From: Daniel Vetter <daniel@ffwll.ch>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
Gerd Hoffmann <kraxel@redhat.com>,
DRI Development <dri-devel@lists.freedesktop.org>,
Daniel Vetter <daniel.vetter@intel.com>
Subject: Re: [PATCH 6/9] drm/shmem-helpers: Don't call get/put_pages on imported dma-buf in vmap
Date: Thu, 14 May 2020 14:49:47 +0200 [thread overview]
Message-ID: <20200514124947.GZ206103@phenom.ffwll.local> (raw)
In-Reply-To: <6910cb3c-7169-fe1c-efc1-3acb8a218384@suse.de>
On Thu, May 14, 2020 at 09:16:54AM +0200, Thomas Zimmermann wrote:
> Hi
>
> Am 11.05.20 um 11:35 schrieb Daniel Vetter:
> > There's no direct harm, because for the shmem helpers these are noops
> > on imported buffers. The trouble is in the locks these take - I want
> > to change dma_buf_vmap locking, and so need to make sure that we only
> > ever take certain locks on one side of the dma-buf interface: Either
> > for exporters, or for importers.
> >
> > Cc: Gerd Hoffmann <kraxel@redhat.com>
> > Cc: Rob Herring <robh@kernel.org>
> > Cc: Noralf Trønnes <noralf@tronnes.org>
> > Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> > ---
> > drivers/gpu/drm/drm_gem_shmem_helper.c | 17 +++++++++--------
> > 1 file changed, 9 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > index 2a70159d50ef..b9cba5cc61c3 100644
> > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c
> > @@ -252,32 +252,33 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem)
> > if (shmem->vmap_use_count++ > 0)
> > return shmem->vaddr;
> >
> > - ret = drm_gem_shmem_get_pages(shmem);
> > - if (ret)
> > - goto err_zero_use;
> > -
> > if (obj->import_attach) {
> > shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);
> > } else {
> > pgprot_t prot = PAGE_KERNEL;
> >
> > + ret = drm_gem_shmem_get_pages(shmem);
> > + if (ret)
> > + goto err;
> > +
> > if (!shmem->map_cached)
> > prot = pgprot_writecombine(prot);
> > shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
> > VM_MAP, prot);
> > +
> > + if (!shmem->vaddr)
> > + drm_gem_shmem_put_pages(shmem);
> > }
> >
> > if (!shmem->vaddr) {
> > DRM_DEBUG_KMS("Failed to vmap pages\n");
> > ret = -ENOMEM;
> > - goto err_put_pages;
> > + goto err;
> > }
> >
> > return shmem->vaddr;
> >
> > -err_put_pages:
> > - drm_gem_shmem_put_pages(shmem);
>
> I found the new code to be less readable. Maybe keep the error rollback
> as-is and protect _put_pages() with if (!import_attach).
Hm yeah I guess I can leave this as-is mostly, makes at least the diff
smaller. Imo it all looks a bit awkward, but what I've done isn't clearly
better than just leaving stuff mostly where it was.
-Daniel
>
> In any case
>
> Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
>
> > -err_zero_use:
> > +err:
> > shmem->vmap_use_count = 0;
> >
> > return ERR_PTR(ret);
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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next prev parent reply other threads:[~2020-05-14 12:49 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-11 9:35 [PATCH 0/9] shmem helper untangling Daniel Vetter
2020-05-11 9:35 ` [PATCH 1/9] drm/msm: Don't call dma_buf_vunmap without _vmap Daniel Vetter
2020-05-11 15:24 ` Rob Clark
2020-05-11 15:28 ` Daniel Vetter
2020-05-11 20:36 ` Rob Clark
2020-05-14 20:11 ` [PATCH] " Daniel Vetter
2020-05-28 8:29 ` Daniel Vetter
2020-05-31 16:02 ` Rob Clark
2020-06-03 12:46 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 2/9] drm/gem: WARN if drm_gem_get_pages is called on a private obj Daniel Vetter
2020-05-14 7:45 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 3/9] drm/doc: Some polish for shmem helpers Daniel Vetter
2020-05-11 11:12 ` Thomas Zimmermann
2020-05-14 20:05 ` Daniel Vetter
2020-05-15 6:26 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 4/9] drm/virtio: Call the right " Daniel Vetter
2020-05-14 7:46 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 5/9] drm/udl: Don't call get/put_pages on imported dma-buf Daniel Vetter
2020-05-11 11:23 ` Thomas Zimmermann
2020-05-11 11:37 ` Daniel Vetter
2020-05-11 12:04 ` Thomas Zimmermann
2020-05-14 7:25 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter
2020-06-03 12:57 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 6/9] drm/shmem-helpers: Don't call get/put_pages on imported dma-buf in vmap Daniel Vetter
2020-05-14 7:16 ` Thomas Zimmermann
2020-05-14 12:49 ` Daniel Vetter [this message]
2020-05-14 20:22 ` [PATCH] " Daniel Vetter
2020-05-11 9:35 ` [PATCH 7/9] drm/shmem-helpers: Redirect mmap for imported dma-buf Daniel Vetter
2020-05-14 7:23 ` Thomas Zimmermann
2020-05-14 12:47 ` Daniel Vetter
2020-05-27 18:32 ` Thomas Zimmermann
2020-05-27 19:34 ` Daniel Vetter
2020-05-28 12:53 ` Thomas Zimmermann
2020-05-11 9:35 ` [PATCH 8/9] drm/shmem-helpers: Ensure get_pages is not called on " Daniel Vetter
2020-05-14 7:30 ` Thomas Zimmermann
2020-06-03 13:12 ` Daniel Vetter
2020-06-08 14:40 ` Thomas Zimmermann
2020-06-08 15:04 ` Daniel Vetter
2020-05-11 9:35 ` [PATCH 9/9] drm/shmem-helpers: Simplify dma-buf importing Daniel Vetter
2020-05-14 7:44 ` Thomas Zimmermann
2020-05-14 12:55 ` Daniel Vetter
2020-05-14 15:26 ` Thomas Zimmermann
2020-05-20 18:02 ` [PATCH] " Daniel Vetter
2020-05-29 13:34 ` Boris Brezillon
2020-05-29 13:35 ` Boris Brezillon
2020-05-29 13:49 ` Boris Brezillon
2020-05-29 14:05 ` Daniel Vetter
2020-05-29 14:36 ` Boris Brezillon
2020-06-15 8:23 ` [PATCH 9/9] " Thomas Zimmermann
2020-05-29 13:52 ` [PATCH 0/9] shmem helper untangling Boris Brezillon
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