highmem: fix kmap_to_page() for kmap_local_page() addresses

Browse source

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.

[akpm@linux-foundation.org: fix warning]
Link: https://lkml.kernel.org/r/20221006040555.1502679-1-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: kernel test robot <lkp@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

...

This commit is contained in:

Ira Weiny 2022-10-05 21:05:55 -07:00 • committed by Andrew Morton

parent 15cd90049d

commit ef6e06b2ef

1 changed files with 31 additions and 12 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

43

mm/highmem.c

View file