On Sat, Aug 07, 2010 at 12:13:06PM +0200, Tejun Heo wrote:
> The patch was on top of v2.6.35 but was generated against dirty tree
> and wouldn't apply cleanly. Here's the proper one.
Here's an updated version:
(a) ported to Jens' current block tree
(b) optimize barriers on devices not requiring flushes to be no-ops
(b) redo the blk_queue_ordered interface to just set QUEUE_HAS_FLUSH
and QUEUE_HAS_FUA flags.
Index: linux-2.6/block/blk-barrier.c
===================================================================
--- linux-2.6.orig/block/blk-barrier.c 2010-08-07 12:53:23.727479189 -0400
+++ linux-2.6/block/blk-barrier.c 2010-08-07 14:52:21.402479191 -0400
@@ -9,37 +9,36 @@
#include "blk.h"
+/*
+ * Ordered operation sequence.
+ */
+enum {
+ QUEUE_ORDSEQ_STARTED = (1 << 0), /* flushing in progress */
+ QUEUE_ORDSEQ_PREFLUSH = (1 << 1), /* pre-flushing in progress */
+ QUEUE_ORDSEQ_BAR = (1 << 2), /* barrier write in progress */
+ QUEUE_ORDSEQ_POSTFLUSH = (1 << 3), /* post-flushing in progress */
+ QUEUE_ORDSEQ_DONE = (1 << 4),
+};
+
+static struct request *queue_next_ordseq(struct request_queue *q);
+
/**
- * blk_queue_ordered - does this queue support ordered writes
- * @q: the request queue
- * @ordered: one of QUEUE_ORDERED_*
- *
- * Description:
- * For journalled file systems, doing ordered writes on a commit
- * block instead of explicitly doing wait_on_buffer (which is bad
- * for performance) can be a big win. Block drivers supporting this
- * feature should call this function and indicate so.
- *
+ * blk_queue_cache_features - set the supported cache control features
+ * @q: the request queue
+ * @cache_features: the support features
**/
-int blk_queue_ordered(struct request_queue *q, unsigned ordered)
+int blk_queue_cache_features(struct request_queue *q, unsigned cache_features)
{
- if (ordered != QUEUE_ORDERED_NONE &&
- ordered != QUEUE_ORDERED_DRAIN &&
- ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
- ordered != QUEUE_ORDERED_DRAIN_FUA &&
- ordered != QUEUE_ORDERED_TAG &&
- ordered != QUEUE_ORDERED_TAG_FLUSH &&
- ordered != QUEUE_ORDERED_TAG_FUA) {
- printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
+ if (cache_features & ~(QUEUE_HAS_FLUSH|QUEUE_HAS_FUA)) {
+ printk(KERN_ERR "blk_queue_cache_features: bad value %d\n",
+ cache_features);
return -EINVAL;
}
- q->ordered = ordered;
- q->next_ordered = ordered;
-
+ q->cache_features = cache_features;
return 0;
}
-EXPORT_SYMBOL(blk_queue_ordered);
+EXPORT_SYMBOL(blk_queue_cache_features);
/*
* Cache flushing for ordered writes handling
@@ -51,38 +50,10 @@ unsigned blk_ordered_cur_seq(struct requ
return 1 << ffz(q->ordseq);
}
-unsigned blk_ordered_req_seq(struct request *rq)
-{
- struct request_queue *q = rq->q;
-
- BUG_ON(q->ordseq == 0);
-
- if (rq == &q->pre_flush_rq)
- return QUEUE_ORDSEQ_PREFLUSH;
- if (rq == &q->bar_rq)
- return QUEUE_ORDSEQ_BAR;
- if (rq == &q->post_flush_rq)
- return QUEUE_ORDSEQ_POSTFLUSH;
-
- /*
- * !fs requests don't need to follow barrier ordering. Always
- * put them at the front. This fixes the following deadlock.
