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Subject[RFC PATCH 3/8] mm/madvise: remove unnecessary checks on madvise_free_single_vma()
Date
From: Nadav Amit <namit@vmware.com>

madvise_free_single_vma() currently rechecks that the range fits within
the VMA, adapts it accordingly, and returns -EINVAL if the range is
entirely outside of the VMA.

The error-code of -EINVAL is incorrect according to the man pages (as it
should have been -ENOMEM), but anyhow the range that is provided to
madvise_free_single_vma() should always be valid. It is set correctly in
do_madvise() and then rechecked in madvise_dontneed_free() is the
mmap-lock is dropped.

Remove this check.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Colin Cross <ccross@google.com>
Cc: Suren Baghdasarya <surenb@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
---
mm/madvise.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index fe843513a4e8..17e39c70704b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -716,14 +716,8 @@ static int madvise_free_single_vma(struct vm_area_struct *vma,
if (!vma_is_anonymous(vma))
return -EINVAL;

- range.start = max(vma->vm_start, start_addr);
- if (range.start >= vma->vm_end)
- return -EINVAL;
- range.end = min(vma->vm_end, end_addr);
- if (range.end <= vma->vm_start)
- return -EINVAL;
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
- range.start, range.end);
+ start_addr, end_addr);

lru_add_drain();
tlb_gather_mmu(&tlb, mm);
--
2.25.1
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