From: "Danilo Krummrich" <dakr@kernel.org>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: <christian.koenig@amd.com>, <thomas.hellstrom@linux.intel.com>,
<ecourtney@nvidia.com>, <simona@ffwll.ch>,
<matthew.brost@intel.com>, <nat@pixelcluster.dev>,
<airlied@gmail.com>, <dri-devel@lists.freedesktop.org>,
<linux-kernel@vger.kernel.org>, <intel-gfx@lists.freedesktop.org>,
<intel-xe@lists.freedesktop.org>, <amd-gfx@lists.freedesktop.org>
Subject: Re: [PATCH 09/12] drm/ttm: nuke buffer refcounting
Date: Sat, 11 Jul 2026 15:26:18 +0200 [thread overview]
Message-ID: <DJVRYBLM3B94.MAUO8T8NXM5P@kernel.org> (raw)
In-Reply-To: <20260710190752.2355-10-christian.koenig@amd.com>
On Fri Jul 10, 2026 at 8:52 PM CEST, =?UTF-8?q?Christian=20K=C3=B6nig?= wrote:
> +/**
> + * ttm_bo_is_deleted - test if buffer is already deleted
> + * @bo: the struct ttm_buffer_object to test
> + *
> + * Returns true if the buffer is already deleted and only waiting for
> + * destruction.
> + */
> +static inline bool ttm_bo_is_deleted(struct ttm_buffer_object *bo)
> +{
> + return !kref_read(&bo->base.refcount);
> +}
This is an anti-pattern, branch decisions cannot rely on an atomic reference
count unless additional invariants are upheld that otherwise guarantee that the
read values does not instantly become meaningless.
Something like this should at least document in which context and under which
conditions it is valid to rely on the returned value.
next prev parent reply other threads:[~2026-07-11 13:26 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-10 18:52 Refcounting dma_resv and using that for drm_exec support in TTM Christian König
2026-07-10 18:52 ` [PATCH 01/12] dma-buf: Add reference counting to dma_resv Christian König
2026-07-11 1:27 ` Matthew Brost
2026-07-11 13:10 ` Danilo Krummrich
2026-07-10 18:52 ` [PATCH 02/12] dma-buf/tests: Convert st-dma-resv tests to use dma_resv_alloc Christian König
2026-07-10 18:52 ` [PATCH 03/12] drm/gem: Add helper for drm_gem_object resv assignment Christian König
2026-07-10 18:52 ` [PATCH 04/12] drm/ttm: Switch LRU cursor to track dma_resv instead of buffer objects Christian König
2026-07-10 18:52 ` [PATCH 05/12] drm/ttm: switch to ttm_bo_lru_for_each_reserved_guarded for swapout Christian König
2026-07-10 18:52 ` [PATCH 06/12] drm/ttm: move delete handling into ttm_bo_evict Christian König
2026-07-10 18:52 ` [PATCH 07/12] drm/ttm: use ttm_bo_lru_for_each_reserved_guarded in evict_all Christian König
2026-07-10 18:52 ` [PATCH 08/12] drm/ttm: use dma_resv reference in ttm_device_clear_lru_dma_mappings Christian König
2026-07-10 18:52 ` [PATCH 09/12] drm/ttm: nuke buffer refcounting Christian König
2026-07-11 13:26 ` Danilo Krummrich [this message]
2026-07-10 18:52 ` [PATCH 10/12] drm/exec: add drm_exec_lock_resv function Christian König
2026-07-10 18:52 ` [PATCH 11/12] drm/ttm: support using drm_exec during eviction v4 Christian König
2026-07-10 18:52 ` [PATCH 12/12] drm/amdgpu: use drm_exec during BO validation Christian König
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=DJVRYBLM3B94.MAUO8T8NXM5P@kernel.org \
--to=dakr@kernel.org \
--cc=airlied@gmail.com \
--cc=amd-gfx@lists.freedesktop.org \
--cc=christian.koenig@amd.com \
--cc=ckoenig.leichtzumerken@gmail.com \
--cc=dri-devel@lists.freedesktop.org \
--cc=ecourtney@nvidia.com \
--cc=intel-gfx@lists.freedesktop.org \
--cc=intel-xe@lists.freedesktop.org \
--cc=linux-kernel@vger.kernel.org \
--cc=matthew.brost@intel.com \
--cc=nat@pixelcluster.dev \
--cc=simona@ffwll.ch \
--cc=thomas.hellstrom@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox