From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751278AbZH1NUv (ORCPT ); Fri, 28 Aug 2009 09:20:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750856AbZH1NUu (ORCPT ); Fri, 28 Aug 2009 09:20:50 -0400 Received: from einhorn.in-berlin.de ([192.109.42.8]:57010 "EHLO einhorn.in-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbZH1NUu (ORCPT ); Fri, 28 Aug 2009 09:20:50 -0400 X-Envelope-From: stefanr@s5r6.in-berlin.de Date: Fri, 28 Aug 2009 15:20:29 +0200 (CEST) From: Stefan Richter Subject: [PATCH] firewire: core: reduce stack usage in bus reset tasklet To: linux1394-devel@lists.sourceforge.net cc: linux-kernel@vger.kernel.org Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; CHARSET=us-ascii Content-Disposition: INLINE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org fw_compute_block_crc() used 1024 bytes of the kernel stack. This function is called - in process context when the local node's config ROM is updated, - in tasklet context of the bus reset handler. Replace the stack-allocated buffer by a static buffer. Serialize buffer accesses by a static local spinlock. Signed-off-by: Stefan Richter --- drivers/firewire/core-card.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) Index: linux-2.6.31-rc8/drivers/firewire/core-card.c =================================================================== --- linux-2.6.31-rc8.orig/drivers/firewire/core-card.c +++ linux-2.6.31-rc8/drivers/firewire/core-card.c @@ -40,13 +40,19 @@ int fw_compute_block_crc(u32 *block) { - __be32 be32_block[256]; + static DEFINE_SPINLOCK(buffer_lock); + static __be32 buffer[256]; + unsigned long flags; int i, length; + spin_lock_irqsave(&buffer_lock, flags); + length = (*block >> 16) & 0xff; for (i = 0; i < length; i++) - be32_block[i] = cpu_to_be32(block[i + 1]); - *block |= crc_itu_t(0, (u8 *) be32_block, length * 4); + buffer[i] = cpu_to_be32(block[i + 1]); + *block |= crc_itu_t(0, (u8 *)buffer, length * 4); + + spin_unlock_irqrestore(&buffer_lock, flags); return length; } -- Stefan Richter -=====-==--= =--- ===-- http://arcgraph.de/sr/