- *
- * http://thread.gmane.org/gmane.linux.kernel/537473
- */
- if (rq->cmd_type != REQ_TYPE_FS)
- return QUEUE_ORDSEQ_DRAIN;
-
- if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
- (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
- return QUEUE_ORDSEQ_DRAIN;
- else
- return QUEUE_ORDSEQ_DONE;
-}
-
-bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
+static struct request *blk_ordered_complete_seq(struct request_queue *q,
+ unsigned seq, int error)
{
- struct request *rq;
+ struct request *rq = NULL;
if (error && !q->orderr)
q->orderr = error;
@@ -90,16 +61,22 @@ bool blk_ordered_complete_seq(struct req
BUG_ON(q->ordseq & seq);
q->ordseq |= seq;
- if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
- return false;
-
- /*
- * Okay, sequence complete.
- */
- q->ordseq = 0;
- rq = q->orig_bar_rq;
- __blk_end_request_all(rq, q->orderr);
- return true;
+ if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) {
+ /* not complete yet, queue the next ordered sequence */
+ rq = queue_next_ordseq(q);
+ } else {
+ /* complete this barrier request */
+ __blk_end_request_all(q->orig_bar_rq, q->orderr);
+ q->orig_bar_rq = NULL;
+ q->ordseq = 0;
+
+ /* dispatch the next barrier if there's one */
+ if (!list_empty(&q->pending_barriers)) {
+ rq = list_entry_rq(q->pending_barriers.next);
+ list_move(&rq->queuelist, &q->queue_head);
+ }
+ }
+ return rq;
}
static void pre_flush_end_io(struct request *rq, int error)
@@ -120,155 +97,100 @@ static void post_flush_end_io(struct req
blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
}
-static void queue_flush(struct request_queue *q, unsigned which)
+static void init_flush_request(struct request_queue *q, struct request *rq)
{
- struct request *rq;
- rq_end_io_fn *end_io;
+ rq->cmd_type = REQ_TYPE_FS;
+ rq->cmd_flags = REQ_FLUSH;
+ rq->rq_disk = q->orig_bar_rq->rq_disk;
+}
- if (which == QUEUE_ORDERED_DO_PREFLUSH) {
- rq = &q->pre_flush_rq;
- end_io = pre_flush_end_io;
- } else {
- rq = &q->post_flush_rq;
- end_io = post_flush_end_io;
- }
+/*
+ * Initialize proxy request and queue it.
+ */
+static struct request *queue_next_ordseq(struct request_queue *q)
+{
+ struct request *rq = &q->bar_rq;
blk_rq_init(q, rq);
- rq->cmd_type = REQ_TYPE_FS;
- rq->cmd_flags = REQ_HARDBARRIER | REQ_FLUSH;
- rq->rq_disk = q->orig_bar_rq->rq_disk;
- rq->end_io = end_io;
+
+ switch (blk_ordered_cur_seq(q)) {
+ case QUEUE_ORDSEQ_PREFLUSH:
+ init_flush_request(q, rq);
+ rq->end_io = pre_flush_end_io;
+ break;
+ case QUEUE_ORDSEQ_BAR:
+ init_request_from_bio(rq, q->orig_bar_rq->bio);
+ rq->cmd_flags &= ~REQ_HARDBARRIER;
+ if (q->cache_features & QUEUE_HAS_FUA)
+ rq->cmd_flags |= REQ_FUA;
+ rq->end_io = bar_end_io;
+ break;
+ case QUEUE_ORDSEQ_POSTFLUSH:
+ init_flush_request(q, rq);
+ rq->end_io = post_flush_end_io;
+ break;
+ default:
+ BUG();
+ }
elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+ return rq;
}
-static inline bool start_ordered(struct request_queue *q, struct request **rqp)
+struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
{
- struct request *rq = *rqp;
unsigned skip = 0;
- q->orderr = 0;
- q->ordered = q->next_ordered;
- q->ordseq |= QUEUE_ORDSEQ_STARTED;
+ if (rq->cmd_type != REQ_TYPE_FS)
+ return rq;
+ if (!(rq->cmd_flags & REQ_HARDBARRIER))
+ return rq;
- /*
- * For an empty barrier, there's no actual BAR request, which
- * in turn makes POSTFLUSH unnecessary. Mask them off.
- */
- if (!blk_rq_sectors(rq)) {
- q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
- QUEUE_ORDERED_DO_POSTFLUSH);
+ if (!(q->cache_features & QUEUE_HAS_FLUSH)) {
/*
- * Empty barrier on a write-through device w/ ordered
- * tag has no command to issue and without any command
- * to issue, ordering by tag can't be used. Drain
- * instead.
+ * No flush required. We can just send on write requests
+ * and complete cache flush requests ASAP.
*/
- if ((q->ordered & QUEUE_ORDERED_BY_TAG) &&
- !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) {
- q->ordered &= ~QUEUE_ORDERED_BY_TAG;
- q->ordered |= QUEUE_ORDERED_BY_DRAIN;
+ if (blk_rq_sectors(rq)) {
+ rq->cmd_flags &= ~REQ_HARDBARRIER;
+ return rq;
}
+ blk_dequeue_request(rq);
+ __blk_end_request_all(rq, 0);
+ return NULL;
}
- /* stash away the original request */
- blk_dequeue_request(rq);
- q->orig_bar_rq = rq;
- rq = NULL;
-
- /*
- * Queue ordered sequence. As we stack them at the head, we
- * need to queue in reverse order. Note that we rely on that
- * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
- * request gets inbetween ordered sequence.
- */
- if (q->ordered & QUEUE_ORDERED_DO_POSTFLUSH) {
- queue_flush(q, QUEUE_ORDERED_DO_POSTFLUSH);
- rq = &q->post_flush_rq;
- } else
- skip |= QUEUE_ORDSEQ_POSTFLUSH;
-
- if (q->ordered & QUEUE_ORDERED_DO_BAR) {
- rq = &q->bar_rq;
-
- /* initialize proxy request and queue it */
- blk_rq_init(q, rq);
- if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
- rq->cmd_flags |= REQ_WRITE;
- if (q->ordered & QUEUE_ORDERED_DO_FUA)
- rq->cmd_flags |= REQ_FUA;
- init_request_from_bio(rq, q->orig_bar_rq->bio);
- rq->end_io = bar_end_io;
-
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
- } else
- skip |= QUEUE_ORDSEQ_BAR;
-
- if (q->ordered & QUEUE_ORDERED_DO_PREFLUSH) {
- queue_flush(q, QUEUE_ORDERED_DO_PREFLUSH);
- rq = &q->pre_flush_rq;
- } else
- skip |= QUEUE_ORDSEQ_PREFLUSH;
-
- if ((q->ordered & QUEUE_ORDERED_BY_DRAIN) && queue_in_flight(q))
- rq = NULL;
- else
- skip |= QUEUE_ORDSEQ_DRAIN;
+ if (q->ordseq) {
+ /*
+ * Barrier is already in progress and they can't be
+ * processed in parallel. Queue for later processing.
+ */
+ list_move_tail(&rq->queuelist, &q->pending_barriers);
+ return NULL;
+ }
- *rqp = rq;
/*
- * Complete skipped sequences. If whole sequence is complete,
- * return false to tell elevator that this request is gone.
+ * Start a new ordered sequence
*/
- return !blk_ordered_complete_seq(q, skip, 0);
-}
-
-bool blk_do_ordered(struct request_queue *q, struct request **rqp)
-{
- struct request *rq = *rqp;
- const int is_barrier = rq->cmd_type == REQ_TYPE_FS &&
- (rq->cmd_flags & REQ_HARDBARRIER);
-
- if (!q->ordseq) {
- if (!is_barrier)
- return true;
-
- if (q->next_ordered != QUEUE_ORDERED_NONE)
- return start_ordered(q, rqp);
- else {
- /*
- * Queue ordering not supported. Terminate
- * with prejudice.
- */
- blk_dequeue_request(rq);
- __blk_end_request_all(rq, -EOPNOTSUPP);
- *rqp = NULL;
- return false;
- }
- }
+ q->orderr = 0;
+ q->ordseq |= QUEUE_ORDSEQ_STARTED;
/*
- * Ordered sequence in progress
+ * For an empty barrier, there's no actual BAR request, which
+ * in turn makes POSTFLUSH unnecessary. Mask them off.
