s390/mm: optimize randomize_et_dyn for !PF_RANDOMIZE
Skip the call to brk_rnd() if the PF_RANDOMIZE flag is not set for
the process. This avoids the costly get_random_int() call. Modify
arch_randomize_brk() as well to make it look like randomize_et_dyn().
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 7ed0d4e..dd14532 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -261,20 +261,18 @@
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
- unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
+ unsigned long ret;
- if (ret < mm->brk)
- return mm->brk;
- return ret;
+ ret = PAGE_ALIGN(mm->brk + brk_rnd());
+ return (ret > mm->brk) ? ret : mm->brk;
}
unsigned long randomize_et_dyn(unsigned long base)
{
- unsigned long ret = PAGE_ALIGN(base + brk_rnd());
+ unsigned long ret;
if (!(current->flags & PF_RANDOMIZE))
return base;
- if (ret < base)
- return base;
- return ret;
+ ret = PAGE_ALIGN(base + brk_rnd());
+ return (ret > base) ? ret : base;
}