On Fri, 27 Jul 2007 21:30:48 +0200
Michael Buesch <mb@xxxxxxxxx> wrote:
> > ERROR: "foo * bar" should be "foo *bar"
> > #4156: FILE: drivers/ssb/ssb_private.h:119:
> > +extern struct ssb_bus * ssb_pci_dev_to_bus(struct pci_dev *pdev);
> >
> > are worth addressing.
>
> Well, I intentionally wrote that this way, as in my opinion
> it it easier to read. I only use this additional space for
> functions returning a pointer.
>
> struct foo * function(int a, int b);
>
> vs:
>
> struct foo *function(int a, int b);
>
> But I can change that, if that's really an issue and a
> style violation.
It's a microissue but yeah, no-space is more conventional.
> > > +static ssize_t ssb_pci_attr_sprom_show(struct device *pcidev,
> > > + struct device_attribute *attr,
> > > + char *buf)
> > > +{
> > > + struct pci_dev *pdev = container_of(pcidev, struct pci_dev, dev);
> > > + struct ssb_bus *bus;
> > > + u16 *sprom;
> > > + int err = -ENODEV;
> > > + ssize_t count = 0;
> > > +
> > > + bus = ssb_pci_dev_to_bus(pdev);
> > > + if (!bus)
> > > + goto out;
> > > + err = -ENOMEM;
> > > + sprom = kcalloc(SSB_SPROMSIZE_WORDS, sizeof(u16), GFP_KERNEL);
> > > + if (!sprom)
> > > + goto out;
> > > +
> > > + err = -ERESTARTSYS;
> > > + if (mutex_lock_interruptible(&bus->pci_sprom_mutex))
> > > + goto out_kfree;
> > > + sprom_do_read(bus, sprom);
> > > + mutex_unlock(&bus->pci_sprom_mutex);
> > > +
> > > + count = sprom2hex(sprom, buf, PAGE_SIZE);
> > > + err = 0;
> > > +
> > > +out_kfree:
> > > + kfree(sprom);
> > > +out:
> > > + return err ? err : count;
> > > +}
> >
> > The mutex_lock_interruptible() looks fishy. Some commented explanation of
> > what it's doing would be good here. It's quite unobvious to this reader.
> > Cheesy deadlock avoidance? Hope not.
>
> No, it's simply to avoid writing the SPROM concurrently.
> SPROM writing is hairy and we must make sure here that
> we are the only one accessing the whole bus. We do that
> by suspending all devices and taking a lock to protect
> the SPROM from write concurrency.
Sure, but why is the locking interruptible rather than plain old
mutex_lock()?
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