Re: [PATCH] staging: r8188eu: remove unused members of struct xmit_buf

[Larry Finger]

On 7/13/20 1:28 PM, Ivan Safonov wrote:
> On 7/13/20 5:23 PM, Dan Carpenter wrote:
> > 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@xxxxxxxxx>
> > > > ---
> > > >  drivers/staging/rtl8188eu/include/rtw_xmit.h | 5 -----
> > > > Â drivers/staging/rtl8188eu/os_dep/xmit_linux.c | 1 -
> > > > Â 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 {
> > > > ÂÂÂÂÂ void *priv_data;
> > > > ÂÂÂÂÂ u16 ext_tag; /*Â 0: Normal xmitbuf, 1: extension xmitbuf. */
> > > > ÂÂÂÂÂ u16 flags;
> > > > -ÂÂÂ u32 alloc_sz;
> > > > ÂÂÂÂÂ u32Â len;
> > > > ÂÂÂÂÂ struct submit_ctx *sctx;
> > > > -ÂÂÂ u32ÂÂÂ ff_hwaddr;
> > > > ÂÂÂÂÂ struct urb *pxmit_urb[8];
> > > > -ÂÂÂ dma_addr_t dma_transfer_addr;ÂÂÂ /* (in) dma addr for transfer_buffer */
> > > > -ÂÂÂ u8 bpending[8];
> > > > -ÂÂÂ int last[8];
> > > > Â };
> > > > Â 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,
> > > > ÂÂÂÂÂÂÂÂÂ return _FAIL;
> > > > ÂÂÂÂÂ 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.
>
> 4-byte alignment for 8-byte pointer (for example void *priv_data) on 64-bit arch 
> is an _error_. Itâs good that kmalloc (and vmalloc) is already aligned to 8 bytes.
>
> > 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
>
> I have already fixed 4 places with unnecessary alignment, but, alas, there is no 
> great desire to test them on real hardware.

I have now tested on real hardware and it works fine.

Acked-by: Larry Finger <Larry.Finger@xxxxxxxxxxxx>

Larry