From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jim Nelson <james4765@verizon.net>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: A general question on SMP-safe driver code.
Date: Sat, 25 Dec 2004 12:23:24 +0000 [thread overview]
Message-ID: <1103977401.22646.9.camel@localhost.localdomain> (raw)
In-Reply-To: <41CC9F2A.9080905@verizon.net>
On Gwe, 2004-12-24 at 22:58, Jim Nelson wrote:
> Looking at a few older drivers, I'm trying to figure out the best ways to handle
> some locking. Using drivers/char/esp.c as an example (since it's the one I'm
> trying to grok right now), here is one example:
> ;
> serial_out(info, UART_ESI_CMD1, ESI_GET_TX_AVAIL);
> spin_unlock_irq(&info->esp_lock);
>
> while ((serial_in(info, UART_ESI_STAT1) != 0x03) ||
> (serial_in(info, UART_ESI_STAT2) != 0xff)) {
You need to guard these as well in the locks. It might actually look a
lot cleaner to have functions esp_send_command(info, a, b) and the like
which do the locking internally ?
prev parent reply other threads:[~2004-12-25 13:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-24 22:58 Jim Nelson
2004-12-24 23:28 ` Linus Torvalds
2004-12-25 12:23 ` Alan Cox [this message]
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