From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:33822 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbeFRMnO (ORCPT ); Mon, 18 Jun 2018 08:43:14 -0400 Received: by mail-wr0-f193.google.com with SMTP id a12-v6so16705362wro.1 for ; Mon, 18 Jun 2018 05:43:13 -0700 (PDT) Reply-To: christian.koenig@amd.com Subject: Re: [PATCH 3/5] dma-buf: lock the reservation object during (un)map_dma_buf To: Daniel Vetter Cc: linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org References: <20180601120020.11520-1-christian.koenig@amd.com> <20180601120020.11520-3-christian.koenig@amd.com> <20180618082224.GW3438@phenom.ffwll.local> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: <832d4f04-ced2-ce9f-723d-d611e8241e07@gmail.com> Date: Mon, 18 Jun 2018 14:43:11 +0200 MIME-Version: 1.0 In-Reply-To: <20180618082224.GW3438@phenom.ffwll.local> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-media-owner@vger.kernel.org List-ID: Am 18.06.2018 um 10:22 schrieb Daniel Vetter: > On Fri, Jun 01, 2018 at 02:00:18PM +0200, Christian König wrote: >> First step towards unpinned DMA buf operation. >> >> I've checked the DRM drivers to potential locking of the reservation >> object, but essentially we need to audit all implementations of the >> dma_buf _ops for this to work. >> >> Signed-off-by: Christian König > Agreed in principle, but I expect a fireworks show with just this patch > applied. It's not just that we need to audit all the implementations of > dma-buf-ops, we also need to audit all the callers. Ah, yeah of course a good point. > No idea yet how to go about merging this, but for a start might be good to > throw this at the intel-gfx CI (just Cc: the intel-gfx mailing lists, but > make sure your series applies without amd-staging-next stuff which isn't > in drm.git yet). Ok, going to incorporate all your other comments as well and then send the next round of this with CCing intel-gfx as well. Thanks for the review, Christian. > -Daniel > >> --- >> drivers/dma-buf/dma-buf.c | 4 ++++ >> include/linux/dma-buf.h | 4 ++++ >> 2 files changed, 8 insertions(+) >> >> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c >> index e4c657d9fad7..4f0708cb58a7 100644 >> --- a/drivers/dma-buf/dma-buf.c >> +++ b/drivers/dma-buf/dma-buf.c >> @@ -631,7 +631,9 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, >> if (WARN_ON(!attach || !attach->dmabuf)) >> return ERR_PTR(-EINVAL); >> >> + reservation_object_lock(attach->dmabuf->resv, NULL); >> sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction); >> + reservation_object_unlock(attach->dmabuf->resv); >> if (!sg_table) >> sg_table = ERR_PTR(-ENOMEM); >> >> @@ -658,8 +660,10 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, >> if (WARN_ON(!attach || !attach->dmabuf || !sg_table)) >> return; >> >> + reservation_object_lock(attach->dmabuf->resv, NULL); >> attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, >> direction); >> + reservation_object_unlock(attach->dmabuf->resv); >> } >> EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment); >> >> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h >> index d17cadd76802..d2ba7a027a78 100644 >> --- a/include/linux/dma-buf.h >> +++ b/include/linux/dma-buf.h >> @@ -118,6 +118,8 @@ struct dma_buf_ops { >> * any other kind of sharing that the exporter might wish to make >> * available to buffer-users. >> * >> + * This is called with the dmabuf->resv object locked. >> + * >> * Returns: >> * >> * A &sg_table scatter list of or the backing storage of the DMA buffer, >> @@ -138,6 +140,8 @@ struct dma_buf_ops { >> * It should also unpin the backing storage if this is the last mapping >> * of the DMA buffer, it the exporter supports backing storage >> * migration. >> + * >> + * This is called with the dmabuf->resv object locked. >> */ >> void (*unmap_dma_buf)(struct dma_buf_attachment *, >> struct sg_table *, >> -- >> 2.14.1 >> >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel