.c
> @@ -19,12 +19,9 @@
> */
> int pm_generic_runtime_suspend(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> - int ret;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> - ret = pm && pm->runtime_suspend ? pm->runtime_suspend(dev) : 0;
> -
> - return ret;
> + return pm && pm->runtime_suspend ? pm->runtime_suspend(dev) : 0;
> }
> EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
>
> @@ -38,12 +35,9 @@ EXPORT_SYMBOL_GPL(pm_generic_runtime_suspend);
> */
> int pm_generic_runtime_resume(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> - int ret;
> -
> - ret = pm && pm->runtime_resume ? pm->runtime_resume(dev) : 0;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> - return ret;
> + return pm && pm->runtime_resume ? pm->runtime_resume(dev) : 0;
> }
> EXPORT_SYMBOL_GPL(pm_generic_runtime_resume);
> #endif /* CONFIG_PM */
> @@ -57,13 +51,12 @@ EXPORT_SYMBOL_GPL(pm_generic_runtime_resume);
> */
> int pm_generic_prepare(struct device *dev)
> {
> - struct device_driver *drv = dev->driver;
> - int ret = 0;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> - if (drv && drv->pm && drv->pm->prepare)
> - ret = drv->pm->prepare(dev);
> + if (pm && pm->prepare)
> + return pm->prepare(dev);
>
> - return ret;
> + return 0;
> }
>
> /**
> @@ -72,7 +65,7 @@ int pm_generic_prepare(struct device *dev)
> */
> int pm_generic_suspend_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->suspend_noirq ? pm->suspend_noirq(dev) : 0;
> }
> @@ -84,7 +77,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend_noirq);
> */
> int pm_generic_suspend_late(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->suspend_late ? pm->suspend_late(dev) : 0;
> }
> @@ -96,7 +89,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend_late);
> */
> int pm_generic_suspend(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->suspend ? pm->suspend(dev) : 0;
> }
> @@ -108,7 +101,7 @@ EXPORT_SYMBOL_GPL(pm_generic_suspend);
> */
> int pm_generic_freeze_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->freeze_noirq ? pm->freeze_noirq(dev) : 0;
> }
> @@ -120,7 +113,7 @@ EXPORT_SYMBOL_GPL(pm_generic_freeze_noirq);
> */
> int pm_generic_freeze_late(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->freeze_late ? pm->freeze_late(dev) : 0;
> }
> @@ -132,7 +125,7 @@ EXPORT_SYMBOL_GPL(pm_generic_freeze_late);
> */
> int pm_generic_freeze(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->freeze ? pm->freeze(dev) : 0;
> }
> @@ -144,7 +137,7 @@ EXPORT_SYMBOL_GPL(pm_generic_freeze);
> */
> int pm_generic_poweroff_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->poweroff_noirq ? pm->poweroff_noirq(dev) : 0;
> }
> @@ -156,7 +149,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff_noirq);
> */
> int pm_generic_poweroff_late(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->poweroff_late ? pm->poweroff_late(dev) : 0;
> }
> @@ -168,7 +161,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff_late);
> */
> int pm_generic_poweroff(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->poweroff ? pm->poweroff(dev) : 0;
> }
> @@ -180,7 +173,7 @@ EXPORT_SYMBOL_GPL(pm_generic_poweroff);
> */
> int pm_generic_thaw_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->thaw_noirq ? pm->thaw_noirq(dev) : 0;
> }
> @@ -192,7 +185,7 @@ EXPORT_SYMBOL_GPL(pm_generic_thaw_noirq);
> */
> int pm_generic_thaw_early(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->thaw_early ? pm->thaw_early(dev) : 0;
> }
> @@ -204,7 +197,7 @@ EXPORT_SYMBOL_GPL(pm_generic_thaw_early);
> */
> int pm_generic_thaw(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->thaw ? pm->thaw(dev) : 0;
> }
> @@ -216,7 +209,7 @@ EXPORT_SYMBOL_GPL(pm_generic_thaw);
> */