*/
+ if (!blk_rq_sectors(rq))
+ skip |= (QUEUE_ORDSEQ_BAR|QUEUE_ORDSEQ_POSTFLUSH);
+ else if (q->cache_features & QUEUE_HAS_FUA)
+ skip |= QUEUE_ORDSEQ_POSTFLUSH;
- /* Special requests are not subject to ordering rules. */
- if (rq->cmd_type != REQ_TYPE_FS &&
- rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
- return true;
-
- if (q->ordered & QUEUE_ORDERED_BY_TAG) {
- /* Ordered by tag. Blocking the next barrier is enough. */
- if (is_barrier && rq != &q->bar_rq)
- *rqp = NULL;
- } else {
- /* Ordered by draining. Wait for turn. */
- WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
- if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
- *rqp = NULL;
- }
+ /* stash away the original request */
+ blk_dequeue_request(rq);
+ q->orig_bar_rq = rq;
- return true;
+ /* complete skipped sequences and return the first sequence */
+ return blk_ordered_complete_seq(q, skip, 0);
}
static void bio_end_empty_barrier(struct bio *bio, int err)
Index: linux-2.6/include/linux/blkdev.h
===================================================================
--- linux-2.6.orig/include/linux/blkdev.h 2010-08-07 12:53:23.774479189 -0400
+++ linux-2.6/include/linux/blkdev.h 2010-08-07 14:51:42.751479190 -0400
@@ -354,13 +354,20 @@ struct request_queue
#ifdef CONFIG_BLK_DEV_IO_TRACE
struct blk_trace *blk_trace;
#endif
+
+ /*
+ * Features this queue understands.
+ */
+ unsigned int cache_features;
+
/*
* reserved for flush operations
*/
- unsigned int ordered, next_ordered, ordseq;
- int orderr, ordcolor;
- struct request pre_flush_rq, bar_rq, post_flush_rq;
- struct request *orig_bar_rq;
+ unsigned int ordseq;
+ int orderr;
+ struct request bar_rq;
+ struct request *orig_bar_rq;
+ struct list_head pending_barriers;
struct mutex sysfs_lock;
@@ -461,54 +468,12 @@ static inline void queue_flag_clear(unsi
__clear_bit(flag, &q->queue_flags);
}
+/*
+ * Possible features to control a volatile write cache.
+ */
enum {
- /*
- * Hardbarrier is supported with one of the following methods.
- *
- * NONE : hardbarrier unsupported
- * DRAIN : ordering by draining is enough
- * DRAIN_FLUSH : ordering by draining w/ pre and post flushes
- * DRAIN_FUA : ordering by draining w/ pre flush and FUA write
- * TAG : ordering by tag is enough
- * TAG_FLUSH : ordering by tag w/ pre and post flushes
- * TAG_FUA : ordering by tag w/ pre flush and FUA write
- */
- QUEUE_ORDERED_BY_DRAIN = 0x01,
- QUEUE_ORDERED_BY_TAG = 0x02,
- QUEUE_ORDERED_DO_PREFLUSH = 0x10,
- QUEUE_ORDERED_DO_BAR = 0x20,
- QUEUE_ORDERED_DO_POSTFLUSH = 0x40,
- QUEUE_ORDERED_DO_FUA = 0x80,
-
- QUEUE_ORDERED_NONE = 0x00,
-
- QUEUE_ORDERED_DRAIN = QUEUE_ORDERED_BY_DRAIN |
- QUEUE_ORDERED_DO_BAR,
- QUEUE_ORDERED_DRAIN_FLUSH = QUEUE_ORDERED_DRAIN |
- QUEUE_ORDERED_DO_PREFLUSH |
- QUEUE_ORDERED_DO_POSTFLUSH,
- QUEUE_ORDERED_DRAIN_FUA = QUEUE_ORDERED_DRAIN |
- QUEUE_ORDERED_DO_PREFLUSH |
- QUEUE_ORDERED_DO_FUA,
-
- QUEUE_ORDERED_TAG = QUEUE_ORDERED_BY_TAG |
- QUEUE_ORDERED_DO_BAR,
- QUEUE_ORDERED_TAG_FLUSH = QUEUE_ORDERED_TAG |
- QUEUE_ORDERED_DO_PREFLUSH |
- QUEUE_ORDERED_DO_POSTFLUSH,
- QUEUE_ORDERED_TAG_FUA = QUEUE_ORDERED_TAG |
- QUEUE_ORDERED_DO_PREFLUSH |
- QUEUE_ORDERED_DO_FUA,
-
- /*
- * Ordered operation sequence
- */
- QUEUE_ORDSEQ_STARTED = 0x01, /* flushing in progress */
- QUEUE_ORDSEQ_DRAIN = 0x02, /* waiting for the queue to be drained */
- QUEUE_ORDSEQ_PREFLUSH = 0x04, /* pre-flushing in progress */
