| Message ID | 20201109080938.4174745-2-zhangqilong3@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] PM: runtime: Add a general runtime get sync operation to deal with usage counter | expand |
On Mon, Nov 9, 2020 at 2:24 PM zhangqilong <zhangqilong3@huawei.com> wrote: > > Hi > > > > On Mon, Nov 9, 2020 at 9:05 AM Zhang Qilong <zhangqilong3@huawei.com> > > wrote: > > > > > > In many case, we need to check return value of pm_runtime_get_sync, > > > but it brings a trouble to the usage counter processing. Many callers > > > forget to decrease the usage counter when it failed. It has been > > > discussed a lot[0][1]. So we add a function to deal with the usage > > > counter for better coding. > > > > > > [0]https://lkml.org/lkml/2020/6/14/88 > > > [1]https://patchwork.ozlabs.org/project/linux-tegra/patch/202005200951 > > > 48.10995-1-dinghao.liu@zju.edu.cn/ > > > Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> > > > --- > > > include/linux/pm_runtime.h | 32 ++++++++++++++++++++++++++++++++ > > > 1 file changed, 32 insertions(+) > > > > > > diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h > > > index 4b708f4e8eed..2b0af5b1dffd 100644 > > > --- a/include/linux/pm_runtime.h > > > +++ b/include/linux/pm_runtime.h > > > @@ -386,6 +386,38 @@ static inline int pm_runtime_get_sync(struct device > > *dev) > > > return __pm_runtime_resume(dev, RPM_GET_PUT); } > > > > > > +/** > > > + * gene_pm_runtime_get_sync - Bump up usage counter of a device and > > resume it. > > > + * @dev: Target device. > > > > The force argument is not documented. > > (1) Good catch, I will add it in next version. > > > > > > + * > > > + * Increase runtime PM usage counter of @dev first, and carry out > > > + runtime-resume > > > + * of it synchronously. If __pm_runtime_resume return negative > > > + value(device is in > > > + * error state) or return positive value(the runtime of device is > > > + already active) > > > + * with force is true, it need decrease the usage counter of the > > > + device when > > > + * return. > > > + * > > > + * The possible return values of this function is zero or negative value. > > > + * zero: > > > + * - it means success and the status will store the resume operation > > status > > > + * if needed, the runtime PM usage counter of @dev remains > > incremented. > > > + * negative: > > > + * - it means failure and the runtime PM usage counter of @dev has > > been > > > + * decreased. > > > + * positive: > > > + * - it means the runtime of the device is already active before that. If > > > + * caller set force to true, we still need to decrease the usage > > counter. > > > > Why is this needed? > > (2) If caller set force, it means caller will return even the device has already been active > (__pm_runtime_resume return positive value) after calling gene_pm_runtime_get_sync, > we still need to decrease the usage count. But who needs this? I don't think that it is a good idea to complicate the API this way.
Hi, > > On Mon, Nov 9, 2020 at 2:24 PM zhangqilong <zhangqilong3@huawei.com> > wrote: > > > > Hi > > > > > > On Mon, Nov 9, 2020 at 9:05 AM Zhang Qilong > > > <zhangqilong3@huawei.com> > > > wrote: > > > > > > > > In many case, we need to check return value of > > > > pm_runtime_get_sync, but it brings a trouble to the usage counter > > > > processing. Many callers forget to decrease the usage counter when > > > > it failed. It has been discussed a lot[0][1]. So we add a function > > > > to deal with the usage counter for better coding. > > > > > > > > [0]https://lkml.org/lkml/2020/6/14/88 > > > > [1]https://patchwork.ozlabs.org/project/linux-tegra/patch/20200520 > > > > 0951 48.10995-1-dinghao.liu@zju.edu.cn/ > > > > Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> > > > > --- > > > > include/linux/pm_runtime.h | 32 > ++++++++++++++++++++++++++++++++ > > > > 1 file changed, 32 insertions(+) > > > > > > > > diff --git a/include/linux/pm_runtime.h > > > > b/include/linux/pm_runtime.h index 4b708f4e8eed..2b0af5b1dffd > > > > 100644 > > > > --- a/include/linux/pm_runtime.h > > > > +++ b/include/linux/pm_runtime.h > > > > @@ -386,6 +386,38 @@ static inline int pm_runtime_get_sync(struct > > > > device > > > *dev) > > > > return __pm_runtime_resume(dev, RPM_GET_PUT); } > > > > > > > > +/** > > > > + * gene_pm_runtime_get_sync - Bump up usage counter of a device > > > > +and > > > resume it. > > > > + * @dev: Target device. > > > > > > The force argument is not documented. > > > > (1) Good catch, I will add it in next version. > > > > > > > > > + * > > > > + * Increase runtime PM usage counter of @dev first, and carry out > > > > + runtime-resume > > > > + * of it synchronously. If __pm_runtime_resume return negative > > > > + value(device is in > > > > + * error state) or return positive value(the runtime of device is > > > > + already active) > > > > + * with force is true, it need decrease