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SubjectRe: [PATCH v7 06/12] powerpc/vas: Define helpers to alloc/free windows
Michael Ellerman [mpe@ellerman.id.au] wrote:
> Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> writes:
> > diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c

> > + rc = ida_pre_get(ida, GFP_KERNEL);
> > + if (!rc)
> > + return -EAGAIN;
> > +
> > + spin_lock(&vas_ida_lock);
> > + rc = ida_get_new_above(ida, 0, &winid);
>
> If you're passing 0 you can just use ida_get_new().

Ok.

>
> Or did you actually want to exclude 0? In which case you should pass 1.
>
> > + spin_unlock(&vas_ida_lock);
> > +
> > + if (rc)
> > + return rc;
>
> You're supposed to handle EAGAIN I thought.

Yes, I will retry the pre_get()
>
> > +
> > + if (winid > VAS_WINDOWS_PER_CHIP) {
> > + pr_err("VAS: Too many (%d) open windows\n", winid);
> > + vas_release_window_id(ida, winid);
> > + return -EAGAIN;
> > + }
> > +
> > + return winid;
> > +}
> > +
> > +void vas_window_free(struct vas_window *window)
>
> static.

Ok

>
> > +{
> > + int winid = window->winid;
> > + struct vas_instance *vinst = window->vinst;
> > +
> > + unmap_winctx_mmio_bars(window);
> > + kfree(window);
> > +
> > + vas_release_window_id(&vinst->ida, winid);
> > +}
> > +
> > +struct vas_window *vas_window_alloc(struct vas_instance *vinst)
> > +{
> > + int winid;
> > + struct vas_window *window;
> > +
> > + winid = vas_assign_window_id(&vinst->ida);
> > + if (winid < 0)
> > + return ERR_PTR(winid);
> > +
> > + window = kzalloc(sizeof(*window), GFP_KERNEL);
> > + if (!window)
> > + return ERR_PTR(-ENOMEM);
>
> You leak an id here.

Argh. Yes.

>
> The error handling would be easier in here if the caller did the alloc,
> or if you split alloc and init, and alloc just did the kzalloc().

I was trying to simplify error handling in the callers where they have
to only deal with one failure now.
>
> One of the callers even prints "unable to allocate memory" if this
> function fails, but that's not accurate, there's several failure modes.

Yes, will fix that message and the leaks.

Thanks,

Suka

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