gpu: nvgpu: check sema pool alloc failure properly

nvgpu_semaphore_pool_alloc() returns an ERR_PTR instead of NULL which
the caller checks on failure. Common code should not use ERR_PTRs
though, so modify nvgpu_semaphore_pool_alloc() to return error code
separately and fix nvgpu_init_sema_pool() to consider this.

Jira NVGPU-513

Change-Id: I435c0d2794d226774ed4c6b3bcbdde1e741854d8
Signed-off-by: Konsta Holtta <kholtta@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1673458
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

3 files changed, 15 insertions, 16 deletions

diff --git a/drivers/gpu/nvgpu/common/mm/vm.c b/drivers/gpu/nvgpu/common/mm/vm.c
index f57b1c9c..13fd641e 100644
--- a/drivers/gpu/nvgpu/common/mm/vm.c
+++ b/drivers/gpu/nvgpu/common/mm/vm.c
@@ -230,9 +230,9 @@ static int nvgpu_init_sema_pool(struct vm_gk20a *vm)
         if (!sema_sea)
                 return -ENOMEM;
 
-        vm->sema_pool = nvgpu_semaphore_pool_alloc(sema_sea);
-        if (!vm->sema_pool)
-                return -ENOMEM;
+        err = nvgpu_semaphore_pool_alloc(sema_sea, &vm->sema_pool);
+        if (err)
+                return err;
 
         /*
          * Allocate a chunk of GPU VA space for mapping the semaphores. We will
diff --git a/drivers/gpu/nvgpu/common/semaphore.c b/drivers/gpu/nvgpu/common/semaphore.c
index b2238bb7..fe4131c3 100644
--- a/drivers/gpu/nvgpu/common/semaphore.c
+++ b/drivers/gpu/nvgpu/common/semaphore.c
@@ -146,29 +146,27 @@ static int __semaphore_bitmap_alloc(unsigned long *bitmap, unsigned long len)
 /*
  * Allocate a pool from the sea.
  */
-struct nvgpu_semaphore_pool *nvgpu_semaphore_pool_alloc(
-                                struct nvgpu_semaphore_sea *sea)
+int nvgpu_semaphore_pool_alloc(struct nvgpu_semaphore_sea *sea,
+                               struct nvgpu_semaphore_pool **pool)
 {
         struct nvgpu_semaphore_pool *p;
         unsigned long page_idx;
-        int ret, err = 0;
+        int ret;
 
         p = nvgpu_kzalloc(sea->gk20a, sizeof(*p));
         if (!p)
-                return ERR_PTR(-ENOMEM);
+                return -ENOMEM;
 
         __lock_sema_sea(sea);
 
-        err = nvgpu_mutex_init(&p->pool_lock);
-        if (err)
+        ret = nvgpu_mutex_init(&p->pool_lock);
+        if (ret)
                 goto fail;
 
         ret = __semaphore_bitmap_alloc(sea->pools_alloced,
                                        SEMAPHORE_POOL_COUNT);
-        if (ret < 0) {
-                err = ret;
+        if (ret < 0)
                 goto fail_alloc;
-        }
 
         page_idx = (unsigned long)ret;
 
@@ -184,7 +182,8 @@ struct nvgpu_semaphore_pool *nvgpu_semaphore_pool_alloc(
         gpu_sema_dbg(sea->gk20a,
                      "Allocated semaphore pool: page-idx=%d", p->page_idx);
 
-        return p;
+        *pool = p;
+        return 0;
 
 fail_alloc:
         nvgpu_mutex_destroy(&p->pool_lock);
@@ -192,7 +191,7 @@ fail:
         __unlock_sema_sea(sea);
         nvgpu_kfree(sea->gk20a, p);
         gpu_sema_dbg(sea->gk20a, "Failed to allocate semaphore pool!");
-        return ERR_PTR(err);
+        return ret;
 }
 
 /*
diff --git a/drivers/gpu/nvgpu/include/nvgpu/semaphore.h b/drivers/gpu/nvgpu/include/nvgpu/semaphore.h
index e66b2188..771cc7e1 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/semaphore.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/semaphore.h
@@ -173,8 +173,8 @@ struct nvgpu_semaphore_sea *nvgpu_semaphore_get_sea(struct gk20a *g);
 /*
  * Semaphore pool functions.
  */
-struct nvgpu_semaphore_pool *nvgpu_semaphore_pool_alloc(
-        struct nvgpu_semaphore_sea *sea);
+int nvgpu_semaphore_pool_alloc(struct nvgpu_semaphore_sea *sea,
+                               struct nvgpu_semaphore_pool **pool);
 int nvgpu_semaphore_pool_map(struct nvgpu_semaphore_pool *pool,
                              struct vm_gk20a *vm);
 void nvgpu_semaphore_pool_unmap(struct nvgpu_semaphore_pool *pool,