From 42c06a0e8ebe95b81e5fb41c6556ff22d9255b0c Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Mon, 17 Jul 2023 12:02:27 -0400
Subject: mm: kill frontswap

The only user of frontswap is zswap, and has been for a long time.  Have
swap call into zswap directly and remove the indirection.

[hannes@cmpxchg.org: remove obsolete comment, per Yosry]
  Link: https://lkml.kernel.org/r/20230719142832.GA932528@cmpxchg.org
[fengwei.yin@intel.com: don't warn if none swapcache folio is passed to zswap_load]
  Link: https://lkml.kernel.org/r/20230810095652.3905184-1-fengwei.yin@intel.com
Link: https://lkml.kernel.org/r/20230717160227.GA867137@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/page_io.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'mm/page_io.c')

diff --git a/mm/page_io.c b/mm/page_io.c
index ff4156a44d5d..5d0baba3578b 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -19,12 +19,12 @@
 #include <linux/bio.h>
 #include <linux/swapops.h>
 #include <linux/writeback.h>
-#include <linux/frontswap.h>
 #include <linux/blkdev.h>
 #include <linux/psi.h>
 #include <linux/uio.h>
 #include <linux/sched/task.h>
 #include <linux/delayacct.h>
+#include <linux/zswap.h>
 #include "swap.h"
 
 static void __end_swap_bio_write(struct bio *bio)
@@ -195,7 +195,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 		folio_unlock(folio);
 		return ret;
 	}
-	if (frontswap_store(&folio->page) == 0) {
+	if (zswap_store(&folio->page)) {
 		folio_start_writeback(folio);
 		folio_unlock(folio);
 		folio_end_writeback(folio);
@@ -512,7 +512,7 @@ void swap_readpage(struct page *page, bool synchronous, struct swap_iocb **plug)
 	}
 	delayacct_swapin_start();
 
-	if (frontswap_load(page) == 0) {
+	if (zswap_load(page)) {
 		SetPageUptodate(page);
 		unlock_page(page);
 	} else if (data_race(sis->flags & SWP_FS_OPS)) {
-- 
cgit