Split the block device case from swap_readpage into a separate helper,
following the abstraction for file based swap and frontswap.

Signed-off-by: Christoph Hellwig <[email protected]>
---
 mm/page_io.c | 68 +++++++++++++++++++++++++++-------------------------
 1 file changed, 35 insertions(+), 33 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index 6f7166fdc4b2bb..ce0b3638094f85 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -445,44 +445,15 @@ static void swap_readpage_fs(struct page *page,
                *plug = sio;
 }
 
-void swap_readpage(struct page *page, bool synchronous, struct swap_iocb 
**plug)
+static void swap_readpage_bdev(struct page *page, bool synchronous,
+               struct swap_info_struct *sis)
 {
        struct bio *bio;
-       struct swap_info_struct *sis = page_swap_info(page);
-       bool workingset = PageWorkingset(page);
-       unsigned long pflags;
-       bool in_thrashing;
-
-       VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
-       VM_BUG_ON_PAGE(!PageLocked(page), page);
-       VM_BUG_ON_PAGE(PageUptodate(page), page);
-
-       /*
-        * Count submission time as memory stall and delay. When the device
-        * is congested, or the submitting cgroup IO-throttled, submission
-        * can be a significant part of overall IO time.
-        */
-       if (workingset) {
-               delayacct_thrashing_start(&in_thrashing);
-               psi_memstall_enter(&pflags);
-       }
-       delayacct_swapin_start();
-
-       if (frontswap_load(page) == 0) {
-               SetPageUptodate(page);
-               unlock_page(page);
-               goto out;
-       }
-
-       if (data_race(sis->flags & SWP_FS_OPS)) {
-               swap_readpage_fs(page, plug);
-               goto out;
-       }
 
        if ((sis->flags & SWP_SYNCHRONOUS_IO) &&
            !bdev_read_page(sis->bdev, swap_page_sector(page), page)) {
                count_vm_event(PSWPIN);
-               goto out;
+               return;
        }
 
        bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
@@ -509,8 +480,39 @@ void swap_readpage(struct page *page, bool synchronous, 
struct swap_iocb **plug)
        }
        __set_current_state(TASK_RUNNING);
        bio_put(bio);
+}
+
+void swap_readpage(struct page *page, bool synchronous, struct swap_iocb 
**plug)
+{
+       struct swap_info_struct *sis = page_swap_info(page);
+       bool workingset = PageWorkingset(page);
+       unsigned long pflags;
+       bool in_thrashing;
+
+       VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
+       VM_BUG_ON_PAGE(!PageLocked(page), page);
+       VM_BUG_ON_PAGE(PageUptodate(page), page);
+
+       /*
+        * Count submission time as memory stall and delay. When the device
+        * is congested, or the submitting cgroup IO-throttled, submission
+        * can be a significant part of overall IO time.
+        */
+       if (workingset) {
+               delayacct_thrashing_start(&in_thrashing);
+               psi_memstall_enter(&pflags);
+       }
+       delayacct_swapin_start();
+
+       if (frontswap_load(page) == 0) {
+               SetPageUptodate(page);
+               unlock_page(page);
+       } else if (data_race(sis->flags & SWP_FS_OPS)) {
+               swap_readpage_fs(page, plug);
+       } else {
+               swap_readpage_bdev(page, synchronous, sis);
+       }
 
-out:
        if (workingset) {
                delayacct_thrashing_end(&in_thrashing);
                psi_memstall_leave(&pflags);
-- 
2.39.0


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