linux-kernel - [PATCH 5.15 38/42] drm/amdkfd: process

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Date:   Wed, 15 Dec 2021 18:21:19 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Philip Yang <Philip.Yang@....com>,
        Felix Kuehling <Felix.Kuehling@....com>,
        Alex Deucher <alexander.deucher@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 38/42] drm/amdkfd: process_info lock not needed for svm

From: Philip Yang <Philip.Yang@....com>

[ Upstream commit 3abfe30d803e62cc75dec254eefab3b04d69219b ]

process_info->lock is used to protect kfd_bo_list, vm_list_head, n_vms
and userptr valid/inval list, svm_range_restore_work and
svm_range_set_attr don't access those, so do not need to take
process_info lock. This will avoid potential circular locking issue.

Signed-off-by: Philip Yang <Philip.Yang@....com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@....com>
Signed-off-by: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 179080329af89..5a674235ae41a 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -1565,7 +1565,6 @@ svm_range_list_lock_and_flush_work(struct svm_range_list *svms,
 static void svm_range_restore_work(struct work_struct *work)
 {
 	struct delayed_work *dwork = to_delayed_work(work);
-	struct amdkfd_process_info *process_info;
 	struct svm_range_list *svms;
 	struct svm_range *prange;
 	struct kfd_process *p;
@@ -1585,12 +1584,10 @@ static void svm_range_restore_work(struct work_struct *work)
 	 * the lifetime of this thread, kfd_process and mm will be valid.
 	 */
 	p = container_of(svms, struct kfd_process, svms);
-	process_info = p->kgd_process_info;
 	mm = p->mm;
 	if (!mm)
 		return;
 
-	mutex_lock(&process_info->lock);
 	svm_range_list_lock_and_flush_work(svms, mm);
 	mutex_lock(&svms->lock);
 
@@ -1643,7 +1640,6 @@ static void svm_range_restore_work(struct work_struct *work)
 out_reschedule:
 	mutex_unlock(&svms->lock);
 	mmap_write_unlock(mm);
-	mutex_unlock(&process_info->lock);
 
 	/* If validation failed, reschedule another attempt */
 	if (evicted_ranges) {
@@ -2974,7 +2970,6 @@ static int
 svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 		   uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
 {
-	struct amdkfd_process_info *process_info = p->kgd_process_info;
 	struct mm_struct *mm = current->mm;
 	struct list_head update_list;
 	struct list_head insert_list;
@@ -2993,8 +2988,6 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 
 	svms = &p->svms;
 
-	mutex_lock(&process_info->lock);
-
 	svm_range_list_lock_and_flush_work(svms, mm);
 
 	if (!svm_range_is_valid(mm, start, size)) {
@@ -3070,8 +3063,6 @@ svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
 	mutex_unlock(&svms->lock);
 	mmap_read_unlock(mm);
 out:
-	mutex_unlock(&process_info->lock);
-
 	pr_debug("pasid 0x%x svms 0x%p [0x%llx 0x%llx] done, r=%d\n", p->pasid,
 		 &p->svms, start, start + size - 1, r);
 
-- 
2.33.0