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: sta...@vger.kernel.org
Cc: Ville Syrjala <ville.syrj...@linux.intel.com>
Cc: Vidya Srinivas <vidya.srini...@intel.com>
Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13487
Link: https://lore.kernel.org/lkml/20250116135636.410164-1-bgef...@google.com/
Fixes: 0b62af28f249 ("i915: convert shmem_sg_free_table() to use a folio_batch")
Signed-off-by: Brian Geffon <bgef...@google.com>
Suggested-by: Tomasz Figa <tf...@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

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