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iwlegacy: fix channel switch locking

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We use priv->mutex to avoid race conditions between chswitch_done()
and mac_channel_switch(), when marking channel switch in
progress. But chswitch_done() can be called in atomic context
from rx_csa() or with mutex already taken from commit_rxon().

To fix remove mutex from chswitch_done() and use atomic bitops
for marking channel switch pending.

Cc: stable@kernel.org # 2.6.39+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Stanislaw Gruszka 2011-06-08 15:26:31 +02:00 committed by John W. Linville
parent f3209bea11
commit 51e6525714
5 changed files with 28 additions and 46 deletions
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9
drivers/net/wireless/iwlegacy/iwl-4965.c
View File

@ -1218,10 +1218,10 @@ static int iwl4965_commit_rxon(struct iwl_priv *priv, struct iwl_rxon_context *c
* receive commit_rxon request
* abort any previous channel switch if still in process
*/
if (priv->switch_rxon.switch_in_progress &&
(priv->switch_rxon.channel != ctx->staging.channel)) {
if (test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status) &&
(priv->switch_channel != ctx->staging.channel)) {
IWL_DEBUG_11H(priv, "abort channel switch on %d\n",
le16_to_cpu(priv->switch_rxon.channel));
le16_to_cpu(priv->switch_channel));
iwl_legacy_chswitch_done(priv, false);
}
@ -1404,9 +1404,6 @@ static int iwl4965_hw_channel_switch(struct iwl_priv *priv,
return rc;
}
priv->switch_rxon.channel = cmd.channel;
priv->switch_rxon.switch_in_progress = true;
return iwl_legacy_send_cmd_pdu(priv,
REPLY_CHANNEL_SWITCH, sizeof(cmd), &cmd);
}

30
drivers/net/wireless/iwlegacy/iwl-core.c
View File

@ -859,12 +859,8 @@ void iwl_legacy_chswitch_done(struct iwl_priv *priv, bool is_success)
if (test_bit(STATUS_EXIT_PENDING, &priv->status))
return;
if (priv->switch_rxon.switch_in_progress) {
if (test_and_clear_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
ieee80211_chswitch_done(ctx->vif, is_success);
mutex_lock(&priv->mutex);
priv->switch_rxon.switch_in_progress = false;
mutex_unlock(&priv->mutex);
}
}
EXPORT_SYMBOL(iwl_legacy_chswitch_done);
@ -876,19 +872,19 @@ void iwl_legacy_rx_csa(struct iwl_priv *priv, struct iwl_rx_mem_buffer *rxb)
struct iwl_rxon_context *ctx = &priv->contexts[IWL_RXON_CTX_BSS];
struct iwl_legacy_rxon_cmd *rxon = (void *)&ctx->active;
if (priv->switch_rxon.switch_in_progress) {
if (!le32_to_cpu(csa->status) &&
(csa->channel == priv->switch_rxon.channel)) {
rxon->channel = csa->channel;
ctx->staging.channel = csa->channel;
IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
if (!test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
return;
if (!le32_to_cpu(csa->status) && csa->channel == priv->switch_channel) {
rxon->channel = csa->channel;
ctx->staging.channel = csa->channel;
IWL_DEBUG_11H(priv, "CSA notif: channel %d\n",
le16_to_cpu(csa->channel));
iwl_legacy_chswitch_done(priv, true);
} else {
IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
le16_to_cpu(csa->channel));
iwl_legacy_chswitch_done(priv, false);
}
iwl_legacy_chswitch_done(priv, true);
} else {
IWL_ERR(priv, "CSA notif (fail) : channel %d\n",
le16_to_cpu(csa->channel));
iwl_legacy_chswitch_done(priv, false);
}
}
EXPORT_SYMBOL(iwl_legacy_rx_csa);

2
drivers/net/wireless/iwlegacy/iwl-core.h
View File

@ -560,7 +560,7 @@ void iwl_legacy_free_geos(struct iwl_priv *priv);
#define STATUS_SCAN_HW 15
#define STATUS_POWER_PMI 16
#define STATUS_FW_ERROR 17
#define STATUS_CHANNEL_SWITCH_PENDING 18
static inline int iwl_legacy_is_ready(struct iwl_priv *priv)
{

13
drivers/net/wireless/iwlegacy/iwl-dev.h
View File

@ -854,17 +854,6 @@ struct traffic_stats {
#endif
};
/*
* iwl_switch_rxon: "channel switch" structure
*
* @ switch_in_progress: channel switch in progress
* @ channel: new channel
*/
struct iwl_switch_rxon {
bool switch_in_progress;
__le16 channel;
};
/*
* schedule the timer to wake up every UCODE_TRACE_PERIOD milliseconds
* to perform continuous uCode event logging operation if enabled
@ -1115,7 +1104,7 @@ struct iwl_priv {
struct iwl_rxon_context contexts[NUM_IWL_RXON_CTX];
struct iwl_switch_rxon switch_rxon;
__le16 switch_channel;
/* 1st responses from initialize and runtime uCode images.
* _4965's initialize alive response contains some calibration data. */

20
drivers/net/wireless/iwlegacy/iwl4965-base.c
View File

@ -2861,16 +2861,13 @@ void iwl4965_mac_channel_switch(struct ieee80211_hw *hw,
goto out;
if (test_bit(STATUS_EXIT_PENDING, &priv->status) ||
test_bit(STATUS_SCANNING, &priv->status))
test_bit(STATUS_SCANNING, &priv->status) ||
test_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status))
goto out;
if (!iwl_legacy_is_associated_ctx(ctx))
goto out;
/* channel switch in progress */
if (priv->switch_rxon.switch_in_progress == true)
goto out;
if (priv->cfg->ops->lib->set_channel_switch) {
ch = channel->hw_value;
@ -2919,15 +2916,18 @@ void iwl4965_mac_channel_switch(struct ieee80211_hw *hw,
* at this point, staging_rxon has the
* configuration for channel switch
*/
if (priv->cfg->ops->lib->set_channel_switch(priv,
ch_switch))
priv->switch_rxon.switch_in_progress = false;
set_bit(STATUS_CHANNEL_SWITCH_PENDING, &priv->status);
priv->switch_channel = cpu_to_le16(ch);
if (priv->cfg->ops->lib->set_channel_switch(priv, ch_switch)) {
clear_bit(STATUS_CHANNEL_SWITCH_PENDING,
&priv->status);
priv->switch_channel = 0;
ieee80211_chswitch_done(ctx->vif, false);
}
}
}
out:
mutex_unlock(&priv->mutex);
if (!priv->switch_rxon.switch_in_progress)
ieee80211_chswitch_done(ctx->vif, false);
IWL_DEBUG_MAC80211(priv, "leave\n");
}