Date: Mon, 11 Jun 2012 07:15:49 +0000 (UTC) From: Adrian Chadd <adrian@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r236876 - head/sys/dev/ath Message-ID: <201206110715.q5B7Fn8h049682@svn.freebsd.org>
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Author: adrian Date: Mon Jun 11 07:15:48 2012 New Revision: 236876 URL: http://svn.freebsd.org/changeset/base/236876 Log: Retried frames need to be inserted in the head of the list, not the tail. This is an unfortunate byproduct of how the routine is used - it's called with the head frame on the queue, but if the frame is failed, it's inserted into the tail of the queue. Because of this, the sequence numbers would get all shuffled around and the BAW would be bumped past this sequence number, that's now at the end of the software queue. Then, whenever it's time for that frame to be transmitted, it'll be immediately outside of the BAW and TX will stall until the BAW catches up. It can also result in all kinds of weird duplicate BAW frames, leading to hilarious panics. PR: kern/166190 Modified: head/sys/dev/ath/if_ath_tx.c Modified: head/sys/dev/ath/if_ath_tx.c ============================================================================== --- head/sys/dev/ath/if_ath_tx.c Mon Jun 11 07:11:34 2012 (r236875) +++ head/sys/dev/ath/if_ath_tx.c Mon Jun 11 07:15:48 2012 (r236876) @@ -2309,7 +2309,7 @@ ath_tx_xmit_aggr(struct ath_softc *sc, s /* paused? queue */ if (tid->paused) { - ATH_TXQ_INSERT_TAIL(tid, bf, bf_list); + ATH_TXQ_INSERT_HEAD(tid, bf, bf_list); /* XXX don't sched - we're paused! */ return; }
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