Messages in this thread | | | Date | Wed, 10 May 2006 13:50:57 +1000 | From | Nick Piggin <> | Subject | Re: [PATCH -mm] swsusp: support creating bigger images |
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Hugh Dickins wrote:
>On Tue, 9 May 2006, Rafael J. Wysocki wrote: > >>On Tuesday 09 May 2006 09:33, Andrew Morton wrote: >> >> >>>task_struct.mm can sometimes be NULL. This function assumes that it will >>>never be NULL. That makes it a somewhat risky interface. Are we sure it >>>can never be NULL? >>> >>Well, now it's only called for task == current, but I can add a check. >> > >Better fold it into the (renamed and recommented) page_to_copy, >applying only to current. > >The "use" of page_table_lock there is totally bogus. Normally you >need down_read(¤t->mm->mmap_sem) to walk that vma chain; but >I'm guessing you have everything sufficiently frozen here that you >don't need that. >
I have to admit that I suggested making this change, because the function was sufficently generic looking. I guess the mm == NULL case should logically return 0... unless you did that, making page_mapped_by_task use current still leaves the burden of ensuring ->mm != NULL on the caller.
But I don't much mind which way the consensus goes.
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