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authorJes Sorensen <jes@sgi.com>2006-09-27 10:50:10 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-27 17:26:13 +0200
commitf4b81804a2d1ab341a4613089dc31ecce0800ed8 (patch)
treefdad77a7c40790908546a74a9b5918400d01333d /drivers/char/mspec.c
parent[PATCH] zone_statistics: Use hot node instead of cold zone_pgdat (diff)
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[PATCH] do_no_pfn()
Implement do_no_pfn() for handling mapping of memory without a struct page backing it. This avoids creating fake page table entries for regions which are not backed by real memory. This feature is used by the MSPEC driver and other users, where it is highly undesirable to have a struct page sitting behind the page (for instance if the page is accessed in cached mode via the struct page in parallel to the the driver accessing it uncached, which can result in data corruption on some architectures, such as ia64). This version uses specific NOPFN_{SIGBUS,OOM} return values, rather than expect all negative pfn values would be an error. It also bugs on cow mappings as this would not work with the VM. [akpm@osdl.org: micro-optimise] Signed-off-by: Jes Sorensen <jes@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/char/mspec.c')
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