[PATCH] PCI: endpoint: Use 'bitmap_zalloc()' when applicable

[PATCH] PCI: endpoint: Use 'bitmap_zalloc()' when applicable

[Christophe JAILLET]

'mem->bitmap' is a bitmap. So use 'bitmap_zalloc()' to simplify code,
improve the semantic and avoid some open-coded arithmetic in allocator
arguments.

Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
consistency.

Finally, while at it, axe the useless 'bitmap' variable and use
'mem->bitmap' directly.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/pci/endpoint/pci-epc-mem.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
index a97b56a6d2db..b15a264f19af 100644
--- a/drivers/pci/endpoint/pci-epc-mem.c
+++ b/drivers/pci/endpoint/pci-epc-mem.c
@@ -49,10 +49,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
 			   unsigned int num_windows)
 {
 	struct pci_epc_mem *mem = NULL;
-	unsigned long *bitmap = NULL;
 	unsigned int page_shift;
 	size_t page_size;
-	int bitmap_size;
 	int pages;
 	int ret;
 	int i;
@@ -72,7 +70,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
 			page_size = PAGE_SIZE;
 		page_shift = ilog2(page_size);
 		pages = windows[i].size >> page_shift;
-		bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
 
 		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
 		if (!mem) {
@@ -81,8 +78,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
 			goto err_mem;
 		}
 
-		bitmap = kzalloc(bitmap_size, GFP_KERNEL);
-		if (!bitmap) {
+		mem->bitmap = bitmap_zalloc(pages, GFP_KERNEL);
+		if (!mem->bitmap) {
 			ret = -ENOMEM;
 			kfree(mem);
 			i--;
@@ -92,7 +89,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
 		mem->window.phys_base = windows[i].phys_base;
 		mem->window.size = windows[i].size;
 		mem->window.page_size = page_size;
-		mem->bitmap = bitmap;
 		mem->pages = pages;
 		mutex_init(&mem->lock);
 		epc->windows[i] = mem;
@@ -106,7 +102,7 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
 err_mem:
 	for (; i >= 0; i--) {
 		mem = epc->windows[i];
-		kfree(mem->bitmap);
+		bitmap_free(mem->bitmap);
 		kfree(mem);
 	}
 	kfree(epc->windows);
@@ -145,7 +141,7 @@ void pci_epc_mem_exit(struct pci_epc *epc)
 
 	for (i = 0; i < epc->num_windows; i++) {
 		mem = epc->windows[i];
-		kfree(mem->bitmap);
+		bitmap_free(mem->bitmap);
 		kfree(mem);
 	}
 	kfree(epc->windows);
-- 
2.30.2

Re: [PATCH] PCI: endpoint: Use 'bitmap_zalloc()' when applicable

[Krzysztof Wilczyński]

Hi Christophe,

> 'mem->bitmap' is a bitmap. So use 'bitmap_zalloc()' to simplify code,
> improve the semantic and avoid some open-coded arithmetic in allocator
> arguments.
> 
> Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
> consistency.

Thank you!

> Finally, while at it, axe the useless 'bitmap' variable and use
> 'mem->bitmap' directly.

Personally, I would keep the bitmap variable - this might be what Bjorn
would also prefer, as I believe he prefers not to store what is a "failed"
state of sorts in a target variable directly, if memory serves me right.

[...]
> @@ -49,10 +49,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>  			   unsigned int num_windows)
>  {
>  	struct pci_epc_mem *mem = NULL;
> -	unsigned long *bitmap = NULL;
>  	unsigned int page_shift;
>  	size_t page_size;
> -	int bitmap_size;
>  	int pages;
>  	int ret;
>  	int i;
> @@ -72,7 +70,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>  			page_size = PAGE_SIZE;
>  		page_shift = ilog2(page_size);
>  		pages = windows[i].size >> page_shift;
> -		bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>  
>  		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>  		if (!mem) {
> @@ -81,8 +78,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>  			goto err_mem;
>  		}
>  
> -		bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> -		if (!bitmap) {
> +		mem->bitmap = bitmap_zalloc(pages, GFP_KERNEL);
> +		if (!mem->bitmap) {
>  			ret = -ENOMEM;
>  			kfree(mem);
>  			i--;
> @@ -92,7 +89,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>  		mem->window.phys_base = windows[i].phys_base;
>  		mem->window.size = windows[i].size;
>  		mem->window.page_size = page_size;
> -		mem->bitmap = bitmap;
>  		mem->pages = pages;
>  		mutex_init(&mem->lock);
>  		epc->windows[i] = mem;
> @@ -106,7 +102,7 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>  err_mem:
>  	for (; i >= 0; i--) {
>  		mem = epc->windows[i];
> -		kfree(mem->bitmap);
> +		bitmap_free(mem->bitmap);
>  		kfree(mem);
>  	}
>  	kfree(epc->windows);
> @@ -145,7 +141,7 @@ void pci_epc_mem_exit(struct pci_epc *epc)
>  
>  	for (i = 0; i < epc->num_windows; i++) {
>  		mem = epc->windows[i];
> -		kfree(mem->bitmap);
> +		bitmap_free(mem->bitmap);
>  		kfree(mem);
>  	}
>  	kfree(epc->windows);

