On Mon, May 19, 2025 at 03:50:15PM +0200, Mikulas Patocka wrote:
>
>
> On Fri, 16 May 2025, Mikulas Patocka wrote:
>
> >
> >
> > On Thu, 15 May 2025, Benjamin Marzinski wrote:
> >
> > > @@ -2077,35 +2095,55 @@ static int probe_path(struct pgpath *pgpath)
> > > static int probe_active_paths(struct multipath *m)
> > > {
> > > struct pgpath *pgpath;
> > > - struct priority_group *pg;
> > > + struct priority_group *pg = NULL;
> > > unsigned long flags;
> > > int r = 0;
> > >
> > > - mutex_lock(&m->work_mutex);
> > > -
> > > spin_lock_irqsave(&m->lock, flags);
> >
> > Hi
> >
> > I suggest replacing spin_lock_irqsave/spin_unlock_irqrestore with
> > spin_lock_irq/spin_unlock_irq here and in some other places where it is
> > known that interrupts are enabled (for example __map_bio,
> > process_queued_bios, multipath_ctr, flush_multipath_work,
> > multipath_resume, multipath_status, multipath_prepare_ioctl, ...).
> >
> > I accepted this patch, so you can send the spinlock changes in a follow-up
> > patch.
> >
> > Mikulas
>
> Hi
>
> I've created a patch for this. Please test it (with spinlock debugging
> enabled), if it passes the tests, I'll stage it.
I tested this with CONFIG_DEBUG_SPINLOCK=y and everything looks fine.
Actually, I tested a slightly different patch. Your patch applies on top
of dm-6.15, but that means it doesn't clean up the spin_lock_irqsave()
calls in my last patch. I tested using a version of your patch that goes
on top of dm-for-next, and changes the spinlocks in probe_active_paths()
and multipath_presuspend(), both of which can also only be called with
interrupts enabled. Here it is:
From: Mikulas Patocka <mpato...@redhat.com>
Replace spin_lock_irqsave/spin_unlock_irqrestore with
spin_lock_irq/spin_unlock_irq at places where it is known that interrupts
are enabled.
Signed-off-by: Mikulas Patocka <mpato...@redhat.com>
Signed-off-by: Benjamin Marzinski <bmarz...@redhat.com>
---
drivers/md/dm-mpath.c | 75 ++++++++++++++++++-------------------------
1 file changed, 31 insertions(+), 44 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 12b7bcae490c..81fec2e1e0ef 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -617,7 +617,6 @@ static void multipath_queue_bio(struct multipath *m, struct
bio *bio)
static struct pgpath *__map_bio(struct multipath *m, struct bio *bio)
{
struct pgpath *pgpath;
- unsigned long flags;
/* Do we need to select a new pgpath? */
pgpath = READ_ONCE(m->current_pgpath);
@@ -625,12 +624,12 @@ static struct pgpath *__map_bio(struct multipath *m,
struct bio *bio)
pgpath = choose_pgpath(m, bio->bi_iter.bi_size);
if (!pgpath) {
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
__multipath_queue_bio(m, bio);
pgpath = ERR_PTR(-EAGAIN);
}
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
} else if (mpath_double_check_test_bit(MPATHF_QUEUE_IO, m) ||
mpath_double_check_test_bit(MPATHF_PG_INIT_REQUIRED, m)) {
@@ -693,7 +692,6 @@ static void process_queued_io_list(struct multipath *m)
static void process_queued_bios(struct work_struct *work)
{
int r;
- unsigned long flags;
struct bio *bio;
struct bio_list bios;
struct blk_plug plug;
@@ -702,16 +700,16 @@ static void process_queued_bios(struct work_struct *work)
bio_list_init(&bios);
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (bio_list_empty(&m->queued_bios)) {
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
return;
}
bio_list_merge_init(&bios, &m->queued_bios);
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
blk_start_plug(&plug);
while ((bio = bio_list_pop(&bios))) {
@@ -1195,7 +1193,6 @@ static int multipath_ctr(struct dm_target *ti, unsigned
int argc, char **argv)
struct dm_arg_set as;
unsigned int pg_count = 0;
unsigned int next_pg_num;
- unsigned long flags;
as.argc = argc;
as.argv = argv;
@@ -1260,9 +1257,9 @@ static int multipath_ctr(struct dm_target *ti, unsigned
int argc, char **argv)
goto bad;
}
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
enable_nopath_timeout(m);
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
@@ -1297,23 +1294,21 @@ static void
multipath_wait_for_pg_init_completion(struct multipath *m)
static void flush_multipath_work(struct multipath *m)
{
if (m->hw_handler_name) {
- unsigned long flags;
-
if (!atomic_read(&m->pg_init_in_progress))
goto skip;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (atomic_read(&m->pg_init_in_progress) &&
!test_and_set_bit(MPATHF_PG_INIT_DISABLED, &m->flags)) {
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
flush_workqueue(kmpath_handlerd);
multipath_wait_for_pg_init_completion(m);
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
clear_bit(MPATHF_PG_INIT_DISABLED, &m->flags);
}
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
}
skip:
if (m->queue_mode == DM_TYPE_BIO_BASED)
@@ -1375,11 +1370,10 @@ static int fail_path(struct pgpath *pgpath)
static int reinstate_path(struct pgpath *pgpath)
{
int r = 0, run_queue = 0;
- unsigned long flags;
struct multipath *m = pgpath->pg->m;
unsigned int nr_valid_paths;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (pgpath->is_active)
goto out;
@@ -1409,7 +1403,7 @@ static int reinstate_path(struct pgpath *pgpath)
schedule_work(&m->trigger_event);
out:
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
if (run_queue) {
dm_table_run_md_queue_async(m->ti->table);