- QUEUE_ORDSEQ_BAR = 0x08, /* original barrier req in progress */
- QUEUE_ORDSEQ_POSTFLUSH = 0x10, /* post-flushing in progress */
- QUEUE_ORDSEQ_DONE = 0x20,
+ QUEUE_HAS_FLUSH = 1 << 0, /* supports REQ_FLUSH */
+ QUEUE_HAS_FUA = 1 << 1, /* supports REQ_FUA */
};
#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
@@ -879,11 +844,9 @@ extern void blk_queue_softirq_done(struc
extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
-extern int blk_queue_ordered(struct request_queue *, unsigned);
-extern bool blk_do_ordered(struct request_queue *, struct request **);
+extern int blk_queue_cache_features(struct request_queue *, unsigned);
extern unsigned blk_ordered_cur_seq(struct request_queue *);
extern unsigned blk_ordered_req_seq(struct request *);
-extern bool blk_ordered_complete_seq(struct request_queue *, unsigned, int);
extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
extern void blk_dump_rq_flags(struct request *, char *);
Index: linux-2.6/drivers/block/virtio_blk.c
===================================================================
--- linux-2.6.orig/drivers/block/virtio_blk.c 2010-08-07 12:53:23.800479189 -0400
+++ linux-2.6/drivers/block/virtio_blk.c 2010-08-07 14:51:34.198479189 -0400
@@ -388,31 +388,8 @@ static int __devinit virtblk_probe(struc
vblk->disk->driverfs_dev = &vdev->dev;
index++;
- if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) {
- /*
- * If the FLUSH feature is supported we do have support for
- * flushing a volatile write cache on the host. Use that
- * to implement write barrier support.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH);
- } else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) {
- /*
- * If the BARRIER feature is supported the host expects us
- * to order request by tags. This implies there is not
- * volatile write cache on the host, and that the host
- * never re-orders outstanding I/O. This feature is not
- * useful for real life scenarious and deprecated.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_TAG);
- } else {
- /*
- * If the FLUSH feature is not supported we must assume that
- * the host does not perform any kind of volatile write
- * caching. We still need to drain the queue to provider
- * proper barrier semantics.
- */
- blk_queue_ordered(q, QUEUE_ORDERED_DRAIN);
- }
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
+ blk_queue_cache_features(q, QUEUE_HAS_FLUSH);
/* If disk is read-only in the host, the guest should obey */
if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
Index: linux-2.6/drivers/scsi/sd.c
===================================================================
--- linux-2.6.orig/drivers/scsi/sd.c 2010-08-07 12:53:23.872479189 -0400
+++ linux-2.6/drivers/scsi/sd.c 2010-08-07 14:54:47.812479189 -0400
@@ -2109,7 +2109,7 @@ static int sd_revalidate_disk(struct gen
struct scsi_disk *sdkp = scsi_disk(disk);
struct scsi_device *sdp = sdkp->device;
unsigned char *buffer;
- unsigned ordered;
+ unsigned ordered = 0;
SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
"sd_revalidate_disk\n"));
@@ -2151,17 +2151,14 @@ static int sd_revalidate_disk(struct gen
/*
* We now have all cache related info, determine how we deal
- * with ordered requests. Note that as the current SCSI
- * dispatch function can alter request order, we cannot use
- * QUEUE_ORDERED_TAG_* even when ordered tag is supported.
+ * with barriers.
