From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752456AbeEOH26 (ORCPT ); Tue, 15 May 2018 03:28:58 -0400 Received: from mail-lf0-f67.google.com ([209.85.215.67]:45221 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752433AbeEOH2z (ORCPT ); Tue, 15 May 2018 03:28:55 -0400 X-Google-Smtp-Source: AB8JxZp/Xa3T+/8mDsVk22WO/XZ/1coPMkkBJDJPO9oUs5JFRd1dezq7y7IlRXQzE1dTmxy7onqhMw== Subject: Re: [RFC PATCH 2/5] media: cec-notifier: Get notifier by device and connector name To: Hans Verkuil , airlied@linux.ie, hans.verkuil@cisco.com, lee.jones@linaro.org, olof@lixom.net, seanpaul@google.com Cc: sadolfsson@google.com, felixe@google.com, bleung@google.com, darekm@google.com, marcheu@chromium.org, fparent@baylibre.com, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <1526337639-3568-1-git-send-email-narmstrong@baylibre.com> <1526337639-3568-3-git-send-email-narmstrong@baylibre.com> From: Neil Armstrong Openpgp: preference=signencrypt Autocrypt: addr=narmstrong@baylibre.com; prefer-encrypt=mutual; keydata= xsBNBE1ZBs8BCAD78xVLsXPwV/2qQx2FaO/7mhWL0Qodw8UcQJnkrWmgTFRobtTWxuRx8WWP GTjuhvbleoQ5Cxjr+v+1ARGCH46MxFP5DwauzPekwJUD5QKZlaw/bURTLmS2id5wWi3lqVH4 BVF2WzvGyyeV1o4RTCYDnZ9VLLylJ9bneEaIs/7cjCEbipGGFlfIML3sfqnIvMAxIMZrvcl9 qPV2k+KQ7q+aXavU5W+yLNn7QtXUB530Zlk/d2ETgzQ5FLYYnUDAaRl+8JUTjc0CNOTpCeik 80TZcE6f8M76Xa6yU8VcNko94Ck7iB4vj70q76P/J7kt98hklrr85/3NU3oti3nrIHmHABEB AAHNKE5laWwgQXJtc3Ryb25nIDxuYXJtc3Ryb25nQGJheWxpYnJlLmNvbT7CwHsEEwEKACUC GyMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheABQJXDO2CAhkBAAoJEBaat7Gkz/iubGIH/iyk RqvgB62oKOFlgOTYCMkYpm2aAOZZLf6VKHKc7DoVwuUkjHfIRXdslbrxi4pk5VKU6ZP9AKsN NtMZntB8WrBTtkAZfZbTF7850uwd3eU5cN/7N1Q6g0JQihE7w4GlIkEpQ8vwSg5W7hkx3yQ6 2YzrUZh/b7QThXbNZ7xOeSEms014QXazx8+txR7jrGF3dYxBsCkotO/8DNtZ1R+aUvRfpKg5 ZgABTC0LmAQnuUUf2PHcKFAHZo5KrdO+tyfL+LgTUXIXkK+tenkLsAJ0cagz1EZ5gntuheLD YJuzS4zN+1Asmb9kVKxhjSQOcIh6g2tw7vaYJgL/OzJtZi6JlIXOwE0ETVkGzwEIALyKDN/O GURaHBVzwjgYq+ZtifvekdrSNl8TIDH8g1xicBYpQTbPn6bbSZbdvfeQPNCcD4/EhXZuhQXM coJsQQQnO4vwVULmPGgtGf8PVc7dxKOeta+qUh6+SRh3vIcAUFHDT3f/Zdspz+e2E0hPV2hi SvICLk11qO6cyJE13zeNFoeY3ggrKY+IzbFomIZY4yG6xI99NIPEVE9lNBXBKIlewIyVlkOa YvJWSV+p5gdJXOvScNN1epm5YHmf9aE2ZjnqZGoMMtsyw18YoX9BqMFInxqYQQ3j/HpVgTSv mo5ea5qQDDUaCsaTf8UeDcwYOtgI8iL4oHcsGtUXoUk33HEAEQEAAcLAXwQYAQIACQUCTVkG zwIbDAAKCRAWmrexpM/4rrXiB/sGbkQ6itMrAIfnM7IbRuiSZS1unlySUVYu3SD6YBYnNi3G 5EpbwfBNuT3H8//rVvtOFK4OD8cRYkxXRQmTvqa33eDIHu/zr1HMKErm+2SD6PO9umRef8V8 2o2oaCLvf4WeIssFjwB0b6a12opuRP7yo3E3gTCSKmbUuLv1CtxKQF+fUV1cVaTPMyT25Od+ RC1K+iOR0F54oUJvJeq7fUzbn/KdlhA8XPGzwGRy4zcsPWvwnXgfe5tk680fEKZVwOZKIEuJ C3v+/yZpQzDvGYJvbyix0lHnrCzq43WefRHI5XTTQbM0WUIBIcGmq38+OgUsMYu4NzLu7uZF Acmp6h8g Organization: Baylibre Message-ID: <9a20dfa6-d61a-637a-0311-e260e555f86f@baylibre.com> Date: Tue, 15 May 2018 09:28:51 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 >> --- >> 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 >