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RDMA/rtrs-clt: Avoid run destroy_con_cq_qp/create_con_cq_qp in parallel

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It could happen two kworkers race with each other:

        CPU0                             CPU1
    addr_resolver kworker           reconnect kworker
    rtrs_clt_rdma_cm_handler
    rtrs_rdma_addr_resolved
    create_con_cq_qp: s.dev_ref++
    "s.dev_ref is 1"
                                    wait in create_cm fails with TIMEOUT
                                    destroy_con_cq_qp: --s.dev_ref
                                    "s.dev_ref is 0"
                                    destroy_con_cq_qp: sess->s.dev = NULL
     rtrs_cq_qp_create -> create_qp(con, sess->dev->ib_pd...)
    sess->dev is NULL, panic.

To fix the problem using mutex to serialize create_con_cq_qp and
destroy_con_cq_qp.

Fixes: 6a98d71dae ("RDMA/rtrs: client: main functionality")
Link: https://lore.kernel.org/r/20201023074353.21946-4-jinpu.wang@cloud.ionos.com
Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Reviewed-by: Gioh Kim <gi-oh.kim@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jack Wang
2020-10-23 09:43:44 +02:00
committed by Jason Gunthorpe
parent 73385fdbc4
commit fcf2959da6
2 changed files with 14 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
drivers/infiniband/ulp/rtrs/rtrs-clt.c
View File

@@ -1499,6 +1499,7 @@ static int create_con(struct rtrs_clt_sess *sess, unsigned int cid)
con->c.cid = cid;
con->c.sess = &sess->s;
atomic_set(&con->io_cnt, 0);
mutex_init(&con->con_mutex);
sess->s.con[cid] = &con->c;
@@ -1510,6 +1511,7 @@ static void destroy_con(struct rtrs_clt_con *con)
struct rtrs_clt_sess *sess = to_clt_sess(con->c.sess);
sess->s.con[con->c.cid] = NULL;
mutex_destroy(&con->con_mutex);
kfree(con);
}
@@ -1520,6 +1522,7 @@ static int create_con_cq_qp(struct rtrs_clt_con *con)
int err, cq_vector;
struct rtrs_msg_rkey_rsp *rsp;
lockdep_assert_held(&con->con_mutex);
if (con->c.cid == 0) {
/*
* One completion for each receive and two for each send
@@ -1593,7 +1596,7 @@ static void destroy_con_cq_qp(struct rtrs_clt_con *con)
* Be careful here: destroy_con_cq_qp() can be called even
* create_con_cq_qp() failed, see comments there.
*/
lockdep_assert_held(&con->con_mutex);
rtrs_cq_qp_destroy(&con->c);
if (con->rsp_ius) {
rtrs_iu_free(con->rsp_ius, DMA_FROM_DEVICE,
@@ -1625,7 +1628,9 @@ static int rtrs_rdma_addr_resolved(struct rtrs_clt_con *con)
struct rtrs_sess *s = con->c.sess;
int err;
mutex_lock(&con->con_mutex);
err = create_con_cq_qp(con);
mutex_unlock(&con->con_mutex);
if (err) {
rtrs_err(s, "create_con_cq_qp(), err: %d\n", err);
return err;
@@ -1938,8 +1943,9 @@ static int create_cm(struct rtrs_clt_con *con)
errr:
stop_cm(con);
/* Is safe to call destroy if cq_qp is not inited */
mutex_lock(&con->con_mutex);
destroy_con_cq_qp(con);
mutex_unlock(&con->con_mutex);
destroy_cm:
destroy_cm(con);
@@ -2046,7 +2052,9 @@ static void rtrs_clt_stop_and_destroy_conns(struct rtrs_clt_sess *sess)
if (!sess->s.con[cid])
break;
con = to_clt_con(sess->s.con[cid]);
mutex_lock(&con->con_mutex);
destroy_con_cq_qp(con);
mutex_unlock(&con->con_mutex);
destroy_cm(con);
destroy_con(con);
}
@@ -2213,7 +2221,10 @@ static int init_conns(struct rtrs_clt_sess *sess)
struct rtrs_clt_con *con = to_clt_con(sess->s.con[cid]);
stop_cm(con);
mutex_lock(&con->con_mutex);
destroy_con_cq_qp(con);
mutex_unlock(&con->con_mutex);
destroy_cm(con);
destroy_con(con);
}

1
drivers/infiniband/ulp/rtrs/rtrs-clt.h
View File

@@ -72,6 +72,7 @@ struct rtrs_clt_con {
struct rtrs_iu *rsp_ius;
u32 queue_size;
unsigned int cpu;
struct mutex con_mutex;
atomic_t io_cnt;
int cm_err;
};