On Thu, Oct 08, 2020 at 01:23:39PM +0200, Christian König wrote: > Add the new vma_set_file() function to allow changing > vma->vm_file with the necessary refcount dance. > > v2: add more users of this. > > Signed-off-by: Christian König <christian.koe...@amd.com> > --- > drivers/dma-buf/dma-buf.c | 16 +++++----------- > drivers/gpu/drm/etnaviv/etnaviv_gem.c | 4 +--- > drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 3 +-- > drivers/gpu/drm/i915/gem/i915_gem_mman.c | 4 ++-- > drivers/gpu/drm/msm/msm_gem.c | 4 +--- > drivers/gpu/drm/omapdrm/omap_gem.c | 3 +-- > drivers/gpu/drm/vgem/vgem_drv.c | 3 +-- > drivers/staging/android/ashmem.c | 5 ++--- > include/linux/mm.h | 2 ++ > mm/mmap.c | 16 ++++++++++++++++ > 10 files changed, 32 insertions(+), 28 deletions(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index a6ba4d598f0e..e4316aa7e0f4 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -1163,20 +1163,14 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct > vm_area_struct *vma, > return -EINVAL; > > /* readjust the vma */ > - get_file(dmabuf->file); > - oldfile = vma->vm_file; > - vma->vm_file = dmabuf->file; > + oldfile = vma_set_file(vma, dmabuf->file); > vma->vm_pgoff = pgoff; > > ret = dmabuf->ops->mmap(dmabuf, vma); > - if (ret) { > - /* restore old parameters on failure */ > - vma->vm_file = oldfile; > - fput(dmabuf->file); > - } else { > - if (oldfile) > - fput(oldfile); > - } > + /* restore old parameters on failure */ > + if (ret) > + vma_set_file(vma, oldfile);
I think these two lines here are cargo-cult: If this fails, the mmap fails and therefore the vma structure is kfreed. No point at all in restoring anything. With that: Reviewed-by: Daniel Vetter <daniel.vet...@ffwll.ch> > + > return ret; > > } > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c > b/drivers/gpu/drm/etnaviv/etnaviv_gem.c > index 312e9d58d5a7..10ce267c0947 100644 > --- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c > @@ -145,10 +145,8 @@ static int etnaviv_gem_mmap_obj(struct > etnaviv_gem_object *etnaviv_obj, > * address_space (so unmap_mapping_range does what we want, > * in particular in the case of mmap'd dmabufs) > */ > - fput(vma->vm_file); > - get_file(etnaviv_obj->base.filp); > vma->vm_pgoff = 0; > - vma->vm_file = etnaviv_obj->base.filp; > + vma_set_file(vma, etnaviv_obj->base.filp); > > vma->vm_page_prot = vm_page_prot; > } > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > index fec0e1e3dc3e..8ce4c9e28b87 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c > @@ -119,8 +119,7 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, > struct vm_area_struct * > if (ret) > return ret; > > - fput(vma->vm_file); > - vma->vm_file = get_file(obj->base.filp); > + vma_set_file(vma, obj->base.filp); > > return 0; > } > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c > b/drivers/gpu/drm/i915/gem/i915_gem_mman.c > index 3d69e51f3e4d..c9d5f1a38af3 100644 > --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c > +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c > @@ -893,8 +893,8 @@ int i915_gem_mmap(struct file *filp, struct > vm_area_struct *vma) > * requires avoiding extraneous references to their filp, hence why > * we prefer to use an anonymous file for their mmaps. > */ > - fput(vma->vm_file); > - vma->vm_file = anon; > + vma_set_file(vma, anon); > + fput(anon); > > switch (mmo->mmap_type) { > case I915_MMAP_TYPE_WC: > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c > index de915ff6f4b4..a71f42870d5e 100644 > --- a/drivers/gpu/drm/msm/msm_gem.c > +++ b/drivers/gpu/drm/msm/msm_gem.c > @@ -223,10 +223,8 @@ int msm_gem_mmap_obj(struct drm_gem_object *obj, > * address_space (so unmap_mapping_range does what we want, > * in particular in the case of mmap'd dmabufs) > */ > - fput(vma->vm_file); > - get_file(obj->filp); > vma->vm_pgoff = 0; > - vma->vm_file = obj->filp; > + vma_set_file(vma, obj->filp); > > vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); > } > diff --git a/drivers/gpu/drm/omapdrm/omap_gem.c > b/drivers/gpu/drm/omapdrm/omap_gem.c > index 979d53a93c2b..0d4542ff1d7d 100644 > --- a/drivers/gpu/drm/omapdrm/omap_gem.c > +++ b/drivers/gpu/drm/omapdrm/omap_gem.c > @@ -564,9 +564,8 @@ int omap_gem_mmap_obj(struct drm_gem_object *obj, > * address_space (so unmap_mapping_range does what we want, > * in particular in the case of mmap'd dmabufs) > */ > - fput(vma->vm_file); > vma->vm_pgoff = 0; > - vma->vm_file = get_file(obj->filp); > + vma_set_file(vma, obj->filp); > > vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); > } > diff --git a/drivers/gpu/drm/vgem/vgem_drv.c b/drivers/gpu/drm/vgem/vgem_drv.c > index fa54a6d1403d..ea0eecae5153 100644 > --- a/drivers/gpu/drm/vgem/vgem_drv.c > +++ b/drivers/gpu/drm/vgem/vgem_drv.c > @@ -397,8 +397,7 @@ static int vgem_prime_mmap(struct drm_gem_object *obj, > if (ret) > return ret; > > - fput(vma->vm_file); > - vma->vm_file = get_file(obj->filp); > + vma_set_file(vma, obj->filp); > vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; > vma->vm_page_prot = > pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); > > diff --git a/drivers/staging/android/ashmem.c > b/drivers/staging/android/ashmem.c > index 10b4be1f3e78..a51dc089896e 100644 > --- a/drivers/staging/android/ashmem.c > +++ b/drivers/staging/android/ashmem.c > @@ -450,9 +450,8 @@ static int ashmem_mmap(struct file *file, struct > vm_area_struct *vma) > vma_set_anonymous(vma); > } > > - if (vma->vm_file) > - fput(vma->vm_file); > - vma->vm_file = asma->file; > + vma_set_file(vma, asma->file); > + fput(asma->file); > > out: > mutex_unlock(&ashmem_mutex); > diff --git a/include/linux/mm.h b/include/linux/mm.h > index ca6e6a81576b..a558602afe1b 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -2693,6 +2693,8 @@ static inline void vma_set_page_prot(struct > vm_area_struct *vma) > } > #endif > > +struct file *vma_set_file(struct vm_area_struct *vma, struct file *file); > + > #ifdef CONFIG_NUMA_BALANCING > unsigned long change_prot_numa(struct vm_area_struct *vma, > unsigned long start, unsigned long end); > diff --git a/mm/mmap.c b/mm/mmap.c > index 40248d84ad5f..d3c3c510f643 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -136,6 +136,22 @@ void vma_set_page_prot(struct vm_area_struct *vma) > WRITE_ONCE(vma->vm_page_prot, vm_page_prot); > } > > +/* > + * Change backing file, only valid to use during initial VMA setup. > + */ > +struct file *vma_set_file(struct vm_area_struct *vma, struct file *file) > +{ > + if (file) > + get_file(file); > + > + swap(vma->vm_file, file); > + > + if (file) > + fput(file); > + > + return file; > +} > + > /* > * Requires inode->i_mapping->i_mmap_rwsem > */ > -- > 2.17.1 > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel