RE: [PATCH v4 07/10] ntb_tool: Add link status and files to debugfs

RE: [PATCH v4 07/10] ntb_tool: Add link status and files to debugfs

[Allen Hubbe]

From: Logan Gunthorpe
> In order to more successfully script with ntb_tool it's useful to
> have a link file to check the link status so that the script
> doesn't use the other files until the link is up.
> 
> This commit adds a 'link' file to the debugfs directory which reads
> boolean (Y or N) depending on the link status. Writing to the file
> change the link state using ntb_link_enable or ntb_link_disable.
> 
> A 'link_event' file is also provided so an application can block until
> the link changes to the desired state. If the user writes a 1, it will
> block until the link is up. If the user writes a 0, it will block until
> the link is down.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>

Acked-by: Allen Hubbe <Allen.Hubbe@emc.com>

> ---
>  drivers/ntb/test/ntb_tool.c | 92 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 92 insertions(+)
> 
> diff --git a/drivers/ntb/test/ntb_tool.c b/drivers/ntb/test/ntb_tool.c
> index 031723d..b7f4f4e 100644
> --- a/drivers/ntb/test/ntb_tool.c
> +++ b/drivers/ntb/test/ntb_tool.c
> @@ -59,6 +59,12 @@
>   *
>   * Eg: check if clearing the doorbell mask generates an interrupt.
>   *
> + * # Check the link status
> + * root@self# cat $DBG_DIR/link
> + *
> + * # Block until the link is up
> + * root@self# echo Y > $DBG_DIR/link_event
> + *
>   * # Set the doorbell mask
>   * root@self# echo 's 1' > $DBG_DIR/mask
>   *
> @@ -131,6 +137,7 @@ struct tool_mw {
>  struct tool_ctx {
>  	struct ntb_dev *ntb;
>  	struct dentry *dbgfs;
> +	wait_queue_head_t link_wq;
>  	int mw_count;
>  	struct tool_mw mws[MAX_MWS];
>  };
> @@ -159,6 +166,7 @@ static void tool_link_event(void *ctx)
>  	dev_dbg(&tc->ntb->dev, "link is %s speed %d width %d\n",
>  		up ? "up" : "down", speed, width);
> 
> +	wake_up(&tc->link_wq);
>  }
> 
>  static void tool_db_event(void *ctx, int vec)
> @@ -473,6 +481,83 @@ static TOOL_FOPS_RDWR(tool_peer_spad_fops,
>  		      tool_peer_spad_read,
>  		      tool_peer_spad_write);
> 
> +static ssize_t tool_link_read(struct file *filep, char __user *ubuf,
> +			      size_t size, loff_t *offp)
> +{
> +	struct tool_ctx *tc = filep->private_data;
> +	char buf[3];
> +
> +	buf[0] = ntb_link_is_up(tc->ntb, NULL, NULL) ? 'Y' : 'N';
> +	buf[1] = '\n';
> +	buf[2] = '\0';
> +
> +	return simple_read_from_buffer(ubuf, size, offp, buf, 2);
> +}
> +
> +static ssize_t tool_link_write(struct file *filep, const char __user *ubuf,
> +			       size_t size, loff_t *offp)
> +{
> +	struct tool_ctx *tc = filep->private_data;
> +	char buf[32];
> +	size_t buf_size;
> +	bool val;
> +	int rc;
> +
> +	buf_size = min(size, (sizeof(buf) - 1));
> +	if (copy_from_user(buf, ubuf, buf_size))
> +		return -EFAULT;
> +
> +	buf[buf_size] = '\0';
> +
> +	rc = strtobool(buf, &val);
> +	if (rc)
> +		return rc;
> +
> +	if (val)
> +		rc = ntb_link_enable(tc->ntb, NTB_SPEED_AUTO, NTB_WIDTH_AUTO);
> +	else
> +		rc = ntb_link_disable(tc->ntb);
> +
> +	if (rc)
> +		return rc;
> +
> +	return size;
> +}
> +
> +static TOOL_FOPS_RDWR(tool_link_fops,
> +		      tool_link_read,
> +		      tool_link_write);
> +
> +static ssize_t tool_link_event_write(struct file *filep,
> +				     const char __user *ubuf,
> +				     size_t size, loff_t *offp)
> +{
> +	struct tool_ctx *tc = filep->private_data;
> +	char buf[32];
> +	size_t buf_size;
> +	bool val;
> +	int rc;
> +
> +	buf_size = min(size, (sizeof(buf) - 1));
> +	if (copy_from_user(buf, ubuf, buf_size))
> +		return -EFAULT;
> +
> +	buf[buf_size] = '\0';
> +
> +	rc = strtobool(buf, &val);
> +	if (rc)
> +		return rc;
> +
> +	if (wait_event_interruptible(tc->link_wq,
> +		ntb_link_is_up(tc->ntb, NULL, NULL) == val))
> +		return -ERESTART;
> +
> +	return size;
> +}
> +
> +static TOOL_FOPS_RDWR(tool_link_event_fops,
> +		      NULL,
> +		      tool_link_event_write);
> 
>  static ssize_t tool_mw_read(struct file *filep, char __user *ubuf,
>  			    size_t size, loff_t *offp)
> @@ -793,6 +878,12 @@ static void tool_setup_dbgfs(struct tool_ctx *tc)
>  	debugfs_create_file("peer_spad", S_IRUSR | S_IWUSR, tc->dbgfs,
>  			    tc, &tool_peer_spad_fops);
> 
> +	debugfs_create_file("link", S_IRUSR | S_IWUSR, tc->dbgfs,
> +			    tc, &tool_link_fops);
> +
> +	debugfs_create_file("link_event", S_IWUSR, tc->dbgfs,
> +			    tc, &tool_link_event_fops);
> +
>  	for (i = 0; i < tc->mw_count; i++) {
>  		char buf[30];
> 
> @@ -825,6 +916,7 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
>  	}
> 
>  	tc->ntb = ntb;
> +	init_waitqueue_head(&tc->link_wq);
> 
>  	tc->mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
>  	for (i = 0; i < tc->mw_count; i++) {
> --
> 2.1.4

