From: Eric Dumazet Date: Thu, 24 Mar 2011 07:13:14 +0000 (-0700) Subject: net_sched: fix THROTTLED/RUNNING race X-Git-Tag: v2.6.39-rc1~54^2~7 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef352e7cdf714596f51ad18809404edeaa50e8fd;p=pandora-kernel.git net_sched: fix THROTTLED/RUNNING race commit fd245a4adb52 (net_sched: move TCQ_F_THROTTLED flag) added a race. qdisc_watchdog() is run from softirq, so special care should be taken or we can lose one state transition (THROTTLED/RUNNING) Prior to fd245a4adb52, we were manipulating q->flags (qdisc->flags &= ~TCQ_F_THROTTLED;) and this manipulation could only race with qdisc_warn_nonwc(). Since we want to avoid atomic ops in qdisc fast path - it was the meaning of commit 371121057607e (QDISC_STATE_RUNNING dont need atomic bit ops) - fix is to move THROTTLE bit into 'state' field, this one being manipulated with SMP and IRQ safe operations. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- Reading git-diff-tree failed