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authorJan Kara <jack@suse.cz>2017-11-03 12:21:21 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-12-20 10:04:59 +0100
commitb59614cfd2d3619eedc1b711ac51efb7636efba6 (patch)
tree91ad3bafc5d682f5b797fed51c5b76650ffb2a53
parent44de70ecec2d9aaf2a0f0c790ae4bba592c6ca3a (diff)
mm: Handle 0 flags in _calc_vm_trans() macro
[ 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>
-rw-r--r--include/linux/mman.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/mman.h b/include/linux/mman.h
index 16373c8f5f57..369bc3405a6d 100644
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -63,8 +63,9 @@ static inline int arch_validate_prot(unsigned long prot)
* ("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.