[FIX] multithread message write

file:
    /sys/kernel/debug/swap/writer/raw

Change-Id: I2b499abd9c6298e9cf53a936c7c44cea34a6f4ab
Signed-off-by: Vyacheslav Cherkashin <v.cherkashin@samsung.com>

diff --git a/writer/debugfs_writer.c b/writer/debugfs_writer.c
index a12107d..7be639b 100644 (file)
--- a/writer/debugfs_writer.c
+++ b/writer/debugfs_writer.c
@@ -37,20 +37,31 @@
  * ===                               BUFFER                                 ===
  * ============================================================================
  */
-static char *buf = NULL;
-enum { buf_size = 64*1024*1024 };
+static char *common_buf = NULL;
+enum { subbuf_size = 8*1024 };
+enum { common_buf_size = subbuf_size * NR_CPUS };
 
 static int init_buffer(void)
 {
-       buf = vmalloc(buf_size);
+       common_buf = vmalloc(common_buf_size);
 
-       return buf ? 0 : -ENOMEM;
+       return common_buf ? 0 : -ENOMEM;
 }
 
 static void exit_buffer(void)
 {
-       vfree(buf);
-       buf = NULL;
+       vfree(common_buf);
+       common_buf = NULL;
+}
+
+static void *get_current_buf(void)
+{
+       return common_buf + subbuf_size * get_cpu();
+}
+
+static void put_current_buf(void)
+{
+       put_cpu();
 }
 
 
@@ -64,13 +75,23 @@ static void exit_buffer(void)
 static ssize_t write_raw(struct file *file, const char __user *user_buf,
                         size_t count, loff_t *ppos)
 {
-       if (count > buf_size)
+       int ret;
+       void *buf;
+
+       if (count > subbuf_size)
                return -EINVAL;
 
-       if (copy_from_user(buf, user_buf, count))
-               return -EFAULT;
+       buf = get_current_buf();
+       if (copy_from_user(buf, user_buf, count)) {
+               ret = -EFAULT;
+               goto put_buf;
+       }
+
+       ret = raw_msg(buf, count);
 
-       return raw_msg(buf, count);
+put_buf:
+       put_current_buf();
+       return ret;
 }
 
 static const struct file_operations fops_raw = {