* [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
@ 2024-01-20 9:56 Christophe JAILLET
2024-01-20 12:00 ` Simon Horman
` (3 more replies)
0 siblings, 4 replies; 7+ messages in thread
From: Christophe JAILLET @ 2024-01-20 9:56 UTC (permalink / raw)
To: Krzysztof Kozlowski, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni
Cc: linux-kernel, kernel-janitors, Christophe JAILLET, netdev
nfc_llc_register() calls pass a string literal as the 'name' parameter.
So kstrdup_const() can be used instead of kfree() to avoid a memory
allocation in such cases.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
net/nfc/hci/llc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/nfc/hci/llc.c b/net/nfc/hci/llc.c
index 2140f6724644..8c7b5a817b25 100644
--- a/net/nfc/hci/llc.c
+++ b/net/nfc/hci/llc.c
@@ -49,7 +49,7 @@ int nfc_llc_register(const char *name, const struct nfc_llc_ops *ops)
if (llc_engine == NULL)
return -ENOMEM;
- llc_engine->name = kstrdup(name, GFP_KERNEL);
+ llc_engine->name = kstrdup_const(name, GFP_KERNEL);
if (llc_engine->name == NULL) {
kfree(llc_engine);
return -ENOMEM;
@@ -83,7 +83,7 @@ void nfc_llc_unregister(const char *name)
return;
list_del(&llc_engine->entry);
- kfree(llc_engine->name);
+ kfree_const(llc_engine->name);
kfree(llc_engine);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-01-20 9:56 [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine Christophe JAILLET
@ 2024-01-20 12:00 ` Simon Horman
2024-01-23 13:24 ` Krzysztof Kozlowski
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Simon Horman @ 2024-01-20 12:00 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Krzysztof Kozlowski, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, linux-kernel, kernel-janitors,
netdev
On Sat, Jan 20, 2024 at 10:56:06AM +0100, Christophe JAILLET wrote:
> nfc_llc_register() calls pass a string literal as the 'name' parameter.
>
> So kstrdup_const() can be used instead of kfree() to avoid a memory
> allocation in such cases.
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
## Form letter - net-next-closed
[adapted from text by Jakub]
The merge window for v6.8 has begun and therefore net-next is closed
for new drivers, features, code refactoring and optimizations.
We are currently accepting bug fixes only.
Please repost when net-next reopens on or after 22nd January.
RFC patches sent for review only are obviously welcome at any time.
See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#development-cycle
--
pw-bot: defer
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-01-20 9:56 [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine Christophe JAILLET
2024-01-20 12:00 ` Simon Horman
@ 2024-01-23 13:24 ` Krzysztof Kozlowski
2024-01-27 9:58 ` [PATCH RESEND] " Christophe JAILLET
2024-01-31 23:08 ` Jakub Kicinski
3 siblings, 0 replies; 7+ messages in thread
From: Krzysztof Kozlowski @ 2024-01-23 13:24 UTC (permalink / raw)
To: Christophe JAILLET, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni
Cc: linux-kernel, kernel-janitors, netdev
On 20/01/2024 10:56, Christophe JAILLET wrote:
> nfc_llc_register() calls pass a string literal as the 'name' parameter.
>
> So kstrdup_const() can be used instead of kfree() to avoid a memory
> allocation in such cases.
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
You probably need to resend it, because that time net-next was closed.
If resending, keep my tag.
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH RESEND] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-01-20 9:56 [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine Christophe JAILLET
2024-01-20 12:00 ` Simon Horman
2024-01-23 13:24 ` Krzysztof Kozlowski
@ 2024-01-27 9:58 ` Christophe JAILLET
2024-01-31 23:08 ` Jakub Kicinski
3 siblings, 0 replies; 7+ messages in thread
From: Christophe JAILLET @ 2024-01-27 9:58 UTC (permalink / raw)
To: Krzysztof Kozlowski, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni
Cc: linux-kernel, kernel-janitors, Christophe JAILLET, netdev
nfc_llc_register() calls pass a string literal as the 'name' parameter.
So kstrdup_const() can be used instead of kfree() to avoid a memory
allocation in such cases.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
Resent because of 'net-next-closed' message on previous try.
