| Message ID | 20210909222513.2184795-7-arequipeno@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Introduce block device LED trigger | expand |
On Thu, Sep 09, 2021 at 05:25:04PM -0500, Ian Pilcher wrote: > Add ledtrig_blkdev_get_disk() to find block device by name and increment > its reference count. (Caller must call put_disk().) Must be built-in to > access block_class and disk_type symbols. > > Signed-off-by: Ian Pilcher <arequipeno@gmail.com> > --- > drivers/leds/trigger/ledtrig-blkdev-core.c | 20 ++++++++++++++++++++ > drivers/leds/trigger/ledtrig-blkdev.h | 3 +++ > 2 files changed, 23 insertions(+) > > diff --git a/drivers/leds/trigger/ledtrig-blkdev-core.c b/drivers/leds/trigger/ledtrig-blkdev-core.c > index d7b02e760b06..5fd741aa14a6 100644 > --- a/drivers/leds/trigger/ledtrig-blkdev-core.c > +++ b/drivers/leds/trigger/ledtrig-blkdev-core.c > @@ -33,3 +33,23 @@ void ledtrig_blkdev_disk_cleanup(struct gendisk *const gd) > > mutex_unlock(&ledtrig_blkdev_mutex); > } > + > +/* class_find_device() callback. Must be built-in to access disk_type. */ > +static int blkdev_match_name(struct device *const dev, const void *const name) > +{ > + return dev->type == &disk_type > + && sysfs_streq(dev_to_disk(dev)->disk_name, name); > +} > + > +/* Must be built-in to access block_class */ > +struct gendisk *ledtrig_blkdev_get_disk(const char *const name) > +{ > + struct device *dev; > + > + dev = class_find_device(&block_class, NULL, name, blkdev_match_name); > + if (dev == NULL) > + return NULL; You now have bumped the reference count on this structure. Where do you decrement it when you are finished with it? thanks, greg k-h
On 9/10/21 1:45 AM, Greg KH wrote: > You now have bumped the reference count on this structure. Where do you > decrement it when you are finished with it? That happens when I "unlink" the block device from the LED in blkdev_disk_unlink_locked() at ledtrig-blkdev.c:410. (And also in the error path of link_device_store() at ledtrig-blkdev.c:372.) -- ======================================================================== In Soviet Russia, Google searches you! ========================================================================
On Fri, Sep 10, 2021 at 10:17:03AM -0500, Ian Pilcher wrote: > On 9/10/21 1:45 AM, Greg KH wrote: > > You now have bumped the reference count on this structure. Where do you > > decrement it when you are finished with it? > > That happens when I "unlink" the block device from the LED in > blkdev_disk_unlink_locked() at ledtrig-blkdev.c:410. I have no context here anymore, so I have no idea if this is really true :(
On 9/10/21 1:45 AM, Greg KH wrote: > On Thu, Sep 09, 2021 at 05:25:04PM -0500, Ian Pilcher wrote: >> +/* Must be built-in to access block_class */ >> +struct gendisk *ledtrig_blkdev_get_disk(const char *const name) >> +{ >> + struct device *dev; >> + >> + dev = class_find_device(&block_class, NULL, name, blkdev_match_name); >> + if (dev == NULL) >> + return NULL; > > You now have bumped the reference count on this structure. Where do you > decrement it when you are finished with it? With context this time. Sorry about that. That happens when I "unlink" the block device from the LED in blkdev_disk_unlink_locked() at ledtrig-blkdev.c:410. (And also in the error path of link_device_store() at ledtrig-blkdev.c:372.) -- ======================================================================== In Soviet Russia, Google searches you! ========================================================================
diff --git a/drivers/leds/trigger/ledtrig-blkdev-core.c b/drivers/leds/trigger/ledtrig-blkdev-core.c index d7b02e760b06..5fd741aa14a6 100644 --- a/drivers/leds/trigger/ledtrig-blkdev-core.c +++ b/drivers/leds/trigger/ledtrig-blkdev-core.c @@ -33,3 +33,23 @@ void ledtrig_blkdev_disk_cleanup(struct gendisk *const gd) mutex_unlock(&ledtrig_blkdev_mutex); } + +/* class_find_device() callback. Must be built-in to access disk_type. */ +static int blkdev_match_name(struct device *const dev, const void *const name) +{ + return dev->type == &disk_type + && sysfs_streq(dev_to_disk(dev)->disk_name, name); +} + +/* Must be built-in to access block_class */ +struct gendisk *ledtrig_blkdev_get_disk(const char *const name) +{ + struct device *dev; + + dev = class_find_device(&block_class, NULL, name, blkdev_match_name); + if (dev == NULL) + return NULL; + + return dev_to_disk(dev); +} +EXPORT_SYMBOL_NS_GPL(ledtrig_blkdev_get_disk, LEDTRIG_BLKDEV); diff --git a/drivers/leds/trigger/ledtrig-blkdev.h b/drivers/leds/trigger/ledtrig-blkdev.h index b1294da17ba3..a6ff24fad0c2 100644 --- a/drivers/leds/trigger/ledtrig-blkdev.h +++ b/drivers/leds/trigger/ledtrig-blkdev.h @@ -12,4 +12,7 @@ extern struct mutex ledtrig_blkdev_mutex; extern void (*__ledtrig_blkdev_disk_cleanup)(struct gendisk *gd); +/* Caller must call put_disk() */ +struct gendisk *ledtrig_blkdev_get_disk(const char *const name); + #endif /* __LEDTRIG_BLKDEV_H */
Add ledtrig_blkdev_get_disk() to find block device by name and increment its reference count. (Caller must call put_disk().) Must be built-in to access block_class and disk_type symbols. Signed-off-by: Ian Pilcher <arequipeno@gmail.com> --- drivers/leds/trigger/ledtrig-blkdev-core.c | 20 ++++++++++++++++++++ drivers/leds/trigger/ledtrig-blkdev.h | 3 +++ 2 files changed, 23 insertions(+)