From mboxrd@z Thu Jan  1 00:00:00 1970
From: sshtylyov@mvista.com (Sergei Shtylyov)
Date: Mon, 31 Jan 2011 15:31:28 +0300
Subject: [PATCH] mmci: calculate remaining bytes at error correctly
In-Reply-To: <20110131122520.GA11694@n2100.arm.linux.org.uk>
References: <1296137666-30906-1-git-send-email-linus.walleij@stericsson.com>
	<20110130212856.GA32737@n2100.arm.linux.org.uk>
	<4D46A44C.3030609@ru.mvista.com>
	<20110131122520.GA11694@n2100.arm.linux.org.uk>
Message-ID: <4D46ABA0.9010809@ru.mvista.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hello.

On 31-01-2011 15:25, Russell King - ARM Linux wrote:

>>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>>> index b6fd6dc..175a623 100644
>>> --- a/drivers/mmc/host/mmci.c
>>> +++ b/drivers/mmc/host/mmci.c
>>> @@ -319,7 +319,7 @@ mmci_data_irq(struct mmci_host *host, struct mmc_data *data,
>>>    	if (status&   MCI_DATABLOCKEND)
>>>    		dev_err(mmc_dev(host->mmc), "stray MCI_DATABLOCKEND interrupt\n");

>>> -	if (status & MCI_DATAEND) {
>>> +	if (status & MCI_DATAEND

>>     Shouldn't 'status & MCI_DATAEND' be enclosed in parens?

> No.  Only people who don't want to know operator precedence enclose
> everything in parens.  Here's the grammar:

> logical-OR-expression:
>                 logical-AND-expression
>                 logical-OR-expression || logical-AND-expression
> logical-AND-expression:
>                 inclusive-OR-expression
>                 logical-AND-expression&&  inclusive-OR-expression
> inclusive-OR-expression:
>                 exclusive-OR-expression
>                 inclusive-OR-expression | exclusive-OR-expression
> exclusive-OR-expression:
>                 AND-expression
>                 exclusive-OR-expression ^ AND-expression
> AND-expression:
>                 equality-expression
>                 AND-expression&  equality-expression

> So, a & b || c gives:

> logical-OR-expression := a & b || c
> +-logical-OR-expression := a & b
> | `-logical-AND-expression := a & b
> |   `-inclusive-OR-expression := a & b
> |     `-exclusive-OR-expression := a & b
> |       `-AND-expression := a & b
> |         +-AND-expression := a
> |         | `-equality-expression := a
> |         `-equality-expression := b
> +-logical-AND-expression := c
>    `-inclusive-OR-expression := c
>      `-exclusive-OR-expression := c
>        `-AND-expression := c
>         `-equality-expression := c

> So, a&  b || c is evaluated as ((a)&  (b)) || (c), which is exactly what
> we want it to be.

> If it were && and ||, then there is reason to use parens as people often
> get the relative precedence of && and || mixed up.

    Well, that's certainly not my case. :-)

> If you insist on putting parens around a&  b there, then for the sake of
> consistency, you should be putting parens around every sub-expression
> involving || and &&  - as if you think that a & b || c could be incorrectly
> evaluated, a < b || c falls into exactly the same category, as does
> a < b || c < d.

    I mainly noted about those parens because gcc tends to give warnings in 
such cases, if I remember right.
    Thanks for your elaborate reply. :-)

WBR, Sergei