diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index c6c9a9c10d7f88b5f894990e45878acadbb2ea64..3adaace328a660fac9591e7a4b0726661dd3d832 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -946,6 +946,13 @@ elevator_merged_fn called when a request in the scheduler has been
scheduler for example, to reposition the request
if its sorting order has changed.
+elevator_allow_merge_fn called whenever the block layer determines
+ that a bio can be merged into an existing
+ request safely. The io scheduler may still
+ want to stop a merge at this point if it
+ results in some sort of conflict internally,
+ this hook allows it to do that.
+
elevator_dispatch_fn fills the dispatch queue with ready requests.
I/O schedulers are free to postpone requests by
not filling the dispatch queue unless @force
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 533a2938ffd6740f6f41f2c5bd52177e8dde8a0e..9fc5eafa6c0e6283398aafc4bc6a5c584438f10b 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -568,6 +568,38 @@ cfq_merged_requests(request_queue_t *q, struct request *rq,
cfq_remove_request(next);
}
+static int cfq_allow_merge(request_queue_t *q, struct request *rq,
+ struct bio *bio)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ const int rw = bio_data_dir(bio);
+ struct cfq_queue *cfqq;
+ pid_t key;
+
+ /*
+ * If bio is async or a write, always allow merge
+ */
+ if (!bio_sync(bio) || rw == WRITE)
+ return 1;
+
+ /*
+ * bio is sync. if request is not, disallow.
+ */
+ if (!rq_is_sync(rq))
+ return 0;
+
+ /*
+ * Ok, both bio and request are sync. Allow merge if they are
+ * from the same queue.
+ */
+ key = cfq_queue_pid(current, rw, 1);
+ cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
+ if (cfqq != RQ_CFQQ(rq))
+ return 0;
+
+ return 1;
+}
+
static inline void
__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
@@ -2125,6 +2157,7 @@ static struct elevator_type iosched_cfq = {
.elevator_merge_fn = cfq_merge,
.elevator_merged_fn = cfq_merged_request,
.elevator_merge_req_fn = cfq_merged_requests,
+ .elevator_allow_merge_fn = cfq_allow_merge,
.elevator_dispatch_fn = cfq_dispatch_requests,
.elevator_add_req_fn = cfq_insert_request,
.elevator_activate_req_fn = cfq_activate_request,
diff --git a/block/elevator.c b/block/elevator.c
index c0063f345c5d620320cd82438394eefe71b442dc..62c7a3069d3a20981067e1865c77be04a3990847 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -50,6 +50,21 @@ static const int elv_hash_shift = 6;
#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
+/*
+ * Query io scheduler to see if the current process issuing bio may be
+ * merged with rq.
+ */
+static int elv_iosched_allow_merge(struct request *rq, struct bio *bio)
+{
+ request_queue_t *q = rq->q;
+ elevator_t *e = q->elevator;
+
+ if (e->ops->elevator_allow_merge_fn)
+ return e->ops->elevator_allow_merge_fn(q, rq, bio);
+
+ return 1;
+}
+
/*
* can we safely merge with this request?
*/
@@ -65,12 +80,15 @@ inline int elv_rq_merge_ok(struct request *rq, struct bio *bio)
return 0;
/*
- * same device and no special stuff set, merge is ok
+ * must be same device and not a special request
*/
- if (rq->rq_disk == bio->bi_bdev->bd_disk && !rq->special)
- return 1;
+ if (rq->rq_disk != bio->bi_bdev->bd_disk || !rq->special)
+ return 0;
- return 0;
+ if (!elv_iosched_allow_merge(rq, bio))
+ return 0;
+
+ return 1;
}
EXPORT_SYMBOL(elv_rq_merge_ok);
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 79807dbc306e58b063464a716c8ace72fb110f10..e07c079e07e604efbcb61ed0bebba5ed89822973 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1405,8 +1405,7 @@ static inline int ll_new_hw_segment(request_queue_t *q,
return 1;
}
-static int ll_back_merge_fn(request_queue_t *q, struct request *req,
- struct bio *bio)
+int ll_back_merge_fn(request_queue_t *q, struct request *req, struct bio *bio)
{
unsigned short max_sectors;
int len;
@@ -1442,6 +1441,7 @@ static int ll_back_merge_fn(request_queue_t *q, struct request *req,
return ll_new_hw_segment(q, req, bio);
}
+EXPORT_SYMBOL(ll_back_merge_fn);
static int ll_front_merge_fn(request_queue_t *q, struct request *req,
struct bio *bio)
@@ -1912,9 +1912,6 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
}
q->request_fn = rfn;
- q->back_merge_fn = ll_back_merge_fn;
- q->front_merge_fn = ll_front_merge_fn;
- q->merge_requests_fn = ll_merge_requests_fn;
q->prep_rq_fn = NULL;
q->unplug_fn = generic_unplug_device;
q->queue_flags = (1 << QUEUE_FLAG_CLUSTER);
@@ -2350,40 +2347,29 @@ static int __blk_rq_map_user(request_queue_t *q, struct request *rq,
else
bio = bio_copy_user(q, uaddr, len, reading);
- if (IS_ERR(bio)) {
+ if (IS_ERR(bio))
return PTR_ERR(bio);
- }
orig_bio = bio;
blk_queue_bounce(q, &bio);
+
/*
* We link the bounce buffer in and could have to traverse it
* later so we have to get a ref to prevent it from being freed
*/
bio_get(bio);
- /*
- * for most (all? don't know of any) queues we could
- * skip grabbing the queue lock here. only drivers with
- * funky private ->back_merge_fn() function could be
- * problematic.
