msm: camera: Make use of mutex lock to avoid race condition

Make use of mutex lock to access IOCTL so that two threads
can avoid race condition.

Change-Id: I00db78a42c86eef8a157b5b3547e4ca0006b0853
Signed-off-by: annamraj <annamraj@codeaurora.org>

drivers/media/platform/msm/camera_v2/fd/msm_fd_dev.c

@@ -1057,14 +1057,18 @@ static int msm_fd_s_ctrl(struct file *file, void *fh, struct v4l2_control *a)
 			a->value = ctx->format.size->work_size;
 		break;
 	case V4L2_CID_FD_WORK_MEMORY_FD:
+		mutex_lock(&ctx->fd_device->recovery_lock);
 		if (ctx->work_buf.fd != -1)
 			msm_fd_hw_unmap_buffer(&ctx->work_buf);
 		if (a->value >= 0) {
 			ret = msm_fd_hw_map_buffer(&ctx->mem_pool,
 				a->value, &ctx->work_buf);
-			if (ret < 0)
+			if (ret < 0) {
+				mutex_unlock(&ctx->fd_device->recovery_lock);
 				return ret;
+			}
 		}
+		mutex_unlock(&ctx->fd_device->recovery_lock);
 		break;
 	default:
 		return -EINVAL;