From: Willy Tarreau <w@1wt.eu>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: benjamin.cherian.kernel@gmail.com, linux-kernel@vger.kernel.org,
linux-usb-devel@lists.sourceforge.net
Subject: Re: Bug with USB proc_bulk in 2.4 kernel
Date: Thu, 3 Aug 2006 08:29:03 +0200 [thread overview]
Message-ID: <20060803062903.GA19176@1wt.eu> (raw)
In-Reply-To: <20060802230058.0ff73025.zaitcev@redhat.com>
On Wed, Aug 02, 2006 at 11:00:58PM -0700, Pete Zaitcev wrote:
> Replace the semaphore exclusive_access with an open-coded lock for
> the special use. The lock can be taken for: read, write, and both.
> This way, two bulk URBs can be submitted simultaneously with ioctl
> USBDEVFS_BULK: one read and one write. Such access was possible
> before 2.4.28.
>
> Signed-off-By: Pete Zaitcev <zaitcev@redhat.com>
>
> ---
>
> The semaphore was introduced in 2.4.28 for the purpose of exclusion
> between access from device.c (cat /proc/bus/usb/devices), devio.c
> through libusb, and in-kernel driver. Currently, only usb-storage
> observes the locking protocol. The most popular device which locks
> in case of simultaneous access is TEAC CD-210PU.
Perfect. Patch queued, thanks Pete.
Willy
next prev parent reply other threads:[~2006-08-03 6:37 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.1152332281.24203.linux-kernel2news@redhat.com>
2006-07-08 20:28 ` Bug with USB proc_bulk in 2.4 kernel and possibly bug in proc_ioctl in 2.6 Pete Zaitcev
2006-07-10 19:58 ` Bug with USB proc_bulk in 2.4 kernel Benjamin Cherian
2006-07-10 20:40 ` Pete Zaitcev
2006-07-17 21:35 ` Benjamin Cherian
2006-07-17 22:19 ` Pete Zaitcev
2006-07-18 17:04 ` Benjamin Cherian
2006-07-19 1:33 ` Pete Zaitcev
2006-07-20 17:43 ` Benjamin Cherian
2006-07-25 6:07 ` Pete Zaitcev
2006-07-25 19:31 ` Willy Tarreau
2006-07-27 22:21 ` Benjamin Cherian
2006-07-27 23:49 ` Pete Zaitcev
2006-07-28 17:37 ` Benjamin Cherian
2006-07-30 7:35 ` Pete Zaitcev
2006-07-31 18:41 ` Benjamin Cherian
2006-08-02 19:51 ` Willy Tarreau
2006-08-03 1:02 ` Pete Zaitcev
2006-08-03 2:33 ` Willy Tarreau
2006-08-03 6:00 ` Pete Zaitcev
2006-08-03 6:29 ` Willy Tarreau [this message]
2006-08-04 16:57 ` Benjamin Cherian
2006-08-04 16:55 ` Willy Tarreau
2006-08-09 17:01 ` Benjamin Cherian
2006-08-09 17:02 ` Willy Tarreau
2006-08-12 0:14 ` Marcelo Tosatti
2006-08-12 3:21 ` Willy Tarreau
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