Re: [PATCH] brcmfmac: abort and release host after error

From: Franky Lin <franky.lin@broadcom.com>
To: Brian Norris <briannorris@chromium.org>
Cc: Guenter Roeck <linux@roeck-us.net>,
	Doug Anderson <dianders@chromium.org>,
	Kalle Valo <kvalo@codeaurora.org>,
	Arend van Spriel <arend.vanspriel@broadcom.com>,
	Hante Meuleman <hante.meuleman@broadcom.com>,
	Chi-Hsien Lin <chi-hsien.lin@cypress.com>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	"open list:BROADCOM BRCM80211 IEEE802.11n WIRELESS DRIVER" 
	<brcm80211-dev-list.pdl@broadcom.com>,
	brcm80211-dev-list <brcm80211-dev-list@cypress.com>,
	netdev <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Matthias Kaehlcke <mka@chromium.org>
Subject: Re: [PATCH] brcmfmac: abort and release host after error
Date: Wed, 29 Jan 2020 15:12:54 -0800	[thread overview]
Message-ID: <CA+8PC_cr8D-tFT1QwS=DSNOW1X2sW3f__Aqts33bUseu9L7yfg@mail.gmail.com> (raw)
In-Reply-To: <20200129180428.GA99393@google.com>

On Wed, Jan 29, 2020 at 10:04 AM Brian Norris <briannorris@chromium.org> wrote:
>
> Hi Franky,
>
> [I'm very unfamiliar with this driver, but I had the same questions as
> Guenter, I think:]
>
> On Tue, Jan 28, 2020 at 04:57:59PM -0800, Franky Lin wrote:
> > On Tue, Jan 28, 2020 at 4:05 PM Guenter Roeck <linux@roeck-us.net> wrote:
> > > On Tue, Jan 28, 2020 at 03:14:45PM -0800, Doug Anderson wrote:
> > > > On Tue, Jan 28, 2020 at 2:15 PM Guenter Roeck <linux@roeck-us.net> wrote:
> > > > > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> > > > > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
> > > > > @@ -1938,6 +1938,8 @@ static uint brcmf_sdio_readframes(struct brcmf_sdio *bus, uint maxframes)
> > > > >                         if (brcmf_sdio_hdparse(bus, bus->rxhdr, &rd_new,
> > > > >                                                BRCMF_SDIO_FT_NORMAL)) {
> > > > >                                 rd->len = 0;
> > > > > +                               brcmf_sdio_rxfail(bus, true, true);
> > > > > +                               sdio_release_host(bus->sdiodev->func1);
> > > >
> > > > I don't know much about this driver so I don't personally know if
> > > > "true, true" is the correct thing to pass to brcmf_sdio_rxfail(), but
> > > > it seems plausible.  Definitely the fix to call sdio_release_host() is
> > > > sane.
> > > >
> > > > Thus, unless someone knows for sure that brcmf_sdio_rxfail()'s
> > > > parameters should be different:
> > > >
> > > Actually, looking at brcmf_sdio_hdparse() and its other callers,
> > > I think it may not be needed at all - other callers don't do it, and
> > > there already are some calls to brcmf_sdio_rxfail() in that function.
> > > It would be nice though to get a confirmation before I submit v2.
> >
> > I think invoking rxfail with both abort and NACK set to true is the
> > right thing to do here so that the pipeline can be properly purged.
>
> Thanks for looking here. I'm not sure I totally understand your answer:
> brcmf_sdio_hdparse() already calls brcmf_sdio_rxfail() in several error
> cases. Is it really OK to call it twice in a row?

Yes. brcmf_sdio_rxglom does the same thing that calls
brcmf_sdio_rxfail again in error handling. For this instance I think
it's better using the same logic as the length mismatch block below (
calling brcmf_sdio_rxfail with true ture).

Thanks,
- Franky