scsi: qla2xxx: Enhance driver tracing with separate tunable and more

Older tracing of driver messages was to:

    - log only debug messages to kernel main trace buffer; and

    - log only if extended logging bits corresponding to this message is
      off

This has been modified and extended as follows:

    - Tracing is now controlled via ql2xextended_error_logging_ktrace
      module parameter. Bit usages same as ql2xextended_error_logging.

    - Tracing uses "qla2xxx" trace instance, unless instance creation have
      issues.

    - Tracing is enabled (compile time tunable).

    - All driver messages, include debug and log messages are now traced in
      kernel trace buffer.

Trace messages can be viewed by looking at the qla2xxx instance at:

    /sys/kernel/tracing/instances/qla2xxx/trace

Trace tunable that takes the same bit mask as ql2xextended_error_logging
is:

    ql2xextended_error_logging_ktrace (default=1)

Link: https://lore.kernel.org/r/20220826102559.17474-6-njavali@marvell.com
Suggested-by: Daniel Wagner <dwagner@suse.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Tested-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index ce7cf7750f62..f76ae8a64ea9 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -15,6 +15,8 @@
 #include <linux/blk-mq-pci.h>
 #include <linux/refcount.h>
 #include <linux/crash_dump.h>
+#include <linux/trace_events.h>
+#include <linux/trace.h>
 
 #include <scsi/scsi_tcq.h>
 #include <scsi/scsicam.h>
@@ -35,6 +37,8 @@ static int apidev_major;
  */
 struct kmem_cache *srb_cachep;
 
+struct trace_array *qla_trc_array;
+
 int ql2xfulldump_on_mpifail;
 module_param(ql2xfulldump_on_mpifail, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(ql2xfulldump_on_mpifail,
@@ -117,6 +121,11 @@ MODULE_PARM_DESC(ql2xextended_error_logging,
 		"ql2xextended_error_logging=1).\n"
 		"\t\tDo LOGICAL OR of the value to enable more than one level");
 
+int ql2xextended_error_logging_ktrace = 1;
+module_param(ql2xextended_error_logging_ktrace, int, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(ql2xextended_error_logging_ktrace,
+		"Same BIT definiton as ql2xextended_error_logging, but used to control logging to kernel trace buffer (default=1).\n");
+
 int ql2xshiftctondsd = 6;
 module_param(ql2xshiftctondsd, int, S_IRUGO);
 MODULE_PARM_DESC(ql2xshiftctondsd,
@@ -2839,6 +2848,27 @@ static void qla2x00_iocb_work_fn(struct work_struct *work)
 	spin_unlock_irqrestore(&vha->work_lock, flags);
 }
 
+static void
+qla_trace_init(void)
+{
+	qla_trc_array = trace_array_get_by_name("qla2xxx");
+	if (!qla_trc_array) {
+		ql_log(ql_log_fatal, NULL, 0x0001,
+		       "Unable to create qla2xxx trace instance, instance logging will be disabled.\n");
+		return;
+	}
+
+	QLA_TRACE_ENABLE(qla_trc_array);
+}
+
+static void
+qla_trace_uninit(void)
+{
+	if (!qla_trc_array)
+		return;
+	trace_array_put(qla_trc_array);
+}
+
 /*
  * PCI driver interface
  */
@@ -8181,6 +8211,8 @@ qla2x00_module_init(void)
 	BUILD_BUG_ON(sizeof(sw_info_t) != 32);
 	BUILD_BUG_ON(sizeof(target_id_t) != 2);
 
+	qla_trace_init();
+
 	/* Allocate cache for SRBs. */
 	srb_cachep = kmem_cache_create("qla2xxx_srbs", sizeof(srb_t), 0,
 	    SLAB_HWCACHE_ALIGN, NULL);
@@ -8259,6 +8291,8 @@ qlt_exit:
 
 destroy_cache:
 	kmem_cache_destroy(srb_cachep);
+
+	qla_trace_uninit();
 	return ret;
 }
 
@@ -8277,6 +8311,7 @@ qla2x00_module_exit(void)
 	fc_release_transport(qla2xxx_transport_template);
 	qlt_exit();
 	kmem_cache_destroy(srb_cachep);
+	qla_trace_uninit();
 }
 
 module_init(qla2x00_module_init);