[PATCH v2] drm/i915: Fix page cleanup on DMA remap failure
Brian Geffon
bgeffon at google.com
Fri Jan 24 15:19:47 UTC 2025
On Wed, Jan 22, 2025 at 10:07 PM Srinivas, Vidya
<vidya.srinivas at intel.com> wrote:
>
> Hello Brian, Many thanks for the fix. I am adding my tested-by.
> Tested-by: Vidya Srinivas <vidya.srinivas at intel.com>
Thanks for testing Vidya.
Can we get a maintainer to take a look?
>
>
> > -----Original Message-----
> > From: Brian Geffon <bgeffon at google.com>
> > Sent: 16 January 2025 21:24
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Wilson, Chris P <chris.p.wilson at intel.com>; Saarinen, Jani
> > <jani.saarinen at intel.com>; Mistat, Tomasz <tomasz.mistat at intel.com>;
> > Srinivas, Vidya <vidya.srinivas at intel.com>; ville.syrjala at linux.intel.com;
> > jani.nikula at linux.intel.com; linux-kernel at vger.kernel.org; dri-
> > devel at lists.freedesktop.org; Joonas Lahtinen
> > <joonas.lahtinen at linux.intel.com>; Brian Geffon <bgeffon at google.com>;
> > stable at vger.kernel.org; Tomasz Figa <tfiga at google.com>
> > Subject: [PATCH v2] drm/i915: Fix page cleanup on DMA remap failure
> >
> > When converting to folios the cleanup path of shmem_get_pages() was
> > missed. When a DMA remap fails and the max segment size is greater than
> > PAGE_SIZE it will attempt to retry the remap with a PAGE_SIZEd segment size.
> > The cleanup code isn't properly using the folio apis and as a result isn't
> > handling compound pages correctly.
> >
> > v1 -> v2:
> > (Ville) Fixed locations where we were not clearing mapping unevictable.
> >
> > Cc: stable at vger.kernel.org
> > Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
> > Cc: Vidya Srinivas <vidya.srinivas at intel.com>
> > Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13487
> > Link: https://lore.kernel.org/lkml/20250116135636.410164-1-
> > bgeffon at google.com/
> > Fixes: 0b62af28f249 ("i915: convert shmem_sg_free_table() to use a
> > folio_batch")
> > Signed-off-by: Brian Geffon <bgeffon at google.com>
> > Suggested-by: Tomasz Figa <tfiga at google.com>
> > ---
> > drivers/gpu/drm/i915/gem/i915_gem_object.h | 3 +--
> > drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 23 +++++++++-------------
> > drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 7 ++++---
> > 3 files changed, 14 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > index 3dc61cbd2e11..0f122a12d4a5 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > @@ -843,8 +843,7 @@ int shmem_sg_alloc_table(struct drm_i915_private
> > *i915, struct sg_table *st,
> > size_t size, struct intel_memory_region *mr,
> > struct address_space *mapping,
> > unsigned int max_segment);
> > -void shmem_sg_free_table(struct sg_table *st, struct address_space
> > *mapping,
> > - bool dirty, bool backup);
> > +void shmem_sg_free_table(struct sg_table *st, bool dirty, bool backup);
> > void __shmem_writeback(size_t size, struct address_space *mapping);
> >
> > #ifdef CONFIG_MMU_NOTIFIER
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> > b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> > index fe69f2c8527d..b320d9dfd6d3 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> > @@ -29,16 +29,13 @@ static void check_release_folio_batch(struct
> > folio_batch *fbatch)
> > cond_resched();
> > }
> >
> > -void shmem_sg_free_table(struct sg_table *st, struct address_space
> > *mapping,
> > - bool dirty, bool backup)
> > +void shmem_sg_free_table(struct sg_table *st, bool dirty, bool backup)
> > {
> > struct sgt_iter sgt_iter;
> > struct folio_batch fbatch;
> > struct folio *last = NULL;
> > struct page *page;
> >
> > - mapping_clear_unevictable(mapping);
> > -
> > folio_batch_init(&fbatch);
> > for_each_sgt_page(page, sgt_iter, st) {
> > struct folio *folio = page_folio(page); @@ -180,10 +177,10
> > @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table
> > *st,
> > return 0;
> > err_sg:
> > sg_mark_end(sg);
> > + mapping_clear_unevictable(mapping);
> > if (sg != st->sgl) {
> > - shmem_sg_free_table(st, mapping, false, false);
> > + shmem_sg_free_table(st, false, false);
> > } else {
> > - mapping_clear_unevictable(mapping);
> > sg_free_table(st);
> > }
> >
> > @@ -209,8 +206,6 @@ static int shmem_get_pages(struct
> > drm_i915_gem_object *obj)
> > struct address_space *mapping = obj->base.filp->f_mapping;
> > unsigned int max_segment = i915_sg_segment_size(i915->drm.dev);
> > struct sg_table *st;
> > - struct sgt_iter sgt_iter;
> > - struct page *page;
> > int ret;
> >
> > /*
> > @@ -239,9 +234,8 @@ static int shmem_get_pages(struct
> > drm_i915_gem_object *obj)
> > * for PAGE_SIZE chunks instead may be helpful.
