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yaml
---
r: 101483
b: refs/heads/master
c: cfae5c9
h: refs/heads/master
i:
  101481: a965d91
  101479: 2bbdb43
v: v3
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Chandra Seetharaman authored and James Bottomley committed Jun 5, 2008
1 parent 26d6528 commit 0a5befd
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Showing 3 changed files with 82 additions and 52 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 5e7dccad3621f6e2b572f309cf830a2c902cae80
refs/heads/master: cfae5c9bb66325cd32d5f2ee41f14749f062a53c
1 change: 1 addition & 0 deletions trunk/drivers/md/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -252,6 +252,7 @@ config DM_ZERO
config DM_MULTIPATH
tristate "Multipath target"
depends on BLK_DEV_DM
select SCSI_DH
---help---
Allow volume managers to support multipath hardware.

Expand Down
131 changes: 80 additions & 51 deletions trunk/drivers/md/dm-mpath.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,7 @@
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/workqueue.h>
#include <scsi/scsi_dh.h>
#include <asm/atomic.h>

#define DM_MSG_PREFIX "multipath"
Expand Down Expand Up @@ -61,7 +62,7 @@ struct multipath {

spinlock_t lock;

struct hw_handler hw_handler;
const char *hw_handler_name;
unsigned nr_priority_groups;
struct list_head priority_groups;
unsigned pg_init_required; /* pg_init needs calling? */
Expand Down Expand Up @@ -109,6 +110,7 @@ static struct kmem_cache *_mpio_cache;
static struct workqueue_struct *kmultipathd;
static void process_queued_ios(struct work_struct *work);
static void trigger_event(struct work_struct *work);
static void pg_init_done(struct dm_path *, int);


/*-----------------------------------------------
Expand Down Expand Up @@ -193,18 +195,13 @@ static struct multipath *alloc_multipath(struct dm_target *ti)
static void free_multipath(struct multipath *m)
{
struct priority_group *pg, *tmp;
struct hw_handler *hwh = &m->hw_handler;

list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
list_del(&pg->list);
free_priority_group(pg, m->ti);
}

if (hwh->type) {
hwh->type->destroy(hwh);
dm_put_hw_handler(hwh->type);
}

kfree(m->hw_handler_name);
mempool_destroy(m->mpio_pool);
kfree(m);
}
Expand All @@ -216,12 +213,10 @@ static void free_multipath(struct multipath *m)

static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
{
struct hw_handler *hwh = &m->hw_handler;

m->current_pg = pgpath->pg;

/* Must we initialise the PG first, and queue I/O till it's ready? */
if (hwh->type && hwh->type->pg_init) {
if (m->hw_handler_name) {
m->pg_init_required = 1;
m->queue_io = 1;
} else {
Expand Down Expand Up @@ -409,7 +404,6 @@ static void process_queued_ios(struct work_struct *work)
{
struct multipath *m =
container_of(work, struct multipath, process_queued_ios);
struct hw_handler *hwh = &m->hw_handler;
struct pgpath *pgpath = NULL;
unsigned init_required = 0, must_queue = 1;
unsigned long flags;
Expand Down Expand Up @@ -438,8 +432,11 @@ static void process_queued_ios(struct work_struct *work)
out:
spin_unlock_irqrestore(&m->lock, flags);

if (init_required)
hwh->type->pg_init(hwh, pgpath->pg->bypassed, &pgpath->path);
if (init_required) {
struct dm_path *path = &pgpath->path;
int ret = scsi_dh_activate(bdev_get_queue(path->dev->bdev));
pg_init_done(path, ret);
}

if (!must_queue)
dispatch_queued_ios(m);
Expand Down Expand Up @@ -652,39 +649,25 @@ static struct priority_group *parse_priority_group(struct arg_set *as,

static int parse_hw_handler(struct arg_set *as, struct multipath *m)
{
int r;
struct hw_handler_type *hwht;
unsigned hw_argc;
struct dm_target *ti = m->ti;

static struct param _params[] = {
{0, 1024, "invalid number of hardware handler args"},
};

r = read_param(_params, shift(as), &hw_argc, &ti->error);
if (r)
if (read_param(_params, shift(as), &hw_argc, &ti->error))
return -EINVAL;

if (!hw_argc)
return 0;

hwht = dm_get_hw_handler(shift(as));
if (!hwht) {
m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
request_module("scsi_dh_%s", m->hw_handler_name);
if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
ti->error = "unknown hardware handler type";
return -EINVAL;
}

