Merge branch 'for-linus' into for-5.5/block

Pull on for-linus to resolve what otherwise would have been a conflict
with the cgroups rstat patchset from Tejun.

* for-linus: (942 commits)
  blkcg: make blkcg_print_stat() print stats only for online blkgs
  nvme: change nvme_passthru_cmd64 to explicitly mark rsvd
  nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths
  nvme-rdma: fix a segmentation fault during module unload
  iocost: don't nest spin_lock_irq in ioc_weight_write()
  io_uring: ensure we clear io_kiocb->result before each issue
  um-ubd: Entrust re-queue to the upper layers
  nvme-multipath: remove unused groups_only mode in ana log
  nvme-multipath: fix possible io hang after ctrl reconnect
  io_uring: don't touch ctx in setup after ring fd install
  io_uring: Fix leaked shadow_req
  Linux 5.4-rc5
  riscv: cleanup do_trap_break
  nbd: verify socket is supported during setup
  ata: libahci_platform: Fix regulator_get_optional() misuse
  nbd: handle racing with error'ed out commands
  nbd: protect cmd->status with cmd->lock
  io_uring: fix bad inflight accounting for SETUP_IOPOLL|SETUP_SQTHREAD
  io_uring: used cached copies of sq->dropped and cq->overflow
  ARM: dts: stm32: relax qspi pins slew-rate for stm32mp157
  ...

19 files changed, 121 insertions, 46 deletions

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index c3feccb99ff5..4cdbae6f4e61 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -63,6 +63,13 @@ TARGETS += zram
 TARGETS_HOTPLUG = cpu-hotplug
 TARGETS_HOTPLUG += memory-hotplug
 
+# User can optionally provide a TARGETS skiplist.
+SKIP_TARGETS ?=
+ifneq ($(SKIP_TARGETS),)
+	TMP := $(filter-out $(SKIP_TARGETS), $(TARGETS))
+	override TARGETS := $(TMP)
+endif
+
 # Clear LDFLAGS and MAKEFLAGS if called from main
 # Makefile to avoid test build failures when test
 # Makefile doesn't have explicit build rules.
@@ -171,9 +178,12 @@ run_pstore_crash:
 # 1. output_dir=kernel_src
 # 2. a separate output directory is specified using O= KBUILD_OUTPUT
 # 3. a separate output directory is specified using KBUILD_OUTPUT
+# Avoid conflict with INSTALL_PATH set by the main Makefile
 #
-INSTALL_PATH ?= $(BUILD)/install
-INSTALL_PATH := $(abspath $(INSTALL_PATH))
+KSFT_INSTALL_PATH ?= $(BUILD)/kselftest_install
+KSFT_INSTALL_PATH := $(abspath $(KSFT_INSTALL_PATH))
+# Avoid changing the rest of the logic here and lib.mk.
+INSTALL_PATH := $(KSFT_INSTALL_PATH)
 ALL_SCRIPT := $(INSTALL_PATH)/run_kselftest.sh
 
 install: all
@@ -198,11 +208,16 @@ ifdef INSTALL_PATH
 	echo "  cat /dev/null > \$$logfile" >> $(ALL_SCRIPT)
 	echo "fi" >> $(ALL_SCRIPT)
 
+	@# While building run_kselftest.sh skip also non-existent TARGET dirs:
+	@# they could be the result of a build failure and should NOT be
+	@# included in the generated runlist.
 	for TARGET in $(TARGETS); do \
 		BUILD_TARGET=$$BUILD/$$TARGET;	\
+		[ ! -d $$INSTALL_PATH/$$TARGET ] && echo "Skipping non-existent dir: $$TARGET" && continue; \
 		echo "[ -w /dev/kmsg ] && echo \"kselftest: Running tests in $$TARGET\" >> /dev/kmsg" >> $(ALL_SCRIPT); \
 		echo "cd $$TARGET" >> $(ALL_SCRIPT); \
 		echo -n "run_many" >> $(ALL_SCRIPT); \
+		echo -n "Emit Tests for $$TARGET\n"; \
 		$(MAKE) -s --no-print-directory OUTPUT=$$BUILD_TARGET -C $$TARGET emit_tests >> $(ALL_SCRIPT); \
 		echo "" >> $(ALL_SCRIPT);	    \
 		echo "cd \$$ROOT" >> $(ALL_SCRIPT); \
diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c b/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c
index 6cbeea7b4bf1..8547ecbdc61f 100644
--- a/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockopt_inherit.c
@@ -195,7 +195,7 @@ static void run_test(int cgroup_fd)
 
