iwlwifi: always check if got h/w access before write

Before we write to the device registers always check if
iwl_grap_nic_access() was successful.

On the way change return type of grab_nic_access() to bool, and add
likely()/unlikely() statement.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

6 files changed, 35 insertions, 30 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tt.c b/drivers/net/wireless/iwlwifi/iwl-agn-tt.c
index 7712c5537370..9a12b70c7d4f 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tt.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tt.c
@@ -189,7 +189,7 @@ static void iwl_tt_check_exit_ct_kill(unsigned long data)
                 }
                 iwl_read32(trans(priv), CSR_UCODE_DRV_GP1);
                 spin_lock_irqsave(&trans(priv)->reg_lock, flags);
-                if (!iwl_grab_nic_access(trans(priv)))
+                if (likely(iwl_grab_nic_access(trans(priv))))
                         iwl_release_nic_access(trans(priv));
                 spin_unlock_irqrestore(&trans(priv)->reg_lock, flags);
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 5f390f8d3b8b..ce9ebeb89e4c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -327,7 +327,7 @@ static void iwl_print_cont_event_trace(struct iwl_priv *priv, u32 base,
 
         /* Make sure device is powered up for SRAM reads */
         spin_lock_irqsave(&trans(priv)->reg_lock, reg_flags);
-        if (iwl_grab_nic_access(trans(priv))) {
+        if (unlikely(!iwl_grab_nic_access(trans(priv)))) {
                 spin_unlock_irqrestore(&trans(priv)->reg_lock, reg_flags);
                 return;
         }
diff --git a/drivers/net/wireless/iwlwifi/iwl-io.c b/drivers/net/wireless/iwlwifi/iwl-io.c
index fc365350a3e7..fa69845954cf 100644
--- a/drivers/net/wireless/iwlwifi/iwl-io.c
+++ b/drivers/net/wireless/iwlwifi/iwl-io.c
@@ -118,16 +118,17 @@ int iwl_grab_nic_access_silent(struct iwl_trans *trans)
         return 0;
 }
 
-int iwl_grab_nic_access(struct iwl_trans *trans)
+bool iwl_grab_nic_access(struct iwl_trans *trans)
 {
         int ret = iwl_grab_nic_access_silent(trans);
         if (unlikely(ret)) {
                 u32 val = iwl_read32(trans, CSR_GP_CNTRL);
                 WARN_ONCE(1, "Timeout waiting for hardware access "
                              "(CSR_GP_CNTRL 0x%08x)\n", val);
+                return false;
         }
 
-        return ret;
+        return true;
 }
 
 void iwl_release_nic_access(struct iwl_trans *trans)
@@ -156,7 +157,7 @@ void iwl_write_direct32(struct iwl_trans *trans, u32 reg, u32 value)
         unsigned long flags;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        if (!iwl_grab_nic_access(trans)) {
+        if (likely(iwl_grab_nic_access(trans))) {
                 iwl_write32(trans, reg, value);
                 iwl_release_nic_access(trans);
         }
@@ -211,7 +212,7 @@ void iwl_write_prph(struct iwl_trans *trans, u32 addr, u32 val)
         unsigned long flags;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        if (!iwl_grab_nic_access(trans)) {
+        if (likely(iwl_grab_nic_access(trans))) {
                 __iwl_write_prph(trans, addr, val);
                 iwl_release_nic_access(trans);
         }
@@ -223,9 +224,11 @@ void iwl_set_bits_prph(struct iwl_trans *trans, u32 reg, u32 mask)
         unsigned long flags;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        iwl_grab_nic_access(trans);
-        __iwl_write_prph(trans, reg, __iwl_read_prph(trans, reg) | mask);
-        iwl_release_nic_access(trans);
+        if (likely(iwl_grab_nic_access(trans))) {
+                __iwl_write_prph(trans, reg,
+                                 __iwl_read_prph(trans, reg) | mask);
+                iwl_release_nic_access(trans);
+        }
         spin_unlock_irqrestore(&trans->reg_lock, flags);
 }
 
@@ -235,10 +238,11 @@ void iwl_set_bits_mask_prph(struct iwl_trans *trans, u32 reg,
         unsigned long flags;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        iwl_grab_nic_access(trans);
-        __iwl_write_prph(trans, reg,
-                         (__iwl_read_prph(trans, reg) & mask) | bits);
-        iwl_release_nic_access(trans);
+        if (likely(iwl_grab_nic_access(trans))) {
+                __iwl_write_prph(trans, reg,
+                                 (__iwl_read_prph(trans, reg) & mask) | bits);
+                iwl_release_nic_access(trans);
+        }
         spin_unlock_irqrestore(&trans->reg_lock, flags);
 }
 
