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>

1 files changed, 28 insertions, 25 deletions

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();