linux-kernel - Re: [PATCH 4/6] Xarray: skip unneeded xas_store() and xas_clear_mark() in __xa

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ad978b0c-b814-02ad-6304-6096d5cacf9a@huaweicloud.com>
Date: Mon, 4 Nov 2024 09:55:42 +0800
From: Kemeng Shi <shikemeng@...weicloud.com>
To: Matthew Wilcox <willy@...radead.org>
Cc: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
 linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 4/6] Xarray: skip unneeded xas_store() and
 xas_clear_mark() in __xa_alloc()



on 11/2/2024 12:02 AM, Matthew Wilcox wrote:
> On Fri, Nov 01, 2024 at 11:50:26PM +0800, Kemeng Shi wrote:
>> If xas_find_marked() failed, there is no need to call xas_store() and
>> xas_clear_mark(). Just call xas_store() and xas_clear_mark() if
>> xas_find_marked() succeed.
> 
> No.  The point of the xas interfaces is that they turn into no-ops once
> an error has occurred.
Yes, xas interfaces can tolerate error. The question is do we really need to
call xas_store(...) here if we already know there is no room to store new entry.
But no insistant on this as it's not a big deal anyway.

Will drop this on next version if you still disklike this.
Thanks.

> 
>> -		else
>> +		else {
>>  			*id = xas.xa_index;
>> -		xas_store(&xas, entry);
>> -		xas_clear_mark(&xas, XA_FREE_MARK);
>> +			xas_store(&xas, entry);
>> +			xas_clear_mark(&xas, XA_FREE_MARK);
>> +		}
>>  	} while (__xas_nomem(&xas, gfp));
>>  
>>  	return xas_error(&xas);
>> -- 
>> 2.30.0
>>
>