> > */
> > if (max_segment > PAGE_SIZE) {
> > - for_each_sgt_page(page, sgt_iter, st)
> > - put_page(page);
> > - sg_free_table(st);
> > + /* Leave the mapping unevictable while we retry */
> > + shmem_sg_free_table(st, false, false);
> > kfree(st);
> >
> > max_segment = PAGE_SIZE;
> > @@ -265,7 +259,8 @@ static int shmem_get_pages(struct
> > drm_i915_gem_object *obj)
> > return 0;
> >
> > err_pages:
> > - shmem_sg_free_table(st, mapping, false, false);
> > + mapping_clear_unevictable(mapping);
> > + shmem_sg_free_table(st, false, false);
> > /*
> > * shmemfs first checks if there is enough memory to allocate the
> > page
> > * and reports ENOSPC should there be insufficient, along with the
> > usual @@ -402,8 +397,8 @@ void
> > i915_gem_object_put_pages_shmem(struct drm_i915_gem_object *obj,
> > struct sg_
> > if (i915_gem_object_needs_bit17_swizzle(obj))
> > i915_gem_object_save_bit_17_swizzle(obj, pages);
> >
> > - shmem_sg_free_table(pages, file_inode(obj->base.filp)->i_mapping,
> > - obj->mm.dirty, obj->mm.madv ==
> > I915_MADV_WILLNEED);
> > + mapping_clear_unevictable(file_inode(obj->base.filp)->i_mapping);
> > + shmem_sg_free_table(pages, obj->mm.dirty, obj->mm.madv ==
> > +I915_MADV_WILLNEED);
> > kfree(pages);
> > obj->mm.dirty = false;
> > }
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > index 10d8673641f7..37f51a04b838 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> > @@ -232,7 +232,8 @@ static int i915_ttm_tt_shmem_populate(struct
> > ttm_device *bdev,
> > return 0;
> >
> > err_free_st:
> > - shmem_sg_free_table(st, filp->f_mapping, false, false);
> > + mapping_clear_unevictable(filp->f_mapping);
> > + shmem_sg_free_table(st, false, false);
> >
> > return err;
> > }
> > @@ -243,8 +244,8 @@ static void i915_ttm_tt_shmem_unpopulate(struct
> > ttm_tt *ttm)
> > bool backup = ttm->page_flags & TTM_TT_FLAG_SWAPPED;
> > struct sg_table *st = &i915_tt->cached_rsgt.table;
> >
> > - shmem_sg_free_table(st, file_inode(i915_tt->filp)->i_mapping,
> > - backup, backup);
> > + mapping_clear_unevictable(file_inode(i915_tt->filp)->i_mapping);
> > + shmem_sg_free_table(st, backup, backup);
> > }
> >
> > static void i915_ttm_tt_release(struct kref *ref)
> > --
> > 2.48.0.rc2.279.g1de40edade-goog
>
Thanks
Brian
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