| Message ID | 20200511093554.211493-7-daniel.vetter@ffwll.ch (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | shmem helper untangling | expand |
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). In any case Acked-by: Thomas Zimmermann <tzimmermann@suse.de> > -err_zero_use: > +err: > shmem->vmap_use_count = 0; > > return ERR_PTR(ret); >
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 >
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); -err_zero_use: +err: shmem->vmap_use_count = 0; return ERR_PTR(ret);
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(-)