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mac80211: annotate sleeping driver ops
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To make it easier to notice cases of calling sleeping ops in atomic context,
annotate driver-ops.h with appropiate might_sleep() calls. At the same time,
also document in mac80211.h the op functions with missing contexts.

mac80211 doesn't seem to use get_tx_stats anywhere currently. Just to be on
the safe side, I documented it to be atomic, but hopefully the op can be
removed in the future.

Compile-tested only.

Signed-off-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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Kalle Valo authored and John W. Linville committed Dec 28, 2009
1 parent 095d5ef commit e1781ed
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Showing 2 changed files with 87 additions and 16 deletions.
43 changes: 31 additions & 12 deletions include/net/mac80211.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1383,15 +1383,15 @@ enum ieee80211_ampdu_mlme_action {
* When the device is started it should not have a MAC address
* to avoid acknowledging frames before a non-monitor device
* is added.
* Must be implemented.
* Must be implemented and can sleep.
*
* @stop: Called after last netdevice attached to the hardware
* is disabled. This should turn off the hardware (at least
* it must turn off frame reception.)
* May be called right after add_interface if that rejects
* an interface. If you added any work onto the mac80211 workqueue
* you should ensure to cancel it on this callback.
* Must be implemented.
* Must be implemented and can sleep.
*
* @add_interface: Called when a netdevice attached to the hardware is
* enabled. Because it is not called for monitor mode devices, @start
Expand All @@ -1401,7 +1401,7 @@ enum ieee80211_ampdu_mlme_action {
* interface is given in the conf parameter.
* The callback may refuse to add an interface by returning a
* negative error code (which will be seen in userspace.)
* Must be implemented.
* Must be implemented and can sleep.
*
* @remove_interface: Notifies a driver that an interface is going down.
* The @stop callback is called after this if it is the last interface
Expand All @@ -1410,40 +1410,43 @@ enum ieee80211_ampdu_mlme_action {
* must be cleared so the device no longer acknowledges packets,
* the mac_addr member of the conf structure is, however, set to the
* MAC address of the device going away.
* Hence, this callback must be implemented.
* Hence, this callback must be implemented. It can sleep.
*
* @config: Handler for configuration requests. IEEE 802.11 code calls this
* function to change hardware configuration, e.g., channel.
* This function should never fail but returns a negative error code
* if it does.
* if it does. The callback can sleep.
*
* @bss_info_changed: Handler for configuration requests related to BSS
* parameters that may vary during BSS's lifespan, and may affect low
* level driver (e.g. assoc/disassoc status, erp parameters).
* This function should not be used if no BSS has been set, unless
* for association indication. The @changed parameter indicates which
* of the bss parameters has changed when a call is made.
* of the bss parameters has changed when a call is made. The callback
* can sleep.
*
* @prepare_multicast: Prepare for multicast filter configuration.
* This callback is optional, and its return value is passed
* to configure_filter(). This callback must be atomic.
*
* @configure_filter: Configure the device's RX filter.
* See the section "Frame filtering" for more information.
* This callback must be implemented.
* This callback must be implemented and can sleep.
*
* @set_tim: Set TIM bit. mac80211 calls this function when a TIM bit
* must be set or cleared for a given STA. Must be atomic.
*
* @set_key: See the section "Hardware crypto acceleration"
* This callback can sleep, and is only called between add_interface
* and remove_interface calls, i.e. while the given virtual interface
* This callback is only called between add_interface and
* remove_interface calls, i.e. while the given virtual interface
* is enabled.
* Returns a negative error code if the key can't be added.
* The callback can sleep.
*
* @update_tkip_key: See the section "Hardware crypto acceleration"
* This callback will be called in the context of Rx. Called for drivers
* which set IEEE80211_KEY_FLAG_TKIP_REQ_RX_P1_KEY.
* The callback can sleep.
*
* @hw_scan: Ask the hardware to service the scan request, no need to start
* the scan state machine in stack. The scan must honour the channel
Expand All @@ -1457,21 +1460,28 @@ enum ieee80211_ampdu_mlme_action {
* When the scan finishes, ieee80211_scan_completed() must be called;
* note that it also must be called when the scan cannot finish due to
* any error unless this callback returned a negative error code.
* The callback can sleep.
*
* @sw_scan_start: Notifier function that is called just before a software scan
* is started. Can be NULL, if the driver doesn't need this notification.
* The callback can sleep.
*
* @sw_scan_complete: Notifier function that is called just after a software scan
* finished. Can be NULL, if the driver doesn't need this notification.
* @sw_scan_complete: Notifier function that is called just after a
* software scan finished. Can be NULL, if the driver doesn't need
* this notification.
* The callback can sleep.
*
* @get_stats: Return low-level statistics.
* Returns zero if statistics are available.
* The callback can sleep.
*
* @get_tkip_seq: If your device implements TKIP encryption in hardware this
* callback should be provided to read the TKIP transmit IVs (both IV32
* and IV16) for the given key from hardware.
* The callback must be atomic.
*
* @set_rts_threshold: Configuration of RTS threshold (if device needs it)
* The callback can sleep.
*
* @sta_notify: Notifies low level driver about addition, removal or power
* state transition of an associated station, AP, IBSS/WDS/mesh peer etc.
Expand All @@ -1480,30 +1490,36 @@ enum ieee80211_ampdu_mlme_action {
* @conf_tx: Configure TX queue parameters (EDCF (aifs, cw_min, cw_max),
* bursting) for a hardware TX queue.
* Returns a negative error code on failure.
* The callback can sleep.
*
* @get_tx_stats: Get statistics of the current TX queue status. This is used
* to get number of currently queued packets (queue length), maximum queue
* size (limit), and total number of packets sent using each TX queue
* (count). The 'stats' pointer points to an array that has hw->queues
* items.
* The callback must be atomic.
*
* @get_tsf: Get the current TSF timer value from firmware/hardware. Currently,
* this is only used for IBSS mode BSSID merging and debugging. Is not a
* required function.
* The callback can sleep.
*
* @set_tsf: Set the TSF timer to the specified value in the firmware/hardware.
* Currently, this is only used for IBSS mode debugging. Is not a
* required function.
* The callback can sleep.
*
* @reset_tsf: Reset the TSF timer and allow firmware/hardware to synchronize
* with other STAs in the IBSS. This is only used in IBSS mode. This
* function is optional if the firmware/hardware takes full care of
* TSF synchronization.
* The callback can sleep.
*
* @tx_last_beacon: Determine whether the last IBSS beacon was sent by us.
* This is needed only for IBSS mode and the result of this function is
* used to determine whether to reply to Probe Requests.
* Returns non-zero if this device sent the last beacon.
* The callback can sleep.
*
* @ampdu_action: Perform a certain A-MPDU action
* The RA/TID combination determines the destination and TID we want
Expand All @@ -1512,16 +1528,19 @@ enum ieee80211_ampdu_mlme_action {
* is the first frame we expect to perform the action on. Notice
* that TX/RX_STOP can pass NULL for this parameter.
* Returns a negative error code on failure.
* The callback must be atomic.
*
* @rfkill_poll: Poll rfkill hardware state. If you need this, you also
* need to set wiphy->rfkill_poll to %true before registration,
* and need to call wiphy_rfkill_set_hw_state() in the callback.
* The callback can sleep.
*
* @testmode_cmd: Implement a cfg80211 test mode command.
* The callback can sleep.
*
* @flush: Flush all pending frames from the hardware queue, making sure
* that the hardware queues are empty. If the parameter @drop is set
* to %true, pending frames may be dropped.
* to %true, pending frames may be dropped. The callback can sleep.
*/
struct ieee80211_ops {
int (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
Expand Down
60 changes: 56 additions & 4 deletions net/mac80211/driver-ops.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,8 @@ static inline int drv_start(struct ieee80211_local *local)
{
int ret;

