RE: [PATCH v2 wireless] wifi: rtw88: debugfs: don't vzalloc(0) when rsvd_page is read unconfigured

[Ping-Ke Shih <pkshih@realtek.com>]

Abdurrahman Karadag <abdurrahmankaradag19@gmail.com> wrote:
> Reading the rsvd_page debugfs entry before writing a page offset and
> count to it calls vzalloc() with a size of zero, because
> rsvd_page.page_num defaults to 0.  vmalloc warns about this:
> 
>   WARNING: mm/vmalloc.c:4019 at __vmalloc_node_range_noprof+0x9ac/0xa30
>   ...
>   Call Trace:
>    __vmalloc_node_noprof+0x4c/0x70
>    rtw_debugfs_get_rsvd_page+0x4c/0x110 [rtw88_core]
>    seq_read_iter+0x132/0x4b0
>    seq_read+0x12e/0x1c0
>    full_proxy_read+0x6f/0xc0
>    vfs_read+0xdd/0x490
> 
> rtw_fw_dump_fifo() would reject the zero size anyway, but only after
> the allocation.  Check for a zero buffer size first and print a short
> usage hint instead of allocating.
> 
> Fixes: e3037485c68e ("rtw88: new Realtek 802.11ac driver")
> Signed-off-by: Abdurrahman Karadag <abdurrahmankaradag19@gmail.com>

Acked-by: Ping-Ke Shih <pkshih@realtek.com>

> ---
> v2: no code change. Add the wireless target tree to the subject and Cc
>     the maintainers/blamed authors that v1 missed.

Actually, target tree of Realtek Wifi driver should be rtw-next or rtw. 

[1] https://github.com/pkshih/rtw.git rtw-next