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Message-ID: <20240131085112.21668-13-dwagner@suse.de>
Date: Wed, 31 Jan 2024 09:51:12 +0100
From: Daniel Wagner <dwagner@...e.de>
To: James Smart <james.smart@...adcom.com>
Cc: Keith Busch <kbusch@...nel.org>,
Christoph Hellwig <hch@....de>,
Hannes Reinecke <hare@...e.de>,
linux-nvme@...ts.infradead.org,
linux-kernel@...r.kernel.org,
Daniel Wagner <dwagner@...e.de>
Subject: [PATCH v5 12/12] nvmet-fc: use RCU list iterator for assoc_list
The assoc_list is a RCU protected list, thus use the RCU flavor of list
functions.
Let's use this opportunity and refactor this code and move the lookup
into a helper and give it a descriptive name.
Signed-off-by: Daniel Wagner <dwagner@...e.de>
---
drivers/nvme/target/fc.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 671d096745a5..fd229f310c93 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -1114,14 +1114,27 @@ nvmet_fc_schedule_delete_assoc(struct nvmet_fc_tgt_assoc *assoc)
queue_work(nvmet_wq, &assoc->del_work);
}
+static bool
+nvmet_fc_assoc_exits(struct nvmet_fc_tgtport *tgtport, u64 association_id)
+{
+ struct nvmet_fc_tgt_assoc *a;
+
+ list_for_each_entry_rcu(a, &tgtport->assoc_list, a_list) {
+ if (association_id == a->association_id)
+ return true;
+ }
+
+ return false;
+}
+
static struct nvmet_fc_tgt_assoc *
nvmet_fc_alloc_target_assoc(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
{
- struct nvmet_fc_tgt_assoc *assoc, *tmpassoc;
+ struct nvmet_fc_tgt_assoc *assoc;
unsigned long flags;
+ bool done;
u64 ran;
int idx;
- bool needrandom = true;
if (!tgtport->pe)
return NULL;
@@ -1145,24 +1158,21 @@ nvmet_fc_alloc_target_assoc(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
INIT_WORK(&assoc->del_work, nvmet_fc_delete_assoc_work);
atomic_set(&assoc->terminating, 0);
- while (needrandom) {
+ done = false;
+ do {
get_random_bytes(&ran, sizeof(ran) - BYTES_FOR_QID);
ran = ran << BYTES_FOR_QID_SHIFT;
spin_lock_irqsave(&tgtport->lock, flags);
- needrandom = false;
- list_for_each_entry(tmpassoc, &tgtport->assoc_list, a_list) {
- if (ran == tmpassoc->association_id) {
- needrandom = true;
- break;
- }
- }
- if (!needrandom) {
+ rcu_read_lock();
+ if (!nvmet_fc_assoc_exits(tgtport, ran)) {
assoc->association_id = ran;
list_add_tail_rcu(&assoc->a_list, &tgtport->assoc_list);
+ done = true;
}
+ rcu_read_unlock();
spin_unlock_irqrestore(&tgtport->lock, flags);
- }
+ } while (!done);
return assoc;
--
2.43.0
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