 	if (CHECK_FAIL(pthread_create(&tid, NULL, server_thread,
 				      (void *)&server_fd)))
-		goto close_bpf_object;
+		goto close_server_fd;
 
 	pthread_mutex_lock(&server_started_mtx);
 	pthread_cond_wait(&server_started, &server_started_mtx);
diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
index a82da555b1b0..f4cd60d6fba2 100644
--- a/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
+++ b/tools/testing/selftests/bpf/prog_tests/tcp_rtt.c
@@ -260,13 +260,14 @@ void test_tcp_rtt(void)
 
 	if (CHECK_FAIL(pthread_create(&tid, NULL, server_thread,
 				      (void *)&server_fd)))
-		goto close_cgroup_fd;
+		goto close_server_fd;
 
 	pthread_mutex_lock(&server_started_mtx);
 	pthread_cond_wait(&server_started, &server_started_mtx);
 	pthread_mutex_unlock(&server_started_mtx);
 
 	CHECK_FAIL(run_test(cgroup_fd, server_fd));
+close_server_fd:
 	close(server_fd);
 close_cgroup_fd:
 	close(cgroup_fd);
diff --git a/tools/testing/selftests/bpf/test_flow_dissector.sh b/tools/testing/selftests/bpf/test_flow_dissector.sh
index d23d4da66b83..e2d06191bd35 100755
--- a/tools/testing/selftests/bpf/test_flow_dissector.sh
+++ b/tools/testing/selftests/bpf/test_flow_dissector.sh
@@ -63,6 +63,9 @@ fi
 
 # Setup
 tc qdisc add dev lo ingress
+echo 0 > /proc/sys/net/ipv4/conf/default/rp_filter
+echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter
+echo 0 > /proc/sys/net/ipv4/conf/lo/rp_filter
 
 echo "Testing IPv4..."
 # Drops all IP/UDP packets coming from port 9
diff --git a/tools/testing/selftests/bpf/test_lwt_ip_encap.sh b/tools/testing/selftests/bpf/test_lwt_ip_encap.sh
index acf7a74f97cd..59ea56945e6c 100755
--- a/tools/testing/selftests/bpf/test_lwt_ip_encap.sh
+++ b/tools/testing/selftests/bpf/test_lwt_ip_encap.sh
@@ -314,15 +314,15 @@ test_gso()
 	command -v nc >/dev/null 2>&1 || \
 		{ echo >&2 "nc is not available: skipping TSO tests"; return; }
 
-	# listen on IPv*_DST, capture TCP into $TMPFILE
+	# listen on port 9000, capture TCP into $TMPFILE
 	if [ "${PROTO}" == "IPv4" ] ; then
 		IP_DST=${IPv4_DST}
 		ip netns exec ${NS3} bash -c \
-			"nc -4 -l -s ${IPv4_DST} -p 9000 > ${TMPFILE} &"
+			"nc -4 -l -p 9000 > ${TMPFILE} &"
 	elif [ "${PROTO}" == "IPv6" ] ; then
 		IP_DST=${IPv6_DST}
 		ip netns exec ${NS3} bash -c \
-			"nc -6 -l -s ${IPv6_DST} -p 9000 > ${TMPFILE} &"
+			"nc -6 -l -p 9000 > ${TMPFILE} &"
 		RET=$?
 	else
 		echo "    test_gso: unknown PROTO: ${PROTO}"
diff --git a/tools/testing/selftests/kselftest/runner.sh b/tools/testing/selftests/kselftest/runner.sh
index 00c9020bdda8..84de7bc74f2c 100644
--- a/tools/testing/selftests/kselftest/runner.sh
+++ b/tools/testing/selftests/kselftest/runner.sh
@@ -3,9 +3,14 @@
 #
 # Runs a set of tests in a given subdirectory.
 export skip_rc=4
+export timeout_rc=124
 export logfile=/dev/stdout
 export per_test_logging=
 
