git: 40c1672e886b - main - swap_pager: fix seek_data with invalid first page

[Doug Moore]

The branch main has been updated by dougm:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=40c1672e886b86f4956c16e9f1161683328504ff

commit 40c1672e886b86f4956c16e9f1161683328504ff
Author:     Doug Moore <do...@freebsd.org>
AuthorDate: 2024-11-26 18:12:08 +0000
Commit:     Doug Moore <do...@freebsd.org>
CommitDate: 2024-11-26 18:12:08 +0000

    swap_pager: fix seek_data with invalid first page
    
    Correct swap_pager_seek_data so that, when the first lookup finds no
    valid pages, second and subsequent lookups are attempted anyway.
    
    This was broken by db08b0b04deced766c3b5f07bcfb82333666226c.
    
    Reported by:    mark...@yahoo.com
    Reviewed by:    kib
    Tested by:      mark...@yahoo.com
    Fixes:  db08b0b04deced76 tmpfs_vnops: move swap work to swap_pager
    Differential Revision:  https://reviews.freebsd.org/D47767
---
 sys/vm/swap_pager.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index db925f4ae7f6..3d02f365cad9 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -2503,26 +2503,23 @@ swap_pager_seek_data(vm_object_t object, vm_pindex_t 
pindex)
        VM_OBJECT_ASSERT_RLOCKED(object);
        vm_page_iter_init(&pages, object);
        m = vm_page_iter_lookup_ge(&pages, pindex);
-       if (m != NULL) {
-               if (!vm_page_any_valid(m))
-                       m = NULL;
-               else if (pages.index == pindex)
-                       return (pages.index);
-       }
+       if (m != NULL && pages.index == pindex && vm_page_any_valid(m))
+               return (pages.index);
        swblk_iter_init_only(&blks, object);
        swap_index = swap_pager_iter_find_least(&blks, pindex);
        if (swap_index == pindex)
                return (swap_index);
-       if (swap_index == OBJ_MAX_SIZE)
-               swap_index = object->size;
-       if (m == NULL)
-               return (swap_index);
 
-       while ((m = vm_radix_iter_step(&pages)) != NULL &&
-           pages.index < swap_index) {
+       /*
+        * Find the first resident page after m, before swap_index.
+        */
+       while (m != NULL && pages.index < swap_index) {
                if (vm_page_any_valid(m))
                        return (pages.index);
+               m = vm_radix_iter_step(&pages);
        }
+       if (swap_index == OBJ_MAX_SIZE)
+               swap_index = object->size;
        return (swap_index);
 }