diff mbox series

mm/mempool: Add 'else' to split mutually exclusive case

Message ID 20200824115354.7879-1-linmiaohe@huawei.com (mailing list archive)
State New, archived
Headers show
Series mm/mempool: Add 'else' to split mutually exclusive case | expand

Commit Message

Miaohe Lin Aug. 24, 2020, 11:53 a.m. UTC 
Add else to split mutually exclusive case and avoid some unnecessary check.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/mempool.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

Comments

Andrew Morton Aug. 24, 2020, 7:18 p.m. UTC | #1 
On Mon, 24 Aug 2020 07:53:54 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:

> Add else to split mutually exclusive case and avoid some unnecessary check.
> 
> --- a/mm/mempool.c
> +++ b/mm/mempool.c
> @@ -60,9 +60,8 @@ static void check_element(mempool_t *pool, void *element)
>  	/* 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 */
> -	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);
>  

It doesn't seem to change code generation (compiler is smart), but I
think it helps readability.
Matthew Wilcox Aug. 24, 2020, 7:22 p.m. UTC | #2 
On Mon, Aug 24, 2020 at 12:18:40PM -0700, Andrew Morton wrote:
> On Mon, 24 Aug 2020 07:53:54 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:
> 
> > Add else to split mutually exclusive case and avoid some unnecessary check.
> > 
> > --- a/mm/mempool.c
> > +++ b/mm/mempool.c
> > @@ -60,9 +60,8 @@ static void check_element(mempool_t *pool, void *element)
> >  	/* 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 */
> > -	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);
> >  
> 
> It doesn't seem to change code generation (compiler is smart), but I
> think it helps readability.

Not with the comments where they are
Joe Perches Aug. 24, 2020, 7:27 p.m. UTC | #3 
On Mon, 2020-08-24 at 12:18 -0700, Andrew Morton wrote:
> On Mon, 24 Aug 2020 07:53:54 -0400 Miaohe Lin <linmiaohe@huawei.com> wrote:
> 
> > Add else to split mutually exclusive case and avoid some unnecessary check.
> > 
> > --- a/mm/mempool.c
> > +++ b/mm/mempool.c
> > @@ -60,9 +60,8 @@ static void check_element(mempool_t *pool, void *element)
> >  	/* 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 */
> > -	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);
> >  
> 
> It doesn't seem to change code generation (compiler is smart), but I
> think it helps readability.

style: braces should be added to the first test.

Perhaps better as:
---
 mm/mempool.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/mempool.c b/mm/mempool.c
index 79bff63ecf27..d0206eab86a4 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -57,12 +57,12 @@ 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) {
+		/* Mempools backed by slab allocator */
 		__check_element(pool, element, ksize(element));
-
-	/* Mempools backed by page allocator */
-	if (pool->free == mempool_free_pages) {
+	} 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);
diff mbox series

Patch

diff --git a/mm/mempool.c b/mm/mempool.c
index 79bff63ecf27..73fb2e548b43 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -60,9 +60,8 @@  static void check_element(mempool_t *pool, void *element)
 	/* 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 */
-	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);
 
@@ -84,9 +83,8 @@  static void poison_element(mempool_t *pool, void *element)
 	/* 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 */
-	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);
 }