This patch clarifies the use of the irqsafe vs. non-irq-safe functions and their respective locking requirements. Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> --- include/net/mac80211.h | 37 ++++++++++++++++++++++++++++++++++--- 1 file changed, 34 insertions(+), 3 deletions(-) --- everything.orig/include/net/mac80211.h 2008-02-22 11:45:11.000000000 +0100 +++ everything/include/net/mac80211.h 2008-02-22 11:49:23.000000000 +0100 @@ -38,7 +38,11 @@ * called in hardware interrupt context. The low-level driver must not call any * other functions in hardware interrupt context. If there is a need for such * call, the low-level driver should first ACK the interrupt and perform the - * IEEE 802.11 code call after this, e.g. from a scheduled workqueue function. + * IEEE 802.11 code call after this, e.g. from a scheduled workqueue or even + * tasklet function. + * + * NOTE: If the driver opts to use the _irqsafe() functions, it may not also + * use the non-irqsafe functions! */ /** @@ -1204,7 +1208,10 @@ void __ieee80211_rx(struct ieee80211_hw * buffer in @skb must start with an IEEE 802.11 header or a radiotap * header if %RX_FLAG_RADIOTAP is set in the @status flags. * - * This function may not be called in IRQ context. + * This function may not be called in IRQ context. Calls to this function + * for a single hardware must be synchronized against each other. Calls + * to this function and ieee80211_rx_irqsafe() may not be mixed for a + * single hardware. * * @hw: the hardware this frame came in on * @skb: the buffer to receive, owned by mac80211 after this call @@ -1221,7 +1228,10 @@ static inline void ieee80211_rx(struct i * ieee80211_rx_irqsafe - receive frame * * Like ieee80211_rx() but can be called in IRQ context - * (internally defers to a workqueue.) + * (internally defers to a tasklet.) + * + * Calls to this function and ieee80211_rx() may not be mixed for a + * single hardware. * * @hw: the hardware this frame came in on * @skb: the buffer to receive, owned by mac80211 after this call @@ -1240,6 +1250,11 @@ void ieee80211_rx_irqsafe(struct ieee802 * transmitted. It is permissible to not call this function for * multicast frames but this can affect statistics. * + * This function may not be called in IRQ context. Calls to this function + * for a single hardware must be synchronized against each other. Calls + * to this function and ieee80211_tx_status_irqsafe() may not be mixed + * for a single hardware. + * * @hw: the hardware the frame was transmitted by * @skb: the frame that was transmitted, owned by mac80211 after this call * @status: status information for this frame; the status pointer need not @@ -1249,6 +1264,22 @@ void ieee80211_rx_irqsafe(struct ieee802 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb, struct ieee80211_tx_status *status); + +/** + * ieee80211_tx_status_irqsafe - irq-safe transmit status callback + * + * Like ieee80211_tx_status() but can be called in IRQ context + * (internally defers to a tasklet.) + * + * Calls to this function and ieee80211_tx_status() may not be mixed for a + * single hardware. + * + * @hw: the hardware the frame was transmitted by + * @skb: the frame that was transmitted, owned by mac80211 after this call + * @status: status information for this frame; the status pointer need not + * be valid after this function returns and is not freed by mac80211, + * it is recommended that it points to a stack area + */ void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb, struct ieee80211_tx_status *status); -- - To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