+# Defaults for "settings" file fields:
+# "timeout" how many seconds to let each test run before failing.
+export kselftest_default_timeout=45
+
 # There isn't a shell-agnostic way to find the path of a sourced file,
 # so we must rely on BASE_DIR being set to find other tools.
 if [ -z "$BASE_DIR" ]; then
@@ -24,6 +29,16 @@ tap_prefix()
 	fi
 }
 
+tap_timeout()
+{
+	# Make sure tests will time out if utility is available.
+	if [ -x /usr/bin/timeout ] ; then
+		/usr/bin/timeout "$kselftest_timeout" "$1"
+	else
+		"$1"
+	fi
+}
+
 run_one()
 {
 	DIR="$1"
@@ -32,6 +47,18 @@ run_one()
 
 	BASENAME_TEST=$(basename $TEST)
 
+	# Reset any "settings"-file variables.
+	export kselftest_timeout="$kselftest_default_timeout"
+	# Load per-test-directory kselftest "settings" file.
+	settings="$BASE_DIR/$DIR/settings"
+	if [ -r "$settings" ] ; then
+		while read line ; do
+			field=$(echo "$line" | cut -d= -f1)
+			value=$(echo "$line" | cut -d= -f2-)
+			eval "kselftest_$field"="$value"
+		done < "$settings"
+	fi
+
 	TEST_HDR_MSG="selftests: $DIR: $BASENAME_TEST"
 	echo "# $TEST_HDR_MSG"
 	if [ ! -x "$TEST" ]; then
@@ -44,14 +71,17 @@ run_one()
 		echo "not ok $test_num $TEST_HDR_MSG"
 	else
 		cd `dirname $TEST` > /dev/null
-		(((((./$BASENAME_TEST 2>&1; echo $? >&3) |
+		((((( tap_timeout ./$BASENAME_TEST 2>&1; echo $? >&3) |
 			tap_prefix >&4) 3>&1) |
 			(read xs; exit $xs)) 4>>"$logfile" &&
 		echo "ok $test_num $TEST_HDR_MSG") ||
-		(if [ $? -eq $skip_rc ]; then	\
+		(rc=$?;	\
+		if [ $rc -eq $skip_rc ]; then	\
 			echo "not ok $test_num $TEST_HDR_MSG # SKIP"
+		elif [ $rc -eq $timeout_rc ]; then \
+			echo "not ok $test_num $TEST_HDR_MSG # TIMEOUT"
 		else
-			echo "not ok $test_num $TEST_HDR_MSG"
+			echo "not ok $test_num $TEST_HDR_MSG # exit=$rc"
 		fi)
 		cd - >/dev/null
 	fi
diff --git a/tools/testing/selftests/kselftest_install.sh b/tools/testing/selftests/kselftest_install.sh
index ec304463883c..e2e1911d62d5 100755
--- a/tools/testing/selftests/kselftest_install.sh
+++ b/tools/testing/selftests/kselftest_install.sh
@@ -24,12 +24,12 @@ main()
 		echo "$0: Installing in specified location - $install_loc ..."
 	fi
 
-	install_dir=$install_loc/kselftest
+	install_dir=$install_loc/kselftest_install
 
