block, cfq: unlink cfq_io_context's immediately

[karo-tx-linux.git] / include / linux / blkdev.h

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7fbaa9103344a261082afd872127f736abdcd56f..65c2f8c700894368543f5c9b92e00aa6f1f58f04 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -14,7 +14,6 @@
 #include <linux/wait.h>
 #include <linux/mempool.h>
 #include <linux/bio.h>
-#include <linux/module.h>
 #include <linux/stringify.h>
 #include <linux/gfp.h>
 #include <linux/bsg.h>
@@ -22,6 +21,7 @@
 
 #include <asm/scatterlist.h>
 
+struct module;
 struct scsi_ioctl_command;
 
 struct request_queue;
@@ -195,7 +195,7 @@ struct request_pm_state
 #include <linux/elevator.h>
 
 typedef void (request_fn_proc) (struct request_queue *q);
-typedef int (make_request_fn) (struct request_queue *q, struct bio *bio);
+typedef void (make_request_fn) (struct request_queue *q, struct bio *bio);
 typedef int (prep_rq_fn) (struct request_queue *, struct request *);
 typedef void (unprep_rq_fn) (struct request_queue *, struct request *);
 
@@ -310,6 +310,12 @@ struct request_queue {
         */
        unsigned long           queue_flags;
 
+       /*
+        * ida allocated id for this queue.  Used to index queues from
+        * ioctx.
+        */
+       int                     id;
+
        /*
         * queue needs bounce pages for pages above this limit
         */
@@ -387,6 +393,9 @@ struct request_queue {
        /* Throttle data */
        struct throtl_data *td;
 #endif
+#ifdef CONFIG_LOCKDEP
+       int                     ioc_release_depth;
+#endif
 };
 
 #define QUEUE_FLAG_QUEUED      1       /* uses generic tag queueing */
@@ -481,6 +490,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
 
 #define blk_queue_tagged(q)    test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
 #define blk_queue_stopped(q)   test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_dead(q)      test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 #define blk_queue_nomerges(q)  test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 #define blk_queue_noxmerges(q) \
        test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
@@ -660,7 +670,6 @@ extern void __blk_put_request(struct request_queue *, struct request *);
 extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
 extern struct request *blk_make_request(struct request_queue *, struct bio *,
                                        gfp_t);
-extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
 extern void blk_requeue_request(struct request_queue *, struct request *);
 extern void blk_add_request_payload(struct request *rq, struct page *page,
                unsigned int len);
@@ -680,6 +689,8 @@ extern int scsi_cmd_ioctl(struct request_queue *, struct gendisk *, fmode_t,
 extern int sg_scsi_ioctl(struct request_queue *, struct gendisk *, fmode_t,
                         struct scsi_ioctl_command __user *);
 
+extern void blk_queue_bio(struct request_queue *q, struct bio *bio);
+
 /*
  * A queue has just exitted congestion.  Note this in the global counter of
  * congested queues, and wake up anyone who was waiting for requests to be
@@ -857,22 +868,28 @@ extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatte
 extern void blk_dump_rq_flags(struct request *, char *);
 extern long nr_blockdev_pages(void);
 
-int blk_get_queue(struct request_queue *);
+bool __must_check blk_get_queue(struct request_queue *);
 struct request_queue *blk_alloc_queue(gfp_t);
 struct request_queue *blk_alloc_queue_node(gfp_t, int);
 extern void blk_put_queue(struct request_queue *);
 
 /*
- * Note: Code in between changing the blk_plug list/cb_list or element of such
- * lists is preemptable, but such code can't do sleep (or be very careful),
- * otherwise data is corrupted. For details, please check schedule() where
- * blk_schedule_flush_plug() is called.
+ * blk_plug permits building a queue of related requests by holding the I/O
+ * fragments for a short period. This allows merging of sequential requests
+ * into single larger request. As the requests are moved from a per-task list to
+ * the device's request_queue in a batch, this results in improved scalability
+ * as the lock contention for request_queue lock is reduced.
+ *
+ * It is ok not to disable preemption when adding the request to the plug list
+ * or when attempting a merge, because blk_schedule_flush_list() will only flush
+ * the plug list when the task sleeps by itself. For details, please see
+ * schedule() where blk_schedule_flush_plug() is called.
  */
 struct blk_plug {
-       unsigned long magic;
-       struct list_head list;
-       struct list_head cb_list;
-       unsigned int should_sort;
+       unsigned long magic; /* detect uninitialized use-cases */
+       struct list_head list; /* requests */
+       struct list_head cb_list; /* md requires an unplug callback */
+       unsigned int should_sort; /* list to be sorted before flushing? */
 };
 #define BLK_MAX_REQUEST_COUNT 16
 
@@ -1189,20 +1206,6 @@ static inline uint64_t rq_io_start_time_ns(struct request *req)
 }
 #endif
 
-#ifdef CONFIG_BLK_DEV_THROTTLING
-extern int blk_throtl_init(struct request_queue *q);
-extern void blk_throtl_exit(struct request_queue *q);
-extern int blk_throtl_bio(struct request_queue *q, struct bio **bio);
-#else /* CONFIG_BLK_DEV_THROTTLING */
-static inline int blk_throtl_bio(struct request_queue *q, struct bio **bio)
-{
-       return 0;
-}
-
-static inline int blk_throtl_init(struct request_queue *q) { return 0; }
-static inline int blk_throtl_exit(struct request_queue *q) { return 0; }
-#endif /* CONFIG_BLK_DEV_THROTTLING */
-
 #define MODULE_ALIAS_BLOCKDEV(major,minor) \
        MODULE_ALIAS("block-major-" __stringify(major) "-" __stringify(minor))
 #define MODULE_ALIAS_BLOCKDEV_MAJOR(major) \