linux-kernel - [PATCH v3 hmm 10/11] drm/amdkfd: use mmu_notifier

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Message-Id: <20190806231548.25242-11-jgg@ziepe.ca>
Date:   Tue,  6 Aug 2019 20:15:47 -0300
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     linux-mm@...ck.org
Cc:     Andrea Arcangeli <aarcange@...hat.com>,
        Christoph Hellwig <hch@....de>,
        John Hubbard <jhubbard@...dia.com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Ralph Campbell <rcampbell@...dia.com>,
        "Kuehling, Felix" <Felix.Kuehling@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>,
        Dimitri Sivanich <sivanich@....com>,
        dri-devel@...ts.freedesktop.org, amd-gfx@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, linux-rdma@...r.kernel.org,
        iommu@...ts.linux-foundation.org, intel-gfx@...ts.freedesktop.org,
        Gavin Shan <shangw@...ux.vnet.ibm.com>,
        Andrea Righi <andrea@...terlinux.com>,
        Jason Gunthorpe <jgg@...lanox.com>
Subject: [PATCH v3 hmm 10/11] drm/amdkfd: use mmu_notifier_put

From: Jason Gunthorpe <jgg@...lanox.com>

The sequence of mmu_notifier_unregister_no_release(),
mmu_notifier_call_srcu() is identical to mmu_notifier_put() with the
free_notifier callback.

As this is the last user of those APIs, converting it means we can drop
them.

Signed-off-by: Jason Gunthorpe <jgg@...lanox.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_priv.h    |  3 ---
 drivers/gpu/drm/amd/amdkfd/kfd_process.c | 10 ++++------
 2 files changed, 4 insertions(+), 9 deletions(-)

I'm really not sure what this is doing, but it is very strange to have a
release with no other callback. It would be good if this would change to use
get as well.

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
index 3933fb6a371efb..9450e20d17093b 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
@@ -686,9 +686,6 @@ struct kfd_process {
 	/* We want to receive a notification when the mm_struct is destroyed */
 	struct mmu_notifier mmu_notifier;
 
-	/* Use for delayed freeing of kfd_process structure */
-	struct rcu_head	rcu;
-
 	unsigned int pasid;
 	unsigned int doorbell_index;
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index c06e6190f21ffa..e5e326f2f2675e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -486,11 +486,9 @@ static void kfd_process_ref_release(struct kref *ref)
 	queue_work(kfd_process_wq, &p->release_work);
 }
 
-static void kfd_process_destroy_delayed(struct rcu_head *rcu)
+static void kfd_process_free_notifier(struct mmu_notifier *mn)
 {
-	struct kfd_process *p = container_of(rcu, struct kfd_process, rcu);
-
-	kfd_unref_process(p);
+	kfd_unref_process(container_of(mn, struct kfd_process, mmu_notifier));
 }
 
 static void kfd_process_notifier_release(struct mmu_notifier *mn,
@@ -542,12 +540,12 @@ static void kfd_process_notifier_release(struct mmu_notifier *mn,
 
 	mutex_unlock(&p->mutex);
 
-	mmu_notifier_unregister_no_release(&p->mmu_notifier, mm);
-	mmu_notifier_call_srcu(&p->rcu, &kfd_process_destroy_delayed);
+	mmu_notifier_put(&p->mmu_notifier);
 }
 
 static const struct mmu_notifier_ops kfd_process_mmu_notifier_ops = {
 	.release = kfd_process_notifier_release,
+	.free_notifier = kfd_process_free_notifier,
 };
 
 static int kfd_process_init_cwsr_apu(struct kfd_process *p, struct file *filep)
-- 
2.22.0