 # Create install directory
 	mkdir -p $install_dir
 # Build tests
-	INSTALL_PATH=$install_dir make install
+	KSFT_INSTALL_PATH=$install_dir make install
 }
 
 main "$@"
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index b35da375530a..409c1fa75e03 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -1,4 +1,5 @@
 /s390x/sync_regs_test
+/s390x/memop
 /x86_64/cr4_cpuid_sync_test
 /x86_64/evmcs_test
 /x86_64/hyperv_cpuid
@@ -9,6 +10,7 @@
 /x86_64/state_test
 /x86_64/sync_regs_test
 /x86_64/vmx_close_while_nested_test
+/x86_64/vmx_dirty_log_test
 /x86_64/vmx_set_nested_state_test
 /x86_64/vmx_tsc_adjust_test
 /clear_dirty_log_test
diff --git a/tools/testing/selftests/kvm/include/x86_64/vmx.h b/tools/testing/selftests/kvm/include/x86_64/vmx.h
index 6ae5a47fe067..f52e0ba84fed 100644
--- a/tools/testing/selftests/kvm/include/x86_64/vmx.h
+++ b/tools/testing/selftests/kvm/include/x86_64/vmx.h
@@ -580,6 +580,8 @@ bool prepare_for_vmx_operation(struct vmx_pages *vmx);
 void prepare_vmcs(struct vmx_pages *vmx, void *guest_rip, void *guest_rsp);
 bool load_vmcs(struct vmx_pages *vmx);
 
+void nested_vmx_check_supported(void);
+
 void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 		   uint64_t nested_paddr, uint64_t paddr, uint32_t eptp_memslot);
 void nested_map(struct vmx_pages *vmx, struct kvm_vm *vm,
diff --git a/tools/testing/selftests/kvm/lib/x86_64/vmx.c b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
index fab8f6b0bf52..f6ec97b7eaef 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
@@ -376,6 +376,16 @@ void prepare_vmcs(struct vmx_pages *vmx, void *guest_rip, void *guest_rsp)
 	init_vmcs_guest_state(guest_rip, guest_rsp);
 }
 
+void nested_vmx_check_supported(void)
+{
+	struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1);
+
+	if (!(entry->ecx & CPUID_VMX)) {
+		fprintf(stderr, "nested VMX not enabled, skipping test\n");
+		exit(KSFT_SKIP);
+	}
+}
+
 void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	 	   uint64_t nested_paddr, uint64_t paddr, uint32_t eptp_memslot)
 {
diff --git a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c
index 11c2a70a7b87..5c8224256294 100644
--- a/tools/testing/selftests/kvm/x86_64/sync_regs_test.c
+++ b/tools/testing/selftests/kvm/x86_64/sync_regs_test.c
@@ -22,18 +22,19 @@
 
 #define VCPU_ID 5
 
+#define UCALL_PIO_PORT ((uint16_t)0x1000)
+
+/*
+ * ucall is embedded here to protect against compiler reshuffling registers
+ * before calling a function. In this test we only need to get KVM_EXIT_IO
+ * vmexit and preserve RBX, no additional information is needed.
+ */
 void guest_code(void)
 {
-	/*
-	 * use a callee-save register, otherwise the compiler
-	 * saves it around the call to GUEST_SYNC.
-	 */
-	register u32 stage asm("rbx");
-	for (;;) {
-		GUEST_SYNC(0);
-		stage++;
-		asm volatile ("" : : "r" (stage));
-	}
+	asm volatile("1: in %[port], %%al\n"
+		     "add $0x1, %%rbx\n"
+		     "jmp 1b"
+		     : : [port] "d" (UCALL_PIO_PORT) : "rax", "rbx");
 }
 
 static void compare_regs(struct kvm_regs *left, struct kvm_regs *right)
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_close_while_nested_test.c b/tools/testing/selftests/kvm/x86_64/vmx_close_while_nested_test.c
index 3b0ffe01dacd..5dfb53546a26 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_close_while_nested_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_close_while_nested_test.c
@@ -53,12 +53,8 @@ static void l1_guest_code(struct vmx_pages *vmx_pages)
 int main(int argc, char *argv[])
 {
 	vm_vaddr_t vmx_pages_gva;
-	struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1);
 
