commit 8e50d384cc1d5afd2989cf0f7093756ed7164eb2
author Zhouyi Zhou <zhouzhouyi@gmail.com> Thu Oct 24 15:43:33 2013 +0800
committer Arnaldo Carvalho de Melo <acme@redhat.com> Mon Oct 28 16:06:00 2013 -0300
tree 87e34b49783a32d8552eaad510d0b5fba94ee08e
parent ae779a630977d93fbebfa06216ea47df5b5c62c8

perf tools: Fixup mmap event consumption

The tail position of the event buffer should only be modified after
actually use that event.

If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.

Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>