[PATCH v3] scsi: add debugfs directories

[Douglas Gilbert <dgilbert@xxxxxxxxxxxx>]

Add a top level "scsi" directory in debugfs (usually at 
/sys/kernel/debugfs/scsi) with two subdirectories: "uld" and "lld".
The idea is to place mid-level related 'knobs' in the "scsi"
directory, and for the ULDs to make subsirectories like
"scsi/uld/sd" and "scsi/uld/st" as required. LLDs could follow a
similar pattern.

Changes since v2:
  - export symbols so other driver can use them [John Garry]
  - make prior code conditional on CONFIG_BLK_DEBUG_FS

Changes since v1:
  - tweak Makefile to keep kbuild test robot happier

Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---

My intention is to add a /sys/kernel/debugfs/scsi/uld/sg
directory containing at least a pseudo file called debug to have
the same actions as /proc/scsi/sg/debug , as part of my v4
patchset.

 drivers/scsi/Makefile       |  2 +-
 drivers/scsi/scsi.c         | 23 +++++++++++++++++++++++
 drivers/scsi/scsi_debugfs.c | 16 ++++++++++++++++
 drivers/scsi/scsi_debugfs.h | 10 ++++++++++
 4 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index fcb41ae329c4..49835e2e5f2d 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -163,7 +163,7 @@ 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-$(CONFIG_DEBUG_FS)	+= scsi_debugfs.o
 scsi_mod-y			+= scsi_trace.o scsi_logging.o
 scsi_mod-$(CONFIG_PM)		+= scsi_pm.o
 scsi_mod-$(CONFIG_SCSI_DH)	+= scsi_dh.o
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fc1356d101b0..01d4d0686699 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -68,6 +68,7 @@
 
 #include "scsi_priv.h"
 #include "scsi_logging.h"
+#include "scsi_debugfs.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/scsi.h>
@@ -812,9 +813,27 @@ static int __init init_scsi(void)
 
 	scsi_netlink_init();
 
+#ifdef CONFIG_DEBUG_FS
+	scsi_debugfs_root = debugfs_create_dir("scsi", NULL);
+	if (!scsi_debugfs_root)
+		goto cleanup_netlink;
+	scsi_debugfs_uld = debugfs_create_dir("uld", scsi_debugfs_root);
+	if (!scsi_debugfs_uld)
+		goto cleanup_debugfs;
+	scsi_debugfs_lld = debugfs_create_dir("lld", scsi_debugfs_root);
+	if (!scsi_debugfs_lld)
+		goto cleanup_debugfs;
+#endif
+
 	printk(KERN_NOTICE "SCSI subsystem initialized\n");
 	return 0;
 
+#ifdef CONFIG_DEBUG_FS
+cleanup_debugfs:
+	debugfs_remove_recursive(scsi_debugfs_root);
+cleanup_netlink:
+	scsi_netlink_exit();
+#endif
 cleanup_sysctl:
 	scsi_exit_sysctl();
 cleanup_hosts:
@@ -832,6 +851,10 @@ static int __init init_scsi(void)
 
 static void __exit exit_scsi(void)
 {
+
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove_recursive(scsi_debugfs_root);
+#endif
 	scsi_netlink_exit();
 	scsi_sysfs_unregister();
 	scsi_exit_sysctl();
diff --git a/drivers/scsi/scsi_debugfs.c b/drivers/scsi/scsi_debugfs.c
index c5a8756384bc..8d680656da38 100644
--- a/drivers/scsi/scsi_debugfs.c
+++ b/drivers/scsi/scsi_debugfs.c
@@ -4,6 +4,20 @@
 #include <scsi/scsi_dbg.h>
 #include "scsi_debugfs.h"
 
+#ifdef CONFIG_DEBUG_FS
+struct dentry *scsi_debugfs_root;
+struct dentry *scsi_debugfs_uld;
+struct dentry *scsi_debugfs_lld;
+
+EXPORT_SYMBOL(scsi_debugfs_root);
+EXPORT_SYMBOL(scsi_debugfs_uld);
+EXPORT_SYMBOL(scsi_debugfs_lld);
+
+#endif
+
+
+#ifdef CONFIG_BLK_DEBUG_FS
+
 #define SCSI_CMD_FLAG_NAME(name)[const_ilog2(SCMD_##name)] = #name
 static const char *const scsi_cmd_flags[] = {
 	SCSI_CMD_FLAG_NAME(TAGGED),
@@ -50,3 +64,5 @@ void scsi_show_rq(struct seq_file *m, struct request *rq)
 		   timeout_ms / 1000, timeout_ms % 1000,
 		   alloc_ms / 1000, alloc_ms % 1000);
 }
+
+#endif
diff --git a/drivers/scsi/scsi_debugfs.h b/drivers/scsi/scsi_debugfs.h
index 951b043e82d0..6de9b4691c82 100644
--- a/drivers/scsi/scsi_debugfs.h
+++ b/drivers/scsi/scsi_debugfs.h
@@ -1,4 +1,14 @@
+#include <linux/debugfs.h>
+
+#ifdef CONFIG_DEBUG_FS
+extern struct dentry *scsi_debugfs_root;
+extern struct dentry *scsi_debugfs_uld;
+extern struct dentry *scsi_debugfs_lld;
+#endif
+
+#ifdef CONFIG_BLK_DEBUG_FS
 struct request;
 struct seq_file;
 
 void scsi_show_rq(struct seq_file *m, struct request *rq);
+#endif
-- 
2.17.1