On Thu, Aug 21 2014, Robert Baldyga <r.bald...@samsung.com> wrote:
> This patch introduces ioctl named FUNCTIONFS_ENDPOINT_DESC, which
> returns endpoint descriptor to userspace. It works only if function
> is active.
>
> Signed-off-by: Robert Baldyga <r.bald...@samsung.com>

With the change described below:

Acked-by: Michal Nazarewicz <min...@mina86.com>

> ---
>  drivers/usb/gadget/function/f_fs.c  | 21 +++++++++++++++++++++
>  include/uapi/linux/usb/functionfs.h |  6 ++++++
>  2 files changed, 27 insertions(+)
>
> diff --git a/drivers/usb/gadget/function/f_fs.c 
> b/drivers/usb/gadget/function/f_fs.c
> index 8096f22..ac7b16d 100644
> --- a/drivers/usb/gadget/function/f_fs.c
> +++ b/drivers/usb/gadget/function/f_fs.c
> @@ -1032,6 +1032,27 @@ static long ffs_epfile_ioctl(struct file *file, 
> unsigned code,
>               case FUNCTIONFS_ENDPOINT_REVMAP:
>                       ret = epfile->ep->num;
>                       break;
> +             case FUNCTIONFS_ENDPOINT_DESC:
> +             {
> +                     int desc_idx;
> +                     struct usb_endpoint_descriptor *desc;
> +
> +                     switch (epfile->ffs->gadget->speed) {
> +                     case USB_SPEED_SUPER:
> +                             desc_idx = 2;
> +                             break;
> +                     case USB_SPEED_HIGH:
> +                             desc_idx = 1;
> +                             break;
> +                     default:
> +                             desc_idx = 0;
> +                     }
> +                     desc = epfile->ep->descs[desc_idx];
> +                     ret = copy_to_user((void *)value, desc, sizeof(*desc));

This is called under a spin lock, so nope…  The simplest will be to just
unlock prior to copying and then return instead of breaking from the switch:

+                       struct usb_endpoint_descriptor desc;
…
+                       desc = *epfile->ep->descs[desc_idx];
+                       spin_unlock_irq(&epfile->ffs->eps_lock);
+                       ret = copy_to_user((void *)value, &desc, sizeof(desc));
+                       return ret ? -EFAULT : 0;

> +                     if (ret)
> +                             ret = -EFAULT;
> +                     break;
> +             }
>               default:
>                       ret = -ENOTTY;
>               }

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +--<m...@google.com>--<xmpp:min...@jabber.org>--ooO--(_)--Ooo--
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