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From:   Gao Xiang <hsiangkao@redhat.com>
To:     linux-erofs@lists.ozlabs.org
Cc:     LKML <linux-kernel@vger.kernel.org>, Chao Yu <yuchao0@huawei.com>,
        Chao Yu <chao@kernel.org>, Gao Xiang <hsiangkao@redhat.com>
Subject: [PATCH v2 2/3] erofs: insert to managed cache after adding to pcl
Date:   Mon,  7 Dec 2020 09:23:45 +0800
Message-Id: <20201207012346.2713857-2-hsiangkao@redhat.com>
In-Reply-To: <20201207012346.2713857-1-hsiangkao@redhat.com>
References: <20201207012346.2713857-1-hsiangkao@redhat.com>
Precedence: bulk

Previously, it could be some concern to call add_to_page_cache_lru()
with page->mapping == Z_EROFS_MAPPING_STAGING (!= NULL).

In contrast, page->private is used instead now, so partially revert
commit 5ddcee1f3a1c ("erofs: get rid of __stagingpage_alloc helper")
with some adaption for simplicity.

Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
---
 fs/erofs/zdata.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index afeadf413c2c..edd7325570e1 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1071,28 +1071,19 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
 	put_page(page);
 out_allocpage:
 	page = erofs_allocpage(pagepool, gfp | __GFP_NOFAIL);
-	if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
-		/* turn into temporary page if fails */
-		set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
-		tocache = false;
-	}
-
 	if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {
-		if (tocache) {
-			/* since it added to managed cache successfully */
-			unlock_page(page);
-			put_page(page);
-		} else {
-			list_add(&page->lru, pagepool);
-		}
+		list_add(&page->lru, pagepool);
 		cond_resched();
 		goto repeat;
 	}
 
-	if (tocache) {
-		set_page_private(page, (unsigned long)pcl);
-		SetPagePrivate(page);
+	if (!tocache || add_to_page_cache_lru(page, mc, index + nr, gfp)) {
+		/* turn into temporary page if fails */
+		set_page_private(page, Z_EROFS_SHORTLIVED_PAGE);
+		goto out;
 	}
+	set_page_private(page, (unsigned long)pcl);
+	SetPagePrivate(page);
 out:	/* the only exit (for tracing and debugging) */
 	return page;
 }
-- 
2.18.4