rt2x00: Fix race condition when using inderect registers

Indirect registers require multiple calls to the CSR
register in order to access the indirect registers.
This must be protected under a lock to prevent race
conditions which could cause invalid data to
be returned when reading from the indirect register or silent
failures when writing data to the indirect register.

USB drivers where already protected under a mutex,
so rename the mutex and make PCI drivers use the mutex
as well.
This now means that BBP and RF registers are no longer
accessible in interrupt context. That is not a bad
situation since the slow behavior of accessing
those registers means we don't _want_ to access them
in interrupt context either.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index f2c8d9733c1d..d1a63e0017da 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -55,7 +55,7 @@ MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");
  * between each attampt. When the busy bit is still set at that time,
  * the access attempt is considered to have failed,
  * and we will print an error.
- * The _lock versions must be used if you already hold the usb_cache_mutex
+ * The _lock versions must be used if you already hold the csr_mutex
  */
 static inline void rt73usb_register_read(struct rt2x00_dev *rt2x00dev,
                                          const unsigned int offset, u32 *value)
@@ -135,7 +135,7 @@ static void rt73usb_bbp_write(struct rt2x00_dev *rt2x00dev,
 {
         u32 reg;
 
-        mutex_lock(&rt2x00dev->usb_cache_mutex);
+        mutex_lock(&rt2x00dev->csr_mutex);
 
         /*
          * Wait until the BBP becomes ready.
@@ -154,12 +154,12 @@ static void rt73usb_bbp_write(struct rt2x00_dev *rt2x00dev,
         rt2x00_set_field32(&reg, PHY_CSR3_READ_CONTROL, 0);
 
         rt73usb_register_write_lock(rt2x00dev, PHY_CSR3, reg);
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+        mutex_unlock(&rt2x00dev->csr_mutex);
 
         return;
 
 exit_fail:
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+        mutex_unlock(&rt2x00dev->csr_mutex);
 
         ERROR(rt2x00dev, "PHY_CSR3 register busy. Write failed.\n");
 }
@@ -169,7 +169,7 @@ static void rt73usb_bbp_read(struct rt2x00_dev *rt2x00dev,
 {
         u32 reg;
 
-        mutex_lock(&rt2x00dev->usb_cache_mutex);
+        mutex_lock(&rt2x00dev->csr_mutex);
 
         /*
          * Wait until the BBP becomes ready.
@@ -196,12 +196,12 @@ static void rt73usb_bbp_read(struct rt2x00_dev *rt2x00dev,
                 goto exit_fail;
 
         *value = rt2x00_get_field32(reg, PHY_CSR3_VALUE);
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+        mutex_unlock(&rt2x00dev->csr_mutex);
 
         return;
 
 exit_fail:
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+        mutex_unlock(&rt2x00dev->csr_mutex);
 
         ERROR(rt2x00dev, "PHY_CSR3 register busy. Read failed.\n");
         *value = 0xff;
@@ -216,7 +216,7 @@ static void rt73usb_rf_write(struct rt2x00_dev *rt2x00dev,
         if (!word)
                 return;
 
-        mutex_lock(&rt2x00dev->usb_cache_mutex);
+        mutex_lock(&rt2x00dev->csr_mutex);
 
         for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
                 rt73usb_register_read_lock(rt2x00dev, PHY_CSR4, &reg);
@@ -225,7 +225,7 @@ static void rt73usb_rf_write(struct rt2x00_dev *rt2x00dev,
                 udelay(REGISTER_BUSY_DELAY);
         }
 
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+        mutex_unlock(&rt2x00dev->csr_mutex);
         ERROR(rt2x00dev, "PHY_CSR4 register busy. Write failed.\n");
         return;
 
@@ -245,7 +245,8 @@ rf_write:
 
         rt73usb_register_write_lock(rt2x00dev, PHY_CSR4, reg);
         rt2x00_rf_write(rt2x00dev, word, value);
-        mutex_unlock(&rt2x00dev->usb_cache_mutex);
+
+        mutex_unlock(&rt2x00dev->csr_mutex);
 }
 
 #ifdef CONFIG_RT2X00_LIB_DEBUGFS