From mboxrd@z Thu Jan 1 00:00:00 1970 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 BD7CBC4167D for ; Fri, 10 Nov 2023 19:34:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345649AbjKJTeX (ORCPT ); Fri, 10 Nov 2023 14:34:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235940AbjKJTds (ORCPT ); Fri, 10 Nov 2023 14:33:48 -0500 Received: from madras.collabora.co.uk (madras.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e5ab]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B61DC2F340 for ; Fri, 10 Nov 2023 03:21:18 -0800 (PST) Received: from localhost (cola.collaboradmins.com [195.201.22.229]) (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: bbrezillon) by madras.collabora.co.uk (Postfix) with ESMTPSA id D191566071D4; Fri, 10 Nov 2023 11:21:16 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1699615277; bh=XlfK0cZ7e+Elesjbsv7sYANR5q9yqJ5B618x/9UvH3Q=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=IRny5HLJNiTBhTGDIjtZeuCwFe1yGtc4lvqLWqckDIK96IB/m5VeNHQmz5h4yQXxA wecs4KRjKDkzteQ7tmeB23cGyzwj6c+AALTMZD6b2QvN9qlpYZRj4PRcYWZB9YoRRZ UexE5wpqJ0QTgpc8bDp55N/UoV38RKw7zqHigRY8/HYiWwaT/6xDCoQHgAZ3cipN6y IRi3a1RUtFItBvvFMDu4vLIflbHlTuX9uTWrN8hTO8mcjZDoH6Jkt8ngBs021YJlWx VTrVVX+zYfbfmpu794HTLRHYQ46kivXAK+aB29MCrJsfdqWs9qUkogmzFiOCVmsPqY LRM5ZL3bBTvCA== Date: Fri, 10 Nov 2023 12:21:12 +0100 From: Boris Brezillon To: Danilo Krummrich Cc: airlied@gmail.com, daniel@ffwll.ch, matthew.brost@intel.com, thomas.hellstrom@linux.intel.com, sarah.walker@imgtec.com, donald.robson@imgtec.com, christian.koenig@amd.com, faith@gfxstrand.net, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH drm-misc-next v9 09/12] drm/gpuvm: reference count drm_gpuvm structures Message-ID: <20231110122112.4aeb2b39@collabora.com> In-Reply-To: <20231108001259.15123-10-dakr@redhat.com> References: <20231108001259.15123-1-dakr@redhat.com> <20231108001259.15123-10-dakr@redhat.com> Organization: Collabora X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 8 Nov 2023 01:12:39 +0100 Danilo Krummrich wrote: > Implement reference counting for struct drm_gpuvm. > > Signed-off-by: Danilo Krummrich Reviewed-by: Boris Brezillon > --- > drivers/gpu/drm/drm_gpuvm.c | 56 +++++++++++++++++++++----- > drivers/gpu/drm/nouveau/nouveau_uvmm.c | 20 ++++++--- > include/drm/drm_gpuvm.h | 31 +++++++++++++- > 3 files changed, 90 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gpuvm.c b/drivers/gpu/drm/drm_gpuvm.c > index 53e2c406fb04..ef968eba6fe6 100644 > --- a/drivers/gpu/drm/drm_gpuvm.c > +++ b/drivers/gpu/drm/drm_gpuvm.c > @@ -746,6 +746,8 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name, > gpuvm->rb.tree = RB_ROOT_CACHED; > INIT_LIST_HEAD(&gpuvm->rb.list); > > + kref_init(&gpuvm->kref); > + > gpuvm->name = name ? name : "unknown"; > gpuvm->flags = flags; > gpuvm->ops = ops; > @@ -770,15 +772,8 @@ drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name, > } > EXPORT_SYMBOL_GPL(drm_gpuvm_init); > > -/** > - * drm_gpuvm_destroy() - cleanup a &drm_gpuvm > - * @gpuvm: pointer to the &drm_gpuvm to clean up > - * > - * Note that it is a bug to call this function on a manager that still > - * holds GPU VA mappings. > - */ > -void > -drm_gpuvm_destroy(struct drm_gpuvm *gpuvm) > +static void > +drm_gpuvm_fini(struct drm_gpuvm *gpuvm) > { > gpuvm->name = NULL; > > @@ -790,7 +785,35 @@ drm_gpuvm_destroy(struct drm_gpuvm *gpuvm) > > drm_gem_object_put(gpuvm->r_obj); > } > -EXPORT_SYMBOL_GPL(drm_gpuvm_destroy); > + > +static void > +drm_gpuvm_free(struct kref *kref) > +{ > + struct drm_gpuvm *gpuvm = container_of(kref, struct drm_gpuvm, kref); > + > + drm_gpuvm_fini(gpuvm); > + > + if (drm_WARN_ON(gpuvm->drm, !gpuvm->ops->vm_free)) > + return; > + > + gpuvm->ops->vm_free(gpuvm); > +} > + > +/** > + * drm_gpuvm_put() - drop a struct drm_gpuvm reference > + * @gpuvm: the &drm_gpuvm to release the reference of > + * > + * This releases a reference to @gpuvm. > + * > + * This function may be called from atomic context. > + */ > +void > +drm_gpuvm_put(struct drm_gpuvm *gpuvm) > +{ > + if (gpuvm) > + kref_put(&gpuvm->kref, drm_gpuvm_free); > +} > +EXPORT_SYMBOL_GPL(drm_gpuvm_put); > > static int > __drm_gpuva_insert(struct drm_gpuvm *gpuvm, > @@ -839,11 +862,21 @@ drm_gpuva_insert(struct drm_gpuvm *gpuvm, > { > u64 addr = va->va.addr; > u64 range = va->va.range; > + int ret; > > if (unlikely(!drm_gpuvm_range_valid(gpuvm, addr, range))) > return -EINVAL; > > - return __drm_gpuva_insert(gpuvm, va); > + ret = __drm_gpuva_insert(gpuvm, va); > + if (likely(!ret)) > + /* Take a reference of the GPUVM for the successfully inserted > + * drm_gpuva. We can't take the reference in > + * __drm_gpuva_insert() itself, since we don't want to increse > + * the reference count for the GPUVM's kernel_alloc_node. > + */ > + drm_gpuvm_get(gpuvm); > + > + return ret; > } > EXPORT_SYMBOL_GPL(drm_gpuva_insert); > > @@ -876,6 +909,7 @@ drm_gpuva_remove(struct drm_gpuva *va) > } > > __drm_gpuva_remove(va); > + drm_gpuvm_put(va->vm); > } > EXPORT_SYMBOL_GPL(drm_gpuva_remove); > > diff --git a/drivers/gpu/drm/nouveau/nouveau_uvmm.c b/drivers/gpu/drm/nouveau/nouveau_uvmm.c > index 54be12c1272f..cb2f06565c46 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_uvmm.c > +++ b/drivers/gpu/drm/nouveau/nouveau_uvmm.c > @@ -1780,6 +1780,18 @@ nouveau_uvmm_bo_unmap_all(struct nouveau_bo *nvbo) > } > } > > +static void > +nouveau_uvmm_free(struct drm_gpuvm *gpuvm) > +{ > + struct nouveau_uvmm *uvmm = uvmm_from_gpuvm(gpuvm); > + > + kfree(uvmm); > +} > + > +static const struct drm_gpuvm_ops gpuvm_ops = { > + .vm_free = nouveau_uvmm_free, > +}; > + > int > nouveau_uvmm_ioctl_vm_init(struct drm_device *dev, > void *data, > @@ -1830,7 +1842,7 @@ nouveau_uvmm_ioctl_vm_init(struct drm_device *dev, > NOUVEAU_VA_SPACE_END, > init->kernel_managed_addr, > init->kernel_managed_size, > - NULL); > + &gpuvm_ops); > /* GPUVM takes care from here on. */ > drm_gem_object_put(r_obj); > > @@ -1849,8 +1861,7 @@ nouveau_uvmm_ioctl_vm_init(struct drm_device *dev, > return 0; > > out_gpuvm_fini: > - drm_gpuvm_destroy(&uvmm->base); > - kfree(uvmm); > + drm_gpuvm_put(&uvmm->base); > out_unlock: > mutex_unlock(&cli->mutex); > return ret; > @@ -1902,7 +1913,6 @@ nouveau_uvmm_fini(struct nouveau_uvmm *uvmm) > > mutex_lock(&cli->mutex); > nouveau_vmm_fini(&uvmm->vmm); > - drm_gpuvm_destroy(&uvmm->base); > - kfree(uvmm); > + drm_gpuvm_put(&uvmm->base); > mutex_unlock(&cli->mutex); > } > diff --git a/include/drm/drm_gpuvm.h b/include/drm/drm_gpuvm.h > index 0c2e24155a93..4e6e1fd3485a 100644 > --- a/include/drm/drm_gpuvm.h > +++ b/include/drm/drm_gpuvm.h > @@ -247,6 +247,11 @@ struct drm_gpuvm { > struct list_head list; > } rb; > > + /** > + * @kref: reference count of this object > + */ > + struct kref kref; > + > /** > * @kernel_alloc_node: > * > @@ -273,7 +278,23 @@ void drm_gpuvm_init(struct drm_gpuvm *gpuvm, const char *name, > u64 start_offset, u64 range, > u64 reserve_offset, u64 reserve_range, > const struct drm_gpuvm_ops *ops); > -void drm_gpuvm_destroy(struct drm_gpuvm *gpuvm); > + > +/** > + * drm_gpuvm_get() - acquire a struct drm_gpuvm reference > + * @gpuvm: the &drm_gpuvm to acquire the reference of > + * > + * This function acquires an additional reference to @gpuvm. It is illegal to > + * call this without already holding a reference. No locks required. > + */ > +static inline struct drm_gpuvm * > +drm_gpuvm_get(struct drm_gpuvm *gpuvm) > +{ > + kref_get(&gpuvm->kref); > + > + return gpuvm; > +} > + > +void drm_gpuvm_put(struct drm_gpuvm *gpuvm); > > bool drm_gpuvm_range_valid(struct drm_gpuvm *gpuvm, u64 addr, u64 range); > bool drm_gpuvm_interval_empty(struct drm_gpuvm *gpuvm, u64 addr, u64 range); > @@ -673,6 +694,14 @@ static inline void drm_gpuva_init_from_op(struct drm_gpuva *va, > * operations to drivers. > */ > struct drm_gpuvm_ops { > + /** > + * @vm_free: called when the last reference of a struct drm_gpuvm is > + * dropped > + * > + * This callback is mandatory. > + */ > + void (*vm_free)(struct drm_gpuvm *gpuvm); > + > /** > * @op_alloc: called when the &drm_gpuvm allocates > * a struct drm_gpuva_op