path: root/samples/firmware_class
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authorAndi Kleen <andi@firstfloor.org>2008-04-21 09:51:05 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-04-21 09:51:05 +0200
commit2472892a3ce17b177cc0d8099a6391949c75abf2 (patch)
tree3e933dc48fa87c29571f235d9fbe3498ceb74add /samples/firmware_class
parentcece933994428974f7a0ee1e8843ba5bd0b18563 (diff)
block: fix memory hotplug and bouncing in block layer
Only noticed this while hacking something else, no test case. blk_max_low_pfn is initialized once at bootup by the block layer from max_low_pfn. But max_low_pfn is not necessarily constant over the runtime of the system when you consider memory hotplug. What could happen if that someone adds memory later the block layer wouldn't get updated and then start bouncing memory unnecessarily. Also on 64bit blk_max_low_pfn actually isn't needed because it just disables bouncing essentially and there is no highmem. And nobody can pass pfns > max_low_pfn to the block layer, because those wouldn't have a struct page and I suspect block layer wouldn't be very happy without that. So set BLK_BOUNCE_HIGH to infinity (-1ULL) on 64bit. That avoids the problem of having to update it on memory hotadd. On 32bit I kept the same behaviour because at least on i386 memory hotadd only adds HIGHMEM, never lowmem. BLK_BOUNCE_ANY is always set to infinity on both 32 and 64bit. Signed-off-by: Andi Kleen <ak@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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