Re: [PATCH 1/5] usb: host: xhci: use ffs() in xhci_mem_init()

[Sergei Shtylyov <sergei.shtylyov@gmail.com>]

Hello!

On 2/16/22 9:59 AM, Linyu Yuan wrote:

> The for loop to find page size bit can be replaced with ffs().
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---
>  drivers/usb/host/xhci-mem.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
> index 0e31206..3cbc7f2 100644
> --- a/drivers/usb/host/xhci-mem.c
> +++ b/drivers/usb/host/xhci-mem.c
> @@ -2395,12 +2395,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
>  	page_size = readl(&xhci->op_regs->page_size);
>  	xhci_dbg_trace(xhci, trace_xhci_dbg_init,
>  			"Supported page size register = 0x%x", page_size);
> -	for (i = 0; i < 16; i++) {
> -		if ((0x1 & page_size) != 0)
> -			break;
> -		page_size = page_size >> 1;
> -	}
> -	if (i < 16)
> +	if ((i = ffs(page_size)) < 16)

   Always run your patches thru scripts/checkpatch.pl -- in this case it will complain
of an assignment in the *if* expression...

[...]

MNR, Sergey