Re: [PATCH RFT] MMC: core/core.c: mmc_rescan detects card changein one run

From: Jörg Schummer
Date: Tue Mar 03 2009 - 02:24:41 EST


Hello,

thanks for your reply.

On Mon, 2009-03-02 at 21:09 +0100, ext Pierre Ossman wrote:
> On Thu, 19 Feb 2009 17:26:26 +0200
> Jorg Schummer <ext-jorg.2.schummer@xxxxxxxxx> wrote:
>
> > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> > index df6ce4a..cd2e29f 100644
> > --- a/drivers/mmc/core/core.c
> > +++ b/drivers/mmc/core/core.c
> > @@ -740,6 +740,22 @@ void mmc_rescan(struct work_struct *work)
> >
> > mmc_bus_get(host);
> >
> > + /* if there is a card registered */
> > + if (host->bus_ops != NULL) {
> > +
> > + if (host->bus_ops->detect && !host->bus_dead) {
> > +
> > + /* check whether the card is still present */
> > + host->bus_ops->detect(host);
> > +
> > + /* release the bus and update bus status in case
> > + the card was removed */
> > + mmc_bus_put(host);
> > + mmc_bus_get(host);
> > + }
> > + }
> > +
> > + /* if there is no card registered */
> > if (host->bus_ops == NULL) {
> > /*
> > * Only we can add a new handler, so it's safe to
>
> Perhaps it's more clear if you grab the lock for the first section,
> release it after and then regrab it for the second section. A bit less
> efficient, but I don't think that will be a problem in practice.

Yes, you're probably right, I should take read- and maintainability into
account there. Will change that.

>
> > @@ -789,12 +805,8 @@ void mmc_rescan(struct work_struct *work)
> >
> > mmc_release_host(host);
> > mmc_power_off(host);
> > - } else {
> > - if (host->bus_ops->detect && !host->bus_dead)
> > - host->bus_ops->detect(host);
> > -
> > + } else
> > mmc_bus_put(host);
> > - }
> > out:
> > if (host->caps & MMC_CAP_NEEDS_POLL)
> > mmc_schedule_delayed_work(&host->detect, HZ);
>
> The else section got a bit small here with that code removed. Perhaps
> we should instead have:
>
> if (host->bus_ops != NULL) {
> mmc_bus_put(host);
> goto out;
> }

I guess you meant

else {
mmc_bus_put(host);
goto out;
}

since it would be the else clause of

if (host->bus_ops == NULL)


Also: Are you sure "goto out" should be added in the else-branch? (Since
it's not present in the end of the corresponding if-branch either, and
is technically not needed.)

Regards,
JÃrg


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