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Commit a34fbc63 authored by Patrick Caulfield's avatar Patrick Caulfield Committed by Steven Whitehouse
Browse files

[DLM] fix softlockup in dlm_recv 



This patch stops the dlm_recv workqueue from busy-waiting when a node
disconnects. This can cause soft lockup errors on debug systems and bad
performance generally.

Signed-Off-By: default avatarPatrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent 62a0f623

fs/dlm/lowcomms-tcp.c

+9 −6
Original line number Original line Diff line number Diff line
@@ -2,7 +2,7 @@ 
*******************************************************************************

*******************************************************************************

**

**

**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.

**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.

**  Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.

**  Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.

**

**

**  This copyrighted material is made available to anyone wishing to use,

**  This copyrighted material is made available to anyone wishing to use,

**  modify, copy, or redistribute it subject to the terms and conditions

**  modify, copy, or redistribute it subject to the terms and conditions
@@ -109,7 +109,6 @@ struct connection { 
	struct page *rx_page;

	struct page *rx_page;

	struct cbuf cb;

	struct cbuf cb;

	int retries;

	int retries;

	atomic_t waiting_requests;

#define MAX_CONNECT_RETRIES 3

#define MAX_CONNECT_RETRIES 3

	struct connection *othercon;

	struct connection *othercon;

	struct work_struct rwork; /* Receive workqueue */

	struct work_struct rwork; /* Receive workqueue */
@@ -278,8 +277,11 @@ static int receive_from_sock(struct connection *con) 




	mutex_lock(&con->sock_mutex);

	mutex_lock(&con->sock_mutex);





	if (con->sock == NULL)

	if (con->sock == NULL) {

		goto out;

		ret = -EAGAIN;

		goto out_close;

	}



	if (con->rx_page == NULL) {

	if (con->rx_page == NULL) {

		/*

		/*

		 * This doesn't need to be atomic, but I think it should

		 * This doesn't need to be atomic, but I think it should
@@ -352,7 +354,6 @@ static int receive_from_sock(struct connection *con) 
		con->rx_page = NULL;

		con->rx_page = NULL;

	}

	}





out:

	if (call_again_soon)

	if (call_again_soon)

		goto out_resched;

		goto out_resched;

	mutex_unlock(&con->sock_mutex);

	mutex_unlock(&con->sock_mutex);
@@ -370,6 +371,9 @@ static int receive_from_sock(struct connection *con) 
		close_connection(con, false);

		close_connection(con, false);

		/* Reconnect when there is something to send */

		/* Reconnect when there is something to send */

	}

	}

	/* Don't return success if we really got EOF */

	if (ret == 0)

		ret = -EAGAIN;





	return ret;

	return ret;

}

}
@@ -847,7 +851,6 @@ int dlm_lowcomms_close(int nodeid) 
	if (con) {

	if (con) {

		clean_one_writequeue(con);

		clean_one_writequeue(con);

		close_connection(con, true);

		close_connection(con, true);

		atomic_set(&con->waiting_requests, 0);

	}

	}

	return 0;

	return 0;