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,