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From: Jason Ekstrand <jason@jlekstrand.net>
To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org
Cc: Jason Ekstrand <jason@jlekstrand.net>
Subject: [PATCH 31/31] drm/i915: Drop some RCU usage around context VMs
Date: Tue,  8 Jun 2021 23:36:13 -0500	[thread overview]
Message-ID: <20210609043613.102962-32-jason@jlekstrand.net> (raw)
In-Reply-To: <20210609043613.102962-1-jason@jlekstrand.net>

This instance now only happens during context creation so there's no way
we can race with a context close/destroy.  We don't need to bother with
the RCU and can access the pointer directly.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
---
 drivers/gpu/drm/i915/gem/i915_gem_context.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c
index 5312142daa0c0..ffdfed536ce9a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
@@ -787,15 +787,12 @@ static int intel_context_set_gem(struct intel_context *ce,
 
 	ce->ring_size = SZ_16K;
 
-	if (rcu_access_pointer(ctx->vm)) {
-		struct i915_address_space *vm;
-
-		rcu_read_lock();
-		vm = context_get_vm_rcu(ctx); /* hmm */
-		rcu_read_unlock();
-
+	if (ctx->vm) {
+		/* This only happens during context creation so no need to
+		 * bother with any RCU nonsense.
+		 */
 		i915_vm_put(ce->vm);
-		ce->vm = vm;
+		ce->vm = i915_vm_get(ctx->vm);
 	}
 
 	if (ctx->sched.priority >= I915_PRIORITY_NORMAL &&
-- 
2.31.1


  parent reply	other threads:[~2021-06-09  4:37 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-09  4:35 [PATCH 00/31] drm/i915/gem: ioctl clean-ups (v6) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 01/31] drm/i915: Drop I915_CONTEXT_PARAM_RINGSIZE Jason Ekstrand
2021-06-09  4:35 ` [PATCH 02/31] drm/i915: Stop storing the ring size in the ring pointer (v2) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 03/31] drm/i915: Drop I915_CONTEXT_PARAM_NO_ZEROMAP Jason Ekstrand
2021-06-09  4:35 ` [PATCH 04/31] drm/i915/gem: Set the watchdog timeout directly in intel_context_set_gem (v2) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 05/31] drm/i915/gem: Return void from context_apply_all Jason Ekstrand
2021-06-09  4:35 ` [PATCH 06/31] drm/i915: Drop the CONTEXT_CLONE API (v2) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 07/31] drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 08/31] drm/i915: Drop getparam support for I915_CONTEXT_PARAM_ENGINES Jason Ekstrand
2021-06-09  4:35 ` [PATCH 09/31] drm/i915/gem: Disallow bonding of virtual engines (v3) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 10/31] drm/i915/gem: Remove engine auto-magic with FENCE_SUBMIT (v2) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 11/31] drm/i915/request: Remove the hook from await_execution Jason Ekstrand
2021-06-09  4:35 ` [PATCH 12/31] drm/i915/gem: Disallow creating contexts with too many engines Jason Ekstrand
2021-06-09  4:35 ` [PATCH 13/31] drm/i915: Stop manually RCU banging in reset_stats_ioctl (v2) Jason Ekstrand
2021-06-09  4:35 ` [PATCH 14/31] drm/i915/gem: Add a separate validate_priority helper Jason Ekstrand
2021-06-09  4:35 ` [PATCH 15/31] drm/i915: Add gem/i915_gem_context.h to the docs Jason Ekstrand
2021-06-09  4:35 ` [PATCH 16/31] drm/i915/gem: Add an intermediate proto_context struct (v4) Jason Ekstrand
2021-06-09 11:28   ` [Intel-gfx] " Daniel Vetter
2021-06-09 16:00     ` Jason Ekstrand
2021-06-10 16:44       ` Daniel Vetter
2021-06-10 16:53         ` Jason Ekstrand
2021-06-09  4:35 ` [PATCH 17/31] drm/i915/gem: Rework error handling in default_engines Jason Ekstrand
2021-06-09  4:36 ` [PATCH 18/31] drm/i915/gem: Optionally set SSEU in intel_context_set_gem Jason Ekstrand
2021-06-09  4:36 ` [PATCH 19/31] drm/i915: Add an i915_gem_vm_lookup helper Jason Ekstrand
2021-06-09  4:36 ` [PATCH 20/31] drm/i915/gem: Make an alignment check more sensible Jason Ekstrand
2021-06-09  4:36 ` [PATCH 21/31] drm/i915/gem: Use the proto-context to handle create parameters (v3) Jason Ekstrand
2021-06-09  4:36 ` [PATCH 22/31] drm/i915/gem: Return an error ptr from context_lookup Jason Ekstrand
2021-06-09  4:36 ` [PATCH 23/31] drm/i915/gt: Drop i915_address_space::file (v2) Jason Ekstrand
2021-06-09  4:36 ` [PATCH 24/31] drm/i915/gem: Delay context creation (v2) Jason Ekstrand
2021-06-09  8:25   ` [Intel-gfx] " kernel test robot
2021-06-09 11:38   ` kernel test robot
2021-06-09 11:44   ` kernel test robot
2021-06-09  4:36 ` [PATCH 25/31] drm/i915/gem: Don't allow changing the VM on running contexts (v2) Jason Ekstrand
2021-06-09  7:39   ` [Intel-gfx] " kernel test robot
2021-06-09 11:34   ` Daniel Vetter
2021-06-09 11:34     ` Daniel Vetter
2021-06-09 16:06     ` Jason Ekstrand
2021-06-09  4:36 ` [PATCH 26/31] drm/i915/gem: Don't allow changing the engine set " Jason Ekstrand
2021-06-09  4:36 ` [PATCH 27/31] drm/i915/selftests: Take a VM in kernel_context() Jason Ekstrand
2021-06-09  4:36 ` [PATCH 28/31] i915/gem/selftests: Assign the VM at context creation in igt_shared_ctx_exec Jason Ekstrand
2021-06-09  4:36 ` [PATCH 29/31] drm/i915/gem: Roll all of context creation together Jason Ekstrand
2021-06-09  4:36 ` [PATCH 30/31] drm/i915: Finalize contexts in GEM_CONTEXT_CREATE on version 13+ Jason Ekstrand
2021-06-09 10:13   ` [Intel-gfx] " kernel test robot
2021-06-09 11:38   ` Daniel Vetter
2021-06-09  4:36 ` Jason Ekstrand [this message]
2021-06-09 11:41   ` [Intel-gfx] [PATCH 31/31] drm/i915: Drop some RCU usage around context VMs Daniel Vetter
2021-06-09 16:07     ` Jason Ekstrand

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