linux-kernel - Re: [PATCH] mm: introduce for_each

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]

Date:	Wed, 13 Aug 2014 00:52:13 +0300
From:	"Kirill A. Shutemov" <kirill@...temov.name>
To:	Davidlohr Bueso <davidlohr@...com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Heiko Carstens <heiko.carstens@...ibm.com>,
	"James E.J. Bottomley" <jejb@...isc-linux.org>,
	Helge Deller <deller@....de>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Paul Mackerras <paulus@...ba.org>,
	Michael Ellerman <mpe@...erman.id.au>,
	Robert Richter <rric@...nel.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, aswin@...com
Subject: Re: [PATCH] mm: introduce for_each_vma helpers

On Tue, Aug 12, 2014 at 10:45:23AM -0700, Davidlohr Bueso wrote:
> The most common way of iterating through the list of vmas, is via:
>     for (vma = mm->mmap; vma; vma = vma->vm_next)
> 
> This patch replaces this logic with a new for_each_vma(vma) helper,
> which 1) encapsulates this logic, and 2) make it easier to read.

Why does it need to be encapsulated?
Do you have problem with reading plain for()?

Your for_each_vma(vma) assumes "mm" from the scope. This can be confusing
for reader: whether it uses "mm" from the scope or "current->mm". This
will lead to very hard to find bug one day.
I don't like this.

> It also updates most of the callers, so its a pretty good start.
> 
> Similarly, we also have for_each_vma_start(vma, start) when the user
> does not want to start at the beginning of the list. And lastly the
> for_each_vma_start_inc(vma, start, inc) helper in introduced to allow
> users to create higher level special vma abstractions, such as with
> the case of ELF binaries.

for_each_vma_start_inc() is pretty much the plain for() but with
really_long_and_fancy_name(). Why?

-- 
 Kirill A. Shutemov
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/