| Message ID | 1526337639-3568-3-git-send-email-narmstrong@baylibre.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Neil, Thanks for this patch series! Some comments below: On 05/15/2018 12:40 AM, Neil Armstrong wrote: > In non device-tree world, we can need to get the notifier by the driver > name directly and eventually defer probe if not yet created. > > This patch adds a variant of the get function by using the device name > instead and will not create a notifier if not yet created. > > But the i915 driver exposes at least 2 HDMI connectors, this patch also > adds the possibility to add a connector name tied to the notifier device > to form a tuple and associate different CEC controllers for each HDMI > connectors. > > Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> > --- > drivers/media/cec/cec-notifier.c | 30 ++++++++++++++++++++++++--- > include/media/cec-notifier.h | 44 ++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 69 insertions(+), 5 deletions(-) > > diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c > index 16dffa0..716070a 100644 > --- a/drivers/media/cec/cec-notifier.c > +++ b/drivers/media/cec/cec-notifier.c > @@ -21,6 +21,7 @@ struct cec_notifier { > struct list_head head; > struct kref kref; > struct device *dev; > + const char *conn; > struct cec_adapter *cec_adap; > void (*callback)(struct cec_adapter *adap, u16 pa); > > @@ -30,13 +31,34 @@ struct cec_notifier { > static LIST_HEAD(cec_notifiers); > static DEFINE_MUTEX(cec_notifiers_lock); > > -struct cec_notifier *cec_notifier_get(struct device *dev) > +struct cec_notifier *cec_notifier_get_byname(const char *name, > + const char *conn) > { > struct cec_notifier *n; > > mutex_lock(&cec_notifiers_lock); > list_for_each_entry(n, &cec_notifiers, head) { > - if (n->dev == dev) { > + if (!strcmp(dev_name(n->dev), name) && > + (!conn || !strcmp(n->conn, conn))) { > + kref_get(&n->kref); > + mutex_unlock(&cec_notifiers_lock); > + return n; > + } > + } > + mutex_unlock(&cec_notifiers_lock); > + > + return NULL; This doesn't seem right. For one it doesn't act like the other cec_notifier_get* functions in that it doesn't make a new notifier if it wasn't found yet in the list. For another, I think this function shouldn't be here at all. How about calling bus_find_device_by_name(), then use cec_notifier_get_conn()? > +} > +EXPORT_SYMBOL_GPL(cec_notifier_get_byname); > + > +struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn) > +{ > + struct cec_notifier *n; > + > + mutex_lock(&cec_notifiers_lock); > + list_for_each_entry(n, &cec_notifiers, head) { > + if (n->dev == dev && > + (!conn || !strcmp(n->conn, conn))) { > kref_get(&n->kref); > mutex_unlock(&cec_notifiers_lock); > return n; > @@ -46,6 +68,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev) > if (!n) > goto unlock; > n->dev = dev; > + if (conn) > + n->conn = devm_kstrdup(dev, conn, GFP_KERNEL); The use of devm_kstrdup worries me. The problem is that when the 'dev' device is removed, this memory is also automatically freed. But the notifier might still have a reference through the CEC driver, so you end up with a n->conn pointer that points to freed memory. I think it is better to just use kstrdup and kfree it when the last notifier reference is released. > n->phys_addr = CEC_PHYS_ADDR_INVALID; > mutex_init(&n->lock); > kref_init(&n->kref); > @@ -54,7 +78,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev) > mutex_unlock(&cec_notifiers_lock); > return n; > } > -EXPORT_SYMBOL_GPL(cec_notifier_get); > +EXPORT_SYMBOL_GPL(cec_notifier_get_conn); > > static void cec_notifier_release(struct kref *kref) > { > diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h > index cf0add7..70f2974 100644 > --- a/include/media/cec-notifier.h > +++ b/include/media/cec-notifier.h > @@ -20,6 +20,37 @@ struct cec_notifier; > #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER) > > /** > + * cec_notifier_get_byname - find a cec_notifier for the given device name > + * and connector tuple. > + * @name: device name that sends the events. > + * @conn: the connector name from which the event occurs > + * > + * If a notifier for device @name exists, then increase the refcount and > + * return that notifier. > + * > + * If it doesn't exist, return NULL > + */ > +struct cec_notifier *cec_notifier_get_byname(const char *name, > + const char *conn); > + > +/** > + * cec_notifier_get_conn - find or create a new cec_notifier for the given > + * device and connector tuple. > + * @dev: device that sends the events. > + * @conn: the connector name from which the event occurs > + * > + * If a notifier for device @dev already exists, then increase the refcount > + * and return that notifier. > + * > + * If it doesn't exist, then allocate a new notifier struct and return a > + * pointer to that new struct. > + * > + * Return NULL if the memory could not be allocated. > + */ > +struct cec_notifier *cec_notifier_get_conn(struct device *dev, > + const char *conn); > + > +/** > * cec_notifier_get - find or create a new cec_notifier for the given device. > * @dev: device that sends the events. > * > @@ -31,7 +62,10 @@ struct cec_notifier; > * > * Return NULL if the memory could not be allocated. > */ > -struct cec_notifier *cec_notifier_get(struct device *dev); > +static inline struct cec_notifier *cec_notifier_get(struct device *dev) > +{ > + return cec_notifier_get_conn(dev, NULL); > +} > > /** > * cec_notifier_put - decrease refcount and delete when the refcount reaches 0. > @@ -85,12 +119,18 @@ void cec_register_cec_notifier(struct cec_adapter *adap, > struct cec_notifier *notifier); > > #else > -static inline struct cec_notifier *cec_notifier_get(struct device *dev) > +static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev, > + const char *conn) > { > /* A non-NULL pointer is expected on success */ > return (struct cec_notifier *)0xdeadfeed; > } > > +static inline struct cec_notifier *cec_notifier_get(struct device *dev) > +{ > + return cec_notifier_get_conn(dev, NULL); > +} > + > static inline void cec_notifier_put(struct cec_notifier *n) > { > } > Regards, Hans
On 15/05/2018 08:27, Hans Verkuil wrote: > Hi Neil, > > Thanks for this patch series! > > Some comments below: > > On 05/15/2018 12:40 AM, Neil Armstrong wrote: >> In non device-tree world, we can need to get the notifier by the driver >> name directly and eventually defer probe if not yet created. >> >> This patch adds a variant of the get function by using the device name >> instead and will not create a notifier if not yet created. >> >> But the i915 driver exposes at least 2 HDMI connectors, this patch also >> adds the possibility to add a connector name tied to the notifier device >> to form a tuple and associate different CEC controllers for each HDMI >> connectors. >> >> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> >> --- >> drivers/media/cec/cec-notifier.c | 30 ++++++++++++++++++++++++--- >> include/media/cec-notifier.h | 44 ++++++++++++++++++++++++++++++++++++++-- >> 2 files changed, 69 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c >> index 16dffa0..716070a 100644 >> --- a/drivers/media/cec/cec-notifier.c >> +++ b/drivers/media/cec/cec-notifier.c >> @@ -21,6 +21,7 @@ struct cec_notifier { >> struct list_head head; >> struct kref kref; >> struct device *dev; >> + const char *conn; >> struct cec_adapter *cec_adap; >> void (*callback)(struct cec_adapter *adap, u16 pa); >> >> @@ -30,13 +31,34 @@ struct cec_notifier { >> static LIST_HEAD(cec_notifiers); >> static DEFINE_MUTEX(cec_notifiers_lock); >> >> -struct cec_notifier *cec_notifier_get(struct device *dev) >> +struct cec_notifier *cec_notifier_get_byname(const char *name, >> + const char *conn) >> { >> struct cec_notifier *n; >> >> mutex_lock(&cec_notifiers_lock); >> list_for_each_entry(n, &cec_notifiers, head) { >> - if (n->dev == dev) { >> + if (!strcmp(dev_name(n->dev), name) && >> + (!conn || !strcmp(n->conn, conn))) { >> + kref_get(&n->kref); >> + mutex_unlock(&cec_notifiers_lock); >> + return n; >> + } >> + } >> + mutex_unlock(&cec_notifiers_lock); >> + >> + return NULL; > > This doesn't seem right. For one it doesn't act like the other cec_notifier_get* > functions in that it doesn't make a new notifier if it wasn't found yet in the > list. > > For another, I think this function shouldn't be here at all. How about calling > bus_find_device_by_name(), then use cec_notifier_get_conn()? Yes, it's safer and will keep the original cec_notifier_get() behavior. > >> +} >> +EXPORT_SYMBOL_GPL(cec_notifier_get_byname); >> + >> +struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn) >> +{ >> + struct cec_notifier *n; >> + >> + mutex_lock(&cec_notifiers_lock); >> + list_for_each_entry(n, &cec_notifiers, head) { >> + if (n->dev == dev && >> + (!conn || !strcmp(n->conn, conn))) { >> kref_get(&n->kref); >> mutex_unlock(&cec_notifiers_lock); >> return n; >> @@ -46,6 +68,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev) >> if (!n) >> goto unlock; >> n->dev = dev; >> + if (conn) >> + n->conn = devm_kstrdup(dev, conn, GFP_KERNEL); > > The use of devm_kstrdup worries me. The problem is that when the 'dev' device > is removed, this memory is also automatically freed. But the notifier might > still have a reference through the CEC driver, so you end up with a n->conn > pointer that points to freed memory. > > I think it is better to just use kstrdup and kfree it when the last notifier > reference is released. Ok > >> n->phys_addr = CEC_PHYS_ADDR_INVALID; >> mutex_init(&n->lock); >> kref_init(&n->kref); >> @@ -54,7 +78,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev) >> mutex_unlock(&cec_notifiers_lock); >> return n; >> } >> -EXPORT_SYMBOL_GPL(cec_notifier_get); >> +EXPORT_SYMBOL_GPL(cec_notifier_get_conn); >> >> static void cec_notifier_release(struct kref *kref) >> { >> diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h >> index cf0add7..70f2974 100644 >> --- a/include/media/cec-notifier.h >> +++ b/include/media/cec-notifier.h >> @@ -20,6 +20,37 @@ struct cec_notifier; >> #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER) >> >> /** >> + * cec_notifier_get_byname - find a cec_notifier for the given device name >> + * and connector tuple. >> + * @name: device name that sends the events. >> + * @conn: the connector name from which the event occurs >> + * >> + * If a notifier for device @name exists, then increase the refcount and >> + * return that notifier. >> + * >> + * If it doesn't exist, return NULL >> + */ >> +struct cec_notifier *cec_notifier_get_byname(const char *name, >> + const char *conn); >> + >> +/** >> + * cec_notifier_get_conn - find or create a new cec_notifier for the given >> + * device and connector tuple. >> + * @dev: device that sends the events. >> + * @conn: the connector name from which the event occurs >> + * >> + * If a notifier for device @dev already exists, then increase the refcount >> + * and return that notifier. >> + * >> + * If it doesn't exist, then allocate a new notifier struct and return a >> + * pointer to that new struct. >> + * >> + * Return NULL if the memory could not be allocated. >> + */ >> +struct cec_notifier *cec_notifier_get_conn(struct device *dev, >> + const char *conn); >> + >> +/** >> * cec_notifier_get - find or create a new cec_notifier for the given device. >> * @dev: device that sends the events. >> * >> @@ -31,7 +62,10 @@ struct cec_notifier; >> * >> * Return NULL if the memory could not be allocated. >> */ >> -struct cec_notifier *cec_notifier_get(struct device *dev); >> +static inline struct cec_notifier *cec_notifier_get(struct device *dev) >> +{ >> + return cec_notifier_get_conn(dev, NULL); >> +} >> >> /** >> * cec_notifier_put - decrease refcount and delete when the refcount reaches 0. >> @@ -85,12 +119,18 @@ void cec_register_cec_notifier(struct cec_adapter *adap, >> struct cec_notifier *notifier); >> >> #else >> -static inline struct cec_notifier *cec_notifier_get(struct device *dev) >> +static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev, >> + const char *conn) >> { >> /* A non-NULL pointer is expected on success */ >> return (struct cec_notifier *)0xdeadfeed; >> } >> >> +static inline struct cec_notifier *cec_notifier_get(struct device *dev) >> +{ >> + return cec_notifier_get_conn(dev, NULL); >> +} >> + >> static inline void cec_notifier_put(struct cec_notifier *n) >> { >> } >> > > Regards, > > Hans >
diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c index 16dffa0..716070a 100644 --- a/drivers/media/cec/cec-notifier.c +++ b/drivers/media/cec/cec-notifier.c @@ -21,6 +21,7 @@ struct cec_notifier { struct list_head head; struct kref kref; struct device *dev; + const char *conn; struct cec_adapter *cec_adap; void (*callback)(struct cec_adapter *adap, u16 pa); @@ -30,13 +31,34 @@ struct cec_notifier { static LIST_HEAD(cec_notifiers); static DEFINE_MUTEX(cec_notifiers_lock); -struct cec_notifier *cec_notifier_get(struct device *dev) +struct cec_notifier *cec_notifier_get_byname(const char *name, + const char *conn) { struct cec_notifier *n; mutex_lock(&cec_notifiers_lock); list_for_each_entry(n, &cec_notifiers, head) { - if (n->dev == dev) { + if (!strcmp(dev_name(n->dev), name) && + (!conn || !strcmp(n->conn, conn))) { + kref_get(&n->kref); + mutex_unlock(&cec_notifiers_lock); + return n; + } + } + mutex_unlock(&cec_notifiers_lock); + + return NULL; +} +EXPORT_SYMBOL_GPL(cec_notifier_get_byname); + +struct cec_notifier *cec_notifier_get_conn(struct device *dev, const char *conn) +{ + struct cec_notifier *n; + + mutex_lock(&cec_notifiers_lock); + list_for_each_entry(n, &cec_notifiers, head) { + if (n->dev == dev && + (!conn || !strcmp(n->conn, conn))) { kref_get(&n->kref); mutex_unlock(&cec_notifiers_lock); return n; @@ -46,6 +68,8 @@ struct cec_notifier *cec_notifier_get(struct device *dev) if (!n) goto unlock; n->dev = dev; + if (conn) + n->conn = devm_kstrdup(dev, conn, GFP_KERNEL); n->phys_addr = CEC_PHYS_ADDR_INVALID; mutex_init(&n->lock); kref_init(&n->kref); @@ -54,7 +78,7 @@ struct cec_notifier *cec_notifier_get(struct device *dev) mutex_unlock(&cec_notifiers_lock); return n; } -EXPORT_SYMBOL_GPL(cec_notifier_get); +EXPORT_SYMBOL_GPL(cec_notifier_get_conn); static void cec_notifier_release(struct kref *kref) { diff --git a/include/media/cec-notifier.h b/include/media/cec-notifier.h index cf0add7..70f2974 100644 --- a/include/media/cec-notifier.h +++ b/include/media/cec-notifier.h @@ -20,6 +20,37 @@ struct cec_notifier; #if IS_REACHABLE(CONFIG_CEC_CORE) && IS_ENABLED(CONFIG_CEC_NOTIFIER) /** + * cec_notifier_get_byname - find a cec_notifier for the given device name + * and connector tuple. + * @name: device name that sends the events. + * @conn: the connector name from which the event occurs + * + * If a notifier for device @name exists, then increase the refcount and + * return that notifier. + * + * If it doesn't exist, return NULL + */ +struct cec_notifier *cec_notifier_get_byname(const char *name, + const char *conn); + +/** + * cec_notifier_get_conn - find or create a new cec_notifier for the given + * device and connector tuple. + * @dev: device that sends the events. + * @conn: the connector name from which the event occurs + * + * If a notifier for device @dev already exists, then increase the refcount + * and return that notifier. + * + * If it doesn't exist, then allocate a new notifier struct and return a + * pointer to that new struct. + * + * Return NULL if the memory could not be allocated. + */ +struct cec_notifier *cec_notifier_get_conn(struct device *dev, + const char *conn); + +/** * cec_notifier_get - find or create a new cec_notifier for the given device. * @dev: device that sends the events. * @@ -31,7 +62,10 @@ struct cec_notifier; * * Return NULL if the memory could not be allocated. */ -struct cec_notifier *cec_notifier_get(struct device *dev); +static inline struct cec_notifier *cec_notifier_get(struct device *dev) +{ + return cec_notifier_get_conn(dev, NULL); +} /** * cec_notifier_put - decrease refcount and delete when the refcount reaches 0. @@ -85,12 +119,18 @@ void cec_register_cec_notifier(struct cec_adapter *adap, struct cec_notifier *notifier); #else -static inline struct cec_notifier *cec_notifier_get(struct device *dev) +static inline struct cec_notifier *cec_notifier_get_conn(struct device *dev, + const char *conn) { /* A non-NULL pointer is expected on success */ return (struct cec_notifier *)0xdeadfeed; } +static inline struct cec_notifier *cec_notifier_get(struct device *dev) +{ + return cec_notifier_get_conn(dev, NULL); +} + static inline void cec_notifier_put(struct cec_notifier *n) { }
In non device-tree world, we can need to get the notifier by the driver name directly and eventually defer probe if not yet created. This patch adds a variant of the get function by using the device name instead and will not create a notifier if not yet created. But the i915 driver exposes at least 2 HDMI connectors, this patch also adds the possibility to add a connector name tied to the notifier device to form a tuple and associate different CEC controllers for each HDMI connectors. Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> --- drivers/media/cec/cec-notifier.c | 30 ++++++++++++++++++++++++--- include/media/cec-notifier.h | 44 ++++++++++++++++++++++++++++++++++++++-- 2 files changed, 69 insertions(+), 5 deletions(-)