[PATCH] dm writecache: reinitialize lru in writeback instead of endio

[Huaisheng Ye <yehs2007@zoho.com>]

From: Huaisheng Ye <yehs1@lenovo.com>

When wc_entry has been removed from wbl->list in writeback, it will
be not used again except waiting to be set free in writecache_free_entry.

That is a little of annoying, it has to reinitialize lru of wc_entry
in endio before calling writecache_free_entry.

Using list_del_init instead of list_del in writeback for simpler code.

Signed-off-by: Huaisheng Ye <yehs1@lenovo.com>
---
 drivers/md/dm-writecache.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 7bbc21b..66f3a3b 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -1519,7 +1519,6 @@ static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *
 			e = wb->wc_list[i];
 			BUG_ON(!e->write_in_progress);
 			e->write_in_progress = false;
-			INIT_LIST_HEAD(&e->lru);
 			if (!writecache_has_error(wc))
 				writecache_free_entry(wc, e);
 			BUG_ON(!wc->writeback_size);
@@ -1555,7 +1554,6 @@ static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *l
 		do {
 			BUG_ON(!e->write_in_progress);
 			e->write_in_progress = false;
-			INIT_LIST_HEAD(&e->lru);
 			if (!writecache_has_error(wc))
 				writecache_free_entry(wc, e);
 
@@ -1654,7 +1652,7 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
 	while (wbl->size) {
 		wbl->size--;
 		e = container_of(wbl->list.prev, struct wc_entry, lru);
-		list_del(&e->lru);
+		list_del_init(&e->lru);
 
 		max_pages = e->wc_list_contiguous;
 
@@ -1685,7 +1683,7 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba
 			if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
 				break;
 			wbl->size--;
-			list_del(&f->lru);
+			list_del_init(&f->lru);
 			wb->wc_list[wb->wc_list_n++] = f;
 			e = f;
 		}
@@ -1712,7 +1710,7 @@ static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writebac
 
 		wbl->size--;
 		e = container_of(wbl->list.prev, struct wc_entry, lru);
-		list_del(&e->lru);
+		list_del_init(&e->lru);
 
 		n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
 
@@ -1732,7 +1730,7 @@ static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writebac
 			wbl->size--;
 			f = container_of(wbl->list.prev, struct wc_entry, lru);
 			BUG_ON(f != e + 1);
-			list_del(&f->lru);
+			list_del_init(&f->lru);
 			e = f;
 		}
 
-- 
1.8.3.1