mm: factor out a swap_readpage_bdev helper

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

Link: https://lkml.kernel.org/r/20230125133436.447864-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/page_io.c b/mm/page_io.c
index 84b348fe4c7c39b51ed6df7684596d1a95297a75..872a226d15dc57cb0b7adda98ca9c745d47dcfba 100644 (file)
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -444,44 +444,15 @@ 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);
@@ -508,8 +479,39 @@ 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);