Re: BUG in shared_policy_replace() ?

[Steve Longerbeam <stevel@mvista.com>]

Hugh Dickins wrote:

>On Tue, 18 Jan 2005, Steve Longerbeam wrote:
>  
>
>>Why free the shared policy created to split up an old
>>policy that spans the whole new range? Ie, see patch.
>>    
>>
>
>I think you're misreading it.  That code comes from when I changed it
>over from sp->sem to sp->lock.  If it finds that it needs to split an
>existing range, so needs to allocate a new2, then it has to drop and
>reacquire the spinlock around that.  It's conceivable that a racing
>task could change the tree while the spinlock is dropped, in such a
>way that this split is no longer necessary once we reacquire the
>spinlock.  The code you're looking at frees up new2 in that case;
>whereas in the normal case, where it is still needed, there's a
>new2 = NULL after inserting it, so that it won't be freed below.
>  
>

got it, except that there is no "new2 = NULL;" in 2.6.10-mm2!

Looks like it was misplaced, because I do see it now in 2.6.10.

Steve

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