linux-kernel - Re: [PATCH v14 02/12] powerpc/irq: use memblock functions returning virtual address

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Message-ID: <20190124172839.GB11163@lakrids.cambridge.arm.com>
Date:   Thu, 24 Jan 2019 17:28:40 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     Mike Rapoport <rppt@...ux.ibm.com>
Cc:     Christophe Leroy <christophe.leroy@....fr>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v14 02/12] powerpc/irq: use memblock functions returning
 virtual address

On Thu, Jan 24, 2019 at 07:25:53PM +0200, Mike Rapoport wrote:
> On Thu, Jan 24, 2019 at 04:51:53PM +0000, Mark Rutland wrote:
> > On Thu, Jan 24, 2019 at 04:19:33PM +0000, Christophe Leroy wrote:
> > > Since only the virtual address of allocated blocks is used,
> > > lets use functions returning directly virtual address.
> > > 
> > > Those functions have the advantage of also zeroing the block.
> > > 
> > > Suggested-by: Mike Rapoport <rppt@...ux.ibm.com>
> > > Acked-by: Mike Rapoport <rppt@...ux.ibm.com>
> > > Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> > 
> > [...]
> > 
> > > +static void *__init alloc_stack(void)
> > > +{
> > > +	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
> > > +
> > > +	if (!ptr)
> > > +		panic("cannot allocate stacks");
> > > +
> > > +	return ptr;
> > > +}
> > 
> > I believe memblock_alloc() will panic() if it cannot allocate memory,
> > since that goes:
> > 
> >  memblock_alloc()
> >  -> memblock_alloc_try_nid()
> >     -> panic()
> > 
> > So you can get rid of the panic() here, or if you want a custom panic
> > message, you can use memblock_alloc_nopanic().
> 
> As we've already discussed it in [1], I'm working on removing the
> _nopanic() versions and dropping the panic() calls from memblock_alloc()
> and friends.
> 
> I've posted v2 of the patches earlier this week [2].
>  
> > [...]
> 
> [1] https://lore.kernel.org/lkml/20190108143428.GB14063@rapoport-lnx/ 
> [2] https://lore.kernel.org/lkml/1548057848-15136-1-git-send-email-rppt@linux.ibm.com/

Fair enough.

Feel free to take the ack regardless, then!

Thanks,
Mark.