RE: [PATCH v4 09/10] ntb_test: Add a selftest script for the NTB subsystem

[Allen Hubbe]

From: Logan Gunthorpe
> This script automates testing doorbells, scratchpads and memory windows
> for an NTB device. It can be run locally, with the NTB looped
> back to the same host or use SSH to remotely control the second host.
> 
> In the single host case, the script just needs to be passed two
> arguments: a PCI ID for each side of the link. In the two host case
> the -r option must be used to specify the remote hostname (which must
> be SSH accessible and should probably have ssh-keys exchanged).
> 
> A sample run looks like this:
> 
> $ sudo ./ntb_test.sh 0000:03:00.1 0000:83:00.1 -p 29
> Starting ntb_tool tests...
> Running link tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> Running link tests on: 0000:83:00.1 / 0000:03:00.1
>   Passed
> Running db tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> Running db tests on: 0000:83:00.1 / 0000:03:00.1
>   Passed
> Running spad tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> Running spad tests on: 0000:83:00.1 / 0000:03:00.1
>   Passed
> Running mw0 tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> Running mw0 tests on: 0000:83:00.1 / 0000:03:00.1
>   Passed
> Running mw1 tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> Running mw1 tests on: 0000:83:00.1 / 0000:03:00.1
>   Passed
> 
> Starting ntb_pingpong tests...
> Running ping pong tests on: 0000:03:00.1 / 0000:83:00.1
>   Passed
> 
> Starting ntb_perf tests...
> Running local perf test without DMA
>   0: copied 536870912 bytes in 164453 usecs, 3264 MBytes/s
>   Passed
> Running remote perf test without DMA
>   0: copied 536870912 bytes in 164453 usecs, 3264 MBytes/s
>   Passed
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
> Acked-by: Shuah Khan <shuahkh@osg.samsung.com>

