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* [PATCH v2] mm/mempool: Add 'else' to split mutually exclusive case
@ 2020-09-24 11:16 Miaohe Lin
  2020-09-25  2:40 ` Andrew Morton
  0 siblings, 1 reply; 3+ messages in thread
From: Miaohe Lin @ 2020-09-24 11:16 UTC (permalink / raw)
  To: akpm; +Cc: linux-mm, linux-kernel, linmiaohe

Add else to split mutually exclusive case and avoid some unnecessary check.
It doesn't seem to change code generation (compiler is smart), but I think
it helps readability.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/mempool.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index 79bff63ecf27..95fa8e601730 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -58,11 +58,10 @@ static void __check_element(mempool_t *pool, void *element, size_t size)
 static void check_element(mempool_t *pool, void *element)
 {
 	/* Mempools backed by slab allocator */
-	if (pool->free == mempool_free_slab || pool->free == mempool_kfree)
+	if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
 		__check_element(pool, element, ksize(element));
-
 	/* Mempools backed by page allocator */
-	if (pool->free == mempool_free_pages) {
+	} else if (pool->free == mempool_free_pages) {
 		int order = (int)(long)pool->pool_data;
 		void *addr = kmap_atomic((struct page *)element);
 
@@ -82,11 +81,10 @@ static void __poison_element(void *element, size_t size)
 static void poison_element(mempool_t *pool, void *element)
 {
 	/* Mempools backed by slab allocator */
-	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
+	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
 		__poison_element(element, ksize(element));
-
 	/* Mempools backed by page allocator */
-	if (pool->alloc == mempool_alloc_pages) {
+	} else if (pool->alloc == mempool_alloc_pages) {
 		int order = (int)(long)pool->pool_data;
 		void *addr = kmap_atomic((struct page *)element);
 
@@ -107,7 +105,7 @@ static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
 {
 	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
 		kasan_poison_kfree(element, _RET_IP_);
-	if (pool->alloc == mempool_alloc_pages)
+	else if (pool->alloc == mempool_alloc_pages)
 		kasan_free_pages(element, (unsigned long)pool->pool_data);
 }
 
@@ -115,7 +113,7 @@ static void kasan_unpoison_element(mempool_t *pool, void *element)
 {
 	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
 		kasan_unpoison_slab(element);
-	if (pool->alloc == mempool_alloc_pages)
+	else if (pool->alloc == mempool_alloc_pages)
 		kasan_alloc_pages(element, (unsigned long)pool->pool_data);
 }
 
-- 
2.19.1



^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH v2] mm/mempool: Add 'else' to split mutually exclusive case
  2020-09-24 11:16 [PATCH v2] mm/mempool: Add 'else' to split mutually exclusive case Miaohe Lin
@ 2020-09-25  2:40 ` Andrew Morton
  0 siblings, 0 replies; 3+ messages in thread
From: Andrew Morton @ 2020-09-25  2:40 UTC (permalink / raw)
  To: Miaohe Lin; +Cc: linux-mm, linux-kernel

On Thu, 24 Sep 2020 07:16:41 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:

> Add else to split mutually exclusive case and avoid some unnecessary check.
> It doesn't seem to change code generation (compiler is smart), but I think
> it helps readability.
> 
> ...
>
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -58,11 +58,10 @@ static void __check_element(mempool_t *pool, void *element, size_t size)
>  static void check_element(mempool_t *pool, void *element)
>  {
>  	/* Mempools backed by slab allocator */
> -	if (pool->free == mempool_free_slab || pool->free == mempool_kfree)
> +	if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
>  		__check_element(pool, element, ksize(element));
> -
>  	/* Mempools backed by page allocator */
> -	if (pool->free == mempool_free_pages) {
> +	} else if (pool->free == mempool_free_pages) {
>  		int order = (int)(long)pool->pool_data;
>  		void *addr = kmap_atomic((struct page *)element);
>  
> @@ -82,11 +81,10 @@ static void __poison_element(void *element, size_t size)
>  static void poison_element(mempool_t *pool, void *element)
>  {
>  	/* Mempools backed by slab allocator */
> -	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
> +	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
>  		__poison_element(element, ksize(element));
> -
>  	/* Mempools backed by page allocator */
> -	if (pool->alloc == mempool_alloc_pages) {
> +	} else if (pool->alloc == mempool_alloc_pages) {
>  		int order = (int)(long)pool->pool_data;
>  		void *addr = kmap_atomic((struct page *)element);
>  

OK, I guess.  But the comments are now in the wrong place.

--- a/mm/mempool.c~mm-mempool-add-else-to-split-mutually-exclusive-case-fix
+++ a/mm/mempool.c
@@ -60,8 +60,8 @@ static void check_element(mempool_t *poo
 	/* Mempools backed by slab allocator */
 	if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
 		__check_element(pool, element, ksize(element));
-	/* Mempools backed by page allocator */
 	} else if (pool->free == mempool_free_pages) {
+		/* Mempools backed by page allocator */
 		int order = (int)(long)pool->pool_data;
 		void *addr = kmap_atomic((struct page *)element);
 
@@ -83,8 +83,8 @@ static void poison_element(mempool_t *po
 	/* Mempools backed by slab allocator */
 	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
 		__poison_element(element, ksize(element));
-	/* Mempools backed by page allocator */
 	} else if (pool->alloc == mempool_alloc_pages) {
+		/* Mempools backed by page allocator */
 		int order = (int)(long)pool->pool_data;
 		void *addr = kmap_atomic((struct page *)element);
 
_



^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH v2] mm/mempool: Add 'else' to split mutually exclusive case
@ 2020-09-25  2:47 linmiaohe
  0 siblings, 0 replies; 3+ messages in thread
From: linmiaohe @ 2020-09-25  2:47 UTC (permalink / raw)
  To: Andrew Morton; +Cc: linux-mm, linux-kernel

Andrew Morton <akpm@linux-foundation.org> wrote:
> On Thu, 24 Sep 2020 07:16:41 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:
>
>> Add else to split mutually exclusive case and avoid some unnecessary check.
>> It doesn't seem to change code generation (compiler is smart), but I 
>> think it helps readability.
>
> OK, I guess.  But the comments are now in the wrong place.
>

Many thanks for kindly reply and fix the wrong comments place.
Have a good day!

> --- a/mm/mempool.c~mm-mempool-add-else-to-split-mutually-exclusive-case-fix
> +++ a/mm/mempool.c
> @@ -60,8 +60,8 @@ static void check_element(mempool_t *poo
>  	/* Mempools backed by slab allocator */
>  	if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
>  		__check_element(pool, element, ksize(element));
> -	/* Mempools backed by page allocator */
>  	} else if (pool->free == mempool_free_pages) {
> +		/* Mempools backed by page allocator */
>  		int order = (int)(long)pool->pool_data;
>  		void *addr = kmap_atomic((struct page *)element);
>  
> @@ -83,8 +83,8 @@ static void poison_element(mempool_t *po
>  	/* Mempools backed by slab allocator */
>  	if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
>  		__poison_element(element, ksize(element));
> -	/* Mempools backed by page allocator */
>  	} else if (pool->alloc == mempool_alloc_pages) {
> +		/* Mempools backed by page allocator */
>  		int order = (int)(long)pool->pool_data;
>  		void *addr = kmap_atomic((struct page *)element);
>  
> _
>
>


^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-09-25  2:48 UTC | newest]

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2020-09-24 11:16 [PATCH v2] mm/mempool: Add 'else' to split mutually exclusive case Miaohe Lin
2020-09-25  2:40 ` Andrew Morton
2020-09-25  2:47 linmiaohe

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