linux-kernel - Re: [PATCH 5.10 045/152] dm crypt: use GFP_ATOMIC when allocating crypto requests from softirq

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Date:   Tue, 19 Jan 2021 00:42:55 +0100
From:   Pavel Machek <pavel@...x.de>
To:     Ignat Korchagin <ignat@...udflare.com>
Cc:     Pavel Machek <pavel@...x.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        stable@...r.kernel.org,
        "Maciej S. Szmigiero" <mail@...iej.szmigiero.name>,
        Mikulas Patocka <mpatocka@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>
Subject: Re: [PATCH 5.10 045/152] dm crypt: use GFP_ATOMIC when allocating
 crypto requests from softirq

Hi!

> > > -static void crypt_alloc_req_aead(struct crypt_config *cc,
> > > +static int crypt_alloc_req_aead(struct crypt_config *cc,
> > >                                struct convert_context *ctx)
> > >  {
> > > -     if (!ctx->r.req_aead)
> > > -             ctx->r.req_aead = mempool_alloc(&cc->req_pool, GFP_NOIO);
> > > +     if (!ctx->r.req) {
> > > +             ctx->r.req = mempool_alloc(&cc->req_pool, in_interrupt() ? GFP_ATOMIC : GFP_NOIO);
> > > +             if (!ctx->r.req)
> > > +                     return -ENOMEM;
> > > +     }
> >
> > But this one can't be good. We are now allocating different field in
> > the structure!
> 
> Good catch! Sorry for the copy-paste. It is actually not a big deal,
> because this is not a structure, but a union:
> as long as the mempool was initialized with the correct size, it
> should be no different.

Ah. I actually thought about unions and went back to definition to see
if it is one, but was somehow blind for the moment.

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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