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authorLiam R. Howlett <Liam.Howlett@Oracle.com>2022-09-06 19:48:47 +0000
committerAndrew Morton <akpm@linux-foundation.org>2022-09-26 19:46:15 -0700
commit7fdbd37da5c6ff002dc6d15e89a7708c2df4928e (patch)
treeb3727a18ff6f2fa78bbcbb0655d55979d9431775 /mm/mmap.c
parentmm/mmap: use the maple tree in find_vma() instead of the rbtree. (diff)
downloadlinux-dev-7fdbd37da5c6ff002dc6d15e89a7708c2df4928e.tar.xz
linux-dev-7fdbd37da5c6ff002dc6d15e89a7708c2df4928e.zip
mm/mmap: use the maple tree for find_vma_prev() instead of the rbtree
Use the maple tree's advanced API and a maple state to walk the tree for the entry at the address of the next vma, then use the maple state to walk back one entry to find the previous entry. Add kernel documentation comments for this API. Link: https://lkml.kernel.org/r/20220906194824.2110408-13-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: David Hildenbrand <david@redhat.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c27
1 files changed, 17 insertions, 10 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index dbbf8ee12f60..948264cd39cd 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2475,23 +2475,30 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
}
EXPORT_SYMBOL(find_vma);
-/*
- * Same as find_vma, but also return a pointer to the previous VMA in *pprev.
+/**
+ * find_vma_prev() - Find the VMA for a given address, or the next vma and
+ * set %pprev to the previous VMA, if any.
+ * @mm: The mm_struct to check
+ * @addr: The address
+ * @pprev: The pointer to set to the previous VMA
+ *
+ * Note that RCU lock is missing here since the external mmap_lock() is used
+ * instead.
+ *
+ * Returns: The VMA associated with @addr, or the next vma.
+ * May return %NULL in the case of no vma at addr or above.
*/
struct vm_area_struct *
find_vma_prev(struct mm_struct *mm, unsigned long addr,
struct vm_area_struct **pprev)
{
struct vm_area_struct *vma;
+ MA_STATE(mas, &mm->mm_mt, addr, addr);
- vma = find_vma(mm, addr);
- if (vma) {
- *pprev = vma->vm_prev;
- } else {
- struct rb_node *rb_node = rb_last(&mm->mm_rb);
-
- *pprev = rb_node ? rb_entry(rb_node, struct vm_area_struct, vm_rb) : NULL;
- }
+ vma = mas_walk(&mas);
+ *pprev = mas_prev(&mas, 0);
+ if (!vma)
+ vma = mas_next(&mas, ULONG_MAX);
return vma;
}