usb: gadget: Zero ffs_io_data

In some cases the "Allocate & copy" block in ffs_epfile_io() is not
executed. Consequently, in such a case ffs_alloc_buffer() is never called
and struct ffs_io_data is not initialized properly. This in turn leads to
problems when ffs_free_buffer() is called at the end of ffs_epfile_io().

This patch uses kzalloc() instead of kmalloc() in the aio case and memset()
in non-aio case to properly initialize struct ffs_io_data.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/function/f_fs.c

@@ -1183,11 +1183,12 @@ static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from)
 	ENTER();
 
 	if (!is_sync_kiocb(kiocb)) {
-		p = kmalloc(sizeof(io_data), GFP_KERNEL);
+		p = kzalloc(sizeof(io_data), GFP_KERNEL);
 		if (unlikely(!p))
 			return -ENOMEM;
 		p->aio = true;
 	} else {
+		memset(p, 0, sizeof(*p));
 		p->aio = false;
 	}
 
@@ -1219,11 +1220,12 @@ static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to)
 	ENTER();
 
 	if (!is_sync_kiocb(kiocb)) {
-		p = kmalloc(sizeof(io_data), GFP_KERNEL);
+		p = kzalloc(sizeof(io_data), GFP_KERNEL);
 		if (unlikely(!p))
 			return -ENOMEM;
 		p->aio = true;
 	} else {
+		memset(p, 0, sizeof(*p));
 		p->aio = false;
 	}