> int pm_generic_resume_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->resume_noirq ? pm->resume_noirq(dev) : 0;
> }
> @@ -228,7 +221,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume_noirq);
> */
> int pm_generic_resume_early(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->resume_early ? pm->resume_early(dev) : 0;
> }
> @@ -240,7 +233,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume_early);
> */
> int pm_generic_resume(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->resume ? pm->resume(dev) : 0;
> }
> @@ -252,7 +245,7 @@ EXPORT_SYMBOL_GPL(pm_generic_resume);
> */
> int pm_generic_restore_noirq(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->restore_noirq ? pm->restore_noirq(dev) : 0;
> }
> @@ -264,7 +257,7 @@ EXPORT_SYMBOL_GPL(pm_generic_restore_noirq);
> */
> int pm_generic_restore_early(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->restore_early ? pm->restore_early(dev) : 0;
> }
> @@ -276,7 +269,7 @@ EXPORT_SYMBOL_GPL(pm_generic_restore_early);
> */
> int pm_generic_restore(struct device *dev)
> {
> - const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> return pm && pm->restore ? pm->restore(dev) : 0;
> }
> @@ -290,9 +283,9 @@ EXPORT_SYMBOL_GPL(pm_generic_restore);
> */
> void pm_generic_complete(struct device *dev)
> {
> - struct device_driver *drv = dev->driver;
> + const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
>
> - if (drv && drv->pm && drv->pm->complete)
> - drv->pm->complete(dev);
> + if (pm && pm->complete)
> + pm->complete(dev);
> }
> #endif /* CONFIG_PM_SLEEP */
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 0e07e17c2def..6c41da0bebb0 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -640,6 +640,7 @@ static pm_callback_t dpm_subsys_suspend_late_cb(struct device *dev,
> static int device_resume_noirq(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback;
> + const struct dev_pm_ops *pm;
> const char *info;
> bool skip_resume;
> int error = 0;
> @@ -687,9 +688,10 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
> }
> }
>
> - if (dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (pm) {
> info = "noirq driver ";
> - callback = pm_noirq_op(dev->driver->pm, state);
> + callback = pm_noirq_op(pm, state);
> }
>
> Run:
> @@ -850,6 +852,7 @@ static pm_callback_t dpm_subsys_resume_early_cb(struct device *dev,
> static int device_resume_early(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback;
> + const struct dev_pm_ops *pm;
> const char *info;
> int error = 0;
>
> @@ -867,9 +870,10 @@ static int device_resume_early(struct device *dev, pm_message_t state, bool asyn
>
> callback = dpm_subsys_resume_early_cb(dev, state, &info);
>
> - if (!callback && dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (!callback && pm) {
> info = "early driver ";
> - callback = pm_late_early_op(dev->driver->pm, state);
> + callback = pm_late_early_op(pm, state);
> }
>
> error = dpm_run_callback(callback, dev, state, info);
> @@ -963,6 +967,7 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback = NULL;
> const char *info = NULL;
> + const struct dev_pm_ops *pm = NULL;
> int error = 0;
> DECLARE_DPM_WATCHDOG_ON_STACK(wd);
>
> @@ -1023,9 +1028,10 @@ static int device_resume(struct device *dev, pm_message_t state, bool async)
> }
>
> Driver:
> - if (!callback && dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (!callback && pm) {
> info = "driver ";
> - callback = pm_op(dev->driver->pm, state);
> + callback = pm_op(pm, state);
> }
>
> End:
> @@ -1116,6 +1122,7 @@ void dpm_resume(pm_message_t state)
> static void device_complete(struct device *dev, pm_message_t state)
> {
> void (*callback)(struct device *) = NULL;
> + const struct dev_pm_ops *pm = NULL;
> const char *info = NULL;
