| From foo@baz Mon Dec 18 15:03:25 CET 2017 |
| From: Jan Kara <jack@suse.cz> |
| Date: Fri, 3 Nov 2017 12:21:21 +0100 |
| Subject: mm: Handle 0 flags in _calc_vm_trans() macro |
| |
| From: Jan Kara <jack@suse.cz> |
| |
| |
| [ Upstream commit 592e254502041f953e84d091eae2c68cba04c10b ] |
| |
| _calc_vm_trans() does not handle the situation when some of the passed |
| flags are 0 (which can happen if these VM flags do not make sense for |
| the architecture). Improve the _calc_vm_trans() macro to return 0 in |
| such situation. Since all passed flags are constant, this does not add |
| any runtime overhead. |
| |
| Signed-off-by: Jan Kara <jack@suse.cz> |
| Signed-off-by: Dan Williams <dan.j.williams@intel.com> |
| Signed-off-by: Sasha Levin <alexander.levin@verizon.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| include/linux/mman.h | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/include/linux/mman.h |
| +++ b/include/linux/mman.h |
| @@ -63,8 +63,9 @@ static inline int arch_validate_prot(uns |
| * ("bit1" and "bit2" must be single bits) |
| */ |
| #define _calc_vm_trans(x, bit1, bit2) \ |
| + ((!(bit1) || !(bit2)) ? 0 : \ |
| ((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \ |
| - : ((x) & (bit1)) / ((bit1) / (bit2))) |
| + : ((x) & (bit1)) / ((bit1) / (bit2)))) |
| |
| /* |
| * Combine the mmap "prot" argument into "vm_flags" used internally. |