Nick Piggin wrote:
> Andrew and or Martin, please test attached patch.
> Thanks.
>
Well, one of the WARN conditions I put in there is clearly
redundant...
--- linux-2.6/drivers/block/as-iosched.c.orig 2003-08-07 18:33:06.000000000 +1000
+++ linux-2.6/drivers/block/as-iosched.c 2003-08-07 18:41:50.000000000 +1000
@@ -1198,8 +1198,10 @@ static int as_dispatch_request(struct as
*/
goto dispatch_writes;
- if (ad->batch_data_dir == REQ_ASYNC)
+ if (ad->batch_data_dir == REQ_ASYNC) {
+ WARN_ON(ad->new_batch);
ad->changed_batch = 1;
+ }
ad->batch_data_dir = REQ_SYNC;
arq = list_entry_fifo(ad->fifo_list[ad->batch_data_dir].next);
ad->last_check_fifo[ad->batch_data_dir] = jiffies;
@@ -1214,8 +1216,16 @@ static int as_dispatch_request(struct as
dispatch_writes:
BUG_ON(RB_EMPTY(&ad->sort_list[REQ_ASYNC]));
- if (ad->batch_data_dir == REQ_SYNC)
+ if (ad->batch_data_dir == REQ_SYNC) {
ad->changed_batch = 1;
+
+ /*
+ * new_batch might be 1 when the queue runs out of
+ * reads. A subsequent submission of a write might
+ * cause a change of batch before the read is finished.
+ */
+ ad->new_batch = 0;
+ }
ad->batch_data_dir = REQ_ASYNC;
ad->current_write_count = ad->write_batch_count;
ad->write_batch_idled = 0;
-
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This archive was generated by hypermail 2b29 : Thu Aug 07 2003 - 22:00:37 EST