linux-kernel - Re: [PATCH v2] lib/string_helpers: Use the given gfp flag when allocating memory

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Message-ID: <6a1b84da-d55e-e058-13a8-9920b05ff20d@wanadoo.fr>
Date:   Mon, 24 Jan 2022 21:45:12 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Andy Shevchenko <andriy.shevchenko@...el.com>
Cc:     Andy Shevchenko <andy@...nel.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mel Gorman <mgorman@...e.de>, Michal Hocko <mhocko@...e.com>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v2] lib/string_helpers: Use the given gfp flag when
 allocating memory

Le 24/01/2022 à 15:26, Andy Shevchenko a écrit :
> On Sun, Jan 16, 2022 at 01:53:37PM +0100, Christophe JAILLET wrote:
>> kstrdup_quotable_cmdline() and kstrdup_quotable_file() are given a gfp flag
>> that is passed and used for memory allocation in kstrdup_quotable() just a
>> few lines below.
>>
>> It looks reasonable to use this gfp value for the buffer allocated and
>> freed in these functions as well.
> 
> Acked-by: Andy Shevchenko <andriy.shevchenko@...el.com>

Hi,
just in case, another patch has been proposed in the thread related to 
the v1 of this patch.
See [1].

I let you see which approach is the more relevant.

CJ

[1]: https://lore.kernel.org/linux-kernel/YeU8PhtvvXIWtTk%2F@dhcp22.suse.cz/

> 
>> Fixes: 0ee931c4e31a ("mm: treewide: remove GFP_TEMPORARY allocation flag")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
>> ---
>> According to what I've found in 5.16, all callers use GFP_KERNEL, so this
>> patch should be a no-op.
>> But who knows how it will be used in the future. Better safe than sorry.
>>
>> v2: Add the change for kstrdup_quotable_file()
>> ---
>>   lib/string_helpers.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/string_helpers.c b/lib/string_helpers.c
>> index 90f9f1b7afec..4433e486b725 100644
>> --- a/lib/string_helpers.c
>> +++ b/lib/string_helpers.c
>> @@ -624,7 +624,7 @@ char *kstrdup_quotable_cmdline(struct task_struct *task, gfp_t gfp)
>>   	char *buffer, *quoted;
>>   	int i, res;
>>   
>> -	buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
>> +	buffer = kmalloc(PAGE_SIZE, gfp);
>>   	if (!buffer)
>>   		return NULL;
>>   
>> @@ -660,7 +660,7 @@ char *kstrdup_quotable_file(struct file *file, gfp_t gfp)
>>   		return kstrdup("<unknown>", gfp);
>>   
>>   	/* We add 11 spaces for ' (deleted)' to be appended */
>> -	temp = kmalloc(PATH_MAX + 11, GFP_KERNEL);
>> +	temp = kmalloc(PATH_MAX + 11, gfp);
>>   	if (!temp)
>>   		return kstrdup("<no_memory>", gfp);
>>   
>> -- 
>> 2.32.0
>>
>