- */
- spin_lock_irq(q->queue_lock);
if (!rq->bio)
blk_rq_bio_prep(q, rq, bio);
- else if (!q->back_merge_fn(q, rq, bio)) {
+ else if (!ll_back_merge_fn(q, rq, bio)) {
ret = -EINVAL;
- spin_unlock_irq(q->queue_lock);
goto unmap_bio;
} else {
rq->biotail->bi_next = bio;
rq->biotail = bio;
- rq->nr_sectors += bio_sectors(bio);
- rq->hard_nr_sectors = rq->nr_sectors;
rq->data_len += bio->bi_size;
}
- spin_unlock_irq(q->queue_lock);
return bio->bi_size;
@@ -2419,6 +2405,7 @@ int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
unsigned long len)
{
unsigned long bytes_read = 0;
+ struct bio *bio = NULL;
int ret;
if (len > (q->max_hw_sectors << 9))
@@ -2445,6 +2432,8 @@ int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
ret = __blk_rq_map_user(q, rq, ubuf, map_len);
if (ret < 0)
goto unmap_rq;
+ if (!bio)
+ bio = rq->bio;
bytes_read += ret;
ubuf += ret;
}
@@ -2452,7 +2441,7 @@ int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
rq->buffer = rq->data = NULL;
return 0;
unmap_rq:
- blk_rq_unmap_user(rq);
+ blk_rq_unmap_user(bio);
return ret;
}
@@ -2509,27 +2498,33 @@ EXPORT_SYMBOL(blk_rq_map_user_iov);
/**
* blk_rq_unmap_user - unmap a request with user data
- * @rq: rq to be unmapped
+ * @bio: start of bio list
*
* Description:
- * Unmap a rq previously mapped by blk_rq_map_user().
- * rq->bio must be set to the original head of the request.
+ * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
+ * supply the original rq->bio from the blk_rq_map_user() return, since
+ * the io completion may have changed rq->bio.
*/
-int blk_rq_unmap_user(struct request *rq)
+int blk_rq_unmap_user(struct bio *bio)
{
- struct bio *bio, *mapped_bio;
+ struct bio *mapped_bio;
+ int ret = 0, ret2;
- while ((bio = rq->bio)) {
- if (bio_flagged(bio, BIO_BOUNCED))
+ while (bio) {
+ mapped_bio = bio;
+ if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
mapped_bio = bio->bi_private;
- else
- mapped_bio = bio;
- __blk_rq_unmap_user(mapped_bio);
- rq->bio = bio->bi_next;
- bio_put(bio);
+ ret2 = __blk_rq_unmap_user(mapped_bio);
+ if (ret2 && !ret)
+ ret = ret2;
+
+ mapped_bio = bio;
+ bio = bio->bi_next;
+ bio_put(mapped_bio);
}
- return 0;
+
+ return ret;
}
EXPORT_SYMBOL(blk_rq_unmap_user);
@@ -2822,7 +2817,7 @@ static int attempt_merge(request_queue_t *q, struct request *req,
* will have updated segment counts, update sector
* counts here.
*/
- if (!q->merge_requests_fn(q, req, next))
+ if (!ll_merge_requests_fn(q, req, next))
return 0;
/*
@@ -2939,7 +2934,7 @@ static int __make_request(request_queue_t *q, struct bio *bio)
case ELEVATOR_BACK_MERGE:
BUG_ON(!rq_mergeable(req));
- if (!q->back_merge_fn(q, req, bio))
+ if (!ll_back_merge_fn(q, req, bio))
break;
blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
@@ -2956,7 +2951,7 @@ static int __make_request(request_queue_t *q, struct bio *bio)
case ELEVATOR_FRONT_MERGE:
BUG_ON(!rq_mergeable(req));
- if (!q->front_merge_fn(q, req, bio))
+ if (!ll_front_merge_fn(q, req, bio))
break;
blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index f322b6a441d82fbe7db9a177ac0837fc54618cf2..2528a0c0dec8bc906533d1b62163f6404d1c697c 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -333,8 +333,7 @@ static int sg_io(struct file *file, request_queue_t *q,
hdr->sb_len_wr = len;
}
- rq->bio = bio;
- if (blk_rq_unmap_user(rq))
+ if (blk_rq_unmap_user(bio))
ret = -EFAULT;
/* may not have succeeded, but output values written to control
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index d719a5d8f4355e45905410f4a1c0b506702d5bb4..9d2ddb209343ac7cd8d91ca5aaf2742df14df17c 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -1907,6 +1907,7 @@ static void cciss_geometry_inquiry(int ctlr, int logvol,
"does not support reading geometry\n");
drv->heads = 255;
drv->sectors = 32; // Sectors per track
+ drv->raid_level = RAID_UNKNOWN;
} else {
drv->heads = inq_buff->data_byte[6];
drv->sectors = inq_buff->data_byte[7];
@@ -2491,7 +2492,7 @@ static void do_cciss_request(request_queue_t *q)
c->Request.Type.Type = TYPE_CMD; // It is a command.
