Re: [PATCH] mm: mmap: Check all failures before set values

From: Chen Gang
Date: Mon Aug 24 2015 - 09:34:31 EST

On 8/24/15 19:32, Michal Hocko wrote:
> On Mon 24-08-15 00:59:39, gang.chen.5i5j@xxxxxx wrote:
>>> From: Chen Gang <gang.chen.5i5j@xxxxxxxxx>
>>> When failure occurs and return, vma->vm_pgoff is already set, which is
>>> not a good idea.
> Why? The vma is not inserted anywhere and the failure path is supposed
> to simply free the vma.

It can save several insns when failure occurs.

It is always a little better to let the external function suppose fewer
callers' behalf.

It can save the code readers' (especially new readers') time resource
to avoid to analyze why set 'vma->vm_pgoff' before checking '-ENOMEM'
(may it cause issue? or is 'vm_pgoff' related with the next checking?).

Chen Gang

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