From: Peter Hurley <peter@hurleysoftware.com>
To: Jonathan Corbet <corbet@lwn.net>,
Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>, Russell King <rmk@arm.linux.org.uk>,
linux-serial@vger.kernel.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH 4/4] serial: doc: .break_ctl() may sleep
Date: Fri, 15 Apr 2016 15:31:30 -0700 [thread overview]
Message-ID: <57116BC2.5070102@hurleysoftware.com> (raw)
In-Reply-To: <20160415160104.6aed0770@lwn.net>
On 04/15/2016 03:01 PM, Jonathan Corbet wrote:
> On Thu, 14 Apr 2016 11:08:11 +0200
> Geert Uytterhoeven <geert+renesas@glider.be> wrote:
>
>> As mutex_lock() must not be called with interrupts disabled,
>> .break_ctl() may sleep.
>
> So I've applied the first three to the docs tree, but this one stopped
> me. The changelog doesn't really say why the patch is correct; what we
> really need to know is that break_ctl() won't be called in atomic
> context.
The only caller of the uart driver's break_ctl() method is
uart_break_ctl(), which is serial core's proxy tty driver break_ctl()
method. uart_break_ctl() claims the struct tty_port::mutex to prevent
concurrent tiocmset().
Thus, the uart driver's break_ctl() method won't be called in atomic
context.
Regards,
Peter Hurley
next prev parent reply other threads:[~2016-04-15 22:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-14 9:08 [PATCH 0/4] serial: doc: Low Level Serial API Documentation Improvements (take two) Geert Uytterhoeven
2016-04-14 9:08 ` [PATCH 1/4] serial: doc: Re-add paragraph documenting uart_console_write() Geert Uytterhoeven
2016-04-14 9:08 ` [PATCH 2/4] serial: doc: .(un)throttle() depends on hardware assisted flow control Geert Uytterhoeven
2016-04-14 9:08 ` [PATCH 3/4] serial: doc: .(un)throttle() are serialized by the tty layer Geert Uytterhoeven
2016-04-14 9:08 ` [PATCH 4/4] serial: doc: .break_ctl() may sleep Geert Uytterhoeven
2016-04-15 22:01 ` Jonathan Corbet
2016-04-15 22:31 ` Peter Hurley [this message]
2016-04-15 22:41 ` Jonathan Corbet
2016-04-15 23:07 ` Peter Hurley
2016-04-16 16:47 ` Jonathan Corbet
2016-04-18 8:24 ` Geert Uytterhoeven
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