This patch fixes two bugs that got introduced recently in setup_scsi_dh():
- Avoid that a memory leak occurs if attached_handler_name is not assigned
to m->hw_handler_name.
- Avoid that m->hw_handler_name becomes a dangling pointer if the
RETAIN_ATTACHED_HW_HANDLER flag is set and scsi_dh_attach() returns
-EBUSY.
Fixes: e8f74a0f0011 ("dm mpath: eliminate need to use scsi_device_from_queue")
Signed-off-by: Bart Van Assche <[email protected]>
Cc: Martin K. Petersen <[email protected]>
Cc: <[email protected]>
---
drivers/md/dm-mpath.c | 14 +++++++++-----
include/scsi/scsi_device.h | 9 +++++++++
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index d94ba6f72ff5..0ba58a537182 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -22,6 +22,7 @@
#include <linux/time.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
+#include <scsi/scsi_device.h>
#include <scsi/scsi_dh.h>
#include <linux/atomic.h>
#include <linux/blk-mq.h>
@@ -806,13 +807,15 @@ static int parse_path_selector(struct dm_arg_set *as,
struct priority_group *pg,
}
static int setup_scsi_dh(struct block_device *bdev, struct multipath *m,
- const char *attached_handler_name, char **error)
+ char **error)
{
struct request_queue *q = bdev_get_queue(bdev);
+ const char *attached_handler_name;
int r;
if (test_bit(MPATHF_RETAIN_ATTACHED_HW_HANDLER, &m->flags)) {
retain:
+ attached_handler_name = scsi_dh_attached_handler_name(q,
GFP_KERNEL);
if (attached_handler_name) {
/*
* Clear any hw_handler_params associated with a
@@ -867,7 +870,7 @@ static struct pgpath *parse_path(struct dm_arg_set *as,
struct path_selector *ps
struct pgpath *p;
struct multipath *m = ti->private;
struct request_queue *q;
- const char *attached_handler_name;
+ struct scsi_device *sdev;
/* we need at least a path arg */
if (as->argc < 1) {
@@ -887,10 +890,11 @@ static struct pgpath *parse_path(struct dm_arg_set *as,
struct path_selector *ps
}
q = bdev_get_queue(p->path.dev->bdev);
- attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
- if (attached_handler_name || m->hw_handler_name) {
+ sdev = scsi_device_from_queue(q);
+ if (sdev) {
+ put_device(&sdev->sdev_gendev);
INIT_DELAYED_WORK(&p->activate_path, activate_path_work);
- r = setup_scsi_dh(p->path.dev->bdev, m, attached_handler_name,
&ti->error);
+ r = setup_scsi_dh(p->path.dev->bdev, m, &ti->error);
if (r) {
dm_put_device(ti, p->path.dev);
goto bad;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 202f4d6a4342..1c839089c711 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -2,6 +2,7 @@
#ifndef _SCSI_SCSI_DEVICE_H
#define _SCSI_SCSI_DEVICE_H
+#include <linux/kconfig.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
@@ -335,7 +336,15 @@ extern void scsi_remove_device(struct scsi_device *);
extern int scsi_unregister_device_handler(struct scsi_device_handler *scsi_dh);
void scsi_attach_vpd(struct scsi_device *sdev);
+#if IS_ENABLED(CONFIG_SCSI)
extern struct scsi_device *scsi_device_from_queue(struct request_queue *q);
+#else
+static inline struct scsi_device *
+scsi_device_from_queue(struct request_queue *q)
+{
+ return NULL;
+}
+#endif
extern int __must_check scsi_device_get(struct scsi_device *);
extern void scsi_device_put(struct scsi_device *);
extern struct scsi_device *scsi_device_lookup(struct Scsi_Host *,
--
2.18.0
--
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