From: Vivek Goyal Date: Fri, 22 Oct 2010 07:48:43 +0000 (+0200) Subject: cfq-iosched: Fix a gcc 4.5 warning and put some comments X-Git-Tag: v2.6.37-rc1~168^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b4627321e18582dcbdeb45d77df29d3177107c65;p=pandora-kernel.git cfq-iosched: Fix a gcc 4.5 warning and put some comments - Andi encountedred following warning with gcc 4.5 linux/block/cfq-iosched.c: In function ‘cfq_dispatch_requests’: linux/block/cfq-iosched.c:2156:3: warning: array subscript is above array bounds - Warning happens due to following code. slice = group_slice * count / max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio], cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg)); gcc is complaining about cfqg->busy_queues_avg[] being indexed by CFQ prio classes (RT, BE and IDLE) while the array size is only 2. - At run time, we never access cfqg->busy_queues_avg[IDLE] and return from function before this code hits. - To fix warning increase the array size though it will remain unused. This patch also puts some comments to clarify some of the confusions. - I have taken Jens's patch and modified it a bit. - Compile tested with gcc 4.4 and boot tested. I don't have gcc 4.5 running, Andi can you please test it with gcc 4.5 to make sure it worked. Reported-by: Andi Kleen Signed-off-by: Vivek Goyal Acked-by: Jeff Moyer Signed-off-by: Jens Axboe --- Reading git-diff-tree failed