@@ -248,10 +252,11 @@ void iwl_clear_bits_prph(struct iwl_trans *trans, u32 reg, u32 mask)
         u32 val;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        iwl_grab_nic_access(trans);
-        val = __iwl_read_prph(trans, reg);
-        __iwl_write_prph(trans, reg, (val & ~mask));
-        iwl_release_nic_access(trans);
+        if (likely(iwl_grab_nic_access(trans))) {
+                val = __iwl_read_prph(trans, reg);
+                __iwl_write_prph(trans, reg, (val & ~mask));
+                iwl_release_nic_access(trans);
+        }
         spin_unlock_irqrestore(&trans->reg_lock, flags);
 }
 
@@ -263,15 +268,13 @@ void _iwl_read_targ_mem_words(struct iwl_trans *trans, u32 addr,
         u32 *vals = buf;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        iwl_grab_nic_access(trans);
-
-        iwl_write32(trans, HBUS_TARG_MEM_RADDR, addr);
-        rmb();
-
-        for (offs = 0; offs < words; offs++)
-                vals[offs] = iwl_read32(trans, HBUS_TARG_MEM_RDAT);
-
-        iwl_release_nic_access(trans);
+        if (likely(iwl_grab_nic_access(trans))) {
+                iwl_write32(trans, HBUS_TARG_MEM_RADDR, addr);
+                rmb();
+                for (offs = 0; offs < words; offs++)
+                        vals[offs] = iwl_read32(trans, HBUS_TARG_MEM_RDAT);
+                iwl_release_nic_access(trans);
+        }
         spin_unlock_irqrestore(&trans->reg_lock, flags);
 }
 
@@ -292,7 +295,7 @@ int _iwl_write_targ_mem_words(struct iwl_trans *trans, u32 addr,
         u32 *vals = buf;
 
         spin_lock_irqsave(&trans->reg_lock, flags);
-        if (!iwl_grab_nic_access(trans)) {
+        if (likely(iwl_grab_nic_access(trans))) {
                 iwl_write32(trans, HBUS_TARG_MEM_WADDR, addr);
                 wmb();
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-io.h b/drivers/net/wireless/iwlwifi/iwl-io.h
index 1136dc19936a..09b856768f62 100644
--- a/drivers/net/wireless/iwlwifi/iwl-io.h
+++ b/drivers/net/wireless/iwlwifi/iwl-io.h
@@ -61,7 +61,7 @@ int iwl_poll_direct_bit(struct iwl_trans *trans, u32 addr, u32 mask,
                         int timeout);
 
 int iwl_grab_nic_access_silent(struct iwl_trans *trans);
-int iwl_grab_nic_access(struct iwl_trans *trans);
+bool iwl_grab_nic_access(struct iwl_trans *trans);
 void iwl_release_nic_access(struct iwl_trans *trans);
 
 u32 iwl_read_direct32(struct iwl_trans *trans, u32 reg);
diff --git a/drivers/net/wireless/iwlwifi/iwl-mac80211.c b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
index bdcbbd0d3467..91a42c3261aa 100644
--- a/drivers/net/wireless/iwlwifi/iwl-mac80211.c
+++ b/drivers/net/wireless/iwlwifi/iwl-mac80211.c
@@ -445,7 +445,7 @@ static int iwlagn_mac_resume(struct ieee80211_hw *hw)
         if (iwlagn_hw_valid_rtc_data_addr(base)) {
                 spin_lock_irqsave(&trans(priv)->reg_lock, flags);
                 ret = iwl_grab_nic_access_silent(trans(priv));
-                if (ret == 0) {
+                if (likely(ret == 0)) {
                         iwl_write32(trans(priv), HBUS_TARG_MEM_RADDR, base);
                         status = iwl_read32(trans(priv), HBUS_TARG_MEM_RDAT);
                         iwl_release_nic_access(trans(priv));
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
index 83cc60e8f607..5d1fc7b1b0a3 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
@@ -745,7 +745,8 @@ static int iwl_print_event_log(struct iwl_trans *trans, u32 start_idx,
 
         /* Make sure device is powered up for SRAM reads */
         spin_lock_irqsave(&trans->reg_lock, reg_flags);
-        iwl_grab_nic_access(trans);
+        if (unlikely(!iwl_grab_nic_access(trans)))
+                goto out_unlock;
 
         /* Set starting address; reads will auto-increment */
         iwl_write32(trans, HBUS_TARG_MEM_RADDR, ptr);
@@ -785,6 +786,7 @@ static int iwl_print_event_log(struct iwl_trans *trans, u32 start_idx,
 
         /* Allow device to power down */
         iwl_release_nic_access(trans);
+out_unlock:
         spin_unlock_irqrestore(&trans->reg_lock, reg_flags);
         return pos;
 }