Acked-by: Allen Hubbe <Allen.Hubbe@emc.com>

> ---
>  MAINTAINERS                             |   1 +
>  tools/testing/selftests/ntb/ntb_test.sh | 422 ++++++++++++++++++++++++++++++++
>  2 files changed, 423 insertions(+)
>  create mode 100755 tools/testing/selftests/ntb/ntb_test.sh
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 9c567a4..f178e7e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7846,6 +7846,7 @@ F:	drivers/ntb/
>  F:	drivers/net/ntb_netdev.c
>  F:	include/linux/ntb.h
>  F:	include/linux/ntb_transport.h
> +F:	tools/testing/selftests/ntb/
> 
>  NTB INTEL DRIVER
>  M:	Jon Mason <jdmason@kudzu.us>
> diff --git a/tools/testing/selftests/ntb/ntb_test.sh
> b/tools/testing/selftests/ntb/ntb_test.sh
> new file mode 100755
> index 0000000..a676d3e
> --- /dev/null
> +++ b/tools/testing/selftests/ntb/ntb_test.sh
> @@ -0,0 +1,422 @@
> +#!/bin/bash
> +# Copyright (c) 2016 Microsemi. All Rights Reserved.
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License as
> +# published by the Free Software Foundation; either version 2 of
> +# the License, or (at your option) any later version.
> +#
> +# This program is distributed in the hope that it would be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# Author: Logan Gunthorpe <logang@deltatee.com>
> +
> +REMOTE_HOST=
> +LIST_DEVS=FALSE
> +
> +DEBUGFS=${DEBUGFS-/sys/kernel/debug}
> +
> +PERF_RUN_ORDER=32
> +MAX_MW_SIZE=0
> +RUN_DMA_TESTS=
> +DONT_CLEANUP=
> +MW_SIZE=65536
> +
> +function show_help()
> +{
> +	echo "Usage: $0 [OPTIONS] LOCAL_DEV REMOTE_DEV"
> +	echo "Run tests on a pair of NTB endpoints."
> +	echo
> +	echo "If the NTB device loops back to the same host then,"
> +	echo "just specifying the two PCI ids on the command line is"
> +	echo "sufficient. Otherwise, if the NTB link spans two hosts"
> +	echo "use the -r option to specify the hostname for the remote"
> +	echo "device. SSH will then be used to test the remote side."
> +	echo "An SSH key between the root users of the host would then"
> +	echo "be highly recommended."
> +	echo
> +	echo "Options:"
> +	echo "  -C              don't cleanup ntb modules on exit"
> +	echo "  -d              run dma tests"
> +	echo "  -h              show this help message"
> +	echo "  -l              list available local and remote PCI ids"
> +	echo "  -r REMOTE_HOST  specify the remote's hostname to connect"
> +        echo "                  to for the test (using ssh)"
> +	echo "  -p NUM          ntb_perf run order (default: $PERF_RUN_ORDER)"
