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/openbmc/linux/net/mac80211/
H A Dagg-tx.cdiff 42624d4913a00219a8fdbb4bafd634d1d843be85 Thu Dec 08 03:26:15 CST 2011 Yogesh Ashok Powar <yogeshp@marvell.com> mac80211: Purge A-MPDU TX queues before station destructions

When a station leaves suddenly while ampdu traffic to that station is still
running, there is a possibility that the ampdu pending queues are not freed due
to a race condition leading to memory leaks. In '__sta_info_destroy' when we
attempt to destroy the ampdu sessions in 'ieee80211_sta_tear_down_BA_sessions',
the driver calls 'ieee80211_stop_tx_ba_cb_irqsafe' to delete the ampdu
structures (tid_tx) and splice the pending queues and this job gets queued in
sdata workqueue. However, the sta entry can get destroyed before the above work
gets scheduled and hence the race.

Purging the queues and freeing the tid_tx to avoid the leak. The better solution
would be to fix the race, but that can be taken up in a separate patch.

Signed-off-by: Nishant Sarmukadam <nishants@marvell.com>
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
H A Dsta_info.cdiff 27bf88829f50cf1af2b052ecee2f6f0dbe4a5141 Fri Dec 16 00:17:15 CST 2011 Yogesh Ashok Powar <yogesh.powar@gmail.com> mac80211: Fixing sparse warning at sta_info.c

The commit 42624d4913a00219a8fdbb4bafd634d1d843be85
created following sparse warning
>net/mac80211/sta_info.c:965:24: warning: incorrect type in assignment (different address spaces)
>net/mac80211/sta_info.c:965:24: expected struct tid_ampdu_tx *tid_tx
>net/mac80211/sta_info.c:965:24: got struct tid_ampdu_tx [noderef] <asn:4>*<noident>

Making use of rcu_dereference_protected to fix the problem.

V2:
- Replacing rcu_dereference with rcu_dereference_protected
as suggested by Johannes.
- Adding mutex_lock/unlock to satisfy the condition at
rcu_dereference_protected

Cc: Nishant Sarmukadam <nishants@marvell.com>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff 42624d4913a00219a8fdbb4bafd634d1d843be85 Thu Dec 08 03:26:15 CST 2011 Yogesh Ashok Powar <yogeshp@marvell.com> mac80211: Purge A-MPDU TX queues before station destructions

When a station leaves suddenly while ampdu traffic to that station is still
running, there is a possibility that the ampdu pending queues are not freed due
to a race condition leading to memory leaks. In '__sta_info_destroy' when we
attempt to destroy the ampdu sessions in 'ieee80211_sta_tear_down_BA_sessions',
the driver calls 'ieee80211_stop_tx_ba_cb_irqsafe' to delete the ampdu
structures (tid_tx) and splice the pending queues and this job gets queued in
sdata workqueue. However, the sta entry can get destroyed before the above work
gets scheduled and hence the race.

Purging the queues and freeing the tid_tx to avoid the leak. The better solution
would be to fix the race, but that can be taken up in a separate patch.

Signed-off-by: Nishant Sarmukadam <nishants@marvell.com>
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>