usb: f_fs: check quirk to pad epout buf size when not aligned to maxpacketsize
Check gadget.quirk_ep_out_aligned_size to decide if buffer size requires
to be aligned to maxpacketsize of an out endpoint. ffs_epfile_io() needs
to pad epout buffer to match above condition if quirk is found.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/gadget/f_fs.c b/drivers/usb/gadget/f_fs.c
index 1222cf9..3494043 100644
--- a/drivers/usb/gadget/f_fs.c
+++ b/drivers/usb/gadget/f_fs.c
@@ -753,9 +753,10 @@
char __user *buf, size_t len, int read)
{
struct ffs_epfile *epfile = file->private_data;
+ struct usb_gadget *gadget = epfile->ffs->gadget;
struct ffs_ep *ep;
char *data = NULL;
- ssize_t ret;
+ ssize_t ret, data_len;
int halt;
/* Are we still active? */
@@ -788,7 +789,13 @@
/* Allocate & copy */
if (!halt) {
- data = kmalloc(len, GFP_KERNEL);
+ /*
+ * Controller may require buffer size to be aligned to
+ * maxpacketsize of an out endpoint.
+ */
+ data_len = read ? usb_ep_align_maybe(gadget, ep->ep, len) : len;
+
+ data = kmalloc(data_len, GFP_KERNEL);
if (unlikely(!data))
return -ENOMEM;
@@ -823,7 +830,7 @@
req->context = &done;
req->complete = ffs_epfile_io_complete;
req->buf = data;
- req->length = len;
+ req->length = data_len;
ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
@@ -835,9 +842,17 @@
ret = -EINTR;
usb_ep_dequeue(ep->ep, req);
} else {
+ /*
+ * XXX We may end up silently droping data here.
+ * Since data_len (i.e. req->length) may be bigger
+ * than len (after being rounded up to maxpacketsize),
+ * we may end up with more data then user space has
+ * space for.
+ */
ret = ep->status;
if (read && ret > 0 &&
- unlikely(copy_to_user(buf, data, ret)))
+ unlikely(copy_to_user(buf, data,
+ min_t(size_t, ret, len))))
ret = -EFAULT;
}
}