> +	echo "  -w max_mw_size  maxmium memory window size"
> +	echo
> +}
> +
> +function parse_args()
> +{
> +	OPTIND=0
> +	while getopts "Cdhlm:r:p:w:" opt; do
> +		case "$opt" in
> +		C)  DONT_CLEANUP=1 ;;
> +		d)  RUN_DMA_TESTS=1 ;;
> +		h)  show_help; exit 0 ;;
> +		l)  LIST_DEVS=TRUE ;;
> +		m)  MW_SIZE=${OPTARG} ;;
> +		r)  REMOTE_HOST=${OPTARG} ;;
> +		p)  PERF_RUN_ORDER=${OPTARG} ;;
> +		w)  MAX_MW_SIZE=${OPTARG} ;;
> +		\?)
> +		    echo "Invalid option: -$OPTARG" >&2
> +		    exit 1
> +		    ;;
> +		esac
> +	done
> +}
> +
> +parse_args "$@"
> +shift $((OPTIND-1))
> +LOCAL_DEV=$1
> +shift
> +parse_args "$@"
> +shift $((OPTIND-1))
> +REMOTE_DEV=$1
> +shift
> +parse_args "$@"
> +
> +set -e
> +
> +function _modprobe()
> +{
> +        modprobe "$@"
> +}
> +
> +function split_remote()
> +{
> +	VPATH=$1
> +	REMOTE=
> +
> +	if [[ "$VPATH" == *":/"* ]]; then
> +		REMOTE=${VPATH%%:*}
> +		VPATH=${VPATH#*:}
> +	fi
> +}
> +
> +function read_file()
> +{
> +	split_remote $1
> +	if [[ "$REMOTE" != "" ]]; then
> +		ssh "$REMOTE" cat "$VPATH"
> +	else
> +		cat "$VPATH"
> +	fi
> +}
> +
> +function write_file()
> +{
> +	split_remote $2
> +	VALUE=$1
> +
> +	if [[ "$REMOTE" != "" ]]; then
> +		ssh "$REMOTE" "echo \"$VALUE\" > \"$VPATH\""
> +	else
> +		echo "$VALUE" > "$VPATH"
> +	fi
> +}
> +
> +function link_test()
> +{
> +	LOC=$1
> +	REM=$2
> +	EXP=0
> +
> +	echo "Running link tests on: $(basename $LOC) / $(basename $REM)"
> +
> +	if ! write_file "N" "$LOC/link" 2> /dev/null; then
> +		echo "  Unsupported"
> +		return
> +	fi
> +
> +	write_file "N" "$LOC/link_event"
> +
> +	if [[ $(read_file "$REM/link") != "N" ]]; then
> +		echo "Expected remote link to be down in $REM/link" >&2
> +		exit -1
> +	fi
> +
> +	write_file "Y" "$LOC/link"
> +	write_file "Y" "$LOC/link_event"
> +
> +	echo "  Passed"
> +}
> +
> +function doorbell_test()
> +{
> +	LOC=$1
> +	REM=$2
> +	EXP=0
> +
> +	echo "Running db tests on: $(basename $LOC) / $(basename $REM)"
> +
> +	write_file "c 0xFFFFFFFF" "$REM/db"
> +
> +	for ((i=1; i <= 8; i++)); do
> +		let DB=$(read_file "$REM/db") || true
> +		if [[ "$DB" != "$EXP" ]]; then
> +			echo "Doorbell doesn't match expected value $EXP " \
> +			     "in $REM/db" >&2
> +			exit -1
> +		fi
> +
> +		let "MASK=1 << ($i-1)" || true
> +		let "EXP=$EXP | $MASK" || true
> +		write_file "s $MASK" "$LOC/peer_db"
> +	done
> +
> +	echo "  Passed"
> +}
> +
> +function read_spad()
> +{
> +       VPATH=$1
> +       IDX=$2
> +
> +       ROW=($(read_file "$VPATH" | grep -e "^$IDX"))
> +       let VAL=${ROW[1]} || true