-	if (!(entry->ecx & CPUID_VMX)) {
-		fprintf(stderr, "nested VMX not enabled, skipping test\n");
-		exit(KSFT_SKIP);
-	}
+	nested_vmx_check_supported();
 
 	vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c b/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c
index 0bca1cfe2c1e..a223a6401258 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_dirty_log_test.c
@@ -78,6 +78,8 @@ int main(int argc, char *argv[])
 	struct ucall uc;
 	bool done = false;
 
+	nested_vmx_check_supported();
+
 	/* Create VM */
 	vm = vm_create_default(VCPU_ID, 0, l1_guest_code);
 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
index 853e370e8a39..9ef7fab39d48 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c
@@ -224,7 +224,6 @@ int main(int argc, char *argv[])
 {
 	struct kvm_vm *vm;
 	struct kvm_nested_state state;
-	struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1);
 
 	have_evmcs = kvm_check_cap(KVM_CAP_HYPERV_ENLIGHTENED_VMCS);
 
@@ -237,10 +236,7 @@ int main(int argc, char *argv[])
 	 * AMD currently does not implement set_nested_state, so for now we
 	 * just early out.
 	 */
-	if (!(entry->ecx & CPUID_VMX)) {
-		fprintf(stderr, "nested VMX not enabled, skipping test\n");
-		exit(KSFT_SKIP);
-	}
+	nested_vmx_check_supported();
 
 	vm = vm_create_default(VCPU_ID, 0, 0);
 
@@ -271,12 +267,7 @@ int main(int argc, char *argv[])
 	state.flags = KVM_STATE_NESTED_RUN_PENDING;
 	test_nested_state_expect_einval(vm, &state);
 
-	/*
-	 * TODO: When SVM support is added for KVM_SET_NESTED_STATE
-	 *       add tests here to support it like VMX.
-	 */
-	if (entry->ecx & CPUID_VMX)
-		test_vmx_nested_state(vm);
+	test_vmx_nested_state(vm);
 
 	kvm_vm_free(vm);
 	return 0;
diff --git a/tools/testing/selftests/kvm/x86_64/vmx_tsc_adjust_test.c b/tools/testing/selftests/kvm/x86_64/vmx_tsc_adjust_test.c
index f36c10eba71e..5590fd2bcf87 100644
--- a/tools/testing/selftests/kvm/x86_64/vmx_tsc_adjust_test.c
+++ b/tools/testing/selftests/kvm/x86_64/vmx_tsc_adjust_test.c
@@ -128,12 +128,8 @@ static void report(int64_t val)
 int main(int argc, char *argv[])
 {
 	vm_vaddr_t vmx_pages_gva;
-	struct kvm_cpuid_entry2 *entry = kvm_get_supported_cpuid_entry(1);
 
-	if (!(entry->ecx & CPUID_VMX)) {
-		fprintf(stderr, "nested VMX not enabled, skipping test\n");
-		exit(KSFT_SKIP);
-	}
+	nested_vmx_check_supported();
 
 	vm = vm_create_default(VCPU_ID, 0, (void *) l1_guest_code);
 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
diff --git a/tools/testing/selftests/powerpc/mm/tlbie_test.c b/tools/testing/selftests/powerpc/mm/tlbie_test.c
index 9868a5ddd847..f85a0938ab25 100644
--- a/tools/testing/selftests/powerpc/mm/tlbie_test.c
+++ b/tools/testing/selftests/powerpc/mm/tlbie_test.c
@@ -636,7 +636,7 @@ int main(int argc, char *argv[])
 			nrthreads = strtoul(optarg, NULL, 10);
 			break;
 		case 'l':
-			strncpy(logdir, optarg, LOGDIR_NAME_SIZE);
+			strncpy(logdir, optarg, LOGDIR_NAME_SIZE - 1);
 			break;
 		case 't':
 			run_time = strtoul(optarg, NULL, 10);
diff --git a/tools/testing/selftests/rtc/settings b/tools/testing/selftests/rtc/settings
new file mode 100644
index 000000000000..ba4d85f74cd6
--- /dev/null
+++ b/tools/testing/selftests/rtc/settings
@@ -0,0 +1 @@
+timeout=90
diff --git a/tools/testing/selftests/vm/gup_benchmark.c b/tools/testing/selftests/vm/gup_benchmark.c
index c0534e298b51..cb3fc09645c4 100644
--- a/tools/testing/selftests/vm/gup_benchmark.c
+++ b/tools/testing/selftests/vm/gup_benchmark.c
@@ -37,7 +37,7 @@ int main(int argc, char **argv)
 	char *file = "/dev/zero";
 	char *p;
 