might_sleep();

local->started = true;
smp_mb();
ret = local->ops->start(&local->hw);
Expand All @@ -23,6 +25,8 @@ static inline int drv_start(struct ieee80211_local *local)

static inline void drv_stop(struct ieee80211_local *local)
{
might_sleep();

local->ops->stop(&local->hw);
trace_drv_stop(local);

Expand All @@ -38,21 +42,31 @@ static inline void drv_stop(struct ieee80211_local *local)
static inline int drv_add_interface(struct ieee80211_local *local,
struct ieee80211_vif *vif)
{
int ret = local->ops->add_interface(&local->hw, vif);
int ret;

might_sleep();

ret = local->ops->add_interface(&local->hw, vif);
trace_drv_add_interface(local, vif_to_sdata(vif), ret);
return ret;
}

static inline void drv_remove_interface(struct ieee80211_local *local,
struct ieee80211_vif *vif)
{
might_sleep();

local->ops->remove_interface(&local->hw, vif);
trace_drv_remove_interface(local, vif_to_sdata(vif));
}

static inline int drv_config(struct ieee80211_local *local, u32 changed)
{
int ret = local->ops->config(&local->hw, changed);
int ret;

might_sleep();

ret = local->ops->config(&local->hw, changed);
trace_drv_config(local, changed, ret);
return ret;
}
Expand All @@ -62,6 +76,8 @@ static inline void drv_bss_info_changed(struct ieee80211_local *local,
struct ieee80211_bss_conf *info,
u32 changed)
{
might_sleep();

