Re: [RFC][PATCH v3 13/33] timers: drm: Use timer_shutdown_sync() before freeing timer

Tvrtko Ursulin
2022-11-04T08:48:42Z

Hi,

On 04/11/2022 05:41, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> Before a timer is freed, timer_shutdown_sync() must be called.
>
> Link: https://lore.kernel.org/all/20220407161745.7d6754b3@gandalf.local.home/
>
> Cc: "Noralf Trønnes" <noralf@tronnes.org>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: dri-devel@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> drivers/gpu/drm/gud/gud_pipe.c | 2 +-
> drivers/gpu/drm/i915/i915_sw_fence.c | 2 +-

If it stays all DRM drivers in one patch then I guess it needs to go via
drm-misc, which for i915 would be okay I think in this case since patch
is extremely unlikely to clash with anything. Or split it up per driver
and then we can handle it in drm-intel-next once core functionality is in.

We do however have some more calls to del_timer_sync, where freeing is
perhaps not immediately next to the site in code, but things definitely
get freed like on module unload. Would we need to convert all of them to
avoid some, presumably new, warnings?

Regards,

Tvrtko

> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
> index 7c6dc2bcd14a..08429bdd57cf 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -272,7 +272,7 @@ static int gud_usb_bulk(struct gud_device *gdrm, size_t len)
>
> usb_sg_wait(&ctx.sgr);
>
> - if (!del_timer_sync(&ctx.timer))
> + if (!timer_shutdown_sync(&ctx.timer))
> ret = -ETIMEDOUT;
> else if (ctx.sgr.status < 0)
> ret = ctx.sgr.status;
> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c
> index 6fc0d1b89690..bfaa9a67dc35 100644
> --- a/drivers/gpu/drm/i915/i915_sw_fence.c
> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c
> @@ -465,7 +465,7 @@ static void irq_i915_sw_fence_work(struct irq_work *wrk)
> struct i915_sw_dma_fence_cb_timer *cb =
> container_of(wrk, typeof(*cb), work);
>
> - del_timer_sync(&cb->timer);
> + timer_shutdown_sync(&cb->timer);
> dma_fence_put(cb->dma);
>
> kfree_rcu(cb, rcu);