staging: westbridge: improve error path

kmalloc() may fail, check for it.
Allocated memory is not freed.
Use IS_ERR() instead of strict checking.
Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
Cc: David Cross <david.cross@cypress.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/westbridge/astoria/gadget/cyasgadget.c

@@ -1123,6 +1123,8 @@ static int cyasgadget_ioctl(
 
 		/* better use fixed size buff*/
 		alloc_filename = kmalloc(k_d.name_length + 1, GFP_KERNEL);
+		if (alloc_filename == NULL)
+			return -ENOMEM;
 
 		/* get the filename */
 		if (copy_from_user(alloc_filename, k_d.file_name,
@@ -1132,12 +1134,13 @@ static int cyasgadget_ioctl(
 				"copy file name from user space failed\n",
 				__func__);
 			#endif
+			kfree(alloc_filename);
 			return -EFAULT;
 		}
 
 		file_to_allocate = filp_open(alloc_filename, O_RDWR, 0);
 
-		if ((int)file_to_allocate != 0xfffffffe) {
+		if (!IS_ERR(file_to_allocate)) {
 
 			struct address_space *mapping =
 				file_to_allocate->f_mapping;
@@ -1379,6 +1382,7 @@ static int cyasgadget_ioctl(
 				__func__, alloc_filename);
 		} /* end if (file_to_allocate)*/
 		#endif
+		kfree(alloc_filename);
 initsoj_safe_exit:
 			ret_stat = 0;
 			retval = __put_user(ret_stat,
@@ -1410,12 +1414,15 @@ static int cyasgadget_ioctl(
 				return -EFAULT;
 
 		map_filename = kmalloc(k_d.name_length + 1, GFP_KERNEL);
+		if (map_filename == NULL)
+			return -ENOMEM;
 		if (copy_from_user(map_filename, k_d.file_name,
 			k_d.name_length + 1)) {
 			#ifndef WESTBRIDGE_NDEBUG
 			cy_as_hal_print_message("%s: copy file name from "
 				"user space failed\n", __func__);
 			#endif
+			kfree(map_filename);
 			return -EFAULT;
 		}
 
@@ -1561,6 +1568,7 @@ static int cyasgadget_ioctl(
 					__func__, map_filename);
 		}
 		#endif
+		kfree(map_filename);
 
 		ret_stat = 0;
 		retval = __put_user(ret_stat, (uint32_t __user *)