From: Brian Norris <computersforpeace@gmail.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, <linux-kernel@vger.kernel.org>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Brian Norris <computersforpeace@gmail.com>
Subject: [RFC PATCH] usb: core: correct usb_get_dev() documentation
Date: Thu, 27 Oct 2016 15:02:30 -0700 [thread overview]
Message-ID: <1477605750-30117-1-git-send-email-computersforpeace@gmail.com> (raw)
In reading through a USB interface driver, I noticed that it called
usb_{get,put}_dev() in its probe() and disconnect() methods. This seemed
unnecessary, but a look at the comments here matched the usage.
USB interface devices seem to be well covered by the parent/child
relationship of the device model, and so it should be unnecessary for a
child device to grab a refcount on its parent device.
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
---
This reflects my understanding (and testing), as well as the majority of usage
-- there are *very* few interface drivers that actually call usb_get_dev(). If
I'm wrong, please feel free to tell me so! But I thought patching the
documentation would be the best way to solicit a response :)
drivers/usb/core/usb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 592151461017..0ba7e070f04e 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -539,9 +539,9 @@ EXPORT_SYMBOL_GPL(usb_alloc_dev);
*
* Each live reference to a device should be refcounted.
*
- * Drivers for USB interfaces should normally record such references in
- * their probe() methods, when they bind to an interface, and release
- * them by calling usb_put_dev(), in their disconnect() methods.
+ * The device driver core automatically handles this refcounting for USB
+ * interface drivers, but this API can be used for non-parent/child
+ * relationships.
*
* Return: A pointer to the device with the incremented reference counter.
*/
--
2.8.0.rc3.226.g39d4020
next reply other threads:[~2016-10-27 22:02 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-27 22:02 Brian Norris [this message]
2016-10-27 23:49 ` [RFC PATCH] usb: core: correct usb_get_dev() documentation Dmitry Torokhov
2016-10-28 5:05 ` Peter Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1477605750-30117-1-git-send-email-computersforpeace@gmail.com \
--to=computersforpeace@gmail.com \
--cc=dmitry.torokhov@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.