Messages in this thread | | | Date | Mon, 09 Sep 2002 14:47:25 -0700 | From | Andrew Morton <> | Subject | Re: Calculating kernel logical address .. |
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Manfred Spraul wrote: > > Andrew Morton wrote: > > Nobody seems to have come forth to implement a thought-out scatter/gather, > > map-user-pages library infrastructure so I'd be a bit reluctant to > > break stuff without offering a replacement. > > > > We'd need one. > > get_user_pages() is broken if a kernel module access the virtual address > of the page and the cpu caches are not coherent:
OK. Most users seem to just want to put the pages under DMA though.
> Most of the flush functions need the vma pointer, but it's impossible to > guarantee that it still exists when the get_user_pages() user calls > page_cache_release().
Well presumably, if the driver is altering user memory by hand, it is synchronous and they can hang onto mmap_sem while doing it? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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