process_queued_io_list(m);
@@ -1470,7 +1464,6 @@ static int switch_pg_num(struct multipath *m, const char
*pgstr)
{
struct priority_group *pg;
unsigned int pgnum;
- unsigned long flags;
char dummy;
if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
@@ -1479,7 +1472,7 @@ static int switch_pg_num(struct multipath *m, const char
*pgstr)
return -EINVAL;
}
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
list_for_each_entry(pg, &m->priority_groups, list) {
pg->bypassed = false;
if (--pgnum)
@@ -1493,7 +1486,7 @@ static int switch_pg_num(struct multipath *m, const char
*pgstr)
}
m->next_pg = pg;
}
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
schedule_work(&m->trigger_event);
return 0;
@@ -1754,11 +1747,10 @@ static int multipath_end_io_bio(struct dm_target *ti,
struct bio *clone,
static void multipath_presuspend(struct dm_target *ti)
{
struct multipath *m = ti->private;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
m->is_suspending = true;
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
/* FIXME: bio-based shouldn't need to always disable queue_if_no_path */
if (m->queue_mode == DM_TYPE_BIO_BASED || !dm_noflush_suspending(m->ti))
queue_if_no_path(m, false, true, __func__);
@@ -1779,9 +1771,8 @@ static void multipath_postsuspend(struct dm_target *ti)
static void multipath_resume(struct dm_target *ti)
{
struct multipath *m = ti->private;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
m->is_suspending = false;
if (test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags)) {
set_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags);
@@ -1793,7 +1784,7 @@ static void multipath_resume(struct dm_target *ti)
test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags),
test_bit(MPATHF_SAVED_QUEUE_IF_NO_PATH, &m->flags));
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
}
/*
@@ -1816,14 +1807,13 @@ static void multipath_status(struct dm_target *ti,
status_type_t type,
unsigned int status_flags, char *result, unsigned
int maxlen)
{
int sz = 0, pg_counter, pgpath_counter;
- unsigned long flags;
struct multipath *m = ti->private;
struct priority_group *pg;
struct pgpath *p;
unsigned int pg_num;
char state;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
/* Features */
if (type == STATUSTYPE_INFO)
@@ -1969,7 +1959,7 @@ static void multipath_status(struct dm_target *ti,
status_type_t type,
break;
}
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
}
static int multipath_message(struct dm_target *ti, unsigned int argc, char
**argv,
@@ -1979,7 +1969,6 @@ static int multipath_message(struct dm_target *ti,
unsigned int argc, char **arg
dev_t dev;
struct multipath *m = ti->private;
action_fn action;
- unsigned long flags;
mutex_lock(&m->work_mutex);
@@ -1991,9 +1980,9 @@ static int multipath_message(struct dm_target *ti,
unsigned int argc, char **arg
if (argc == 1) {
if (!strcasecmp(argv[0], "queue_if_no_path")) {
r = queue_if_no_path(m, true, false, __func__);
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
enable_nopath_timeout(m);
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
goto out;
} else if (!strcasecmp(argv[0], "fail_if_no_path")) {
r = queue_if_no_path(m, false, false, __func__);
@@ -2096,10 +2085,9 @@ static int probe_active_paths(struct multipath *m)
{
struct pgpath *pgpath;
struct priority_group *pg = NULL;
- unsigned long flags;
int r = 0;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (test_bit(MPATHF_DELAY_PG_SWITCH, &m->flags)) {
wait_event_lock_irq(m->probe_wait,
!test_bit(MPATHF_DELAY_PG_SWITCH,
&m->flags),
@@ -2117,7 +2105,7 @@ static int probe_active_paths(struct multipath *m)
goto skip_probe;
set_bit(MPATHF_DELAY_PG_SWITCH, &m->flags);
pg = m->last_probed_pg = m->current_pg;
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
list_for_each_entry(pgpath, &pg->pgpaths, list) {
if (pg != READ_ONCE(m->current_pg) ||
@@ -2132,7 +2120,7 @@ static int probe_active_paths(struct multipath *m)
}
out:
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
clear_bit(MPATHF_DELAY_PG_SWITCH, &m->flags);
if (test_and_clear_bit(MPATHF_NEED_PG_SWITCH, &m->flags)) {
m->current_pgpath = NULL;
@@ -2141,7 +2129,7 @@ static int probe_active_paths(struct multipath *m)
skip_probe:
if (r == 0 && !atomic_read(&m->nr_valid_paths))
r = -ENOTCONN;
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
if (pg)
wake_up(&m->probe_wait);
return r;
@@ -2154,7 +2142,6 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
{
struct multipath *m = ti->private;
struct pgpath *pgpath;
- unsigned long flags;
int r;
if (_IOC_TYPE(cmd) == DM_IOCTL) {
@@ -2182,10 +2169,10 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
} else {
/* No path is available */
r = -EIO;
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags))
r = -ENOTCONN;
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
}
if (r == -ENOTCONN) {
@@ -2193,10 +2180,10 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
/* Path status changed, redo selection */
(void) choose_pgpath(m, 0);
}
- spin_lock_irqsave(&m->lock, flags);
+ spin_lock_irq(&m->lock);
if (test_bit(MPATHF_PG_INIT_REQUIRED, &m->flags))
(void) __pg_init_all_paths(m);
- spin_unlock_irqrestore(&m->lock, flags);
+ spin_unlock_irq(&m->lock);
dm_table_run_md_queue_async(m->ti->table);
process_queued_io_list(m);
}
--
2.46.1
