linux-kernel - Re: [PATCH v3] drm/nouveau: fix incorrect conversion to dma_resv_wait

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Message-ID: <CACO55tsvgOPgpc5Ssm-md_q4-0U6ON-kHzuu+F-RsnZ79ACYrA@mail.gmail.com>
Date:   Mon, 17 Apr 2023 14:46:40 +0200
From:   Karol Herbst <kherbst@...hat.com>
To:     Christian König <christian.koenig@....com>
Cc:     John Ogness <john.ogness@...utronix.de>,
        linux-kernel@...r.kernel.org, Ben Skeggs <bskeggs@...hat.com>,
        Lyude Paul <lyude@...hat.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, nouveau@...ts.freedesktop.org,
        Tanmay Bhushan <007047221b@...il.com>
Subject: Re: [PATCH v3] drm/nouveau: fix incorrect conversion to dma_resv_wait_timeout()

On Mon, Apr 17, 2023 at 7:55 AM Christian König
<christian.koenig@....com> wrote:
>
> Am 15.04.23 um 04:02 schrieb John Ogness:
> > Commit 41d351f29528 ("drm/nouveau: stop using ttm_bo_wait")
> > converted from ttm_bo_wait_ctx() to dma_resv_wait_timeout().
> > However, dma_resv_wait_timeout() returns greater than zero on
> > success as opposed to ttm_bo_wait_ctx(). As a result, relocs
> > will fail and log errors even when it was a success.
> >
> > Change the return code handling to match that of
> > nouveau_gem_ioctl_cpu_prep(), which was already using
> > dma_resv_wait_timeout() correctly.
> >
> > Fixes: 41d351f29528 ("drm/nouveau: stop using ttm_bo_wait")
> > Reported-by: Tanmay Bhushan <007047221b@...il.com>
> > Link: https://lore.kernel.org/lkml/20230119225351.71657-1-007047221b@gmail.com
> > Signed-off-by: John Ogness <john.ogness@...utronix.de>
>
> Reviewed-by: Christian König <christian.koenig@....com>
>

Reviewed-by: Karol Herbst <kherbst@...hat.com>

will push shortly to drm-misc-fixes

> > ---
> >   I just realized that the nouveau driver style prefers to scope
> >   variables used only in loops.
> >
> >   v3: Define @lret within the for-loop.
> >
> >   drivers/gpu/drm/nouveau/nouveau_gem.c | 18 ++++++++++++------
> >   1 file changed, 12 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > index f77e44958037..ab9062e50977 100644
> > --- a/drivers/gpu/drm/nouveau/nouveau_gem.c
> > +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
> > @@ -645,7 +645,7 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
> >                               struct drm_nouveau_gem_pushbuf_reloc *reloc,
> >                               struct drm_nouveau_gem_pushbuf_bo *bo)
> >   {
> > -     long ret = 0;
> > +     int ret = 0;
> >       unsigned i;
> >
> >       for (i = 0; i < req->nr_relocs; i++) {
> > @@ -653,6 +653,7 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
> >               struct drm_nouveau_gem_pushbuf_bo *b;
> >               struct nouveau_bo *nvbo;
> >               uint32_t data;
> > +             long lret;
> >
> >               if (unlikely(r->bo_index >= req->nr_buffers)) {
> >                       NV_PRINTK(err, cli, "reloc bo index invalid\n");
> > @@ -703,13 +704,18 @@ nouveau_gem_pushbuf_reloc_apply(struct nouveau_cli *cli,
> >                               data |= r->vor;
> >               }
> >
> > -             ret = dma_resv_wait_timeout(nvbo->bo.base.resv,
> > -                                         DMA_RESV_USAGE_BOOKKEEP,
> > -                                         false, 15 * HZ);
> > -             if (ret == 0)
> > +             lret = dma_resv_wait_timeout(nvbo->bo.base.resv,
> > +                                          DMA_RESV_USAGE_BOOKKEEP,
> > +                                          false, 15 * HZ);
> > +             if (!lret)
> >                       ret = -EBUSY;
> > +             else if (lret > 0)
> > +                     ret = 0;
> > +             else
> > +                     ret = lret;
> > +
> >               if (ret) {
> > -                     NV_PRINTK(err, cli, "reloc wait_idle failed: %ld\n",
> > +                     NV_PRINTK(err, cli, "reloc wait_idle failed: %d\n",
> >                                 ret);
> >                       break;
> >               }
> >
> > base-commit: 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d
>