highmem: fix kmap_to_page() for kmap_local_page() addresses

kmap_to_page() is used to get the page for a virtual address which may
be kmap'ed.  Unfortunately, kmap_local_page() stores mappings in a
thread local array separate from kmap().  These mappings were not
checked by the call.

Check the kmap_local_page() mappings and return the page if found.

Because it is intended to remove kmap_to_page() add a warn on once to
the kmap checks to flag potential issues early.

NOTE Due to 32bit x86 use of kmap local in iomap atmoic, KMAP_LOCAL does
not require HIGHMEM to be set.  Therefore the support calls required a
new KMAP_LOCAL section to fix 0day build errors.

[[email protected]: fix warning]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ira Weiny <[email protected]>
Reported-by: Al Viro <[email protected]>
Reported-by: kernel test robot <[email protected]>
Cc: "Fabio M. De Francesco" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions