commit 361f050e3148c6188afb45942e06d4a509852b86

Author: Dave Anderson <anderson@redhat.com>

Date:   Mon Jan 7 13:56:15 2019 -0500

    Fix for the "dev -[dD]" options in kernels containing Linux 5.0-rc1

    commit 7ff4f8035695984c513598e2d49c8277d5d234ca, titled "block:

    remove dead queue members", in which the number of I/Os issued to

    a disk driver are no longer stored in the request_queue structure.

    Without the patch, the options indicate "dev: -d option not supported

    or applicable on this architecture or kernel".  With the patch, the

    "DRV" column is not shown.

    (m.mizuma@jp.fujitsu.com)

diff --git a/defs.h b/defs.h

index a3cb5a4..9ebdde6 100644

--- a/defs.h

+++ b/defs.h

@@ -2043,6 +2043,8 @@ struct offset_table {

         long pci_bus_self;

         long device_kobj;

         long kobject_name;

+	long hd_struct_dkstats;

+	long disk_stats_in_flight;

 };

 struct size_table {         /* stash of commonly-used sizes */

diff --git a/dev.c b/dev.c

index 7ce2422..24efea2 100644

--- a/dev.c

+++ b/dev.c

@@ -3974,7 +3974,7 @@ struct iter {

 	 * this function reads request_list.count[2], and the first argument

 	 * is the address of request_queue.

 	 */

-	void (*get_diskio)(unsigned long , struct diskio *);

+	void (*get_diskio)(unsigned long , unsigned long, struct diskio *);

 	/*

 	 * check if device.type == &disk_type

@@ -4187,24 +4187,55 @@ get_mq_diskio(unsigned long q, unsigned long *mq_count)

 	}

 }

+static void

+get_one_diskio_from_dkstats(unsigned long dkstats, unsigned long *count)

+{

+	int cpu;

+	unsigned long dkstats_addr;

+	unsigned long in_flight[2];

+

+	for (cpu = 0; cpu < kt->cpus; cpu++) {

+		if ((kt->flags & SMP) && (kt->flags & PER_CPU_OFF)) {

+			dkstats_addr = dkstats + kt->__per_cpu_offset[cpu];

+			readmem(dkstats_addr + OFFSET(disk_stats_in_flight),

+				KVADDR, in_flight, sizeof(long) * 2,

+				"disk_stats.in_flight", FAULT_ON_ERROR);

+			count[0] += in_flight[0];

+			count[1] += in_flight[1];

+		}

+	}

+}

+

+

 /* read request_queue.rq.count[2] */

 static void 

-get_diskio_1(unsigned long rq, struct diskio *io)

+get_diskio_1(unsigned long rq, unsigned long gendisk, struct diskio *io)

 {

 	int count[2];

-	unsigned long mq_count[2] = { 0 };

+	unsigned long io_counts[2] = { 0 };

+	unsigned long dkstats;

 	if (!use_mq_interface(rq)) {

-		readmem(rq + OFFSET(request_queue_rq) +

-			OFFSET(request_list_count), KVADDR, count,

-			sizeof(int) * 2, "request_list.count", FAULT_ON_ERROR);

+		if (VALID_MEMBER(request_queue_rq)) {

+			readmem(rq + OFFSET(request_queue_rq) +

+				OFFSET(request_list_count), KVADDR, count,

+				sizeof(int) * 2, "request_list.count", FAULT_ON_ERROR);

+

+			io->read = count[0];

+			io->write = count[1];

+		} else {

+			readmem(gendisk + OFFSET(gendisk_part0) +

+				OFFSET(hd_struct_dkstats), KVADDR, &dkstats,

+				sizeof(ulong), "gendisk.part0.dkstats", FAULT_ON_ERROR);

+			get_one_diskio_from_dkstats(dkstats, io_counts);

-		io->read = count[0];

-		io->write = count[1];

+			io->read = io_counts[0];

+			io->write = io_counts[1];

+		}

 	} else {

-		get_mq_diskio(rq, mq_count);

-		io->read = mq_count[0];

-		io->write = mq_count[1];

+		get_mq_diskio(rq, io_counts);

+		io->read = io_counts[0];

+		io->write = io_counts[1];

 	}

 }

@@ -4250,9 +4281,6 @@ init_iter(struct iter *i)

 		i->get_in_flight = get_in_flight_1;

 	} else if (SIZE(rq_in_flight) == sizeof(int) * 2) {

 		i->get_in_flight = get_in_flight_2;

-	} else {

-		option_not_supported('d');

-		return;

 	}

 	i->get_diskio = get_diskio_1;

@@ -4354,7 +4382,7 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)

 		sizeof(ulong), "gen_disk.queue", FAULT_ON_ERROR);

 	readmem(gendisk + OFFSET(gendisk_major), KVADDR, &major, sizeof(int),

 		"gen_disk.major", FAULT_ON_ERROR);

-	i->get_diskio(queue_addr, &io);

+	i->get_diskio(queue_addr, gendisk, &io);

 	if ((flags & DIOF_NONZERO)

 		&& (io.read + io.write == 0))

@@ -4379,11 +4407,14 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)

 			(char *)(unsigned long)io.write),

 		space(MINSPACE));

-	if (!use_mq_interface(queue_addr)) {

-		in_flight = i->get_in_flight(queue_addr);

-		fprintf(fp, "%5u\n", in_flight);

+	if (VALID_MEMBER(request_queue_in_flight)) {

+		if (!use_mq_interface(queue_addr)) {

+			in_flight = i->get_in_flight(queue_addr);

+			fprintf(fp, "%5u\n", in_flight);

+		} else

+			fprintf(fp, "%s\n", "N/A(MQ)");

 	} else

-		fprintf(fp, "%s\n", "N/A(MQ)");

+		fprintf(fp, "\n");

 }

 static void 

@@ -4418,7 +4449,7 @@ display_all_diskio(ulong flags)

 		i.sync_count ? mkstring(buf4, 5, RJUST, "SYNC") :

 			mkstring(buf4, 5, RJUST, "WRITE"),

 		space(MINSPACE),

-		mkstring(buf5, 5, RJUST, "DRV"));

+		VALID_MEMBER(request_queue_in_flight) ? mkstring(buf5, 5, RJUST, "DRV") : "");

 	while ((gendisk = i.next_disk(&i)) != 0)

 		display_one_diskio(&i, gendisk, flags);

@@ -4446,6 +4477,7 @@ void diskio_init(void)

 	MEMBER_OFFSET_INIT(gendisk_part0, "gendisk", "part0");

 	MEMBER_OFFSET_INIT(gendisk_queue, "gendisk", "queue");

 	MEMBER_OFFSET_INIT(hd_struct_dev, "hd_struct", "__dev");

+	MEMBER_OFFSET_INIT(hd_struct_dkstats, "hd_struct", "dkstats");

 	MEMBER_OFFSET_INIT(klist_k_list, "klist", "k_list");

 	MEMBER_OFFSET_INIT(klist_node_n_klist, "klist_node", "n_klist");

 	MEMBER_OFFSET_INIT(klist_node_n_node, "klist_node", "n_node");

@@ -4476,6 +4508,7 @@ void diskio_init(void)

 	MEMBER_SIZE_INIT(rq_in_flight, "request_queue", "in_flight");

 	MEMBER_SIZE_INIT(class_private_devices, "class_private",

 		"class_devices");

+	MEMBER_OFFSET_INIT(disk_stats_in_flight, "disk_stats", "in_flight");

 	dt->flags |= DISKIO_INIT;

 }

diff --git a/help.c b/help.c

index aadd2ed..1593e82 100644

--- a/help.c

+++ b/help.c

@@ -3218,7 +3218,7 @@ char *help_dev[] = {

 "         WRITE: I/O requests that are writes (older kernels)",

 "           DRV: I/O requests that are in-flight in the device driver.",

 "                If the device driver uses blk-mq interface, this field",

-"                shows N/A(MQ).",

+"                shows N/A(MQ).  If not available, this column is not shown.",

 "    -D  same as -d, but filter out disks with no in-progress I/O requests.",

 "\nEXAMPLES",

 "  Display character and block device data:\n",

diff --git a/symbols.c b/symbols.c

index ef6f934..5f77e27 100644

--- a/symbols.c

+++ b/symbols.c

@@ -10021,6 +10021,10 @@ dump_offset_table(char *spec, ulong makestruct)

 		OFFSET(gendisk_queue));

 	fprintf(fp, "                 hd_struct_dev: %ld\n",

 		OFFSET(hd_struct_dev));

+	fprintf(fp, "             hd_struct_dkstats: %ld\n",

+		OFFSET(hd_struct_dkstats));

+	fprintf(fp, "          disk_stats_in_flight: %ld\n",

+		OFFSET(disk_stats_in_flight));

 	fprintf(fp, "                  klist_k_list: %ld\n",

 		OFFSET(klist_k_list));

 	fprintf(fp, "            klist_node_n_klist: %ld\n",