Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/drivers/block/noop-iosched.c b/drivers/block/noop-iosched.c
new file mode 100644
index 0000000..888c477
--- /dev/null
+++ b/drivers/block/noop-iosched.c
@@ -0,0 +1,104 @@
+/*
+ * elevator noop
+ */
+#include <linux/blkdev.h>
+#include <linux/elevator.h>
+#include <linux/bio.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+/*
+ * See if we can find a request that this buffer can be coalesced with.
+ */
+static int elevator_noop_merge(request_queue_t *q, struct request **req,
+ struct bio *bio)
+{
+ struct list_head *entry = &q->queue_head;
+ struct request *__rq;
+ int ret;
+
+ if ((ret = elv_try_last_merge(q, bio))) {
+ *req = q->last_merge;
+ return ret;
+ }
+
+ while ((entry = entry->prev) != &q->queue_head) {
+ __rq = list_entry_rq(entry);
+
+ if (__rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER))
+ break;
+ else if (__rq->flags & REQ_STARTED)
+ break;
+
+ if (!blk_fs_request(__rq))
+ continue;
+
+ if ((ret = elv_try_merge(__rq, bio))) {
+ *req = __rq;
+ q->last_merge = __rq;
+ return ret;
+ }
+ }
+
+ return ELEVATOR_NO_MERGE;
+}
+
+static void elevator_noop_merge_requests(request_queue_t *q, struct request *req,
+ struct request *next)
+{
+ list_del_init(&next->queuelist);
+}
+
+static void elevator_noop_add_request(request_queue_t *q, struct request *rq,
+ int where)
+{
+ if (where == ELEVATOR_INSERT_FRONT)
+ list_add(&rq->queuelist, &q->queue_head);
+ else
+ list_add_tail(&rq->queuelist, &q->queue_head);
+
+ /*
+ * new merges must not precede this barrier
+ */
+ if (rq->flags & REQ_HARDBARRIER)
+ q->last_merge = NULL;
+ else if (!q->last_merge)
+ q->last_merge = rq;
+}
+
+static struct request *elevator_noop_next_request(request_queue_t *q)
+{
+ if (!list_empty(&q->queue_head))
+ return list_entry_rq(q->queue_head.next);
+
+ return NULL;
+}
+
+static struct elevator_type elevator_noop = {
+ .ops = {
+ .elevator_merge_fn = elevator_noop_merge,
+ .elevator_merge_req_fn = elevator_noop_merge_requests,
+ .elevator_next_req_fn = elevator_noop_next_request,
+ .elevator_add_req_fn = elevator_noop_add_request,
+ },
+ .elevator_name = "noop",
+ .elevator_owner = THIS_MODULE,
+};
+
+static int __init noop_init(void)
+{
+ return elv_register(&elevator_noop);
+}
+
+static void __exit noop_exit(void)
+{
+ elv_unregister(&elevator_noop);
+}
+
+module_init(noop_init);
+module_exit(noop_exit);
+
+
+MODULE_AUTHOR("Jens Axboe");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("No-op IO scheduler");