linux-kernel - Avoid needless loop in sdhci

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <3478818.ZVgDgJjmfN@mistral>
Date:	Mon, 04 Nov 2013 10:43:59 -0800
From:	Alexey Neyman <stilor@....net>
To:	Chris Ball <cjb@...top.org>, linux-mmc@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Avoid needless loop in sdhci_irq() for Card Interrupt

[Patch ping #3: anyone interested in making sdhci_irq a bit faster?]

Hi all,

I've discovered that the sdhci_irq() function needlessly iterates re-reading 
the interrupt status and doing nothing (until it runs out of max_loops) when 
it handles the "Card Interrupt" status in the interrupt status register.

The reason is that the "Card Interrupt" bit is not cleared until the 
sdhci_irq() calls mmc_signal_sdio_irq(), so if Card Interrupt was asserted, 
re-reading the interrupt status will find this bit set over and over, even if 
no other bits are reported.

The fix: ignore Card Interrupt bits in the interrupt status if we already know 
that mmc_signal_sdio_irq() is going to be called at the end of sdhci_irq().

Signed-off-by: Alexey Neyman <stilor@....net>
View attachment "sdhci.c.diff" of type "text/x-patch" (689 bytes)