Thank you!

Reviewed-by: Krzysztof Wilczyński <kw@linux.com>

	Krzysztof

Re: [PATCH] PCI: endpoint: Use 'bitmap_zalloc()' when applicable

[Christophe JAILLET]

Le 06/11/2021 à 23:01, Krzysztof Wilczyński a écrit :
> Hi Christophe,
> 
>> 'mem->bitmap' is a bitmap. So use 'bitmap_zalloc()' to simplify code,
>> improve the semantic and avoid some open-coded arithmetic in allocator
>> arguments.
>>
>> Also change the corresponding 'kfree()' into 'bitmap_free()' to keep
>> consistency.
> 
> Thank you!
> 
>> Finally, while at it, axe the useless 'bitmap' variable and use
>> 'mem->bitmap' directly.
> 
> Personally, I would keep the bitmap variable - this might be what Bjorn
> would also prefer, as I believe he prefers not to store what is a "failed"
> state of sorts in a target variable directly, if memory serves me right.

Hi,

mostly a mater of taste.
On another similar patch I got the answer in [1] :).

'mem' is kzalloc'ed, so in case of failure, here we are just replacing 
NULL by NULL.

Let me know the preferred style here and if I should send a V2.

CJ

[1]; https://lore.kernel.org/kernel-janitors/20211028164437.GA4045120@p14s/

> 
> [...]
>> @@ -49,10 +49,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>>   			   unsigned int num_windows)
>>   {
>>   	struct pci_epc_mem *mem = NULL;
>> -	unsigned long *bitmap = NULL;
>>   	unsigned int page_shift;
>>   	size_t page_size;
>> -	int bitmap_size;
>>   	int pages;
>>   	int ret;
>>   	int i;
>> @@ -72,7 +70,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>>   			page_size = PAGE_SIZE;
>>   		page_shift = ilog2(page_size);
>>   		pages = windows[i].size >> page_shift;
>> -		bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
>>   
>>   		mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>>   		if (!mem) {
>> @@ -81,8 +78,8 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>>   			goto err_mem;
>>   		}
>>   
>> -		bitmap = kzalloc(bitmap_size, GFP_KERNEL);
>> -		if (!bitmap) {
>> +		mem->bitmap = bitmap_zalloc(pages, GFP_KERNEL);
>> +		if (!mem->bitmap) {
>>   			ret = -ENOMEM;
>>   			kfree(mem);
>>   			i--;
>> @@ -92,7 +89,6 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>>   		mem->window.phys_base = windows[i].phys_base;
>>   		mem->window.size = windows[i].size;
>>   		mem->window.page_size = page_size;
>> -		mem->bitmap = bitmap;
>>   		mem->pages = pages;
>>   		mutex_init(&mem->lock);
>>   		epc->windows[i] = mem;
>> @@ -106,7 +102,7 @@ int pci_epc_multi_mem_init(struct pci_epc *epc,
>>   err_mem:
>>   	for (; i >= 0; i--) {
>>   		mem = epc->windows[i];
>> -		kfree(mem->bitmap);
>> +		bitmap_free(mem->bitmap);
>>   		kfree(mem);
>>   	}
>>   	kfree(epc->windows);
>> @@ -145,7 +141,7 @@ void pci_epc_mem_exit(struct pci_epc *epc)
>>   
>>   	for (i = 0; i < epc->num_windows; i++) {
>>   		mem = epc->windows[i];
>> -		kfree(mem->bitmap);
>> +		bitmap_free(mem->bitmap);
>>   		kfree(mem);
>>   	}
>>   	kfree(epc->windows);
> 
> Thank you!
> 
> Reviewed-by: Krzysztof Wilczyński <kw@linux.com>
> 
> 	Krzysztof
>