| Message ID | 000e01ce132a$be08b940$3a1a2bc0$%han@samsung.com |
|---|---|
| State | Superseded |
| Headers | show |
On Mon, 25 Feb 2013 16:35:53 +0900 Jingoo Han <jg1.han@samsung.com> wrote: > These functios allows the driver core to automatically clean up > any allocation made by rtc drivers. Thus, it simplifies the error > paths. > > ... > > @@ -259,6 +259,78 @@ void rtc_device_unregister(struct rtc_device *rtc) > } > EXPORT_SYMBOL_GPL(rtc_device_unregister); > > +static void devm_rtc_device_release(struct device *dev, void *res) > +{ > + struct rtc_device *rtc = *(struct rtc_device **)res; > + > + rtc_device_unregister(rtc); > +} > + > +static int devm_rtc_device_match(struct device *dev, void *res, void *data) > +{ > + struct rtc **r = res; > + if (!r || !*r) { > + WARN_ON(!r || !*r); > + return 0; > + } Use if (WARN_ON(!r || !*r)) return 0; However, if anyone ever reports this warning you will be sad because you won't know which condition triggered it. So a more useful approach is if (WARN_ON(!r)) return 0; if (WARN_ON(!*r)) return 0; > + return *r == data; > +} > + > +/** > + * devm_rtc_device_register - resource managed rtc_device_register() > + * @name: the name of the device > + * @dev: the device to register > + * @ops: the rtc operations structure > + * @owner: the module owner > + * > + * Managed rtc_device_register(). The rtc_device returned from this function > + * are automatically freed on driver detach. See rtc_device_register() > + * for more information. > + */ I think the name is inappropriate. devm functions start with "devm" and rtc functions start with "rtc" and this code is a part of rtc core, not a part of devm core. Hence it should be something like "rtc_devm_device_register". > +struct rtc_device *devm_rtc_device_register(const char *name, > + struct device *dev, > + const struct rtc_class_ops *ops, > + struct module *owner) > +{ > + struct rtc_device **ptr, *rtc; > + > + ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL); > + if (!ptr) > + return ERR_PTR(-ENOMEM); > + > + rtc = rtc_device_register(name, dev, ops, owner); > + if (!IS_ERR(rtc)) { > + *ptr = rtc; > + devres_add(dev, ptr); > + } else { > + devres_free(ptr); > + } > + > + return rtc; > +} > +EXPORT_SYMBOL_GPL(devm_rtc_device_register); So this function will return an ERR_PTR on error. Please add a description of the return value into the kerneldoc. > +/** > + * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() > + * @dev: the device to unregister > + * @rtc: the RTC class device to unregister > + * > + * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this > + * function will not need to be called and the resource management code will > + * ensure that the resource is freed. > + */ > +void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc) > +{ > + int rc; > + > + rc = devres_release(dev, devm_rtc_device_release, > + devm_rtc_device_match, rtc); > + if (rc != 0) > + WARN_ON(rc); WARN_ON(!rc); > +} > +EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); > + > > ... >
On Mon, Feb 25, 2013 at 04:35:53PM +0900, Jingoo Han wrote: > +static void devm_rtc_device_release(struct device *dev, void *res) > +{ > + struct rtc_device *rtc = *(struct rtc_device **)res; > + > + rtc_device_unregister(rtc); > +} > + > +static int devm_rtc_device_match(struct device *dev, void *res, void *data) > +{ > + struct rtc **r = res; > + if (!r || !*r) { > + WARN_ON(!r || !*r); > + return 0; > + } if (WARN_ON(!r || !*r)) return 0; But why do we need this at all? Other match functions don't need it. Is something different about devm_rtc? Thanks.
On Mon, Feb 25, 2013 at 02:29:57PM -0800, Andrew Morton wrote: > > + * Managed rtc_device_register(). The rtc_device returned from this function > > + * are automatically freed on driver detach. See rtc_device_register() > > + * for more information. > > + */ > > I think the name is inappropriate. devm functions start with "devm" > and rtc functions start with "rtc" and this code is a part of rtc core, > not a part of devm core. Hence it should be something like > "rtc_devm_device_register". I think devm_rtc_ is better. All other devm interface functions put devm_ prefix first and I think it's better to make devm_ more pronounced as it denotes a somewhat subtle difference in behavior. Thanks.
