[media] mm: Provide new get_vaddr_frames() helper

Provide new function get_vaddr_frames().  This function maps virtual
addresses from given start and fills given array with page frame numbers of
the corresponding pages. If given start belongs to a normal vma, the function
grabs reference to each of the pages to pin them in memory. If start
belongs to VM_IO | VM_PFNMAP vma, we don't touch page structures. Caller
must make sure pfns aren't reused for anything else while he is using
them.

This function is created for various drivers to simplify handling of
their buffers.

Signed-off-by: Jan Kara <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Andrew Morton <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
This commit is contained in:
Jan Kara 2015-07-13 11:55:44 -03:00 • committed by Mauro Carvalho Chehab
commit 8025e5ddf9
4 changed files with 278 additions and 0 deletions

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@ -654,3 +654,6 @@ config DEFERRED_STRUCT_PAGE_INIT
when kswapd starts. This has a potential performance impact on
processes running early in the lifetime of the systemm until kswapd
finishes the initialisation.
config FRAME_VECTOR
bool