From nobody Thu Feb 12 06:32:47 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84C41EEAA7B for ; Thu, 14 Sep 2023 23:29:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231135AbjINX3g (ORCPT ); Thu, 14 Sep 2023 19:29:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230506AbjINX3T (ORCPT ); Thu, 14 Sep 2023 19:29:19 -0400 Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CFC32738 for ; Thu, 14 Sep 2023 16:29:13 -0700 (PDT) Received: from workpc.. (109-252-153-31.dynamic.spd-mgts.ru [109.252.153.31]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by madras.collabora.co.uk (Postfix) with ESMTPSA id 18A936607358; Fri, 15 Sep 2023 00:29:11 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1694734152; bh=H4//Ufjdpiez8DbccVn6AG/tNaxHtIsDVyQbjhwP95k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NAQlPi7KeS+igUiEi/Xyrp4ykvqp34kPm2V/gfZSfw+V4ej4bIeMXFS5GxBbuKY9x vh2ais+pPNtCRH0EnQm0Do8a5WFFl1sXmYwl6R//WuZ0zdF70ZR9RGNSl59iFLv+J7 F8QLVIACwLUpK3AD+4nW0u4wb48pQxxOHsTbtQQNhUxGDw1VfNuTYpol8022xLHlwx 67STPwF0DANHhCrSZOWRUnBBSPD5fvK7CNRVS34B9MGClrwx/AZcYj2aQBhQE0tO/y SbCwnQdqG2qzgFo+uBKjpVmbdTSH5NFLggQTInoWRrhSRosKqzshedMy9jWRMJFcpb zjaV9+3VLjNuw== From: Dmitry Osipenko To: David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Daniel Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , =?UTF-8?q?Christian=20K=C3=B6nig?= , Qiang Yu , Steven Price , Boris Brezillon , Emma Anholt , Melissa Wen Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel@collabora.com, virtualization@lists.linux-foundation.org Subject: [PATCH v17 10/18] drm/shmem-helper: Use refcount_t for vmap_use_count Date: Fri, 15 Sep 2023 02:27:13 +0300 Message-ID: <20230914232721.408581-11-dmitry.osipenko@collabora.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230914232721.408581-1-dmitry.osipenko@collabora.com> References: <20230914232721.408581-1-dmitry.osipenko@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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. Reviewed-by: Boris Brezillon Suggested-by: Boris Brezillon Signed-off-by: Dmitry Osipenko --- drivers/gpu/drm/drm_gem_shmem_helper.c | 28 +++++++++++--------------- include/drm/drm_gem_shmem_helper.h | 2 +- 2 files changed, 13 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_g= em_shmem_helper.c index e33810450324..e1fcb5154209 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -144,7 +144,7 @@ void drm_gem_shmem_free(struct drm_gem_shmem_object *sh= mem) } else { dma_resv_lock(shmem->base.resv, NULL); =20 - drm_WARN_ON(obj->dev, shmem->vmap_use_count); + drm_WARN_ON(obj->dev, refcount_read(&shmem->vmap_use_count)); =20 if (shmem->sgt) { dma_unmap_sgtable(obj->dev->dev, shmem->sgt, @@ -343,23 +343,25 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_ob= ject *shmem, =20 dma_resv_assert_held(shmem->base.resv); =20 - if (shmem->vmap_use_count++ > 0) { + if (refcount_inc_not_zero(&shmem->vmap_use_count)) { iosys_map_set_vaddr(map, shmem->vaddr); return 0; } =20 ret =3D drm_gem_shmem_pin_locked(shmem); if (ret) - goto err_zero_use; + return ret; =20 if (shmem->map_wc) prot =3D pgprot_writecombine(prot); shmem->vaddr =3D vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, prot); - if (!shmem->vaddr) + if (!shmem->vaddr) { ret =3D -ENOMEM; - else + } else { iosys_map_set_vaddr(map, shmem->vaddr); + refcount_set(&shmem->vmap_use_count, 1); + } } =20 if (ret) { @@ -372,8 +374,6 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_obje= ct *shmem, err_put_pages: if (!obj->import_attach) drm_gem_shmem_unpin_locked(shmem); -err_zero_use: - shmem->vmap_use_count =3D 0; =20 return ret; } @@ -401,14 +401,10 @@ void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem= _object *shmem, } else { dma_resv_assert_held(shmem->base.resv); =20 - if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count)) - return; - - if (--shmem->vmap_use_count > 0) - return; - - vunmap(shmem->vaddr); - drm_gem_shmem_unpin_locked(shmem); + if (refcount_dec_and_test(&shmem->vmap_use_count)) { + vunmap(shmem->vaddr); + drm_gem_shmem_unpin_locked(shmem); + } } =20 shmem->vaddr =3D NULL; @@ -654,7 +650,7 @@ void drm_gem_shmem_print_info(const struct drm_gem_shme= m_object *shmem, =20 drm_printf_indent(p, indent, "pages_pin_count=3D%u\n", refcount_read(&shm= em->pages_pin_count)); drm_printf_indent(p, indent, "pages_use_count=3D%u\n", refcount_read(&shm= em->pages_use_count)); - drm_printf_indent(p, indent, "vmap_use_count=3D%u\n", shmem->vmap_use_cou= nt); + drm_printf_indent(p, indent, "vmap_use_count=3D%u\n", refcount_read(&shme= m->vmap_use_count)); drm_printf_indent(p, indent, "vaddr=3D%p\n", shmem->vaddr); } EXPORT_SYMBOL_GPL(drm_gem_shmem_print_info); diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem= _helper.h index 5b1ce7f7a39c..53dbd6a86edf 100644 --- a/include/drm/drm_gem_shmem_helper.h +++ b/include/drm/drm_gem_shmem_helper.h @@ -81,7 +81,7 @@ struct drm_gem_shmem_object { * Reference count on the virtual address. * The address are un-mapped when the count reaches zero. */ - unsigned int vmap_use_count; + refcount_t vmap_use_count; =20 /** * @pages_mark_dirty_on_put: --=20 2.41.0