> +       echo $VAL
> +}
> +
> +function scratchpad_test()
> +{
> +	LOC=$1
> +	REM=$2
> +	CNT=$(read_file "$LOC/spad" | wc -l)
> +
> +	echo "Running spad tests on: $(basename $LOC) / $(basename $REM)"
> +
> +	for ((i = 0; i < $CNT; i++)); do
> +		VAL=$RANDOM
> +		write_file "$i $VAL" "$LOC/peer_spad"
> +		RVAL=$(read_spad "$REM/spad" $i)
> +
> +		if [[ "$VAL" != "$RVAL" ]]; then
> +			echo "Scratchpad doesn't match expected value $VAL " \
> +			     "in $REM/spad, got $RVAL" >&2
> +			exit -1
> +		fi
> +
> +	done
> +
> +	echo "  Passed"
> +}
> +
> +function write_mw()
> +{
> +	split_remote $2
> +
> +	if [[ "$REMOTE" != "" ]]; then
> +		ssh "$REMOTE" \
> +			dd if=/dev/urandom "of=$VPATH" 2> /dev/null || true
> +	else
> +		dd if=/dev/urandom "of=$VPATH" 2> /dev/null || true
> +	fi
> +}
> +
> +function mw_test()
> +{
> +	IDX=$1
> +	LOC=$2
> +	REM=$3
> +
> +	echo "Running $IDX tests on: $(basename $LOC) / $(basename $REM)"
> +
> +	write_mw "$LOC/$IDX"
> +
> +	split_remote "$LOC/$IDX"
> +	if [[ "$REMOTE" == "" ]]; then
> +		A=$VPATH
> +	else
> +		A=/tmp/ntb_test.$$.A
> +		ssh "$REMOTE" cat "$VPATH" > "$A"
> +	fi
> +
> +	split_remote "$REM/peer_$IDX"
> +	if [[ "$REMOTE" == "" ]]; then
> +		B=$VPATH
> +	else
> +		B=/tmp/ntb_test.$$.B
> +		ssh "$REMOTE" cat "$VPATH" > "$B"
> +	fi
> +
> +	cmp -n $MW_SIZE "$A" "$B"
> +	if [[ $? != 0 ]]; then
> +		echo "Memory window $MW did not match!" >&2
> +	fi
> +
> +	if [[ "$A" == "/tmp/*" ]]; then
> +		rm "$A"
> +	fi
> +
> +	if [[ "$B" == "/tmp/*" ]]; then
> +		rm "$B"
> +	fi
> +
> +	echo "  Passed"
> +}
> +
> +function pingpong_test()
> +{
> +	LOC=$1
> +	REM=$2
> +
> +	echo "Running ping pong tests on: $(basename $LOC) / $(basename $REM)"
> +
> +	LOC_START=$(read_file $LOC/count)
> +	REM_START=$(read_file $REM/count)
> +
> +	sleep 7
> +
> +	LOC_END=$(read_file $LOC/count)
> +	REM_END=$(read_file $REM/count)
> +
> +	if [[ $LOC_START == $LOC_END ]] || [[ $REM_START == $REM_END ]]; then
> +		echo "Ping pong counter not incrementing!" >&2
> +		exit 1
> +	fi
> +
> +	echo "  Passed"
> +}
> +
> +function perf_test()
> +{
> +	USE_DMA=$1
> +
> +	if [[ $USE_DMA == "1" ]]; then
> +		WITH="with"
> +	else
> +		WITH="without"
> +	fi
> +
> +	_modprobe ntb_perf run_order=$PERF_RUN_ORDER \
> +		max_mw_size=$MAX_MW_SIZE use_dma=$USE_DMA
> +
> +	echo "Running local perf test $WITH DMA"
> +	write_file "" $LOCAL_PERF/run
> +	echo -n "  "
> +	read_file $LOCAL_PERF/run
> +	echo "  Passed"
> +
> +	echo "Running remote perf test $WITH DMA"
