2022-11-10 03:38:26

by Miaoqian Lin

Subject: [PATCH] mm/demotion: Fix NULL vs IS_ERR checking in memory_tier_init

The alloc_memory_type() function return error pointers on error
instead of NULL.
Use IS_ERR() to check the return value to fix this.

Fixes: 7b88bda3761b ("mm/demotion/dax/kmem: set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE")
Signed-off-by: Miaoqian Lin <[email protected]>
---
mm/memory-tiers.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index fa8c9d07f9ce..ac0dae9e54bf 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -645,7 +645,7 @@ static int __init memory_tier_init(void)
* than default DRAM tier.
*/
default_dram_type = alloc_memory_type(MEMTIER_ADISTANCE_DRAM);
- if (!default_dram_type)
+ if (IS_ERR(default_dram_type))
panic("%s() failed to allocate default DRAM tier\n", __func__);

/*
--
2.37.3.671.ge2130fe6da78.dirty

2022-11-10 03:53:17

by Huang, Ying

Subject: Re: [PATCH] mm/demotion: Fix NULL vs IS_ERR checking in memory_tier_init

Miaoqian Lin <[email protected]> writes:

> The alloc_memory_type() function return error pointers on error
> instead of NULL.
> Use IS_ERR() to check the return value to fix this.
>
> Fixes: 7b88bda3761b ("mm/demotion/dax/kmem: set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE")
> Signed-off-by: Miaoqian Lin <[email protected]>

Thanks!

Reviewed-by: "Huang, Ying" <[email protected]>

> ---
> mm/memory-tiers.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index fa8c9d07f9ce..ac0dae9e54bf 100644
> --- a/mm/memory-tiers.c
> +++ b/mm/memory-tiers.c
> @@ -645,7 +645,7 @@ static int __init memory_tier_init(void)
> * than default DRAM tier.
> */
> default_dram_type = alloc_memory_type(MEMTIER_ADISTANCE_DRAM);
> - if (!default_dram_type)
> + if (IS_ERR(default_dram_type))
> panic("%s() failed to allocate default DRAM tier\n", __func__);
>
> /*