5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
[ Upstream commit a14c573870a664386adc10526a6c2648ea56dae1 ]
ksmbd threads eating masses of cputime when connection is disconnected.
If connection is disconnected, ksmbd thread waits for pending requests
to be processed using schedule_timeout. schedule_timeout() incorrectly
is used, and it is more efficient to use wait_event/wake_up than to check
r_count every time with timeout.
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Reviewed-by: Hyunchul Lee <hyc.lee@xxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ksmbd/connection.c | 6 +++---
fs/ksmbd/connection.h | 1 +
fs/ksmbd/oplock.c | 35 ++++++++++++++++++++++-------------
fs/ksmbd/server.c | 8 +++++++-
4 files changed, 33 insertions(+), 17 deletions(-)
--- a/fs/ksmbd/connection.c
+++ b/fs/ksmbd/connection.c
@@ -66,6 +66,7 @@ struct ksmbd_conn *ksmbd_conn_alloc(void
conn->outstanding_credits = 0;
init_waitqueue_head(&conn->req_running_q);
+ init_waitqueue_head(&conn->r_count_q);
INIT_LIST_HEAD(&conn->conns_list);
INIT_LIST_HEAD(&conn->requests);
INIT_LIST_HEAD(&conn->async_requests);
@@ -165,7 +166,6 @@ int ksmbd_conn_write(struct ksmbd_work *
struct kvec iov[3];
int iov_idx = 0;
- ksmbd_conn_try_dequeue_request(work);
if (!work->response_buf) {
pr_err("NULL response header\n");
return -EINVAL;
@@ -358,8 +358,8 @@ int ksmbd_conn_handler_loop(void *p)
out:
/* Wait till all reference dropped to the Server object*/
- while (atomic_read(&conn->r_count) > 0)
- schedule_timeout(HZ);
+ wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);
+
unload_nls(conn->local_nls);
if (default_conn_ops.terminate_fn)
--- a/fs/ksmbd/connection.h
+++ b/fs/ksmbd/connection.h
@@ -58,6 +58,7 @@ struct ksmbd_conn {
unsigned int outstanding_credits;
spinlock_t credits_lock;
wait_queue_head_t req_running_q;
+ wait_queue_head_t r_count_q;
/* Lock to protect requests list*/
spinlock_t request_lock;
struct list_head requests;
--- a/fs/ksmbd/oplock.c
+++ b/fs/ksmbd/oplock.c
@@ -616,18 +616,13 @@ static void __smb2_oplock_break_noti(str
struct ksmbd_file *fp;
fp = ksmbd_lookup_durable_fd(br_info->fid);
- if (!fp) {
- atomic_dec(&conn->r_count);
- ksmbd_free_work_struct(work);
- return;
- }
+ if (!fp)
+ goto out;
if (allocate_oplock_break_buf(work)) {
pr_err("smb2_allocate_rsp_buf failed! ");
- atomic_dec(&conn->r_count);
ksmbd_fd_put(work, fp);
- ksmbd_free_work_struct(work);
- return;
+ goto out;
}
rsp_hdr = smb2_get_msg(work->response_buf);
@@ -668,8 +663,16 @@ static void __smb2_oplock_break_noti(str
ksmbd_fd_put(work, fp);
ksmbd_conn_write(work);
+
+out:
ksmbd_free_work_struct(work);
- atomic_dec(&conn->r_count);
+ /*
+ * Checking waitqueue to dropping pending requests on
+ * disconnection. waitqueue_active is safe because it
+ * uses atomic operation for condition.
+ */
+ if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
+ wake_up(&conn->r_count_q);
}
/**
@@ -732,9 +735,7 @@ static void __smb2_lease_break_noti(stru
if (allocate_oplock_break_buf(work)) {
ksmbd_debug(OPLOCK, "smb2_allocate_rsp_buf failed! ");
- ksmbd_free_work_struct(work);
- atomic_dec(&conn->r_count);
- return;
+ goto out;
}
rsp_hdr = smb2_get_msg(work->response_buf);
@@ -772,8 +773,16 @@ static void __smb2_lease_break_noti(stru
inc_rfc1001_len(work->response_buf, 44);
ksmbd_conn_write(work);
+
+out:
ksmbd_free_work_struct(work);
- atomic_dec(&conn->r_count);
+ /*
+ * Checking waitqueue to dropping pending requests on
+ * disconnection. waitqueue_active is safe because it
+ * uses atomic operation for condition.
+ */
+ if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
+ wake_up(&conn->r_count_q);
}
/**
--- a/fs/ksmbd/server.c
+++ b/fs/ksmbd/server.c
@@ -266,7 +266,13 @@ static void handle_ksmbd_work(struct wor
ksmbd_conn_try_dequeue_request(work);
ksmbd_free_work_struct(work);
- atomic_dec(&conn->r_count);
+ /*
+ * Checking waitqueue to dropping pending requests on
+ * disconnection. waitqueue_active is safe because it
+ * uses atomic operation for condition.
+ */
+ if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
+ wake_up(&conn->r_count_q);
}
/**
