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Commit 2485f710 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
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mac80211: clarify use of TX status/RX callbacks 



This patch clarifies the use of the irqsafe vs. non-irq-safe
functions and their respective locking requirements.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 38c07b43

include/net/mac80211.h

+34 −3
Original line number Diff line number Diff line
@@ -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 *hw, struct sk_buff *skb, 
 * 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 ieee80211_hw *hw, struct sk_buff *skb, 
 * 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 ieee80211_hw *hw, 
 * 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 ieee80211_hw *hw, 
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);