gpu: nvgpu: Add checking in allocator functions

Add checks to make sure function pointers are valid before attempting
to call said function.

Also, ensure that any allocator created defines the following 3 functions
at minimum:

  alloc()
  free()
  fini()

Bug 1799159

Change-Id: I4cd3d5746ccb721c723a161c9487564846027572
Signed-off-by: Alex Waterman <alexw@nvidia.com>
Reviewed-on: http://git-master/r/1200059
(cherry picked from commit e26557a49d7ca6629ada24f12a3be396b0ae22cd)
Reviewed-on: http://git-master/r/1208476
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 24 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_allocator.c b/drivers/gpu/nvgpu/gk20a/gk20a_allocator.c
index 25d15d0f..d9e38200 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_allocator.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_allocator.c
@@ -29,17 +29,23 @@ static struct dentry *gk20a_alloc_debugfs_root;
 
 u64 gk20a_alloc_length(struct gk20a_allocator *a)
 {
-        return a->ops->length(a);
+        if (a->ops->length)
+                return a->ops->length(a);
+
+        return 0;
 }
 
 u64 gk20a_alloc_base(struct gk20a_allocator *a)
 {
-        return a->ops->base(a);
+        if (a->ops->base)
+                return a->ops->base(a);
+
+        return 0;
 }
 
 u64 gk20a_alloc_initialized(struct gk20a_allocator *a)
 {
-        if (!a->ops)
+        if (!a->ops || !a->ops->inited)
                 return 0;
 
         return a->ops->inited(a);
@@ -47,7 +53,10 @@ u64 gk20a_alloc_initialized(struct gk20a_allocator *a)
 
 u64 gk20a_alloc_end(struct gk20a_allocator *a)
 {
-        return a->ops->end(a);
+        if (a->ops->end)
+                return a->ops->end(a);
+
+        return 0;
 }
 
 u64 gk20a_alloc(struct gk20a_allocator *a, u64 len)
@@ -62,7 +71,10 @@ void gk20a_free(struct gk20a_allocator *a, u64 addr)
 
 u64 gk20a_alloc_fixed(struct gk20a_allocator *a, u64 base, u64 len)
 {
-        return a->ops->alloc_fixed(a, base, len);
+        if (a->ops->alloc_fixed)
+                return a->ops->alloc_fixed(a, base, len);
+
+        return 0;
 }
 
 void gk20a_free_fixed(struct gk20a_allocator *a, u64 base, u64 len)
@@ -92,6 +104,13 @@ int __gk20a_alloc_common_init(struct gk20a_allocator *a,
         if (!ops)
                 return -EINVAL;
 
+        /*
+         * This is the bare minimum operations required for a sensible
+         * allocator.
+         */
+        if (!ops->alloc || !ops->free || !ops->fini)
+                return -EINVAL;
+
         a->ops = ops;
         a->priv = priv;
         a->debug = dbg;