scsi: Implement blk_mq_ops.show_rq()

Show the SCSI CDB for pending SCSI commands in
/sys/kernel/debug/block/*/mq/*/dispatch and */rq_list. An example
of how SCSI commands are displayed by this code:

ffff8801703245c0 {.op=READ, .cmd_flags=META PRIO, .rq_flags=DONTPREP IO_STAT STATS, .tag=14, .internal_tag=-1, .cmd=Read(10) 28 00 2a 81 1b 30 00 00 08 00}

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: <linux-scsi@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index fc2855565a51fd7b65f318f4f96c4caaf059e001..93dbe58c47c845ddbe7faf25e540401f67d6c0ab 100644 (file)
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -166,6 +166,7 @@ scsi_mod-y                  += scsi_scan.o scsi_sysfs.o scsi_devinfo.o
 scsi_mod-$(CONFIG_SCSI_NETLINK)        += scsi_netlink.o
 scsi_mod-$(CONFIG_SYSCTL)      += scsi_sysctl.o
 scsi_mod-$(CONFIG_SCSI_PROC_FS)        += scsi_proc.o
+scsi_mod-$(CONFIG_BLK_DEBUG_FS)        += scsi_debugfs.o
 scsi_mod-y                     += scsi_trace.o scsi_logging.o
 scsi_mod-$(CONFIG_PM)          += scsi_pm.o
 scsi_mod-$(CONFIG_SCSI_DH)     += scsi_dh.o

diff --git a/drivers/scsi/scsi_debugfs.c b/drivers/scsi/scsi_debugfs.c
new file mode 100644 (file)
index 0000000..a97c950
--- /dev/null
+++ b/drivers/scsi/scsi_debugfs.c
@@ -0,0 +1,13 @@
+#include <linux/seq_file.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include "scsi_debugfs.h"
+
+void scsi_show_rq(struct seq_file *m, struct request *rq)
+{
+       struct scsi_cmnd *cmd = container_of(scsi_req(rq), typeof(*cmd), req);
+       char buf[80];
+
+       __scsi_format_command(buf, sizeof(buf), cmd->cmnd, cmd->cmd_len);
+       seq_printf(m, ", .cmd=%s", buf);
+}

diff --git a/drivers/scsi/scsi_debugfs.h b/drivers/scsi/scsi_debugfs.h
new file mode 100644 (file)
index 0000000..951b043
--- /dev/null
+++ b/drivers/scsi/scsi_debugfs.h
@@ -0,0 +1,4 @@
+struct request;
+struct seq_file;
+
+void scsi_show_rq(struct seq_file *m, struct request *rq);

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 4a20e6098f7ca94dd7fc5ee4f1d5ce874fa2dafb..91455dabbfefa7fcbfa97f2b313c0f0846b94a30 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -34,6 +34,7 @@
 
 #include <trace/events/scsi.h>
 
+#include "scsi_debugfs.h"
 #include "scsi_priv.h"
 #include "scsi_logging.h"
 
@@ -2157,6 +2158,9 @@ static const struct blk_mq_ops scsi_mq_ops = {
        .queue_rq       = scsi_queue_rq,
        .complete       = scsi_softirq_done,
        .timeout        = scsi_timeout,
+#ifdef CONFIG_BLK_DEBUG_FS
+       .show_rq        = scsi_show_rq,
+#endif
        .init_request   = scsi_init_request,
        .exit_request   = scsi_exit_request,
        .map_queues     = scsi_map_queues,