On 2019-01-09 4:17 a.m., John Garry wrote:
On 08/01/2019 04:00, Douglas Gilbert wrote:
Add a top level "scsi" directory in debugfs (usually at
/sys/kernel/debug/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 subdirectories like
"scsi/uld/sd" and "scsi/uld/st" as required. LLDs could follow a
similar pattern.
Changes since v4:
- remove export for /sys/kernel/debug/scsi directory but leave
the exports for the uld and lld subdirectories
- put externs for scsi_debugfs_uld and scsi_debugfs_lld in
include/scsi/scsi_dbg.h . So ULDs and LLDs now need to
include <scsi/scsi_dbg.h> to use this facility
- clean-up whitespaces and redundant code [John Garry]
Changes since v3:
- re-arrange as per scsi netlink interface [James Bottomley]
- make all debugfs code conditional on CONFIG_BLK_DEBUG_FS
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>
I think that this gives somewhat better organisation to the debugfs root, so,
apart from comments below, FWIW:
Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
---
My intention is to add a /sys/kernel/debug/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 sg v4
patchset.
John Garry has indicated that he is prepared to modify debugfs
patches to the hisi_sas driver to use the proposed
/sys/kernel/debug/scsi/lld directory.
I can send a patch for this (even if kbuild robot will complain), which you can
pick up. But I think that we still need to see the user of uld.
drivers/scsi/scsi.c | 3 +++
drivers/scsi/scsi_debugfs.c | 32 +++++++++++++++++++++++++++++++-
drivers/scsi/scsi_priv.h | 12 ++++++++++++
include/scsi/scsi_dbg.h | 5 +++++
4 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fc1356d101b0..e8676a19ba6e 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -812,6 +812,8 @@ static int __init init_scsi(void)
scsi_netlink_init();
+ scsi_debugfs_init();
+
printk(KERN_NOTICE "SCSI subsystem initialized\n");
return 0;
@@ -832,6 +834,7 @@ static int __init init_scsi(void)
static void __exit exit_scsi(void)
{
+ scsi_debugfs_exit();
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..5b0c001c150f 100644
--- a/drivers/scsi/scsi_debugfs.c
+++ b/drivers/scsi/scsi_debugfs.c
@@ -1,8 +1,18 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/seq_file.h>
+#include <linux/debugfs.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_dbg.h>
-#include "scsi_debugfs.h"
+#include "scsi_priv.h"
+
+struct dentry *scsi_debugfs_root;
I'm going to sound like a broken record here (and maybe I did not understand the
response to v4 review comment): For now, this only seems to be accessed from
this file, so better to make static until referenced from elsewhere. As I see,
only scsi_debugfs_uld and scsi_debugfs_lld would be referenced externally.
My thinking here is that other parts of the scsi mid-level and transports
(basically the files that include scsi_priv.h (16 files **)) to put debug-
appropriate pseudo files in /sys/kernel/debug/scsi . From a quick scan of
the "knobs" associated with the mid-level
/sys/kernel/debug/scsi/scsi_logging_level
looks like a candidate.
Doug Gilbert
** one of those 16 files is sd.c . Hmmm, so much for ULDs not using scsi_priv.h
+
+struct dentry *scsi_debugfs_uld;
+EXPORT_SYMBOL(scsi_debugfs_uld);
+
+struct dentry *scsi_debugfs_lld;
+EXPORT_SYMBOL(scsi_debugfs_lld);
+
#define SCSI_CMD_FLAG_NAME(name)[const_ilog2(SCMD_##name)] = #name
static const char *const scsi_cmd_flags[] = {
@@ -50,3 +60,23 @@ void scsi_show_rq(struct seq_file *m, struct request *rq)
timeout_ms / 1000, timeout_ms % 1000,
alloc_ms / 1000, alloc_ms % 1000);
}
+
+void scsi_debugfs_init(void)
+{
+ scsi_debugfs_root = debugfs_create_dir("scsi", NULL);
+ if (!scsi_debugfs_root)
+ return;
+ scsi_debugfs_uld = debugfs_create_dir("uld", scsi_debugfs_root);
+ if (!scsi_debugfs_uld) {
+ scsi_debugfs_exit();
+ return;
+ }
+ scsi_debugfs_lld = debugfs_create_dir("lld", scsi_debugfs_root);
+ if (!scsi_debugfs_lld)
+ scsi_debugfs_exit();
+}
+
+void scsi_debugfs_exit(void)
+{
+ debugfs_remove_recursive(scsi_debugfs_root);
+}
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 99f1db5e467e..e24835e8fa4f 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -160,6 +160,18 @@ static inline void scsi_netlink_init(void) {}
static inline void scsi_netlink_exit(void) {}
#endif
+/* scsi_debugfs.c */
+#ifdef CONFIG_BLK_DEBUG_FS
+extern void scsi_debugfs_init(void);
+extern void scsi_debugfs_exit(void);
+extern struct dentry *scsi_debugfs_root;
+extern struct dentry *scsi_debugfs_uld;
+extern struct dentry *scsi_debugfs_lld;
+#else
+static inline void scsi_debugfs_init(void) {}
+static inline void scsi_debugfs_exit(void) {}
+#endif
+
/* scsi_pm.c */
#ifdef CONFIG_PM
extern const struct dev_pm_ops scsi_bus_pm_ops;
diff --git a/include/scsi/scsi_dbg.h b/include/scsi/scsi_dbg.h
index e03bd9d41fa8..00d121bf5eb2 100644
--- a/include/scsi/scsi_dbg.h
+++ b/include/scsi/scsi_dbg.h
@@ -2,6 +2,11 @@
#ifndef _SCSI_SCSI_DBG_H
#define _SCSI_SCSI_DBG_H
+#ifdef CONFIG_BLK_DEBUG_FS
+extern struct dentry *scsi_debugfs_uld;
+extern struct dentry *scsi_debugfs_lld;
+#endif
+
struct scsi_cmnd;
struct scsi_device;
struct scsi_sense_hdr;
