| Message ID | 1555617500-10862-7-git-send-email-linux@roeck-us.net (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Eduardo Valentin |
| Headers | show |
| Series | thermal: Introduce devm_thermal_of_cooling_device_register | expand |
Dear All, On 2019-04-18 21:58, Guenter Roeck wrote: > Use devm_thermal_of_cooling_device_register() to register the cooling > device. Also use devm_add_action_or_reset() to stop the fan on device > removal, and to disable the pwm. Introduce a local 'dev' variable in > the probe function to make the code easier to read. > > As a side effect, this fixes a bug seen if pwm_fan_of_get_cooling_data() > returned an error. In that situation, the pwm was not disabled, and > the fan was not stopped. Using devm functions also ensures that the > pwm is disabled and that the fan is stopped only after the hwmon device > has been unregistered. > > Cc: Lukasz Majewski <l.majewski@samsung.com> > Signed-off-by: Guenter Roeck <linux@roeck-us.net> I've noticed the following lockdep warning after this commit during CPU hotplug tests on TM2e board (ARM64 Exynos5433). It looks like a false positive, but it would be nice to annotate it somehow in the code to make lockdep happy: --->8--- IRQ 8: no longer affine to CPU5 CPU5: shutdown IRQ 9: no longer affine to CPU6 CPU6: shutdown ====================================================== WARNING: possible circular locking dependency detected 5.2.0-rc1+ #6093 Not tainted ------------------------------------------------------ cpuhp/7/43 is trying to acquire lock: 00000000d1a60be3 (thermal_list_lock){+.+.}, at: thermal_cooling_device_unregister+0x34/0x1c0 but task is already holding lock: 00000000a6a56c92 (&policy->rwsem){++++}, at: cpufreq_offline+0x68/0x228 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&policy->rwsem){++++}: down_write+0x48/0x98 cpufreq_cpu_acquire+0x20/0x58 cpufreq_update_policy+0x28/0xc0 cpufreq_set_cur_state+0x44/0x70 thermal_cdev_update+0x7c/0x240 step_wise_throttle+0x4c/0x88 handle_thermal_trip+0xc0/0x348 thermal_zone_device_update.part.7+0x6c/0x250 thermal_zone_device_update+0x28/0x38 exynos_tmu_work+0x28/0x70 process_one_work+0x298/0x6c0 worker_thread+0x48/0x430 kthread+0x100/0x130 ret_from_fork+0x10/0x18 -> #2 (&cdev->lock){+.+.}: __mutex_lock+0x90/0x890 mutex_lock_nested+0x1c/0x28 thermal_zone_bind_cooling_device+0x2cc/0x3e0 of_thermal_bind+0x9c/0xf8 __thermal_cooling_device_register+0x1a4/0x388 thermal_of_cooling_device_register+0xc/0x18 __cpufreq_cooling_register+0x360/0x410 of_cpufreq_cooling_register+0x84/0xf8 cpufreq_online+0x414/0x720 cpufreq_add_dev+0x78/0x88 subsys_interface_register+0xa4/0xf8 cpufreq_register_driver+0x140/0x1e0 dt_cpufreq_probe+0xb0/0x130 platform_drv_probe+0x50/0xa8 really_probe+0x1b0/0x2a0 driver_probe_device+0x58/0x100 __device_attach_driver+0x90/0xc0 bus_for_each_drv+0x70/0xc8 __device_attach+0xdc/0x140 device_initial_probe+0x10/0x18 bus_probe_device+0x94/0xa0 device_add+0x39c/0x5c8 platform_device_add+0x110/0x248 platform_device_register_full+0x134/0x178 cpufreq_dt_platdev_init+0x114/0x14c do_one_initcall+0x84/0x430 kernel_init_freeable+0x440/0x534 kernel_init+0x10/0x108 ret_from_fork+0x10/0x18 -> #1 (&tz->lock){+.+.