> +	write_file "" $REMOTE_PERF/run
> +	echo -n "  "
> +	read_file $LOCAL_PERF/run
> +	echo "  Passed"
> +
> +	_modprobe -r ntb_perf
> +}
> +
> +function ntb_tool_tests()
> +{
> +	LOCAL_TOOL=$DEBUGFS/ntb_tool/$LOCAL_DEV
> +	REMOTE_TOOL=$REMOTE_HOST:$DEBUGFS/ntb_tool/$REMOTE_DEV
> +
> +	echo "Starting ntb_tool tests..."
> +
> +	_modprobe ntb_tool
> +
> +	write_file Y $LOCAL_TOOL/link_event
> +	write_file Y $REMOTE_TOOL/link_event
> +
> +	link_test $LOCAL_TOOL $REMOTE_TOOL
> +	link_test $REMOTE_TOOL $LOCAL_TOOL
> +
> +	for PEER_TRANS in $(ls $LOCAL_TOOL/peer_trans*); do
> +		PT=$(basename $PEER_TRANS)
> +		write_file $MW_SIZE $LOCAL_TOOL/$PT
> +		write_file $MW_SIZE $REMOTE_TOOL/$PT
> +	done
> +
> +	doorbell_test $LOCAL_TOOL $REMOTE_TOOL
> +	doorbell_test $REMOTE_TOOL $LOCAL_TOOL
> +	scratchpad_test $LOCAL_TOOL $REMOTE_TOOL
> +	scratchpad_test $REMOTE_TOOL $LOCAL_TOOL
> +
> +	for MW in $(ls $LOCAL_TOOL/mw*); do
> +		MW=$(basename $MW)
> +
> +		mw_test $MW $LOCAL_TOOL $REMOTE_TOOL
> +		mw_test $MW $REMOTE_TOOL $LOCAL_TOOL
> +	done
> +
> +	_modprobe -r ntb_tool
> +}
> +
> +function ntb_pingpong_tests()
> +{
> +	LOCAL_PP=$DEBUGFS/ntb_pingpong/$LOCAL_DEV
> +	REMOTE_PP=$REMOTE_HOST:$DEBUGFS/ntb_pingpong/$REMOTE_DEV
> +
> +	echo "Starting ntb_pingpong tests..."
> +
> +	_modprobe ntb_pingpong
> +
> +	pingpong_test $LOCAL_PP $REMOTE_PP
> +
> +	_modprobe -r ntb_pingpong
> +}
> +
> +function ntb_perf_tests()
> +{
> +	LOCAL_PERF=$DEBUGFS/ntb_perf/$LOCAL_DEV
> +	REMOTE_PERF=$REMOTE_HOST:$DEBUGFS/ntb_perf/$REMOTE_DEV
> +
> +	echo "Starting ntb_perf tests..."
> +
> +	perf_test 0
> +
> +	if [[ $RUN_DMA_TESTS ]]; then
> +		perf_test 1
> +	fi
> +}
> +
> +function cleanup()
> +{
> +	set +e
> +	_modprobe -r ntb_tool 2> /dev/null
> +	_modprobe -r ntb_perf 2> /dev/null
> +	_modprobe -r ntb_pingpong 2> /dev/null
> +	_modprobe -r ntb_transport 2> /dev/null
> +	set -e
> +}
> +
> +cleanup
> +
> +if ! [[ $$DONT_CLEANUP ]]; then
> +	trap cleanup EXIT
> +fi
> +
> +if [ "$(id -u)" != "0" ]; then
> +	echo "This script must be run as root" 1>&2
> +	exit 1
> +fi
> +
> +if [[ "$LIST_DEVS" == TRUE ]]; then
> +	echo "Local Devices:"
> +	ls -1 /sys/bus/ntb/devices
> +	echo
> +
> +	if [[ "$REMOTE_HOST" != "" ]]; then
> +		echo "Remote Devices:"
> +		ssh $REMOTE_HOST ls -1 /sys/bus/ntb/devices
> +	fi
> +
> +	exit 0
> +fi
> +
> +if [[ "$LOCAL_DEV" == $"" ]] || [[ "$REMOTE_DEV" == $"" ]]; then
> +	show_help
> +	exit 1
> +fi
> +
> +ntb_tool_tests
> +echo
> +ntb_pingpong_tests
> +echo
> +ntb_perf_tests
> +echo
> --
> 2.1.4

