Re: [PATCH HID v2 02/11] HID: core: save one kmemdup during .probe()

From: Peter Hutterer
Date: Thu Sep 12 2024 - 02:11:02 EST


On Tue, Sep 10, 2024 at 11:43:38PM +0900, Benjamin Tissoires wrote:
> Turns out the first kmemdup is only required for the .report_fixup()
> driver callback. There is no need to do two kmemdup() in a raw in case

typo: "in a row"?

Cheers,
Peter

> .report_fixup() is not present.
>
> Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx>
>
> ---
>
> new in v2
> ---
> drivers/hid/hid-core.c | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index a5f5415571cb..172746a082f9 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -1206,7 +1206,7 @@ int hid_open_report(struct hid_device *device)
> struct hid_item item;
> unsigned int size;
> const __u8 *start;
> - __u8 *buf;
> + __u8 *buf = NULL;
> const __u8 *end;
> const __u8 *next;
> int ret;
> @@ -1227,14 +1227,18 @@ int hid_open_report(struct hid_device *device)
> if (WARN_ON(!start))
> return -ENODEV;
>
> - buf = kmemdup(start, size, GFP_KERNEL);
> - if (buf == NULL)
> - return -ENOMEM;
> + if (device->driver->report_fixup) {
> + /*
> + * device->driver->report_fixup() needs to work
> + * on a copy of our report descriptor so it can
> + * change it.
> + */
> + buf = kmemdup(start, size, GFP_KERNEL);
> + if (buf == NULL)
> + return -ENOMEM;
>
> - if (device->driver->report_fixup)
> start = device->driver->report_fixup(device, buf, &size);
> - else
> - start = buf;
> + }
>
> start = kmemdup(start, size, GFP_KERNEL);
> kfree(buf);
>
> --
> 2.46.0
>