Use raid5_run_ops to carry out the memory copies for a raid5 read request.

Changelog:
* cleanup to_read and to_fill accounting
* do not fail reads that have reached the cache

Signed-off-by: Dan Williams <[EMAIL PROTECTED]>
---

 drivers/md/raid5.c |   61 ++++++++++++++++++++++++++--------------------------
 1 files changed, 30 insertions(+), 31 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index f8a4522..6bde174 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -1998,7 +1998,7 @@ static void handle_stripe5(struct stripe_head *sh)
        int i;
        int syncing, expanding, expanded;
        int locked=0, uptodate=0, to_read=0, to_write=0, failed=0, written=0;
-       int compute=0, req_compute=0, non_overwrite=0;
+       int to_fill=0, compute=0, req_compute=0, non_overwrite=0;
        int failed_num=0;
        struct r5dev *dev;
        unsigned long pending=0;
@@ -2022,37 +2022,29 @@ static void handle_stripe5(struct stripe_head *sh)
                dev = &sh->dev[i];
                clear_bit(R5_Insync, &dev->flags);
 
-               PRINTK("check %d: state 0x%lx read %p write %p written %p\n",
-                       i, dev->flags, dev->toread, dev->towrite, dev->written);
-               /* maybe we can reply to a read */
-               if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread) {
-                       struct bio *rbi, *rbi2;
-                       PRINTK("Return read for disc %d\n", i);
-                       spin_lock_irq(&conf->device_lock);
-                       rbi = dev->toread;
-                       dev->toread = NULL;
-                       if (test_and_clear_bit(R5_Overlap, &dev->flags))
-                               wake_up(&conf->wait_for_overlap);
-                       spin_unlock_irq(&conf->device_lock);
-                       while (rbi && rbi->bi_sector < dev->sector + 
STRIPE_SECTORS) {
-                               copy_data(0, rbi, dev->page, dev->sector);
-                               rbi2 = r5_next_bio(rbi, dev->sector);
-                               spin_lock_irq(&conf->device_lock);
-                               if (--rbi->bi_phys_segments == 0) {
-                                       rbi->bi_next = return_bi;
-                                       return_bi = rbi;
-                               }
-                               spin_unlock_irq(&conf->device_lock);
-                               rbi = rbi2;
-                       }
-               }
+               PRINTK("check %d: state 0x%lx toread %p read %p write %p 
written %p\n",
+               i, dev->flags, dev->toread, dev->read, dev->towrite, 
dev->written);
+
+               /* maybe we can request a biofill operation
+                *
+                * new wantfill requests are only permitted while
+                * STRIPE_OP_BIOFILL is clear
+                */
+               if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
+                       !test_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
+                       set_bit(R5_Wantfill, &dev->flags);
 
                /* now count some things */
                if (test_bit(R5_LOCKED, &dev->flags)) locked++;
                if (test_bit(R5_UPTODATE, &dev->flags)) uptodate++;
+
+               if (test_bit(R5_Wantfill, &dev->flags))
+                       to_fill++;
+               else if (dev->toread)
+                       to_read++;
+
                if (test_bit(R5_Wantcompute, &dev->flags)) BUG_ON(++compute > 
1);
 
-               if (dev->toread) to_read++;
                if (dev->towrite) {
                        to_write++;
                        if (!test_bit(R5_OVERWRITE, &dev->flags))
@@ -2073,9 +2065,13 @@ static void handle_stripe5(struct stripe_head *sh)
                        set_bit(R5_Insync, &dev->flags);
        }
        rcu_read_unlock();
+
+       if (to_fill && !test_and_set_bit(STRIPE_OP_BIOFILL, &sh->ops.pending))
+               sh->ops.count++;
+
        PRINTK("locked=%d uptodate=%d to_read=%d"
-               " to_write=%d failed=%d failed_num=%d\n",
-               locked, uptodate, to_read, to_write, failed, failed_num);
+               " to_write=%d to_fill=%d failed=%d failed_num=%d\n",
+               locked, uptodate, to_read, to_write, to_fill, failed, 
failed_num);
        /* check if the array has lost two devices and, if so, some requests 
might
         * need to be failed
         */
@@ -2127,9 +2123,12 @@ static void handle_stripe5(struct stripe_head *sh)
                                bi = bi2;
                        }
 
-                       /* fail any reads if this device is non-operational */
-                       if (!test_bit(R5_Insync, &sh->dev[i].flags) ||
-                           test_bit(R5_ReadError, &sh->dev[i].flags)) {
+                       /* fail any reads if this device is non-operational and
+                        * the data has not reached the cache yet.
+                        */
+                       if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
+                           (!test_bit(R5_Insync, &sh->dev[i].flags) ||
+                             test_bit(R5_ReadError, &sh->dev[i].flags))) {
                                bi = sh->dev[i].toread;
                                sh->dev[i].toread = NULL;
                                if (test_and_clear_bit(R5_Overlap, 
&sh->dev[i].flags))
-
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