[PATCH AUTOSEL 6.7 39/44] nvmet-fc: avoid deadlock on delete association path

Sasha Levin
2024-02-07T21:23:15Z

From: Daniel Wagner <dwagner@suse.de>

[ Upstream commit 710c69dbaccdac312e32931abcb8499c1525d397 ]

When deleting an association the shutdown path is deadlocking because we
try to flush the nvmet_wq nested. Avoid this by deadlock by deferring
the put work into its own work item.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/target/fc.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index 1eda4fa0ae06..4793d1c64401 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -111,6 +111,8 @@ struct nvmet_fc_tgtport {
struct nvmet_fc_port_entry *pe;
struct kref ref;
u32 max_sg_cnt;
+
+ struct work_struct put_work;
};

struct nvmet_fc_port_entry {
@@ -247,6 +249,13 @@ static int nvmet_fc_tgt_a_get(struct nvmet_fc_tgt_assoc *assoc);
static void nvmet_fc_tgt_q_put(struct nvmet_fc_tgt_queue *queue);
static int nvmet_fc_tgt_q_get(struct nvmet_fc_tgt_queue *queue);
static void nvmet_fc_tgtport_put(struct nvmet_fc_tgtport *tgtport);
+static void nvmet_fc_put_tgtport_work(struct work_struct *work)
+{
+ struct nvmet_fc_tgtport *tgtport =
+ container_of(work, struct nvmet_fc_tgtport, put_work);
+
+ nvmet_fc_tgtport_put(tgtport);
+}
static int nvmet_fc_tgtport_get(struct nvmet_fc_tgtport *tgtport);
static void nvmet_fc_handle_fcp_rqst(struct nvmet_fc_tgtport *tgtport,
struct nvmet_fc_fcp_iod *fod);
@@ -358,7 +367,7 @@ __nvmet_fc_finish_ls_req(struct nvmet_fc_ls_req_op *lsop)

if (!lsop->req_queued) {
spin_unlock_irqrestore(&tgtport->lock, flags);
- goto out_puttgtport;
+ goto out_putwork;
}

list_del(&lsop->lsreq_list);
@@ -371,8 +380,8 @@ __nvmet_fc_finish_ls_req(struct nvmet_fc_ls_req_op *lsop)
(lsreq->rqstlen + lsreq->rsplen),
DMA_BIDIRECTIONAL);

-out_puttgtport:
- nvmet_fc_tgtport_put(tgtport);
+out_putwork:
+ queue_work(nvmet_wq, &tgtport->put_work);
}

static int
@@ -1397,6 +1406,7 @@ nvmet_fc_register_targetport(struct nvmet_fc_port_info *pinfo,
kref_init(&newrec->ref);
ida_init(&newrec->assoc_cnt);
newrec->max_sg_cnt = template->max_sgl_segments;
+ INIT_WORK(&newrec->put_work, nvmet_fc_put_tgtport_work);

ret = nvmet_fc_alloc_ls_iodlist(newrec);
if (ret) {
--
2.43.0