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path: root/drivers/md/dm-mpath.c
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Diffstat (limited to 'drivers/md/dm-mpath.c')
-rw-r--r--drivers/md/dm-mpath.c47
1 files changed, 30 insertions, 17 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 754f38f8a692..638dae048b4f 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -18,6 +18,7 @@
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/workqueue.h>
+#include <linux/delay.h>
#include <scsi/scsi_dh.h>
#include <linux/atomic.h>
@@ -61,11 +62,11 @@ struct multipath {
struct list_head list;
struct dm_target *ti;
- spinlock_t lock;
-
const char *hw_handler_name;
char *hw_handler_params;
+ spinlock_t lock;
+
unsigned nr_priority_groups;
struct list_head priority_groups;
@@ -81,16 +82,17 @@ struct multipath {
struct priority_group *next_pg; /* Switch to this PG if set */
unsigned repeat_count; /* I/Os left before calling PS again */
- unsigned queue_io; /* Must we queue all I/O? */
- unsigned queue_if_no_path; /* Queue I/O if last path fails? */
- unsigned saved_queue_if_no_path;/* Saved state during suspension */
+ unsigned queue_io:1; /* Must we queue all I/O? */
+ unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */
+ unsigned saved_queue_if_no_path:1; /* Saved state during suspension */
+
unsigned pg_init_retries; /* Number of times to retry pg_init */
unsigned pg_init_count; /* Number of times pg_init called */
unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */
+ unsigned queue_size;
struct work_struct process_queued_ios;
struct list_head queued_ios;
- unsigned queue_size;
struct work_struct trigger_event;
@@ -328,14 +330,18 @@ static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
/*
* Loop through priority groups until we find a valid path.
* First time we skip PGs marked 'bypassed'.
- * Second time we only try the ones we skipped.
+ * Second time we only try the ones we skipped, but set
+ * pg_init_delay_retry so we do not hammer controllers.
*/
do {
list_for_each_entry(pg, &m->priority_groups, list) {
if (pg->bypassed == bypassed)
continue;
- if (!__choose_path_in_pg(m, pg, nr_bytes))
+ if (!__choose_path_in_pg(m, pg, nr_bytes)) {
+ if (!bypassed)
+ m->pg_init_delay_retry = 1;
return;
+ }
}
} while (bypassed--);
@@ -481,9 +487,6 @@ static void process_queued_ios(struct work_struct *work)
spin_lock_irqsave(&m->lock, flags);
- if (!m->queue_size)
- goto out;
-
if (!m->current_pgpath)
__choose_pgpath(m, 0);
@@ -496,7 +499,6 @@ static void process_queued_ios(struct work_struct *work)
if (m->pg_init_required && !m->pg_init_in_progress && pgpath)
__pg_init_all_paths(m);
-out:
spin_unlock_irqrestore(&m->lock, flags);
if (!must_queue)
dispatch_queued_ios(m);
@@ -1517,11 +1519,16 @@ out:
static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
unsigned long arg)
{
- struct multipath *m = (struct multipath *) ti->private;
- struct block_device *bdev = NULL;
- fmode_t mode = 0;
+ struct multipath *m = ti->private;
+ struct block_device *bdev;
+ fmode_t mode;
unsigned long flags;
- int r = 0;
+ int r;
+
+again:
+ bdev = NULL;
+ mode = 0;
+ r = 0;
spin_lock_irqsave(&m->lock, flags);
@@ -1546,6 +1553,12 @@ static int multipath_ioctl(struct dm_target *ti, unsigned int cmd,
if (!r && ti->len != i_size_read(bdev->bd_inode) >> SECTOR_SHIFT)
r = scsi_verify_blk_ioctl(NULL, cmd);
+ if (r == -EAGAIN && !fatal_signal_pending(current)) {
+ queue_work(kmultipathd, &m->process_queued_ios);
+ msleep(10);
+ goto again;
+ }
+
return r ? : __blkdev_driver_ioctl(bdev, mode, cmd, arg);
}
@@ -1643,7 +1656,7 @@ out:
*---------------------------------------------------------------*/
static struct target_type multipath_target = {
.name = "multipath",
- .version = {1, 3, 0},
+ .version = {1, 4, 0},
.module = THIS_MODULE,
.ctr = multipath_ctr,
.dtr = multipath_dtr,