}: __mutex_lock+0x90/0x890 mutex_lock_nested+0x1c/0x28 thermal_zone_bind_cooling_device+0x2b8/0x3e0 of_thermal_bind+0x9c/0xf8 __thermal_cooling_device_register+0x1a4/0x388 thermal_of_cooling_device_register+0xc/0x18 __cpufreq_cooling_register+0x360/0x410 of_cpufreq_cooling_register+0x84/0xf8 cpufreq_online+0x414/0x720 cpufreq_add_dev+0x78/0x88 subsys_interface_register+0xa4/0xf8 cpufreq_register_driver+0x140/0x1e0 dt_cpufreq_probe+0xb0/0x130 platform_drv_probe+0x50/0xa8 really_probe+0x1b0/0x2a0 driver_probe_device+0x58/0x100 __device_attach_driver+0x90/0xc0 bus_for_each_drv+0x70/0xc8 __device_attach+0xdc/0x140 device_initial_probe+0x10/0x18 bus_probe_device+0x94/0xa0 device_add+0x39c/0x5c8 platform_device_add+0x110/0x248 platform_device_register_full+0x134/0x178 cpufreq_dt_platdev_init+0x114/0x14c do_one_initcall+0x84/0x430 kernel_init_freeable+0x440/0x534 kernel_init+0x10/0x108 ret_from_fork+0x10/0x18 -> #0 (thermal_list_lock){+.+.}: lock_acquire+0xdc/0x260 __mutex_lock+0x90/0x890 mutex_lock_nested+0x1c/0x28 thermal_cooling_device_unregister+0x34/0x1c0 cpufreq_cooling_unregister+0x78/0xd0 cpufreq_offline+0x200/0x228 cpuhp_cpufreq_offline+0xc/0x18 cpuhp_invoke_callback+0xd0/0xcb0 cpuhp_thread_fun+0x1e8/0x258 smpboot_thread_fn+0x1b4/0x2d0 kthread+0x100/0x130 ret_from_fork+0x10/0x18 other info that might help us debug this: Chain exists of: thermal_list_lock --> &cdev->lock --> &policy->rwsem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&policy->rwsem); lock(&cdev->lock); lock(&policy->rwsem); lock(thermal_list_lock); *** DEADLOCK *** 3 locks held by cpuhp/7/43: #0: 00000000ae30cc2b (cpu_hotplug_lock.rw_sem){++++}, at: cpuhp_thread_fun+0x34/0x258 #1: 00000000a0e2460a (cpuhp_state-down){+.+.}, at: cpuhp_thread_fun+0x178/0x258 #2: 00000000a6a56c92 (&policy->rwsem){++++}, at: cpufreq_offline+0x68/0x228 stack backtrace: CPU: 7 PID: 43 Comm: cpuhp/7 Not tainted 5.2.0-rc1+ #6093 Hardware name: Samsung TM2E board (DT) Call trace: dump_backtrace+0x0/0x158 show_stack+0x14/0x20 dump_stack+0xc8/0x114 print_circular_bug+0x1cc/0x2d8 __lock_acquire+0x18f4/0x20f8 lock_acquire+0xdc/0x260 __mutex_lock+0x90/0x890 mutex_lock_nested+0x1c/0x28 thermal_cooling_device_unregister+0x34/0x1c0 cpufreq_cooling_unregister+0x78/0xd0 cpufreq_offline+0x200/0x228 cpuhp_cpufreq_offline+0xc/0x18 cpuhp_invoke_callback+0xd0/0xcb0 cpuhp_thread_fun+0x1e8/0x258 smpboot_thread_fn+0x1b4/0x2d0 kthread+0x100/0x130 ret_from_fork+0x10/0x18 IRQ 10: no longer affine to CPU7 --->8--- > --- > drivers/hwmon/pwm-fan.c | 73 ++++++++++++++++++++----------------------------- > 1 file changed, 29 insertions(+), 44 deletions(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 167221c7628a..0243ba70107e 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -207,33 +207,44 @@ static int pwm_fan_of_get_cooling_data(struct device *dev, > return 0; > } > > +static void pwm_fan_regulator_disable(void *data) > +{ > + regulator_disable(data); > +} > + > +static void pwm_fan_pwm_disable(void *data) > +{ > + pwm_disable(data); > +} > + > static int pwm_fan_probe(struct platform_device *pdev) > { > struct thermal_cooling_device *cdev; > + struct device *dev = &pdev->dev; > struct pwm_fan_ctx *ctx; > struct device *hwmon; > int ret; > struct pwm_state state = { }; > > - ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); > + ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL); > if (!ctx) > return -ENOMEM; > > mutex_init(&ctx->lock); > > - ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); > + ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL); > if (IS_ERR(ctx->pwm)) { > ret = PTR_ERR(ctx->pwm); > > if (ret != -EPROBE_DEFER) > - dev_err(&pdev->dev, "Could not get PWM: %d\n", ret); > + dev_err(dev, "Could not get PWM: %d\n", ret); > > return ret; > } > > platform_set_drvdata(pdev, ctx); > > - ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan"); > + ctx->reg_en = devm_regulator_get_optional(dev, "fan"); > if (IS_ERR(ctx->reg_en)) { > if (PTR_ERR(ctx->reg_en) != -ENODEV) > return