[IMPROVE] Add sync

diff --git a/driver/driver_to_buffer.c b/driver/driver_to_buffer.c
index 0238a5e..5efe439 100644 (file)
--- a/driver/driver_to_buffer.c
+++ b/driver/driver_to_buffer.c
@@ -26,6 +26,7 @@
 #include <linux/slab.h>
 #include <linux/splice.h>
 #include <asm/uaccess.h>
+#include <linux/spinlock.h>
 
 #include <buffer/swap_buffer_module.h>
 #include <buffer/swap_buffer_errors.h>
@@ -45,6 +46,54 @@ static int buffers_to_read = 0;
 /* Pages count in one subbuffer */
 static int pages_per_buffer = 0;
 
+/* Used to sync changes of the buffers_to_read var */
+static spinlock_t buf_to_read;
+
+
+static inline void init_buffers_to_read(void)
+{
+       spin_lock_init(&buf_to_read);
+       buffers_to_read = 0;
+}
+
+static inline void inc_buffers_to_read(void)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&buf_to_read, flags);
+       buffers_to_read++;
+       spin_unlock_irqrestore(&buf_to_read, flags);
+}
+
+static inline void dec_buffers_to_read(void)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&buf_to_read, flags);
+       buffers_to_read--;
+       spin_unlock_irqrestore(&buf_to_read, flags);
+}
+
+static inline void set_buffers_to_read(int count)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&buf_to_read, flags);
+       buffers_to_read = count;
+       spin_unlock_irqrestore(&buf_to_read, flags);
+}
+
+static inline int something_to_read(void)
+{
+       unsigned long flags;
+       int result;
+
+       spin_lock_irqsave(&buf_to_read, flags);
+       result = buffers_to_read;
+       spin_unlock_irqrestore(&buf_to_read, flags);
+
+       return result;
+}
 
 /* TODO Get subbuffer for reading */
 static size_t driver_to_buffer_get(void)
@@ -88,11 +137,10 @@ static int driver_to_buffer_release(void)
 /* Buffers callback function */
 int driver_to_buffer_callback(void)
 {
-//XXX: Think of sync with get next
        int result;
 
        /* Increment buffers_to_read counter */
-       buffers_to_read++;
+       inc_buffers_to_read();
        swap_device_wake_up_process();
 
        return E_SD_SUCCESS;
@@ -163,7 +211,7 @@ int driver_to_buffer_flush(void)
        result = swap_buffer_flush();
 
        if (result >= 0)
-               buffers_to_read = result;
+               set_buffers_to_read(result);
        else if (result < 0)
                return -E_SD_BUFFER_ERROR;
 
@@ -237,7 +285,7 @@ int driver_to_buffer_initialize(size_t size, unsigned int count)
        /* Initialize driver_to_buffer variables */
        pages_per_buffer = result;
        busy_buffer = NULL;
-       buffers_to_read = 0;
+       init_buffers_to_read();
 
        return E_SD_SUCCESS;
 }
@@ -269,7 +317,7 @@ int driver_to_buffer_uninitialize(void)
        }
 
        /* Reinit driver_to_buffer vars */
-       buffers_to_read = 0;
+       init_buffers_to_read();
        pages_per_buffer = 0;
 
        return result;
@@ -278,7 +326,6 @@ int driver_to_buffer_uninitialize(void)
 /* Get next buffer to read */
 int driver_to_buffer_next_buffer_to_read(void)
 {
-//XXX: Think of sync with callback
        int result;
 
        /* If there is busy_buffer first release it */
@@ -290,7 +337,7 @@ int driver_to_buffer_next_buffer_to_read(void)
 
        /* If there is no buffers to read, return E_SD_NO_DATA_TO_READ.
         * SHOULD BE POSITIVE, cause there is no real error. */
-       if (!buffers_to_read) {
+       if (!something_to_read()) {
                return E_SD_NO_DATA_TO_READ;
        }
 
@@ -302,7 +349,7 @@ int driver_to_buffer_next_buffer_to_read(void)
        }
 
        /* Decrement buffers_to_read counter */
-       buffers_to_read--;
+       dec_buffers_to_read();
 
        return E_SD_SUCCESS;
 }