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mm/mmap: use the maple tree in find_vma() instead of the rbtree. 

JIRA: https://issues.redhat.com/browse/RHEL-27736

commit be8432e7166ef8cc5647d6d350e73897d48a9659
Author: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date:   Tue Sep 6 19:48:46 2022 +0000

    mm/mmap: use the maple tree in find_vma() instead of the rbtree.

    Using the maple tree interface mt_find() will handle the RCU locking and
    will start searching at the address up to the limit, ULONG_MAX in this
    case.

    Add kernel documentation to this API.

    Link: https://lkml.kernel.org/r/20220906194824.2110408-12-Liam.Howlett@oracle.com
    Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
    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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
    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>

Signed-off-by: Chris von Recklinghausen <crecklin@redhat.com>
This commit is contained in:
Chris von Recklinghausen 2024-04-01 11:19:42 -04:00
parent 69ac8bdd8a
commit b9ee174385
1 changed files with 10 additions and 18 deletions
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28
mm/mmap.c
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@ -2472,11 +2472,18 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
EXPORT_SYMBOL(get_unmapped_area);
/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
/**
* find_vma() - Find the VMA for a given address, or the next VMA.
* @mm: The mm_struct to check
* @addr: The address
*
* 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(struct mm_struct *mm, unsigned long addr)
{
struct rb_node *rb_node;
struct vm_area_struct *vma;
unsigned long index = addr;
mmap_assert_locked(mm);
/* Check the cache first. */
@ -2484,22 +2491,7 @@ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
if (likely(vma))
return vma;
rb_node = mm->mm_rb.rb_node;
while (rb_node) {
struct vm_area_struct *tmp;
tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
if (tmp->vm_end > addr) {
vma = tmp;
if (tmp->vm_start <= addr)
break;
rb_node = rb_node->rb_left;
} else
rb_node = rb_node->rb_right;
}
vma = mt_find(&mm->mm_mt, &index, ULONG_MAX);
if (vma)
vmacache_update(addr, vma);
return vma;