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Date: Tue, 24 Mar 2009 17:44:10 +0200
From: Adrian Hunter <adrian.hunter@nokia.com>
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To: "Singh, Vimal" <vimalsingh@ti.com>
Subject: Re: Is high_memory check in omap2.c for OneNAND is sufficient?
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Singh, Vimal wrote:
> There is check for 'high_memory' in 'drivers/mtd/onenand/omap2.c', always before doing 'dma_map_single'.
> Snippet:
> ----------------------
>         if (buf >= high_memory) {
>                 struct page *p1;
> ----------------------
> This check seems not sufficient. There should be a check for upper boundary too.
> Thinking scenario when 'buf' is less than 'high_memory', but somewhere near to it, and 'count' is big enough to beyond 'high_memory'.

AFAIK it is not possible to allocate memory that crosses the high_memory boundary.