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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 632DDCA0EFF for ; Fri, 22 Aug 2025 15:14:02 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B147C10EB4E; Fri, 22 Aug 2025 15:14:01 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="b+htDaSY"; dkim-atps=neutral Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) by gabe.freedesktop.org (Postfix) with ESMTPS id 53DFF10EB4E for ; Fri, 22 Aug 2025 15:14:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1755875639; bh=FIVbq4h9WopdJU4m06foToyWvVTvEx6P7jg4PSWPJRM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=b+htDaSYseZPw2jdj8Gl9gayh6d+xlBkzmu1rEwgIieuwejFAUeK2vuNU48UDQFec RfCANnZkGgEHQfeVPSi1YFYyD0E+UCbP6ieyf95vMRJJIASYMQiKhCH+feVC7nM5W9 J93be6Mi2SaWNoCcPzGL9Q2dR2mpKAHaegXpk+w64+Aeyg6MPG1Fs/Jayvmlp7MIqu OtaZImw21Z/wN/Xqoq1Zl0QCx2yBbyVCLpu9BQtqhNM3aViqVT6m63L/b/XKbkPtFY pddchMhYr+RcePnPe8kpulSakkHmdXtwEB2zY7UVexY287p2zfTW6860WATHbCbux6 Q0acT7kGCGu0Q== Received: from fedora (unknown [IPv6:2a01:e0a:2c:6930:d919:a6e:5ea1:8a9f]) (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 bali.collaboradmins.com (Postfix) with ESMTPSA id C5FAD17E12DF; Fri, 22 Aug 2025 17:13:58 +0200 (CEST) Date: Fri, 22 Aug 2025 17:13:54 +0200 From: Boris Brezillon To: Faith Ekstrand Cc: dri-devel@lists.freedesktop.org, Faith Ekstrand Subject: Re: [PATCH 1/7] drm/shmem: Add a drm_gem_shmem_sync_mmap() helper Message-ID: <20250822171354.3c125883@fedora> In-Reply-To: <20250822142954.902402-2-faith.ekstrand@collabora.com> References: <20250822142954.902402-1-faith.ekstrand@collabora.com> <20250822142954.902402-2-faith.ekstrand@collabora.com> Organization: Collabora X-Mailer: Claws Mail 4.3.1 (GTK 3.24.49; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Fri, 22 Aug 2025 10:29:10 -0400 Faith Ekstrand wrote: > This enables syncing mapped GEM objects between the CPU and GPU via calls > to dma_sync_*(). It's a bit annoying as it requires walking the sg_table > so it's best if every driver doesn't hand-roll it. > > Signed-off-by: Faith Ekstrand > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 64 ++++++++++++++++++++++++++ > include/drm/drm_gem_shmem_helper.h | 3 ++ > 2 files changed, 67 insertions(+) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 8ac0b1fa5287..50907c1fa11f 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -658,6 +658,70 @@ int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct > } > EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap); > > +/** > + * drm_gem_shmem_sync_mmap - Sync memor-mapped data to/from the device ^ CPU-mapped > + * @shmem: shmem GEM object > + * @offset: Offset into the GEM object > + * @size: Size of the area to sync > + * > + * Returns: > + * 0 on success or a negative error code on failure. > + */ > +int > +drm_gem_shmem_sync_mmap(struct drm_gem_shmem_object *shmem, > + size_t offset, size_t size, > + enum dma_data_direction dir) Feels weird to name this function sync_mmap when all it's being passed is a region is a GEM, not a virtual address in the process address space. I can also imagine this helper being used for kernel-mapped BOs, making _mmap a bit of a lie. Maybe we should just go for _sync() or _sync_cpu(). > +{ > + struct drm_device *dev = shmem->base.dev; > + struct sg_table *sgt; > + struct scatterlist *sgl; > + unsigned int count; > + > + if (dir == DMA_NONE) > + return 0; > + > + /* Don't bother if it's WC-mapped */ > + if (shmem->map_wc) > + return 0; > + > + if (size == 0) > + return 0; > + > + if (offset + size < offset || offset + size > shmem->base.size) > + return -EINVAL; > + > + sgt = drm_gem_shmem_get_pages_sgt(shmem); > + if (IS_ERR(sgt)) > + return PTR_ERR(sgt); > + > + for_each_sgtable_dma_sg(sgt, sgl, count) { > + if (size == 0) > + break; > + > + dma_addr_t paddr = sg_dma_address(sgl); > + size_t len = sg_dma_len(sgl); > + > + if (len <= offset) { > + offset -= len; > + continue; > + } > + > + paddr += offset; > + len -= offset; > + len = min_t(size_t, len, size); > + size -= len; > + offset = 0; > + > + if (dir == DMA_FROM_DEVICE) > + dma_sync_single_for_cpu(dev->dev, paddr, len, dir); > + else > + dma_sync_single_for_device(dev->dev, paddr, len, dir); > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(drm_gem_shmem_sync_mmap); > + > /** > * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs > * @shmem: shmem GEM object > diff --git a/include/drm/drm_gem_shmem_helper.h b/include/drm/drm_gem_shmem_helper.h > index 92f5db84b9c2..8e057a8e6c83 100644 > --- a/include/drm/drm_gem_shmem_helper.h > +++ b/include/drm/drm_gem_shmem_helper.h > @@ -121,6 +121,9 @@ int drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem, > void drm_gem_shmem_vunmap_locked(struct drm_gem_shmem_object *shmem, > struct iosys_map *map); > int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma); > +int drm_gem_shmem_sync_mmap(struct drm_gem_shmem_object *shmem, > + size_t offset, size_t size, > + enum dma_data_direction dir); > > int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem); > void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem);