[Devel] [RFC PATCH vz9 v3 09/11] ploop: convert suspended_pios list to use lockless list

[Alexander Atanasov]

Signed-off-by: Alexander Atanasov <alexander.atana...@virtuozzo.com>
---
 drivers/md/dm-ploop-cmd.c    | 13 +++++++++++--
 drivers/md/dm-ploop-map.c    |  2 +-
 drivers/md/dm-ploop-target.c |  2 +-
 drivers/md/dm-ploop.h        |  2 +-
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 61daaf8415c9..006495d95db3 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -124,14 +124,23 @@ ALLOW_ERROR_INJECTION(ploop_inflight_bios_ref_switch, 
ERRNO);
 static void ploop_resume_submitting_pios(struct ploop *ploop)
 {
        LIST_HEAD(list);
+       struct llist_node *suspended_pending;
 
        spin_lock_irq(&ploop->deferred_lock);
        WARN_ON_ONCE(!ploop->stop_submitting_pios);
        ploop->stop_submitting_pios = false;
-       list_splice_tail_init(&ploop->suspended_pios, &list);
        spin_unlock_irq(&ploop->deferred_lock);
 
-       ploop_submit_embedded_pios(ploop, &list);
+       suspended_pending = llist_del_all(&ploop->llsuspended_pios);
+       if (suspended_pending) {
+               struct llist_node *pos, *t;
+               suspended_pending = llist_reverse_order(suspended_pending);
+               llist_for_each_safe(pos, t, suspended_pending) {
+                       struct pio *pio = list_entry((struct list_head *)pos, 
typeof(*pio), list);
+                       list_add(&pio->list, &list);
+               }
+               ploop_submit_embedded_pios(ploop, &list);
+       }
 }
 
 static int ploop_suspend_submitting_pios(struct ploop *ploop)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 4bd3e4c557f8..d93e96857d02 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -1870,7 +1870,7 @@ static void ploop_submit_embedded_pio(struct ploop 
*ploop, struct pio *pio)
 
        spin_lock_irqsave(&ploop->deferred_lock, flags);
        if (unlikely(ploop->stop_submitting_pios)) {
-               list_add_tail(&pio->list, &ploop->suspended_pios);
+               llist_add((struct llist_node *)(&pio->list), 
&ploop->llsuspended_pios);
                queue = false;
                goto unlock;
        }
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 3ac9e1f832f5..94d6f661f50c 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -370,7 +370,7 @@ static int ploop_ctr(struct dm_target *ti, unsigned int 
argc, char **argv)
        spin_lock_init(&ploop->inflight_lock);
        spin_lock_init(&ploop->deferred_lock);
 
-       INIT_LIST_HEAD(&ploop->suspended_pios);
+       init_llist_head(&ploop->llsuspended_pios);
 
        for (i = 0; i < PLOOP_LIST_COUNT; i++)
                INIT_LIST_HEAD(&ploop->pios[i]);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index f7d4a4af3381..7e7f82aa1402 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -190,7 +190,7 @@ struct ploop {
        bool inflight_ref_comp_pending;
        unsigned int inflight_bios_ref_index:1;
 
-       struct list_head suspended_pios;
+       struct llist_head llsuspended_pios;
        bool stop_submitting_pios;
 
        spinlock_t inflight_lock;
-- 
2.43.0

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