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Subject[PATCH RESEND 6/8] parisc: Use mmap_base, not mmap_legacy_base, as low_limit for bottom-up mmap
Date
Bottom-up mmap scheme is used twice:

- for legacy mode, in which mmap_legacy_base and mmap_base are equal.

- in case of mmap failure in top-down mode, where there is no need to go
through the whole address space again for the bottom-up fallback: the goal
of this fallback is to find, as a last resort, space between the top-down
mmap base and the stack, which is the only place not covered by the
top-down mmap.

Then this commit removes the usage of mmap_legacy_base field from parisc
code.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
---
arch/parisc/kernel/sys_parisc.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 5d458a44b09c..e987f3a8eb0b 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -119,7 +119,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,

info.flags = 0;
info.length = len;
- info.low_limit = mm->mmap_legacy_base;
+ info.low_limit = mm->mmap_base;
info.high_limit = mmap_upper_limit(NULL);
info.align_mask = last_mmap ? (PAGE_MASK & (SHM_COLOUR - 1)) : 0;
info.align_offset = shared_align_offset(last_mmap, pgoff);
@@ -240,13 +240,11 @@ static unsigned long mmap_legacy_base(void)
*/
void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack)
{
- mm->mmap_legacy_base = mmap_legacy_base();
- mm->mmap_base = mmap_upper_limit(rlim_stack);
-
if (mmap_is_legacy()) {
- mm->mmap_base = mm->mmap_legacy_base;
+ mm->mmap_base = mmap_legacy_base();
mm->get_unmapped_area = arch_get_unmapped_area;
} else {
+ mm->mmap_base = mmap_upper_limit(rlim_stack);
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
}
}
--
2.20.1
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