ath9k: rework tx queue selection and fix queue stopping/waking
The current ath9k tx queue handling code showed a few issues that could lead to locking issues, tx stalls due to stopped queues, and maybe even DMA issues. The main source of these issues is that in some places the queue is selected via skb queue mapping in places where this mapping may no longer be valid. One such place is when data frames are transmitted via the CAB queue (for powersave buffered frames). This is made even worse by a lookup WMM AC values from the assigned tx queue (which is undefined for the CAB queue). This messed up the pending frame counting, which in turn caused issues with queues getting stopped, but not woken again. To fix these issues, this patch removes an unnecessary abstraction separating a driver internal queue number from the skb queue number (not to be confused with the hardware queue number). It seems that this abstraction may have been necessary because of tx queue preinitialization from the initvals. This patch avoids breakage here by pushing the software <-> hardware queue mapping to the function that assigns the tx queues and redefining the WMM AC definitions to match the numbers used by mac80211 (also affects ath9k_htc). To ensure consistency wrt. pending frame count tracking, these counters are moved to the ath_txq struct, updated with the txq lock held, but only where the tx queue selected by the skb queue map actually matches the tx queue used by the driver for the frame. Signed-off-by: Felix Fietkau <nbd@openwrt.org> Reported-by: Björn Smedman <bjorn.smedman@venatech.se> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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