From a14c573870a664386adc10526a6c2648ea56dae1 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Thu, 28 Jul 2022 23:35:18 +0900 Subject: [PATCH] ksmbd: use wait_event instead of schedule_timeout() 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 Reviewed-by: Hyunchul Lee Signed-off-by: Steve French --- 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(-) diff --git a/fs/ksmbd/connection.c b/fs/ksmbd/connection.c index ce23cc89046e..756ad631c019 100644 --- 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 *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; @@ -347,8 +347,8 @@ 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) diff --git a/fs/ksmbd/connection.h b/fs/ksmbd/connection.h index 5b39f0bdeff8..2e4730457c92 100644 --- a/fs/ksmbd/connection.h +++ b/fs/ksmbd/connection.h @@ -65,6 +65,7 @@ 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; diff --git a/fs/ksmbd/oplock.c b/fs/ksmbd/oplock.c index 8b5560574d4c..3ef33ed4cdba 100644 --- a/fs/ksmbd/oplock.c +++ b/fs/ksmbd/oplock.c @@ -615,18 +615,13 @@ static void __smb2_oplock_break_noti(struct work_struct *wk) 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); @@ -667,8 +662,16 @@ static void __smb2_oplock_break_noti(struct work_struct *wk) 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); } /** @@ -731,9 +734,7 @@ static void __smb2_lease_break_noti(struct work_struct *wk) 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); @@ -771,8 +772,16 @@ static void __smb2_lease_break_noti(struct work_struct *wk) 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); } /** diff --git a/fs/ksmbd/server.c b/fs/ksmbd/server.c index 4cd03d661df0..ce42bff42ef9 100644 --- a/fs/ksmbd/server.c +++ b/fs/ksmbd/server.c @@ -261,7 +261,13 @@ static void handle_ksmbd_work(struct work_struct *wk) 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); } /**