bpf: remove VMA linked list

Use vma_next() and remove reference to the start of the linked list

Link: https://lkml.kernel.org/r/20220906194824.2110408-51-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.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: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/bpf/task_iter.c b/kernel/bpf/task_iter.c
index 8c92179..1c8debd 100644 (file)
--- a/kernel/bpf/task_iter.c
+++ b/kernel/bpf/task_iter.c
@@ -299,8 +299,8 @@ struct bpf_iter_seq_task_vma_info {
 };
 
 enum bpf_task_vma_iter_find_op {
-       task_vma_iter_first_vma,   /* use mm->mmap */
-       task_vma_iter_next_vma,    /* use curr_vma->vm_next */
+       task_vma_iter_first_vma,   /* use find_vma() with addr 0 */
+       task_vma_iter_next_vma,    /* use vma_next() with curr_vma */
        task_vma_iter_find_vma,    /* use find_vma() to find next vma */
 };
 
@@ -400,10 +400,10 @@ again:
 
        switch (op) {
        case task_vma_iter_first_vma:
-               curr_vma = curr_task->mm->mmap;
+               curr_vma = find_vma(curr_task->mm, 0);
                break;
        case task_vma_iter_next_vma:
-               curr_vma = curr_vma->vm_next;
+               curr_vma = find_vma(curr_task->mm, curr_vma->vm_end);
                break;
        case task_vma_iter_find_vma:
                /* We dropped mmap_lock so it is necessary to use find_vma
@@ -417,7 +417,7 @@ again:
                if (curr_vma &&
                    curr_vma->vm_start == info->prev_vm_start &&
                    curr_vma->vm_end == info->prev_vm_end)
-                       curr_vma = curr_vma->vm_next;
+                       curr_vma = find_vma(curr_task->mm, curr_vma->vm_end);
                break;
        }
        if (!curr_vma) {