Am 02.01.2018 um 04:05 schrieb He, Roger:

-----Original Message-----
From: Xiongwei Song [mailto:sxwj...@gmail.com]
Sent: Sunday, December 31, 2017 7:40 PM
To: Koenig, Christian <christian.koe...@amd.com>; He, Roger 
<hongbo...@amd.com>; airl...@linux.ie
Cc: dri-devel@lists.freedesktop.org; linux-ker...@vger.kernel.org
Subject: [PATCH] drm/ttm: optimize errors checking and free _manager when 
finishing

In the function ttm_page_alloc_init, kzalloc call is made for variable 
_manager, we need to check its return value, it may return NULL.

In the function ttm_page_alloc_fini, we need to call kfree for variable 
_manager, instead of make _manager NULL directly.

Signed-off-by: Xiongwei Song <sxwj...@gmail.com>
---
  drivers/gpu/drm/ttm/ttm_page_alloc.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc.c 
b/drivers/gpu/drm/ttm/ttm_page_alloc.c
index b5ba6441489f..e20a0b8e352b 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc.c
@@ -1007,6 +1007,10 @@ int ttm_page_alloc_init(struct ttm_mem_global *glob, 
unsigned max_pages)
        pr_info("Initializing pool allocator\n");
_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
+       if (!_manager) {
+               ret = -ENOMEM;
+               goto out;
+       }
Seems we only need above here for this patch I think.
The rest is no need, because ttm_pool_kobj_release will kfree _manager.

Yes, agree. Freeing it again in ttm_page_alloc_fini will actually double free the memory and probably cause some problems.

Please refine the patch with only the additional error handling.

Regards,
Christian.



Thanks
Roger(Hongbo.He)

        ttm_page_pool_init_locked(&_manager->wc_pool, GFP_HIGHUSER, "wc", 0);
@@ -1034,13 +1038,17 @@ int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
                                   &glob->kobj, "pool");
        if (unlikely(ret != 0)) {
                kobject_put(&_manager->kobj);
-               _manager = NULL;
-               return ret;
+               goto out_free_mgr;
        }
ttm_pool_mm_shrink_init(_manager); return 0;
+out_free_mgr:
+       kfree(_manager);
+       _manager = NULL;
+out:
+       return ret;
  }
void ttm_page_alloc_fini(void)
@@ -1055,6 +1063,7 @@ void ttm_page_alloc_fini(void)
                ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES, true);
kobject_put(&_manager->kobj);
+       kfree(_manager);
        _manager = NULL;
  }
--
2.15.1


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