ath5k: optimize rx status processing

Use ACCESS_ONCE to reduce the number of redundant loads on uncached memory

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/ath/ath5k/desc.c b/drivers/net/wireless/ath/ath5k/desc.c
index 3758b967029a9f13d0c64df14b7f7435bc1c955c..e366d30ef0395dd8f3e9aeb3809d6443ae1a402c 100644 (file)
--- a/drivers/net/wireless/ath/ath5k/desc.c
+++ b/drivers/net/wireless/ath/ath5k/desc.c
@@ -603,37 +603,37 @@ static int ath5k_hw_proc_5212_rx_status(struct ath5k_hw *ah,
                                        struct ath5k_rx_status *rs)
 {
        struct ath5k_hw_rx_status *rx_status;
+       u32 rxstat0, rxstat1;
 
        rx_status = &desc->ud.ds_rx.rx_stat;
+       rxstat1 = ACCESS_ONCE(rx_status->rx_status_1);
 
        /* No frame received / not ready */
-       if (unlikely(!(rx_status->rx_status_1 &
-                               AR5K_5212_RX_DESC_STATUS1_DONE)))
+       if (unlikely(!(rxstat1 & AR5K_5212_RX_DESC_STATUS1_DONE)))
                return -EINPROGRESS;
 
        memset(rs, 0, sizeof(struct ath5k_rx_status));
+       rxstat0 = ACCESS_ONCE(rx_status->rx_status_0);
 
        /*
         * Frame receive status
         */
-       rs->rs_datalen = rx_status->rx_status_0 &
-               AR5K_5212_RX_DESC_STATUS0_DATA_LEN;
-       rs->rs_rssi = AR5K_REG_MS(rx_status->rx_status_0,
+       rs->rs_datalen = rxstat0 & AR5K_5212_RX_DESC_STATUS0_DATA_LEN;
+       rs->rs_rssi = AR5K_REG_MS(rxstat0,
                AR5K_5212_RX_DESC_STATUS0_RECEIVE_SIGNAL);
-       rs->rs_rate = AR5K_REG_MS(rx_status->rx_status_0,
+       rs->rs_rate = AR5K_REG_MS(rxstat0,
                AR5K_5212_RX_DESC_STATUS0_RECEIVE_RATE);
-       rs->rs_antenna = AR5K_REG_MS(rx_status->rx_status_0,
+       rs->rs_antenna = AR5K_REG_MS(rxstat0,
                AR5K_5212_RX_DESC_STATUS0_RECEIVE_ANTENNA);
-       rs->rs_more = !!(rx_status->rx_status_0 &
-               AR5K_5212_RX_DESC_STATUS0_MORE);
-       rs->rs_tstamp = AR5K_REG_MS(rx_status->rx_status_1,
+       rs->rs_more = !!(rxstat0 & AR5K_5212_RX_DESC_STATUS0_MORE);
+       rs->rs_tstamp = AR5K_REG_MS(rxstat1,
                AR5K_5212_RX_DESC_STATUS1_RECEIVE_TIMESTAMP);
 
        /*
         * Key table status
         */
-       if (rx_status->rx_status_1 & AR5K_5212_RX_DESC_STATUS1_KEY_INDEX_VALID)
-               rs->rs_keyix = AR5K_REG_MS(rx_status->rx_status_1,
+       if (rxstat1 & AR5K_5212_RX_DESC_STATUS1_KEY_INDEX_VALID)
+               rs->rs_keyix = AR5K_REG_MS(rxstat1,
                                           AR5K_5212_RX_DESC_STATUS1_KEY_INDEX);
        else
                rs->rs_keyix = AR5K_RXKEYIX_INVALID;
@@ -641,27 +641,22 @@ static int ath5k_hw_proc_5212_rx_status(struct ath5k_hw *ah,
        /*
         * Receive/descriptor errors
         */
-       if (!(rx_status->rx_status_1 &
-           AR5K_5212_RX_DESC_STATUS1_FRAME_RECEIVE_OK)) {
-               if (rx_status->rx_status_1 &
-                               AR5K_5212_RX_DESC_STATUS1_CRC_ERROR)
+       if (!(rxstat1 & AR5K_5212_RX_DESC_STATUS1_FRAME_RECEIVE_OK)) {
+               if (rxstat1 & AR5K_5212_RX_DESC_STATUS1_CRC_ERROR)
                        rs->rs_status |= AR5K_RXERR_CRC;
 
-               if (rx_status->rx_status_1 &
-                               AR5K_5212_RX_DESC_STATUS1_PHY_ERROR) {
+               if (rxstat1 & AR5K_5212_RX_DESC_STATUS1_PHY_ERROR) {
                        rs->rs_status |= AR5K_RXERR_PHY;
-                       rs->rs_phyerr = AR5K_REG_MS(rx_status->rx_status_1,
+                       rs->rs_phyerr = AR5K_REG_MS(rxstat1,
                                AR5K_5212_RX_DESC_STATUS1_PHY_ERROR_CODE);
                        if (!ah->ah_capabilities.cap_has_phyerr_counters)
                                ath5k_ani_phy_error_report(ah, rs->rs_phyerr);
                }
 
-               if (rx_status->rx_status_1 &
-                               AR5K_5212_RX_DESC_STATUS1_DECRYPT_CRC_ERROR)
+               if (rxstat1 & AR5K_5212_RX_DESC_STATUS1_DECRYPT_CRC_ERROR)
                        rs->rs_status |= AR5K_RXERR_DECRYPT;
 
-               if (rx_status->rx_status_1 &
-                               AR5K_5212_RX_DESC_STATUS1_MIC_ERROR)
+               if (rxstat1 & AR5K_5212_RX_DESC_STATUS1_MIC_ERROR)
                        rs->rs_status |= AR5K_RXERR_MIC;
        }
        return 0;