On Mon, 25 Feb 2013 15:33:45 -0800 "'Tejun Heo'" <tj@kernel.org> wrote: > On Mon, Feb 25, 2013 at 02:29:57PM -0800, Andrew Morton wrote: > > > + * Managed rtc_device_register(). The rtc_device returned from this function > > > + * are automatically freed on driver detach. See rtc_device_register() > > > + * for more information. > > > + */ > > > > I think the name is inappropriate. devm functions start with "devm" > > and rtc functions start with "rtc" and this code is a part of rtc core, > > not a part of devm core. Hence it should be something like > > "rtc_devm_device_register". > > I think devm_rtc_ is better. All other devm interface functions put > devm_ prefix first makes no sense. Whatever.
diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 9b742d3..bd3c8ca 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -259,6 +259,78 @@ void rtc_device_unregister(struct rtc_device *rtc) } EXPORT_SYMBOL_GPL(rtc_device_unregister); +static void devm_rtc_device_release(struct device *dev, void *res) +{ + struct rtc_device *rtc = *(struct rtc_device **)res; + + rtc_device_unregister(rtc); +} + +static int devm_rtc_device_match(struct device *dev, void *res, void *data) +{ + struct rtc **r = res; + if (!r || !*r) { + WARN_ON(!r || !*r); + return 0; + } + return *r == data; +} + +/** + * devm_rtc_device_register - resource managed rtc_device_register() + * @name: the name of the device + * @dev: the device to register + * @ops: the rtc operations structure + * @owner: the module owner + * + * Managed rtc_device_register(). The rtc_device returned from this function + * are automatically freed on driver detach. See rtc_device_register() + * for more information. + */ + +struct rtc_device *devm_rtc_device_register(const char *name, + struct device *dev, + const struct rtc_class_ops *ops, + struct module *owner) +{ + struct rtc_device **ptr, *rtc; + + ptr = devres_alloc(devm_rtc_device_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + rtc = rtc_device_register(name, dev, ops, owner); + if (!IS_ERR(rtc)) { + *ptr = rtc; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return rtc; +} +EXPORT_SYMBOL_GPL(devm_rtc_device_register); + +/** + * devm_rtc_device_unregister - resource managed devm_rtc_device_unregister() + * @dev: the device to unregister + * @rtc: the RTC class device to unregister + * + * Deallocated a rtc allocated with devm_rtc_device_register(). Normally this + * function will not need to be called and the resource management code will + * ensure that the resource is freed. + */ +void devm_rtc_device_unregister(struct device *dev, struct rtc_device *rtc) +{ + int rc; + + rc = devres_release(dev, devm_rtc_device_release, + devm_rtc_device_match, rtc); + if (rc != 0) + WARN_ON(rc); +} +EXPORT_SYMBOL_GPL(devm_rtc_device_unregister); + static int __init rtc_init(void) { rtc_class = class_create(THIS_MODULE, "rtc"); diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 580b24c..d955768 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -133,7 +133,13 @@ extern struct rtc_device *rtc_device_register(const char *name, struct device *dev, const struct rtc_class_ops *ops, struct module *owner); +extern struct rtc_device *devm_rtc_device_register(const char *name, + struct device *dev, + const struct rtc_class_ops *ops, + struct module *owner); extern void rtc_device_unregister(struct rtc_device *rtc); +extern void devm_rtc_device_unregister(struct device *dev, + struct rtc_device *rtc); extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm); extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
These functios allows the driver core to automatically clean up any allocation made by rtc drivers. Thus, it simplifies the error paths. Signed-off-by: Jingoo Han <jg1.han@samsung.com> --- drivers/rtc/class.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/rtc.h | 6 ++++ 2 files changed, 78 insertions(+), 0 deletions(-)