linux-kernel - [PATCH v2] drm/amdkfd: Change svm_range_get

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Message-ID: <20250331131833.68281-1-a.vatoropin@crpt.ru>
Date: Mon, 31 Mar 2025 13:18:40 +0000
From: Ваторопин Андрей
	<a.vatoropin@...t.ru>
To: Felix Kuehling <Felix.Kuehling@....com>
CC: Ваторопин Андрей
	<a.vatoropin@...t.ru>, Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>, David Airlie
	<airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	"amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
	"dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"lvc-project@...uxtesting.org" <lvc-project@...uxtesting.org>
Subject: [PATCH v2] drm/amdkfd: Change svm_range_get_info return type

From: Andrey Vatoropin <a.vatoropin@...t.ru>

Static analysis shows that pointer "svms" cannot be NULL because it points
to the object "struct svm_range_list". Remove the extra NULL check. It is
meaningless and harms the readability of the code.

In the function svm_range_get_info() there is no possibility of failure.
Therefore, the caller of the function svm_range_get_info() does not need
a return value. Change the function svm_range_get_info() return type from
"int" to "void". 

Since the function svm_range_get_info() has a return type of "void". The
caller of the function svm_range_get_info() does not need a return value.
Delete extra code.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Andrey Vatoropin <a.vatoropin@...t.ru>
---
v1 -> v2: also change return type of svm_range_get_info() per Felix Kuehling suggestion

 drivers/gpu/drm/amd/amdkfd/kfd_chardev.c |  4 +---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c     |  7 ++-----
 drivers/gpu/drm/amd/amdkfd/kfd_svm.h     | 11 +++++------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
index 1e9dd00620bf..a2149afa5803 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
@@ -2039,9 +2039,7 @@ static int criu_get_process_object_info(struct kfd_process *p,
 
 	num_events = kfd_get_num_events(p);
 
-	ret = svm_range_get_info(p, &num_svm_ranges, &svm_priv_data_size);
-	if (ret)
-		return ret;
+	svm_range_get_info(p, &num_svm_ranges, &svm_priv_data_size);
 
 	*num_objects = num_queues + num_events + num_svm_ranges;
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 100717a98ec1..1b7d57a1b245 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -4076,8 +4076,8 @@ int kfd_criu_restore_svm(struct kfd_process *p,
 	return ret;
 }
 
-int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
-		       uint64_t *svm_priv_data_size)
+void svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
+			uint64_t *svm_priv_data_size)
 {
 	uint64_t total_size, accessibility_size, common_attr_size;
 	int nattr_common = 4, nattr_accessibility = 1;
@@ -4089,8 +4089,6 @@ int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
 	*svm_priv_data_size = 0;
 
 	svms = &p->svms;
-	if (!svms)
-		return -EINVAL;
 
 	mutex_lock(&svms->lock);
 	list_for_each_entry(prange, &svms->list, list) {
@@ -4132,7 +4130,6 @@ int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
 
 	pr_debug("num_svm_ranges %u total_priv_size %llu\n", *num_svm_ranges,
 		 *svm_priv_data_size);
-	return 0;
 }
 
 int kfd_criu_checkpoint_svm(struct kfd_process *p,
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index 6ea23c78009c..01c7a4877904 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -184,8 +184,8 @@ void schedule_deferred_list_work(struct svm_range_list *svms);
 void svm_range_dma_unmap_dev(struct device *dev, dma_addr_t *dma_addr,
 			 unsigned long offset, unsigned long npages);
 void svm_range_dma_unmap(struct svm_range *prange);
-int svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
-		       uint64_t *svm_priv_data_size);
+void svm_range_get_info(struct kfd_process *p, uint32_t *num_svm_ranges,
+			uint64_t *svm_priv_data_size);
 int kfd_criu_checkpoint_svm(struct kfd_process *p,
 			    uint8_t __user *user_priv_data,
 			    uint64_t *priv_offset);
@@ -237,13 +237,12 @@ static inline int svm_range_schedule_evict_svm_bo(
 	return -EINVAL;
 }
 
-static inline int svm_range_get_info(struct kfd_process *p,
-				     uint32_t *num_svm_ranges,
-				     uint64_t *svm_priv_data_size)
+static inline void svm_range_get_info(struct kfd_process *p,
+				      uint32_t *num_svm_ranges,
+				      uint64_t *svm_priv_data_size)
 {
 	*num_svm_ranges = 0;
 	*svm_priv_data_size = 0;
-	return 0;
 }
 
 static inline int kfd_criu_checkpoint_svm(struct kfd_process *p,
-- 
2.43.0