PTR_ERR(ctx->reg_en); > @@ -242,10 +253,11 @@ static int pwm_fan_probe(struct platform_device *pdev) > } else { > ret = regulator_enable(ctx->reg_en); > if (ret) { > - dev_err(&pdev->dev, > - "Failed to enable fan supply: %d\n", ret); > + dev_err(dev, "Failed to enable fan supply: %d\n", ret); > return ret; > } > + devm_add_action_or_reset(dev, pwm_fan_regulator_disable, > + ctx->reg_en); > } > > ctx->pwm_value = MAX_PWM; > @@ -257,62 +269,36 @@ static int pwm_fan_probe(struct platform_device *pdev) > > ret = pwm_apply_state(ctx->pwm, &state); > if (ret) { > - dev_err(&pdev->dev, "Failed to configure PWM\n"); > - goto err_reg_disable; > + dev_err(dev, "Failed to configure PWM\n"); > + return ret; > } > + devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx->pwm); > > - hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", > + hwmon = devm_hwmon_device_register_with_groups(dev, "pwmfan", > ctx, pwm_fan_groups); > if (IS_ERR(hwmon)) { > - dev_err(&pdev->dev, "Failed to register hwmon device\n"); > - ret = PTR_ERR(hwmon); > - goto err_pwm_disable; > + dev_err(dev, "Failed to register hwmon device\n"); > + return PTR_ERR(hwmon); > } > > - ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); > + ret = pwm_fan_of_get_cooling_data(dev, ctx); > if (ret) > return ret; > > ctx->pwm_fan_state = ctx->pwm_fan_max_state; > if (IS_ENABLED(CONFIG_THERMAL)) { > - cdev = thermal_of_cooling_device_register(pdev->dev.of_node, > - "pwm-fan", ctx, > - &pwm_fan_cooling_ops); > + cdev = devm_thermal_of_cooling_device_register(dev, > + dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops); > if (IS_ERR(cdev)) { > - dev_err(&pdev->dev, > + dev_err(dev, > "Failed to register pwm-fan as cooling device"); > - ret = PTR_ERR(cdev); > - goto err_pwm_disable; > + return PTR_ERR(cdev); > } > ctx->cdev = cdev; > thermal_cdev_update(cdev); > } > > return 0; > - > -err_pwm_disable: > - state.enabled = false; > - pwm_apply_state(ctx->pwm, &state); > - > -err_reg_disable: > - if (ctx->reg_en) > - regulator_disable(ctx->reg_en); > - > - return ret; > -} > - > -static int pwm_fan_remove(struct platform_device *pdev) > -{ > - struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); > - > - thermal_cooling_device_unregister(ctx->cdev); > - if (ctx->pwm_value) > - pwm_disable(ctx->pwm); > - > - if (ctx->reg_en) > - regulator_disable(ctx->reg_en); > - > - return 0; > } > > #ifdef CONFIG_PM_SLEEP > @@ -380,7 +366,6 @@ MODULE_DEVICE_TABLE(of, of_pwm_fan_match); > > static struct platform_driver pwm_fan_driver = { > .probe = pwm_fan_probe, > - .remove = pwm_fan_remove, > .driver = { > .name = "pwm-fan", > .pm = &pwm_fan_pm, Best regards
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index 167221c7628a..0243ba70107e 100644 --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -207,33 +207,44 @@ static int pwm_fan_of_get_cooling_data(struct device *dev, return 0; } +static void pwm_fan_regulator_disable(void *data) +{ + regulator_disable(data); +} + +static void pwm_fan_pwm_disable(void *data) +{ + pwm_disable(data); +} + static int pwm_fan_probe(struct platform_device *pdev) { struct thermal_cooling_device *cdev; + struct device *dev = &pdev->dev; struct pwm_fan_ctx *ctx; struct device *hwmon; int ret; struct pwm_state state = { }; - ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); + ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; mutex_init(&ctx->lock); - ctx->pwm = devm_of_pwm_get(&pdev->dev, pdev->dev.of_node, NULL); + ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL); if (IS_ERR(ctx->pwm)) { ret = PTR_ERR(ctx->pwm); if (ret != -EPROBE_DEFER) - dev_err(&pdev->dev, "Could not get PWM: %d\n", ret); + dev_err(dev, "Could not get PWM: %d\n", ret); return ret; } platform_set_drvdata(pdev, ctx); - ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan"); + ctx->reg_en = devm_regulator_get_optional(dev, "fan"); if (IS_ERR(ctx->reg_en)) { if (PTR_ERR(ctx->reg_en) != -ENODEV) return PTR_ERR(ctx->reg_en); @@ -242,10 +253,11 @@ static int pwm_fan_probe(struct platform_device *pdev) } else { ret = regulator_enable(ctx->reg_en); if (ret) { - dev_err(&pdev->dev, - "Failed to enable fan supply: %d\n", ret); + dev_err(dev, "Failed to enable fan supply: %d\n", ret); return ret; } + devm_add_action_or_reset(dev, pwm_fan_regulator_disable, + ctx->reg_en); } ctx->pwm_value = MAX_PWM; @@ -257,62 +269,36 @@ static int pwm_fan_probe(struct platform_device *pdev) ret = pwm_apply_state(ctx->pwm, &state); if (ret) { - dev_err(&pdev->dev, "Failed to configure PWM\n"); - goto err_reg_disable; + dev_err(dev, "Failed to configure PWM\n"); + return ret; } + devm_add_action_or_reset(dev, pwm_fan_pwm_disable, ctx->pwm); - hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", + hwmon = devm_hwmon_device_register_with_groups(dev, "pwmfan", ctx, pwm_fan_groups); if (IS_ERR(hwmon)) { - dev_err(&pdev->dev, "Failed to register hwmon device\n"); - ret = PTR_ERR(hwmon); - goto err_pwm_disable; + dev_err(dev, "Failed to register hwmon device\n"); + return PTR_ERR(hwmon); } - ret = pwm_fan_of_get_cooling_data(&pdev->dev, ctx); + ret = pwm_fan_of_get_cooling_data(dev, ctx); if (ret) return ret; ctx->pwm_fan_state = ctx->pwm_fan_max_state; if (IS_ENABLED(CONFIG_THERMAL)) { - cdev = thermal_of_cooling_device_register(pdev->dev.of_node, - "pwm-fan", ctx, - &pwm_fan_cooling_ops); + cdev = devm_thermal_of_cooling_device_register(dev, + dev->of_node, "pwm-fan", ctx, &pwm_fan_cooling_ops); if (IS_ERR(cdev)) { - dev_err(&pdev->dev, + dev_err(dev, "Failed to register pwm-fan as cooling device"); - ret = PTR_ERR(cdev); - goto err_pwm_disable; + return PTR_ERR(cdev); } ctx->cdev = cdev; thermal_cdev_update(cdev); } return 0; - -err_pwm_disable: - state.enabled = false; - pwm_apply_state(ctx->pwm, &state); - -err_reg_disable: - if (ctx->reg_en) - regulator_disable(ctx->reg_en); - - return ret; -} - -static int pwm_fan_remove(struct platform_device *pdev) -{ - struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); - - thermal_cooling_device_unregister(ctx->cdev); - if (ctx->pwm_value) - pwm_disable(ctx->pwm); - - if (ctx->reg_en) - regulator_disable(ctx->reg_en); - - return 0; } #ifdef CONFIG_PM_SLEEP @@ -380,7 +366,6 @@ MODULE_DEVICE_TABLE(of, of_pwm_fan_match); static struct platform_driver pwm_fan_driver = { .probe = pwm_fan_probe, - .remove = pwm_fan_remove, .driver = { .name = "pwm-fan", .pm = &pwm_fan_pm,
Use devm_thermal_of_cooling_device_register() to register the cooling device. Also use devm_add_action_or_reset() to stop the fan on device removal, and to disable the pwm. Introduce a local 'dev' variable in the probe function to make the code easier to read. As a side effect, this fixes a bug seen if pwm_fan_of_get_cooling_data() returned an error. In that situation, the pwm was not disabled, and the fan was not stopped. Using devm functions also ensures that the pwm is disabled and that the fan is stopped only after the hwmon device has been unregistered. Cc: Lukasz Majewski <l.majewski@samsung.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- drivers/hwmon/pwm-fan.c | 73 ++++++++++++++++++++----------------------------- 1 file changed, 29 insertions(+), 44 deletions(-)