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authorAndreas Fenkart <andreas.fenkart@streamunlimited.com>2013-04-04 20:03:52 -0700
committerJohn W. Linville <linville@tuxdriver.com>2013-04-08 15:28:39 -0400
commit333f6b22c5b88a9d856703b440257f46efa714c8 (patch)
tree4cc881717c225356f42d0870997332b424e0a2ae /drivers/net/wireless/mwifiex/11n.c
parent6d2344ec6043a2de8cfa9d8f27909a99ca967a08 (diff)
mwifiex: fix infinite loop by removing NO_PKT_PRIO_TID
Using NO_PKT_PRIO_TID and tx_pkts_queued to check for an empty state, can lead to a contradictory state, resulting in an infinite loop. Currently queueing and dequeuing of packets is not synchronized, and can happen concurrently. While tx_pkts_queued is incremented when adding a packet, max prio is set to NO_PKT when the WMM list is empty. If a packet is added right after the check for empty, but before setting max prio to NO_PKT, that packet is trapped and creates an infinite loop. Because of the new packet, tx_pkts_queued is at least 1, indicating wmm lists are not empty. Opposing that max prio is NO_PKT, which means "skip this wmm queue, it has no packets". The infinite loop results, because the main loop checks the wmm lists for not empty via tx_pkts_queued, but for dequeing it uses max_prio to see if it can skip current list. This will never end, unless a new packet is added which will restore max prio to the level of the trapped packet. The solution here is to rely on tx_pkts_queued solely for checking wmm queue to be empty, and drop the NO_PKT define. It does not address the locking issue. Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com> Signed-off-by: Avinash Patil <patila@marvell.com> Signed-off-by: Bing Zhao <bzhao@marvell.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/mwifiex/11n.c')
0 files changed, 0 insertions, 0 deletions