-	while ((opt = getopt(argc, argv, "m:r:n:f:tTLUSH")) != -1) {
+	while ((opt = getopt(argc, argv, "m:r:n:f:tTLUwSH")) != -1) {
 		switch (opt) {
 		case 'm':
 			size = atoi(optarg) * MB;
diff --git a/tools/testing/selftests/watchdog/watchdog-test.c b/tools/testing/selftests/watchdog/watchdog-test.c
index afff120c7be6..f45e510500c0 100644
--- a/tools/testing/selftests/watchdog/watchdog-test.c
+++ b/tools/testing/selftests/watchdog/watchdog-test.c
@@ -19,7 +19,7 @@
 
 int fd;
 const char v = 'V';
-static const char sopts[] = "bdehp:t:Tn:NLf:";
+static const char sopts[] = "bdehp:t:Tn:NLf:i";
 static const struct option lopts[] = {
 	{"bootstatus",          no_argument, NULL, 'b'},
 	{"disable",             no_argument, NULL, 'd'},
@@ -32,6 +32,7 @@ static const struct option lopts[] = {
 	{"getpretimeout",       no_argument, NULL, 'N'},
 	{"gettimeleft",		no_argument, NULL, 'L'},
 	{"file",          required_argument, NULL, 'f'},
+	{"info",		no_argument, NULL, 'i'},
 	{NULL,                  no_argument, NULL, 0x0}
 };
 
@@ -72,6 +73,7 @@ static void usage(char *progname)
 	printf("Usage: %s [options]\n", progname);
 	printf(" -f, --file\t\tOpen watchdog device file\n");
 	printf("\t\t\tDefault is /dev/watchdog\n");
+	printf(" -i, --info\t\tShow watchdog_info\n");
 	printf(" -b, --bootstatus\tGet last boot status (Watchdog/POR)\n");
 	printf(" -d, --disable\t\tTurn off the watchdog timer\n");
 	printf(" -e, --enable\t\tTurn on the watchdog timer\n");
@@ -97,6 +99,7 @@ int main(int argc, char *argv[])
 	int c;
 	int oneshot = 0;
 	char *file = "/dev/watchdog";
+	struct watchdog_info info;
 
 	setbuf(stdout, NULL);
 
@@ -118,6 +121,16 @@ int main(int argc, char *argv[])
 		exit(-1);
 	}
 
+	/*
+	 * Validate that `file` is a watchdog device
+	 */
+	ret = ioctl(fd, WDIOC_GETSUPPORT, &info);
+	if (ret) {
+		printf("WDIOC_GETSUPPORT error '%s'\n", strerror(errno));
+		close(fd);
+		exit(ret);
+	}
+
 	optind = 0;
 
 	while ((c = getopt_long(argc, argv, sopts, lopts, NULL)) != -1) {
@@ -205,6 +218,18 @@ int main(int argc, char *argv[])
 		case 'f':
 			/* Handled above */
 			break;
+		case 'i':
+			/*
+			 * watchdog_info was obtained as part of file open
+			 * validation. So we just show it here.
+			 */
+			oneshot = 1;
+			printf("watchdog_info:\n");
+			printf(" identity:\t\t%s\n", info.identity);
+			printf(" firmware_version:\t%u\n",
+			       info.firmware_version);
+			printf(" options:\t\t%08x\n", info.options);
+			break;
 
 		default:
 			usage(argv[0]);