Re: [PATCH wireless-next] wifi: rt2x00: allocate anchor with rt2x00dev

[Rosen Penev <rosenp@gmail.com>]

On Sat, May 9, 2026 at 3:13 AM Stanislaw Gruszka <stf_xl@wp.pl> wrote:
>
> Hi,
>
> On Thu, Apr 30, 2026 at 04:22:06PM -0700, Rosen Penev wrote:
> > Instead of being creative with devm, allocate with rt2x00dev by using a
> > flexible array member. Simplifies code slightly.
>
> I think this patch is more creative. Using a flexible array member
> is less conventional than the current approach of allocating separately
> and storing a pointer. But OK, lets get rid of 9 LOC.
I don't see how a FAM is more creative. It's a single allocation. It
also takes up less struct space as the pointer gets removed. The other
usage of ieee80211_alloc_hw and struct_size is in ath12k:

drivers/net/wireless/ath/ath12k/mac.c: hw =
ieee80211_alloc_hw(struct_size(ah, radio, num_pdev_map),

Actually there are more but instead of struct_size they use manual addition.
>
> Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
>
> > It's worth noting that in 25369b22223d1c56e42a0cd4ac9137349d5a898e , the
> > proper device was set to the devm call as it seems there was confusion
> > there.
> >
> > Signed-off-by: Rosen Penev <rosenp@gmail.com>
> >
> > ---
> >  drivers/net/wireless/ralink/rt2x00/rt2x00.h    |  3 ++-
> >  drivers/net/wireless/ralink/rt2x00/rt2x00usb.c | 11 +----------
> >  2 files changed, 3 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00.h b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
> > index 665887e9b118..7d313e86d3f2 100644
> > --- a/drivers/net/wireless/ralink/rt2x00/rt2x00.h
> > +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
> > @@ -1009,11 +1009,12 @@ struct rt2x00_dev {
> >       /* Extra TX headroom required for alignment purposes. */
> >       unsigned int extra_tx_headroom;
> >
> > -     struct usb_anchor *anchor;
> >       unsigned int num_proto_errs;
> >
> >       /* Clock for System On Chip devices. */
> >       struct clk *clk;
> > +
> > +     struct usb_anchor anchor[];
> >  };
> >
> >  struct rt2x00_bar_list_entry {
> > diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
> > index 174d89b0b1d7..47e427ea8622 100644
> > --- a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
> > +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c
> > @@ -804,7 +804,7 @@ int rt2x00usb_probe(struct usb_interface *usb_intf,
> >
> >       usb_reset_device(usb_dev);
> >
> > -     hw = ieee80211_alloc_hw(sizeof(struct rt2x00_dev), ops->hw);
> > +     hw = ieee80211_alloc_hw(struct_size(rt2x00dev, anchor, 1), ops->hw);
> >       if (!hw) {
> >               rt2x00_probe_err("Failed to allocate hardware\n");
> >               return -ENOMEM;
> > @@ -826,13 +826,6 @@ int rt2x00usb_probe(struct usb_interface *usb_intf,
> >       if (retval)
> >               goto exit_free_device;
> >
> > -     rt2x00dev->anchor = devm_kmalloc(&usb_intf->dev,
> > -                                     sizeof(struct usb_anchor),
> > -                                     GFP_KERNEL);
> > -     if (!rt2x00dev->anchor) {
> > -             retval = -ENOMEM;
> > -             goto exit_free_reg;
> > -     }
> >       init_usb_anchor(rt2x00dev->anchor);
> >
> >       retval = rt2x00lib_probe_dev(rt2x00dev);
> > @@ -843,8 +836,6 @@ int rt2x00usb_probe(struct usb_interface *usb_intf,
> >
> >  exit_free_anchor:
> >       usb_kill_anchored_urbs(rt2x00dev->anchor);
> > -
> > -exit_free_reg:
> >       rt2x00usb_free_reg(rt2x00dev);
> >
> >  exit_free_device:
> > --
> > 2.54.0
> >