if (local->ops->bss_info_changed)
local->ops->bss_info_changed(&local->hw, &sdata->vif, info, changed);
trace_drv_bss_info_changed(local, sdata, info, changed);
Expand Down Expand Up @@ -111,7 +127,11 @@ static inline int drv_set_key(struct ieee80211_local *local,
struct ieee80211_sta *sta,
struct ieee80211_key_conf *key)
{
int ret = local->ops->set_key(&local->hw, cmd, &sdata->vif, sta, key);
int ret;

might_sleep();

ret = local->ops->set_key(&local->hw, cmd, &sdata->vif, sta, key);
trace_drv_set_key(local, cmd, sdata, sta, key, ret);
return ret;
}
Expand All @@ -121,6 +141,8 @@ static inline void drv_update_tkip_key(struct ieee80211_local *local,
const u8 *address, u32 iv32,
u16 *phase1key)
{
might_sleep();

if (local->ops->update_tkip_key)
local->ops->update_tkip_key(&local->hw, conf, address,
iv32, phase1key);
Expand All @@ -130,20 +152,28 @@ static inline void drv_update_tkip_key(struct ieee80211_local *local,
static inline int drv_hw_scan(struct ieee80211_local *local,
struct cfg80211_scan_request *req)
{
int ret = local->ops->hw_scan(&local->hw, req);
int ret;

might_sleep();

ret = local->ops->hw_scan(&local->hw, req);
trace_drv_hw_scan(local, req, ret);
return ret;
}

static inline void drv_sw_scan_start(struct ieee80211_local *local)
{
might_sleep();

if (local->ops->sw_scan_start)
local->ops->sw_scan_start(&local->hw);
trace_drv_sw_scan_start(local);
}

static inline void drv_sw_scan_complete(struct ieee80211_local *local)
{
might_sleep();

if (local->ops->sw_scan_complete)
local->ops->sw_scan_complete(&local->hw);
trace_drv_sw_scan_complete(local);
Expand All @@ -154,6 +184,8 @@ static inline int drv_get_stats(struct ieee80211_local *local,
{
int ret = -EOPNOTSUPP;

might_sleep();

if (local->ops->get_stats)
ret = local->ops->get_stats(&local->hw, stats);
trace_drv_get_stats(local, stats, ret);
Expand All @@ -173,6 +205,9 @@ static inline int drv_set_rts_threshold(struct ieee80211_local *local,
u32 value)
{
int ret = 0;

might_sleep();

if (local->ops->set_rts_threshold)
ret = local->ops->set_rts_threshold(&local->hw, value);
trace_drv_set_rts_threshold(local, value, ret);
Expand All @@ -193,6 +228,9 @@ static inline int drv_conf_tx(struct ieee80211_local *local, u16 queue,
const struct ieee80211_tx_queue_params *params)
{
int ret = -EOPNOTSUPP;

might_sleep();

if (local->ops->conf_tx)
ret = local->ops->conf_tx(&local->hw, queue, params);
trace_drv_conf_tx(local, queue, params, ret);
Expand All @@ -210,6 +248,9 @@ static inline int drv_get_tx_stats(struct ieee80211_local *local,
static inline u64 drv_get_tsf(struct ieee80211_local *local)
{
u64 ret = -1ULL;

might_sleep();

if (local->ops->get_tsf)
ret = local->ops->get_tsf(&local->hw);
trace_drv_get_tsf(local, ret);
Expand All @@ -218,13 +259,17 @@ static inline u64 drv_get_tsf(struct ieee80211_local *local)

static inline void drv_set_tsf(struct ieee80211_local *local, u64 tsf)
{
might_sleep();

if (local->ops->set_tsf)
local->ops->set_tsf(&local->hw, tsf);
trace_drv_set_tsf(local, tsf);
}

static inline void drv_reset_tsf(struct ieee80211_local *local)
{
might_sleep();

if (local->ops->reset_tsf)
local->ops->reset_tsf(&local->hw);
trace_drv_reset_tsf(local);
Expand All @@ -233,6 +278,9 @@ static inline void drv_reset_tsf(struct ieee80211_local *local)
static inline int drv_tx_last_beacon(struct ieee80211_local *local)
{
int ret = 1;

might_sleep();

if (local->ops->tx_last_beacon)
ret = local->ops->tx_last_beacon(&local->hw);
trace_drv_tx_last_beacon(local, ret);
Expand All @@ -256,12 +304,16 @@ static inline int drv_ampdu_action(struct ieee80211_local *local,

static inline void drv_rfkill_poll(struct ieee80211_local *local)
{
might_sleep();

if (local->ops->rfkill_poll)
local->ops->rfkill_poll(&local->hw);
}

static inline void drv_flush(struct ieee80211_local *local, bool drop)
{
might_sleep();

trace_drv_flush(local, drop);
if (local->ops->flush)
local->ops->flush(&local->hw, drop);
Expand Down

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