gpu: nvgpu: Deterministic submit fix

Fix some simple pointer arithmetic errors in the deterministic submit
path. The lockless allocator was doing a subtraction to determine the
correct offset of the element to free. However, this subtraction was
using the base address and a numeric offset - not a pointer offset. Thus
the difference computed was in bytes not in elements of the block size.

The fix is simple: just divide by the block size.

Also this modifies the debugging statement a bit so that a bit more
information is printed at more useful times.

Lastly, a pointer to numeric cast was fixed in the fence code.

Change-Id: I514724205f1b73805b21e979481a13ac689f3482
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1538905
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
Reviewed-by: Aingara Paramakuru <aparamakuru@nvidia.com>
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Konsta Holtta <kholtta@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

drivers/gpu/nvgpu/common/mm/lockless_allocator.c

@@ -66,12 +66,16 @@ static u64 nvgpu_lockless_alloc(struct nvgpu_allocator *a, u64 len)
 		if (ret == head) {
 			addr = pa->base + head * pa->blk_size;
 			atomic_inc(&pa->nr_allocs);
-			alloc_dbg(a, "Alloc node # %d @ addr 0x%llx\n", head,
-				  addr);
 			break;
 		}
 		head = ACCESS_ONCE(pa->head);
 	}
+
+	if (addr)
+		alloc_dbg(a, "Alloc node # %d @ addr 0x%llx\n", head, addr);
+	else
+		alloc_dbg(a, "Alloc failed!\n");
+
 	return addr;
 }
 
@@ -81,7 +85,9 @@ static void nvgpu_lockless_free(struct nvgpu_allocator *a, u64 addr)
 	int head, ret;
 	u64 cur_idx;
 
-	cur_idx = addr - pa->base;
+	cur_idx = (addr - pa->base) / pa->blk_size;
+
+	alloc_dbg(a, "Free node # %llu @ addr 0x%llx\n", cur_idx, addr);
 
 	while (1) {
 		head = ACCESS_ONCE(pa->head);
@@ -89,7 +95,6 @@ static void nvgpu_lockless_free(struct nvgpu_allocator *a, u64 addr)
 		ret = cmpxchg(&pa->head, head, cur_idx);
 		if (ret == head) {
 			atomic_dec(&pa->nr_allocs);
-			alloc_dbg(a, "Free node # %llu\n", cur_idx);
 			break;
 		}
 	}

drivers/gpu/nvgpu/gk20a/fence_gk20a.c

@@ -51,7 +51,7 @@ static void gk20a_fence_free(struct kref *ref)
 
 	if (f->allocator) {
 		if (nvgpu_alloc_initialized(f->allocator))
-			nvgpu_free(f->allocator, (size_t)f);
+			nvgpu_free(f->allocator, (u64)(uintptr_t)f);
 	} else
 		nvgpu_kfree(g, f);
 }