Added R-b tag. (see [1])
[1]: https://lore.kernel.org/all/9415e571-50a1-41d3-8205-68e4128bbe6d@linaro.org/
---
net/nfc/hci/llc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/nfc/hci/llc.c b/net/nfc/hci/llc.c
index 2140f6724644..8c7b5a817b25 100644
--- a/net/nfc/hci/llc.c
+++ b/net/nfc/hci/llc.c
@@ -49,7 +49,7 @@ int nfc_llc_register(const char *name, const struct nfc_llc_ops *ops)
if (llc_engine == NULL)
return -ENOMEM;
- llc_engine->name = kstrdup(name, GFP_KERNEL);
+ llc_engine->name = kstrdup_const(name, GFP_KERNEL);
if (llc_engine->name == NULL) {
kfree(llc_engine);
return -ENOMEM;
@@ -83,7 +83,7 @@ void nfc_llc_unregister(const char *name)
return;
list_del(&llc_engine->entry);
- kfree(llc_engine->name);
+ kfree_const(llc_engine->name);
kfree(llc_engine);
}
--
2.43.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH RESEND] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-01-20 9:56 [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine Christophe JAILLET
` (2 preceding siblings ...)
2024-01-27 9:58 ` [PATCH RESEND] " Christophe JAILLET
@ 2024-01-31 23:08 ` Jakub Kicinski
2024-02-02 19:11 ` Christophe JAILLET
3 siblings, 1 reply; 7+ messages in thread
From: Jakub Kicinski @ 2024-01-31 23:08 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Krzysztof Kozlowski, David S. Miller, Eric Dumazet, Paolo Abeni,
linux-kernel, kernel-janitors, netdev
On Sat, 27 Jan 2024 10:58:29 +0100 Christophe JAILLET wrote:
> nfc_llc_register() calls pass a string literal as the 'name' parameter.
>
> So kstrdup_const() can be used instead of kfree() to avoid a memory
> allocation in such cases.
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
There is a kfree() call in nfc_llc_exit() that looks suspiciously
like it may also free the name.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RESEND] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-01-31 23:08 ` Jakub Kicinski
@ 2024-02-02 19:11 ` Christophe JAILLET
2024-02-02 19:33 ` Jakub Kicinski
0 siblings, 1 reply; 7+ messages in thread
From: Christophe JAILLET @ 2024-02-02 19:11 UTC (permalink / raw)
To: Jakub Kicinski
Cc: Krzysztof Kozlowski, David S. Miller, Eric Dumazet, Paolo Abeni,
linux-kernel, kernel-janitors, netdev
Le 01/02/2024 à 00:08, Jakub Kicinski a écrit :
> On Sat, 27 Jan 2024 10:58:29 +0100 Christophe JAILLET wrote:
>> nfc_llc_register() calls pass a string literal as the 'name' parameter.
>>
>> So kstrdup_const() can be used instead of kfree() to avoid a memory
>> allocation in such cases.
>>
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>
> There is a kfree() call in nfc_llc_exit() that looks suspiciously
> like it may also free the name.
>
>
Hi,
you are right.
Should we have something like:
void nfc_llc_exit(void)
{
struct nfc_llc_engine *llc_engine, *n;
list_for_each_entry_safe(llc_engine, n, &llc_engines, entry)
nfc_llc_unregister(&llc_engine->name);
}
It would be slower, but it would reduce code duplication as well.
This is just an _exit() function, so it shouldn't be called that often
anyway, if called at all.
Or, add another function with the list_del()+kfree_const()+kfree(), that
would be called from nfc_llc_exit() and nfc_llc_unregister(), to have
the best of the 2 worlds?
CJ
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH RESEND] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine
2024-02-02 19:11 ` Christophe JAILLET
@ 2024-02-02 19:33 ` Jakub Kicinski
0 siblings, 0 replies; 7+ messages in thread
From: Jakub Kicinski @ 2024-02-02 19:33 UTC (permalink / raw)
To: Christophe JAILLET
Cc: Krzysztof Kozlowski, David S. Miller, Eric Dumazet, Paolo Abeni,
linux-kernel, kernel-janitors, netdev
On Fri, 2 Feb 2024 20:11:56 +0100 Christophe JAILLET wrote:
> It would be slower, but it would reduce code duplication as well.
> This is just an _exit() function, so it shouldn't be called that often
> anyway, if called at all.
>
> Or, add another function with the list_del()+kfree_const()+kfree(), that
> would be called from nfc_llc_exit() and nfc_llc_unregister(), to have
> the best of the 2 worlds?
My vote is the latter - factor out the 3 calls into a new helper, call
it where appropriate.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2024-02-02 19:33 UTC | newest]
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2024-01-20 9:56 [PATCH] nfc: hci: Save a few bytes of memory when registering a 'nfc_llc' engine Christophe JAILLET
2024-01-20 12:00 ` Simon Horman
2024-01-23 13:24 ` Krzysztof Kozlowski
2024-01-27 9:58 ` [PATCH RESEND] " Christophe JAILLET
2024-01-31 23:08 ` Jakub Kicinski
2024-02-02 19:11 ` Christophe JAILLET
2024-02-02 19:33 ` Jakub Kicinski
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