the usage counter of the > > > > + device when > > > > + * return. > > > > + * > > > > + * The possible return values of this function is zero or negative value. > > > > + * zero: > > > > + * - it means success and the status will store the resume operation > > > status > > > > + * if needed, the runtime PM usage counter of @dev remains > > > incremented. > > > > + * negative: > > > > + * - it means failure and the runtime PM usage counter of @dev has > > > been > > > > + * decreased. > > > > + * positive: > > > > + * - it means the runtime of the device is already active before that. > If > > > > + * caller set force to true, we still need to decrease the usage > > > counter. > > > > > > Why is this needed? > > > > (2) If caller set force, it means caller will return even the device > > has already been active (__pm_runtime_resume return positive value) > > after calling gene_pm_runtime_get_sync, we still need to decrease the > usage count. > > But who needs this? > > I don't think that it is a good idea to complicate the API this way. The callers like: ret = pm_runtime_get_sync(dev); if (ret) { ... return (xxx); } drivers/spi/spi-img-spfi.c:734 img_spfi_resume() warn: pm_runtime_get_sync() also returns 1 on success drivers/mfd/arizona-core.c:49 arizona_clk32k_enable() warn: pm_runtime_get_sync() also returns 1 on success drivers/usb/dwc3/dwc3-pci.c:212 dwc3_pci_resume_work() warn: pm_runtime_get_sync() also returns 1 on success drivers/input/keyboard/omap4-keypad.c:279 omap4_keypad_probe() warn: pm_runtime_get_sync() also returns 1 on success drivers/gpu/drm/vc4/vc4_dsi.c:839 vc4_dsi_encoder_enable() warn: pm_runtime_get_sync() also returns 1 on success drivers/gpu/drm/i915/selftests/mock_gem_device.c:157 mock_gem_device() warn: 'pm_runtime_get_sync(&pdev->dev)' returns positive and negative drivers/watchdog/rti_wdt.c:230 rti_wdt_probe() warn: pm_runtime_get_sync() also returns 1 on success drivers/media/platform/exynos4-is/mipi-csis.c:513 s5pcsis_s_stream() warn: pm_runtime_get_sync() also returns 1 on success drivers/media/platform/mtk-vcodec/mtk_vcodec_dec_pm.c:89 mtk_vcodec_dec_pw_on() warn: pm_runtime_get_sync() also returns 1 on success drivers/media/platform/ti-vpe/cal.c:794 cal_probe() warn: pm_runtime_get_sync() also returns 1 on success drivers/media/platform/ti-vpe/vpe.c:2478 vpe_runtime_get() warn: pm_runtime_get_sync() also returns 1 on success drivers/media/i2c/smiapp/smiapp-core.c:1529 smiapp_pm_get_init() warn: pm_runtime_get_sync() also returns 1 on success ... they need it to simplify the function. If we only want to simplify like ret = pm_runtime_get_sync(dev); if (ret < 0) { ... Return (xxx) } The parameter force could be removed. Thanks, Zhang
diff --git a/include/linux/pm_runtime.h b/include/linux/pm_runtime.h index 4b708f4e8eed..2b0af5b1dffd 100644 --- a/include/linux/pm_runtime.h +++ b/include/linux/pm_runtime.h @@ -386,6 +386,38 @@ static inline int pm_runtime_get_sync(struct device *dev) return __pm_runtime_resume(dev, RPM_GET_PUT); } +/** + * gene_pm_runtime_get_sync - Bump up usage counter of a device and resume it. + * @dev: Target device. + * + * Increase runtime PM usage counter of @dev first, and carry out runtime-resume + * of it synchronously. If __pm_runtime_resume return negative value(device is in + * error state) or return positive value(the runtime of device is already active) + * with force is true, it need decrease the usage counter of the device when + * return. + * + * The possible return values of this function is zero or negative value. + * zero: + * - it means success and the status will store the resume operation status + * if needed, the runtime PM usage counter of @dev remains incremented. + * negative: + * - it means failure and the runtime PM usage counter of @dev has been + * decreased. + * positive: + * - it means the runtime of the device is already active before that. If + * caller set force to true, we still need to decrease the usage counter. + */ +static inline int gene_pm_runtime_get_sync(struct device *dev, bool force) +{ + int ret = 0; + + ret = __pm_runtime_resume(dev, RPM_GET_PUT); + if (ret < 0 || (ret > 0 && force)) + pm_runtime_put_noidle(dev); + + return ret; +} + /** * pm_runtime_put - Drop device usage counter and queue up "idle check" if 0. * @dev: Target device.
In many case, we need to check return value of pm_runtime_get_sync, but it brings a trouble to the usage counter processing. Many callers forget to decrease the usage counter when it failed. It has been discussed a lot[0][1]. So we add a function to deal with the usage counter for better coding. [0]https://lkml.org/lkml/2020/6/14/88 [1]https://patchwork.ozlabs.org/project/linux-tegra/patch/20200520095148.10995-1-dinghao.liu@zju.edu.cn/ Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> --- include/linux/pm_runtime.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+)