[PATCH v3] drm/amdkfd: sparse: Fix warning in reading SDMA counters

[Mukul Joshi]

Add __user annotation to fix related sparse warning while reading
SDMA counters from userland.
Also, rework the read SDMA counters function by removing redundant
checks.

Reported-by: kernel test robot <lkp at intel.com>
Signed-off-by: Mukul Joshi <mukul.joshi at amd.com>
---
 .../drm/amd/amdkfd/kfd_device_queue_manager.c | 28 ++-----------------
 .../drm/amd/amdkfd/kfd_device_queue_manager.h |  8 +++++-
 drivers/gpu/drm/amd/amdkfd/kfd_process.c      |  6 ++--
 3 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index e0e60b0d0669..560adc57a050 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -153,30 +153,6 @@ static void decrement_queue_count(struct device_queue_manager *dqm,
 		dqm->active_cp_queue_count--;
 }
 
-int read_sdma_queue_counter(uint64_t q_rptr, uint64_t *val)
-{
-	int ret;
-	uint64_t tmp = 0;
-
-	if (!val)
-		return -EINVAL;
-	/*
-	 * SDMA activity counter is stored at queue's RPTR + 0x8 location.
-	 */
-	if (!access_ok((const void __user *)(q_rptr +
-					sizeof(uint64_t)), sizeof(uint64_t))) {
-		pr_err("Can't access sdma queue activity counter\n");
-		return -EFAULT;
-	}
-
-	ret = get_user(tmp, (uint64_t *)(q_rptr + sizeof(uint64_t)));
-	if (!ret) {
-		*val = tmp;
-	}
-
-	return ret;
-}
-
 static int allocate_doorbell(struct qcm_process_device *qpd, struct queue *q)
 {
 	struct kfd_dev *dev = qpd->dqm->dev;
@@ -552,7 +528,7 @@ static int destroy_queue_nocpsch(struct device_queue_manager *dqm,
 	/* Get the SDMA queue stats */
 	if ((q->properties.type == KFD_QUEUE_TYPE_SDMA) ||
 	    (q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)) {
-		retval = read_sdma_queue_counter((uint64_t)q->properties.read_ptr,
+		retval = read_sdma_queue_counter((uint64_t __user *)q->properties.read_ptr,
 							&sdma_val);
 		if (retval)
 			pr_err("Failed to read SDMA queue counter for queue: %d\n",
@@ -1473,7 +1449,7 @@ static int destroy_queue_cpsch(struct device_queue_manager *dqm,
 	/* Get the SDMA queue stats */
 	if ((q->properties.type == KFD_QUEUE_TYPE_SDMA) ||
 	    (q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)) {
-		retval = read_sdma_queue_counter((uint64_t)q->properties.read_ptr,
+		retval = read_sdma_queue_counter((uint64_t __user *)q->properties.read_ptr,
 							&sdma_val);
 		if (retval)
 			pr_err("Failed to read SDMA queue counter for queue: %d\n",
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
index 49d8e324c636..16262e5d93f5 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.h
@@ -251,5 +251,11 @@ static inline void dqm_unlock(struct device_queue_manager *dqm)
 	mutex_unlock(&dqm->lock_hidden);
 }
 
-int read_sdma_queue_counter(uint64_t q_rptr, uint64_t *val);
+static inline int read_sdma_queue_counter(uint64_t __user *q_rptr, uint64_t *val)
+{
+        /*
+         * SDMA activity counter is stored at queue's RPTR + 0x8 location.
+         */
+	return get_user(*val, q_rptr + 1);
+}
 #endif /* KFD_DEVICE_QUEUE_MANAGER_H_ */
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_process.c b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
index 4480f905814c..ff7686250ae0 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_process.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_process.c
@@ -87,7 +87,7 @@ struct kfd_sdma_activity_handler_workarea {
 };
 
 struct temp_sdma_queue_list {
-	uint64_t rptr;
+	uint64_t __user *rptr;
 	uint64_t sdma_val;
 	unsigned int queue_id;
 	struct list_head list;
@@ -159,7 +159,7 @@ static void kfd_sdma_activity_worker(struct work_struct *work)
 		}
 
 		INIT_LIST_HEAD(&sdma_q->list);
-		sdma_q->rptr = (uint64_t)q->properties.read_ptr;
+		sdma_q->rptr = (uint64_t __user *)q->properties.read_ptr;
 		sdma_q->queue_id = q->properties.queue_id;
 		list_add_tail(&sdma_q->list, &sdma_q_list.list);
 	}
@@ -218,7 +218,7 @@ static void kfd_sdma_activity_worker(struct work_struct *work)
 			continue;
 
 		list_for_each_entry_safe(sdma_q, next, &sdma_q_list.list, list) {
-			if (((uint64_t)q->properties.read_ptr == sdma_q->rptr) &&
+			if (((uint64_t __user *)q->properties.read_ptr == sdma_q->rptr) &&
 			     (sdma_q->queue_id == q->properties.queue_id)) {
 				list_del(&sdma_q->list);
 				kfree(sdma_q);
-- 
2.17.1