Re: [PATCH v4 10/10] ntb_perf: clear link_is_up flag when the link goes down.

[Jiang, Dave]

On Thu, 2016-06-16 at 14:17 -0600, Logan Gunthorpe wrote:
> When the link goes down, the link_is_up flag did not return to
> false. This could have caused some subtle corner case bugs
> when the link goes up and down quickly.
> 
> Once that was fixed, there was found to be a race if the link was
> brought down then immediately up. The link_cleanup work would
> occasionally be scheduled after the next link up event. This would
> cancel the link_work that was supposed to occur and leave ntb_perf
> in an unusable state.
> 
> To fix this we get rid of the link_cleanup work and put the actions
> directly in the link_down event.
> 
> Signed-off-by: Logan Gunthorpe <logang@deltatee.com>

Acked-by: Dave Jiang <dave.jiang@intel.com>

Also patches 1-3 Acked. 

> ---
>  drivers/ntb/test/ntb_perf.c | 28 +++++++++-------------------
>  1 file changed, 9 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/ntb/test/ntb_perf.c
> b/drivers/ntb/test/ntb_perf.c
> index f0784e5..6a50f20 100644
> --- a/drivers/ntb/test/ntb_perf.c
> +++ b/drivers/ntb/test/ntb_perf.c
> @@ -133,7 +133,6 @@ struct perf_ctx {
>  	spinlock_t		db_lock;
>  	struct perf_mw		mw;
>  	bool			link_is_up;
> -	struct work_struct	link_cleanup;
>  	struct delayed_work	link_work;
>  	wait_queue_head_t	link_wq;
>  	struct dentry		*debugfs_node_dir;
> @@ -158,10 +157,16 @@ static void perf_link_event(void *ctx)
>  {
>  	struct perf_ctx *perf = ctx;
>  
> -	if (ntb_link_is_up(perf->ntb, NULL, NULL) == 1)
> +	if (ntb_link_is_up(perf->ntb, NULL, NULL) == 1) {
>  		schedule_delayed_work(&perf->link_work, 2*HZ);
> -	else
> -		schedule_work(&perf->link_cleanup);
> +	} else {
> +		dev_dbg(&perf->ntb->pdev->dev, "link down\n");
> +
> +		if (!perf->link_is_up)
> +			cancel_delayed_work_sync(&perf->link_work);
> +
> +		perf->link_is_up = false;
> +	}
>  }
>  
>  static void perf_db_event(void *ctx, int vec)
> @@ -547,18 +552,6 @@ out:
>  				      msecs_to_jiffies(PERF_LINK_DOW
> N_TIMEOUT));
>  }
>  
> -static void perf_link_cleanup(struct work_struct *work)
> -{
> -	struct perf_ctx *perf = container_of(work,
> -					     struct perf_ctx,
> -					     link_cleanup);
> -
> -	dev_dbg(&perf->ntb->pdev->dev, "%s called\n", __func__);
> -
> -	if (!perf->link_is_up)
> -		cancel_delayed_work_sync(&perf->link_work);
> -}
> -
>  static int perf_setup_mw(struct ntb_dev *ntb, struct perf_ctx *perf)
>  {
>  	struct perf_mw *mw;
> @@ -787,7 +780,6 @@ static int perf_probe(struct ntb_client *client,
> struct ntb_dev *ntb)
>  	perf_setup_mw(ntb, perf);
>  	init_waitqueue_head(&perf->link_wq);
>  	INIT_DELAYED_WORK(&perf->link_work, perf_link_work);
> -	INIT_WORK(&perf->link_cleanup, perf_link_cleanup);
>  
>  	rc = ntb_set_ctx(ntb, perf, &perf_ops);
>  	if (rc)
> @@ -807,7 +799,6 @@ static int perf_probe(struct ntb_client *client,
> struct ntb_dev *ntb)
>  
>  err_ctx:
>  	cancel_delayed_work_sync(&perf->link_work);
> -	cancel_work_sync(&perf->link_cleanup);
>  	kfree(perf);
>  err_perf:
>  	return rc;
> @@ -823,7 +814,6 @@ static void perf_remove(struct ntb_client
> *client, struct ntb_dev *ntb)
>  	mutex_lock(&perf->run_mutex);
>  
>  	cancel_delayed_work_sync(&perf->link_work);
> -	cancel_work_sync(&perf->link_cleanup);
>  
>  	ntb_clear_ctx(ntb);
>  	ntb_link_disable(ntb);
> -- 
> 2.1.4
>