c->Request.Type.Attribute = ATTR_SIMPLE;
c->Request.Type.Direction =
- (rq_data_dir(creq) == READ) ? h->cciss_read : h->cciss_write;
+ (rq_data_dir(creq) == READ) ? XFER_READ : XFER_WRITE;
c->Request.Timeout = 0; // Don't time out
c->Request.CDB[0] =
(rq_data_dir(creq) == READ) ? h->cciss_read : h->cciss_write;
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index e4a2f8f3a1d764f909910dfd03c4b55e2e24f17c..66d028d304390877530c31b2dda46a24af84c88a 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -2139,8 +2139,7 @@ static int cdrom_read_cdda_bpc(struct cdrom_device_info *cdi, __u8 __user *ubuf,
cdi->last_sense = s->sense_key;
}
- rq->bio = bio;
- if (blk_rq_unmap_user(rq))
+ if (blk_rq_unmap_user(bio))
ret = -EFAULT;
if (ret)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1748e27501cdee45da304d4cdfd97f1c0ff37372..f02f48a882a97b4150a7afe9eb403f1ce7f293fb 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -265,13 +265,11 @@ static int scsi_merge_bio(struct request *rq, struct bio *bio)
if (!rq->bio)
blk_rq_bio_prep(q, rq, bio);
- else if (!q->back_merge_fn(q, rq, bio))
+ else if (!ll_back_merge_fn(q, rq, bio))
return -EINVAL;
else {
rq->biotail->bi_next = bio;
rq->biotail = bio;
- rq->hard_nr_sectors += bio_sectors(bio);
- rq->nr_sectors = rq->hard_nr_sectors;
}
return 0;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ea330d7b46c089f28f1b4c4f24e81af99b09150b..36a6eacefe20d2c17f60b9b34c569cc8f425a843 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -331,10 +331,6 @@ struct request_pm_state
#include <linux/elevator.h>
-typedef int (merge_request_fn) (request_queue_t *, struct request *,
- struct bio *);
-typedef int (merge_requests_fn) (request_queue_t *, struct request *,
- struct request *);
typedef void (request_fn_proc) (request_queue_t *q);
typedef int (make_request_fn) (request_queue_t *q, struct bio *bio);
typedef int (prep_rq_fn) (request_queue_t *, struct request *);
@@ -376,9 +372,6 @@ struct request_queue
struct request_list rq;
request_fn_proc *request_fn;
- merge_request_fn *back_merge_fn;
- merge_request_fn *front_merge_fn;
- merge_requests_fn *merge_requests_fn;
make_request_fn *make_request_fn;
prep_rq_fn *prep_rq_fn;
unplug_fn *unplug_fn;
@@ -648,6 +641,11 @@ extern int scsi_cmd_ioctl(struct file *, struct gendisk *, unsigned int, void __
extern int sg_scsi_ioctl(struct file *, struct request_queue *,
struct gendisk *, struct scsi_ioctl_command __user *);
+/*
+ * Temporary export, until SCSI gets fixed up.
+ */
+extern int ll_back_merge_fn(request_queue_t *, struct request *, struct 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
@@ -674,7 +672,7 @@ extern void __blk_stop_queue(request_queue_t *q);
extern void blk_run_queue(request_queue_t *);
extern void blk_start_queueing(request_queue_t *);
extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned long);
-extern int blk_rq_unmap_user(struct request *);
+extern int blk_rq_unmap_user(struct bio *);
extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, gfp_t);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *,
struct sg_iovec *, int, unsigned int);
diff --git a/include/linux/elevator.h b/include/linux/elevator.h
index a24931d244046d72e056fab76f670719256de00a..e88fcbc77f8f381d3c1b801955406f260b0cab4f 100644
--- a/include/linux/elevator.h
+++ b/include/linux/elevator.h
@@ -12,6 +12,8 @@ typedef void (elevator_merge_req_fn) (request_queue_t *, struct request *, struc
typedef void (elevator_merged_fn) (request_queue_t *, struct request *, int);
+typedef int (elevator_allow_merge_fn) (request_queue_t *, struct request *, struct bio *);
+
typedef int (elevator_dispatch_fn) (request_queue_t *, int);
typedef void (elevator_add_req_fn) (request_queue_t *, struct request *);
@@ -33,6 +35,7 @@ struct elevator_ops
elevator_merge_fn *elevator_merge_fn;
elevator_merged_fn *elevator_merged_fn;
elevator_merge_req_fn *elevator_merge_req_fn;
+ elevator_allow_merge_fn *elevator_allow_merge_fn;
elevator_dispatch_fn *elevator_dispatch_fn;
elevator_add_req_fn *elevator_add_req_fn;