[Xen-changelog] [linux-2.6.18-xen] Revert 927:56df01ffed10

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1250408549 -3600
# Node ID a65005adb3ed8a20de6293511cb4920a5e6bda1d
# Parent  56df01ffed10fa046ee7ddd65e439a131166944a
Revert 927:56df01ffed10
---
 drivers/xen/blkback/blkback.c |   25 -------------------------
 drivers/xen/blkback/common.h  |    5 -----
 drivers/xen/blkback/xenbus.c  |   41 -----------------------------------------
 3 files changed, 71 deletions(-)

diff -r 56df01ffed10 -r a65005adb3ed drivers/xen/blkback/blkback.c
--- a/drivers/xen/blkback/blkback.c     Fri Aug 14 17:28:43 2009 +0100
+++ b/drivers/xen/blkback/blkback.c     Sun Aug 16 08:42:29 2009 +0100
@@ -200,16 +200,6 @@ static void print_stats(blkif_t *blkif)
        blkif->st_oo_req = 0;
 }
 
-static void refill_credit(blkif_t *blkif)
-{
-       blkif->credit_time = jiffies + msecs_to_jiffies(blkif->credit_msec);
-       blkif->available_credit += blkif->credit_req;
-
-       /* this allows for bursting. */
-       if (blkif->available_credit > (blkif->credit_req * blkif->credit_msec))
-               blkif->available_credit = blkif->credit_req;
-}
-
 int blkif_schedule(void *arg)
 {
        blkif_t *blkif = arg;
@@ -236,9 +226,6 @@ int blkif_schedule(void *arg)
                if (do_block_io_op(blkif))
                        blkif->waiting_reqs = 1;
                unplug_queue(blkif);
-
-               if (time_after(jiffies, blkif->credit_time))
-                       refill_credit(blkif);
 
                if (log_stats && time_after(jiffies, blkif->st_print))
                        print_stats(blkif);
@@ -326,22 +313,10 @@ static int do_block_io_op(blkif_t *blkif
        rp = blk_rings->common.sring->req_prod;
        rmb(); /* Ensure we see queued requests up to 'rp'. */
 
-       /* if there's no available request credit right now, and limiting
-        * is requested, then don't bother with going any further.
-        */
-       if (blkif->remaining_credit <= 0 && blkif->credit_req != 0)
-               return (rc != rp) ? 1 : 0;
-
        while (rc != rp) {
 
                if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
                        break;
-
-               /* FIXME: Should we report QoS overages as VBD_OO, or not? */
-               if (blkif->credit_req != 0 && --blkif->remaining_credit <= 0) {
-                       more_to_do = 1;
-                       break;
-               }
 
                if (kthread_should_stop()) {
                        more_to_do = 1;
diff -r 56df01ffed10 -r a65005adb3ed drivers/xen/blkback/common.h
--- a/drivers/xen/blkback/common.h      Fri Aug 14 17:28:43 2009 +0100
+++ b/drivers/xen/blkback/common.h      Sun Aug 16 08:42:29 2009 +0100
@@ -96,11 +96,6 @@ typedef struct blkif_st {
 
        grant_handle_t shmem_handle;
        grant_ref_t    shmem_ref;
-
-       int                 credit_req;
-       int                 remaining_credit;
-       int                 credit_msec;
-       unsigned long       credit_time;
 } blkif_t;
 
 blkif_t *blkif_alloc(domid_t domid);
diff -r 56df01ffed10 -r a65005adb3ed drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c      Fri Aug 14 17:28:43 2009 +0100
+++ b/drivers/xen/blkback/xenbus.c      Sun Aug 16 08:42:29 2009 +0100
@@ -255,42 +255,6 @@ fail:
        return err;
 }
 
-static void blkback_read_credit(struct xenbus_transaction xbt,
-                               struct xenbus_device *dev,
-                                unsigned long *credit, unsigned long *msec)
-{
-       char *s, *e;
-       unsigned long b, u;
-       char *ratestr;
-
-       /* Default to unlimited I/O operations. */
-       *credit = ~0UL;
-       *usec = 0;
-
-       ratestr = xenbus_read(xbt, dev->nodename, "credit", NULL);
-       if (IS_ERR(ratestr))
-               return;
-
-       s = ratestr;
-       b = simple_strtoul(s, &e, 10);
-       if ((s == e) || (*e != ','))
-               goto fail;
-
-       s = e + 1;
-       u = simple_strtoul(s, &e, 10);
-       if ((s == e) || (*e != '\0'))
-               goto fail;
-
-       *credit = b;
-       *msec = (u / 1000);
-
-       kfree(ratestr);
-       return;
-
- fail:
-       WPRINTK("Failed to parse I/O credit limit. I/O operations are 
unlimited.\n");
-       kfree(ratestr);
-}
 
 /**
  * Callback received when the hotplug scripts have placed the physical-device
@@ -437,7 +401,6 @@ static void frontend_changed(struct xenb
 /* ** Connection ** */
 
 
-
 /**
  * Write the physical details regarding the block device to the store, and
  * switch to Connected state.
@@ -461,10 +424,6 @@ again:
        err = blkback_barrier(xbt, be, 1);
        if (err)
                goto abort;
-
-       blkback_read_credit(xbt, dev, &be->blkif->credit_req,
-                           &be->blkif->credit_msec);
-       be->blkif->remaining_credit = be->blkif->credit_req;
 
        err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
                            vbd_size(&be->blkif->vbd));

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