Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/shmem-helper: Use refcount_t for vmap_use_count
Use refcount_t helper for vmap_use_count to make refcounting consistent
with pages_use_count and pages_pin_count that use refcount_t. This also
makes vmapping to benefit from the refcount_t's overflow checks.
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.d>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250322212608.40511-11-dmitry.osipenko@collabora.com
+16
-20
+12
-16
drivers/gpu/drm/drm_gem_shmem_helper.c
+12
-16
drivers/gpu/drm/drm_gem_shmem_helper.c
···
165
165
} else {
166
166
dma_resv_lock(shmem->base.resv, NULL);
167
167
168
-
drm_WARN_ON(obj->dev, shmem->vmap_use_count);
168
+
drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count));
169
169
170
170
if (shmem->sgt) {
171
171
dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
···
355
355
356
356
dma_resv_assert_held(shmem->base.resv);
357
357
358
-
if (shmem->vmap_use_count++ > 0) {
358
+
if (refcount_inc_not_zero(&shmem->vmap_use_count)) {
359
359
iosys_map_set_vaddr(map, shmem->vaddr);
360
360
return 0;
361
361
}
362
362
363
363
ret = drm_gem_shmem_pin_locked(shmem);
364
364
if (ret)
365
-
goto err_zero_use;
365
+
return ret;
366
366
367
367
if (shmem->map_wc)
368
368
prot = pgprot_writecombine(prot);
369
369
shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
370
370
VM_MAP, prot);
371
-
if (!shmem->vaddr)
371
+
if (!shmem->vaddr) {
372
372
ret = -ENOMEM;
373
-
else
373
+
} else {
374
374
iosys_map_set_vaddr(map, shmem->vaddr);
375
+
refcount_set(&shmem->vmap_use_count, 1);
376
+
}
375
377
}
376
378
377
379
if (ret) {
···
386
384
err_put_pages:
387
385
if (!drm_gem_is_imported(obj))
388
386
drm_gem_shmem_unpin_locked(shmem);
389
-
err_zero_use:
390
-
shmem->vmap_use_count = 0;
391
387
392
388
return ret;
393
389
}
···
413
413
} else {
414
414
dma_resv_assert_held(shmem->base.resv);
415
415
416
-
if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))
417
-
return;
418
-
419
-
if (--shmem->vmap_use_count > 0)
420
-
return;
421
-
422
-
vunmap(shmem->vaddr);
423
-
drm_gem_shmem_unpin_locked(shmem);
416
+
if (refcount_dec_and_test(&shmem->vmap_use_count)) {
417
+
vunmap(shmem->vaddr);
418
+
drm_gem_shmem_unpin_locked(shmem);
419
+
}
424
420
}
425
421
426
422
shmem->vaddr = NULL;
···
668
672
669
673
drm_printf_indent(p, indent, "pages_pin_count=%u\n", refcount_read(&shmem->pages_pin_count));
670
674
drm_printf_indent(p, indent, "pages_use_count=%u\n", refcount_read(&shmem->pages_use_count));
671
-
drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
675
+
drm_printf_indent(p, indent, "vmap_use_count=%u\n", refcount_read(&shmem->vmap_use_count));
672
676
drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
673
677
}
674
678
EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info);
+3
-3
drivers/gpu/drm/tests/drm_gem_shmem_test.c
+3
-3
drivers/gpu/drm/tests/drm_gem_shmem_test.c
···
168
168
shmem = drm_gem_shmem_create(drm_dev, TEST_SIZE);
169
169
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, shmem);
170
170
KUNIT_EXPECT_NULL(test, shmem->vaddr);
171
-
KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
171
+
KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 0);
172
172
173
173
ret = kunit_add_action_or_reset(test, drm_gem_shmem_free_wrapper, shmem);
174
174
KUNIT_ASSERT_EQ(test, ret, 0);
···
177
177
KUNIT_ASSERT_EQ(test, ret, 0);
178
178
KUNIT_ASSERT_NOT_NULL(test, shmem->vaddr);
179
179
KUNIT_ASSERT_FALSE(test, iosys_map_is_null(&map));
180
-
KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 1);
180
+
KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 1);
181
181
182
182
iosys_map_memset(&map, 0, TEST_BYTE, TEST_SIZE);
183
183
for (i = 0; i < TEST_SIZE; i++)
···
185
185
186
186
drm_gem_shmem_vunmap_locked(shmem, &map);
187
187
KUNIT_EXPECT_NULL(test, shmem->vaddr);
188
-
KUNIT_EXPECT_EQ(test, shmem->vmap_use_count, 0);
188
+
KUNIT_EXPECT_EQ(test, refcount_read(&shmem->vmap_use_count), 0);
189
189
}
190
190
191
191
/*