linux-kernel - Re: [PATCH] staging: r8188eu: remove unused members of struct xmit

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Date:   Mon, 13 Jul 2020 17:23:05 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Ivan Safonov <insafonov@...il.com>
Cc:     devel@...verdev.osuosl.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org,
        Nishka Dasgupta <nishkadg.linux@...il.com>,
        Larry Finger <Larry.Finger@...inger.net>,
        Soumyajit Deb <debsoumyajit100@...il.com>
Subject: Re: [PATCH] staging: r8188eu: remove unused members of struct
 xmit_buf

On Mon, Jul 13, 2020 at 04:16:07PM +0300, Dan Carpenter wrote:
> On Sun, Jul 12, 2020 at 03:38:21PM +0300, Ivan Safonov wrote:
> > Remove unused members of struct xmit_buf: alloc_sz, ff_hwaddr,
> > dma_transfer_addr, bpending and last.
> > 
> > Signed-off-by: Ivan Safonov <insafonov@...il.com>
> > ---
> >  drivers/staging/rtl8188eu/include/rtw_xmit.h  | 5 -----
> >  drivers/staging/rtl8188eu/os_dep/xmit_linux.c | 1 -
> >  2 files changed, 6 deletions(-)
> > 
> > diff --git a/drivers/staging/rtl8188eu/include/rtw_xmit.h b/drivers/staging/rtl8188eu/include/rtw_xmit.h
> > index 12d16e98176a..3c03987c81a1 100644
> > --- a/drivers/staging/rtl8188eu/include/rtw_xmit.h
> > +++ b/drivers/staging/rtl8188eu/include/rtw_xmit.h
> > @@ -193,14 +193,9 @@ struct xmit_buf {
> >  	void *priv_data;
> >  	u16 ext_tag; /*  0: Normal xmitbuf, 1: extension xmitbuf. */
> >  	u16 flags;
> > -	u32 alloc_sz;
> >  	u32  len;
> >  	struct submit_ctx *sctx;
> > -	u32	ff_hwaddr;
> >  	struct urb *pxmit_urb[8];
> > -	dma_addr_t dma_transfer_addr;	/* (in) dma addr for transfer_buffer */
> > -	u8 bpending[8];
> > -	int last[8];
> >  };
> >  
> >  struct xmit_frame {
> > diff --git a/drivers/staging/rtl8188eu/os_dep/xmit_linux.c b/drivers/staging/rtl8188eu/os_dep/xmit_linux.c
> > index 017e1d628461..61ced1160951 100644
> > --- a/drivers/staging/rtl8188eu/os_dep/xmit_linux.c
> > +++ b/drivers/staging/rtl8188eu/os_dep/xmit_linux.c
> > @@ -24,7 +24,6 @@ int rtw_os_xmit_resource_alloc(struct adapter *padapter,
> >  		return _FAIL;
> >  
> >  	pxmitbuf->pbuf = PTR_ALIGN(pxmitbuf->pallocated_buf, XMITBUF_ALIGN_SZ);
> 
> Not related to this patch but kmalloc always returns data which is at
> least ARCH_KMALLOC_MINALIGN aligned which is never less than
> XMITBUF_ALIGN_SZ (4) so this is a no-op.

The alignment in the driver is pretty crazy because it's all unnecessary
and so complicated.  Every allocation is 4 bytes extra so we can align
it later.

Also every buffer is called "pbuf" which stands for pointer to buffer.
"pallocated_buf" is not really useful either.

I tried to look at this to see if we could change the alignment, and
it's complicated because of the naming and the alignment.

regards,
dan carpenter