mm: do not export ioremap_page_range symbol for external module
authorzhong jiang <zhongjiang@huawei.com>
Tue, 24 Jan 2017 23:18:52 +0000 (15:18 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 25 Jan 2017 00:26:14 +0000 (16:26 -0800)
commit3277953de2f31dd03c6375e9a9f680ac37fc9d27
tree6ba22924faa1b82ef2f0277db10a3f5abdc44157
parent3705ccfdd1e8b539225ce20e3925a945cc788d67
mm: do not export ioremap_page_range symbol for external module

Recently, I've found cases in which ioremap_page_range was used
incorrectly, in external modules, leading to crashes.  This can be
partly attributed to the fact that ioremap_page_range is lower-level,
with fewer protections, as compared to the other functions that an
external module would typically call.  Those include:

     ioremap_cache
     ioremap_nocache
     ioremap_prot
     ioremap_uc
     ioremap_wc
     ioremap_wt

...each of which wraps __ioremap_caller, which in turn provides a safer
way to achieve the mapping.

Therefore, stop EXPORT-ing ioremap_page_range.

Link: http://lkml.kernel.org/r/1485173220-29010-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
lib/ioremap.c