m->hw_handler.md = dm_table_get_md(ti->table);
dm_put(m->hw_handler.md);

r = hwht->create(&m->hw_handler, hw_argc - 1, as->argv);
if (r) {
dm_put_hw_handler(hwht);
ti->error = "hardware handler constructor failed";
return r;
}

m->hw_handler.type = hwht;
consume(as, hw_argc - 1);

return 0;
Expand Down Expand Up @@ -1063,14 +1046,74 @@ void dm_pg_init_complete(struct dm_path *path, unsigned err_flags)
spin_unlock_irqrestore(&m->lock, flags);
}

static void pg_init_done(struct dm_path *path, int errors)
{
struct pgpath *pgpath = path_to_pgpath(path);
struct priority_group *pg = pgpath->pg;
struct multipath *m = pg->m;
unsigned long flags;

/* device or driver problems */
switch (errors) {
case SCSI_DH_OK:
break;
case SCSI_DH_NOSYS:
if (!m->hw_handler_name) {
errors = 0;
break;
}
DMERR("Cannot failover device because scsi_dh_%s was not "
"loaded.", m->hw_handler_name);
/*
* Fail path for now, so we do not ping pong
*/
fail_path(pgpath);
break;
case SCSI_DH_DEV_TEMP_BUSY:
/*
* Probably doing something like FW upgrade on the
* controller so try the other pg.
*/
bypass_pg(m, pg, 1);
break;
/* TODO: For SCSI_DH_RETRY we should wait a couple seconds */
case SCSI_DH_RETRY:
case SCSI_DH_IMM_RETRY:
case SCSI_DH_RES_TEMP_UNAVAIL:
if (pg_init_limit_reached(m, pgpath))
fail_path(pgpath);
errors = 0;
break;
default:
/*
* We probably do not want to fail the path for a device
* error, but this is what the old dm did. In future
* patches we can do more advanced handling.
*/
fail_path(pgpath);
}

spin_lock_irqsave(&m->lock, flags);
if (errors) {
DMERR("Could not failover device. Error %d.", errors);
m->current_pgpath = NULL;
m->current_pg = NULL;
} else if (!m->pg_init_required) {
m->queue_io = 0;
pg->bypassed = 0;
}

m->pg_init_in_progress = 0;
queue_work(kmultipathd, &m->process_queued_ios);
spin_unlock_irqrestore(&m->lock, flags);
}

/*
* end_io handling
*/
static int do_end_io(struct multipath *m, struct bio *bio,
int error, struct dm_mpath_io *mpio)
{
struct hw_handler *hwh = &m->hw_handler;
unsigned err_flags = MP_FAIL_PATH; /* Default behavior */
unsigned long flags;

if (!error)
Expand All @@ -1097,19 +1140,8 @@ static int do_end_io(struct multipath *m, struct bio *bio,
}
spin_unlock_irqrestore(&m->lock, flags);

if (hwh->type && hwh->type->error)
err_flags = hwh->type->error(hwh, bio);

if (mpio->pgpath) {
if (err_flags & MP_FAIL_PATH)
fail_path(mpio->pgpath);

if (err_flags & MP_BYPASS_PG)
bypass_pg(m, mpio->pgpath->pg, 1);
}

if (err_flags & MP_ERROR_IO)
return -EIO;
if (mpio->pgpath)
fail_path(mpio->pgpath);

requeue:
dm_bio_restore(&mpio->details, bio);
Expand Down Expand Up @@ -1194,7 +1226,6 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
int sz = 0;
unsigned long flags;
struct multipath *m = (struct multipath *) ti->private;
struct hw_handler *hwh = &m->hw_handler;
struct priority_group *pg;
struct pgpath *p;
unsigned pg_num;
Expand All @@ -1214,12 +1245,10 @@ static int multipath_status(struct dm_target *ti, status_type_t type,
DMEMIT("pg_init_retries %u ", m->pg_init_retries);
}

if (hwh->type && hwh->type->status)
sz += hwh->type->status(hwh, type, result + sz, maxlen - sz);
else if (!hwh->type || type == STATUSTYPE_INFO)
if (!m->hw_handler_name || type == STATUSTYPE_INFO)
DMEMIT("0 ");
else
DMEMIT("1 %s ", hwh->type->name);
DMEMIT("1 %s ", m->hw_handler_name);

DMEMIT("%u ", m->nr_priority_groups);

Expand Down

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