gfx: pvr: debugfs: replace test_and_set_bit with spinlock+flag

The busy variable is not really a bitmap, using a spinlock with a busy
flag better expresses the purpose.

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

diff --git a/drivers/staging/mrst/pvr/pvr_debugfs.c b/drivers/staging/mrst/pvr/pvr_debugfs.c
index fe45bb2..03438a9 100644 (file)
--- a/drivers/staging/mrst/pvr/pvr_debugfs.c
+++ b/drivers/staging/mrst/pvr/pvr_debugfs.c
@@ -77,38 +77,49 @@ DEFINE_SIMPLE_ATTRIBUTE(pvr_debugfs_reset_sgx_fops, NULL,
 static void *trcmd_str_buf;
 static u8 *trcmd_snapshot;
 static size_t trcmd_snapshot_size;
-static unsigned long trcmd_busy;
+static int trcmd_busy;
+static DEFINE_SPINLOCK(trcmd_lock);    /* locks trcmd_busy */
 
 static int pvr_dbg_trcmd_open(struct inode *inode, struct file *file)
 {
        int r;
 
-       if (test_and_set_bit(0, &trcmd_busy))
+       spin_lock(&trcmd_lock);
+       if (trcmd_busy) {
+               spin_unlock(&trcmd_lock);
                return -EBUSY;
+       }
+       trcmd_busy = 1;
+       spin_unlock(&trcmd_lock);
 
        trcmd_str_buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!trcmd_str_buf) {
-               clear_bit(0, &trcmd_busy);
-
-               return -ENOMEM;
+               r = -ENOMEM;
+               goto err;
        }
 
        r = pvr_trcmd_create_snapshot(&trcmd_snapshot, &trcmd_snapshot_size);
        if (r < 0) {
                kfree(trcmd_str_buf);
-               clear_bit(0, &trcmd_busy);
-
-               return r;
+               goto err;
        }
-
        return 0;
+err:
+       spin_lock(&trcmd_lock);
+       trcmd_busy = 0;
+       spin_unlock(&trcmd_lock);
+
+       return r;
 }
 
 static int pvr_dbg_trcmd_release(struct inode *inode, struct file *file)
 {
        pvr_trcmd_destroy_snapshot(trcmd_snapshot);
        kfree(trcmd_str_buf);
-       clear_bit(0, &trcmd_busy);
+
+       spin_lock(&trcmd_lock);
+       trcmd_busy = 0;
+       spin_unlock(&trcmd_lock);
 
        return 0;
 }
@@ -135,7 +146,8 @@ static const struct file_operations pvr_dbg_trcmd_fops = {
 #endif
 
 static struct sgx_fw_state *fw_state;
-static unsigned long fw_state_busy;
+static int fw_state_busy;
+static DEFINE_SPINLOCK(fw_state_lock);  /* locks fw_state_busy */
 
 static int pvr_dbg_fw_state_open(struct inode *inode, struct file *file)
 {
@@ -146,31 +158,42 @@ static int pvr_dbg_fw_state_open(struct inode *inode, struct file *file)
        if (!dev_node)
                return -ENODEV;
 
-       if (test_and_set_bit(0, &fw_state_busy))
+       spin_lock(&fw_state_lock);
+       if (fw_state_busy) {
+               spin_unlock(&fw_state_lock);
                return -EBUSY;
+       }
+       fw_state_busy = 1;
+       spin_unlock(&trcmd_lock);
 
        fw_state = vmalloc(sizeof(*fw_state));
        if (!fw_state) {
-               clear_bit(0, &fw_state_busy);
-
-               return -ENOMEM;
+               r = -ENOMEM;
+               goto err;
        }
 
        r = sgx_save_fw_state(dev_node, fw_state);
        if (r < 0) {
                vfree(fw_state);
-               clear_bit(0, &fw_state_busy);
-
-               return r;
+               goto err;
        }
 
        return 0;
+err:
+       spin_lock(&fw_state_lock);
+       fw_state_busy = 0;
+       spin_unlock(&fw_state_lock);
+
+       return r;
 }
 
 static int pvr_dbg_fw_state_release(struct inode *inode, struct file *file)
 {
        vfree(fw_state);
-       clear_bit(0, &fw_state_busy);
+
+       spin_lock(&fw_state_lock);
+       fw_state_busy = 0;
+       spin_unlock(&fw_state_lock);
 
        return 0;
 }