>
> if (dev->power.syscore)
> @@ -1137,9 +1144,10 @@ static void device_complete(struct device *dev, pm_message_t state)
> callback = dev->bus->pm->complete;
> }
>
> - if (!callback && dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (!callback && pm) {
> info = "completing driver ";
> - callback = dev->driver->pm->complete;
> + callback = pm->complete;
> }
>
> if (callback) {
> @@ -1312,6 +1320,7 @@ static bool device_must_resume(struct device *dev, pm_message_t state,
> static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback;
> + const struct dev_pm_ops *pm;
> const char *info;
> bool no_subsys_cb = false;
> int error = 0;
> @@ -1336,9 +1345,10 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
> if (dev_pm_smart_suspend_and_suspended(dev) && no_subsys_cb)
> goto Skip;
>
> - if (dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (pm) {
> info = "noirq driver ";
> - callback = pm_noirq_op(dev->driver->pm, state);
> + callback = pm_noirq_op(pm, state);
> }
>
> Run:
> @@ -1514,6 +1524,7 @@ static pm_callback_t dpm_subsys_suspend_late_cb(struct device *dev,
> static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback;
> + const struct dev_pm_ops *pm;
> const char *info;
> int error = 0;
>
> @@ -1543,9 +1554,10 @@ static int __device_suspend_late(struct device *dev, pm_message_t state, bool as
> !dpm_subsys_suspend_noirq_cb(dev, state, NULL))
> goto Skip;
>
> - if (dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (pm) {
> info = "late driver ";
> - callback = pm_late_early_op(dev->driver->pm, state);
> + callback = pm_late_early_op(pm, state);
> }
>
> Run:
> @@ -1717,6 +1729,7 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
> static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> {
> pm_callback_t callback = NULL;
> + const struct dev_pm_ops *pm = NULL;
> const char *info = NULL;
> int error = 0;
> DECLARE_DPM_WATCHDOG_ON_STACK(wd);
> @@ -1803,9 +1816,10 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
> }
>
> Run:
> - if (!callback && dev->driver && dev->driver->pm) {
> + pm = driver_to_pm(dev->driver);
> + if (!callback && pm) {
> info = "driver ";
> - callback = pm_op(dev->driver->pm, state);
> + callback = pm_op(pm, state);
> }
>
> error = dpm_run_callback(callback, dev, state, info);
> @@ -1917,6 +1931,7 @@ int dpm_suspend(pm_message_t state)
> static int device_prepare(struct device *dev, pm_message_t state)
> {
> int (*callback)(struct device *) = NULL;
> + const struct dev_pm_ops *pm = NULL;
> int ret = 0;
>
> if (dev->power.syscore)
> @@ -1946,8 +1961,9 @@ static int device_prepare(struct device *dev, pm_message_t state)
> else if (dev->bus && dev->bus->pm)
> callback = dev->bus->pm->prepare;
>
> - if (!callback && dev->driver && dev->driver->pm)
> - callback = dev->driver->pm->prepare;
> + pm = driver_to_pm(dev->driver);
> + if (!callback && pm)
> + callback = pm->prepare;
>
> if (callback)
> ret = callback(dev);
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> index 99c7da112c95..c142824c7541 100644
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -21,7 +21,7 @@ typedef int (*pm_callback_t)(struct device *);
> static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
> {
> pm_callback_t cb;
> - const struct dev_pm_ops *ops;
> + const struct dev_pm_ops *ops, *pm;
>
> if (dev->pm_domain)
> ops = &dev->pm_domain->ops;
> @@ -39,8 +39,9 @@ static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset)
> else
> cb = NULL;
>
> - if (!cb && dev->driver && dev->driver->pm)
> - cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset);
> + pm = driver_to_pm(dev->driver);
> + if (!cb && pm)
> + cb = *(pm_callback_t *)((void *)pm + cb_offset);
>
> return cb;
> }
> --
> 2.26.2
>