*/
- if (sdkp->WCE)
- ordered = sdkp->DPOFUA
- ? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
- else
- ordered = QUEUE_ORDERED_DRAIN;
-
- blk_queue_ordered(sdkp->disk->queue, ordered);
+ if (sdkp->WCE) {
+ ordered |= QUEUE_HAS_FLUSH;
+ if (sdkp->DPOFUA)
+ ordered |= QUEUE_HAS_FUA;
+ }
+ blk_queue_cache_features(sdkp->disk->queue, ordered);
set_capacity(disk, sdkp->capacity);
kfree(buffer);
Index: linux-2.6/block/blk-core.c
===================================================================
--- linux-2.6.orig/block/blk-core.c 2010-08-07 12:53:23.744479189 -0400
+++ linux-2.6/block/blk-core.c 2010-08-07 14:56:35.087479189 -0400
@@ -520,6 +520,7 @@ struct request_queue *blk_alloc_queue_no
init_timer(&q->unplug_timer);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
INIT_LIST_HEAD(&q->timeout_list);
+ INIT_LIST_HEAD(&q->pending_barriers);
INIT_WORK(&q->unplug_work, blk_unplug_work);
kobject_init(&q->kobj, &blk_queue_ktype);
@@ -1037,22 +1038,6 @@ void blk_insert_request(struct request_q
}
EXPORT_SYMBOL(blk_insert_request);
-/*
- * add-request adds a request to the linked list.
- * queue lock is held and interrupts disabled, as we muck with the
- * request queue list.
- */
-static inline void add_request(struct request_queue *q, struct request *req)
-{
- drive_stat_acct(req, 1);
-
- /*
- * elevator indicated where it wants this request to be
- * inserted at elevator_merge time
- */
- __elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
-}
-
static void part_round_stats_single(int cpu, struct hd_struct *part,
unsigned long now)
{
@@ -1201,13 +1186,9 @@ static int __make_request(struct request
const bool sync = (bio->bi_rw & REQ_SYNC);
const bool unplug = (bio->bi_rw & REQ_UNPLUG);
const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
+ int where = ELEVATOR_INSERT_SORT;
int rw_flags;
- if ((bio->bi_rw & REQ_HARDBARRIER) &&
- (q->next_ordered == QUEUE_ORDERED_NONE)) {
- bio_endio(bio, -EOPNOTSUPP);
- return 0;
- }
/*
* low level driver can indicate that it wants pages above a
* certain limit bounced to low memory (ie for highmem, or even
@@ -1217,7 +1198,12 @@ static int __make_request(struct request
spin_lock_irq(q->queue_lock);
- if (unlikely((bio->bi_rw & REQ_HARDBARRIER)) || elv_queue_empty(q))
+ if (bio->bi_rw & REQ_HARDBARRIER) {
+ where = ELEVATOR_INSERT_ORDERED;
+ goto get_rq;
+ }
+
+ if (elv_queue_empty(q))
goto get_rq;
el_ret = elv_merge(q, &req, bio);
@@ -1314,7 +1300,10 @@ get_rq:
req->cpu = blk_cpu_to_group(smp_processor_id());
if (queue_should_plug(q) && elv_queue_empty(q))
blk_plug_device(q);
- add_request(q, req);
+
+ /* insert the request into the elevator */
+ drive_stat_acct(req, 1);
+ __elv_add_request(q, req, where, 0);
out:
if (unplug || !queue_should_plug(q))
__generic_unplug_device(q);
Index: linux-2.6/block/elevator.c
===================================================================
--- linux-2.6.orig/block/elevator.c 2010-08-07 12:53:23.752479189 -0400
+++ linux-2.6/block/elevator.c 2010-08-07 12:53:53.162479190 -0400
@@ -564,7 +564,7 @@ void elv_requeue_request(struct request_
rq->cmd_flags &= ~REQ_STARTED;
- elv_insert(q, rq, ELEVATOR_INSERT_REQUEUE);
+ elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
}
void elv_drain_elevator(struct request_queue *q)
@@ -611,8 +611,6 @@ void elv_quiesce_end(struct request_queu
void elv_insert(struct request_queue *q, struct request *rq, int where)
{
- struct list_head *pos;
- unsigned ordseq;
int unplug_it = 1;
trace_block_rq_insert(q, rq);
@@ -622,10 +620,14 @@ void elv_insert(struct request_queue *q,
switch (where) {
case ELEVATOR_INSERT_FRONT:
rq->cmd_flags |= REQ_SOFTBARRIER;
-
list_add(&rq->queuelist, &q->queue_head);
break;
+ case ELEVATOR_INSERT_ORDERED:
+ rq->cmd_flags |= REQ_SOFTBARRIER;
+ list_add_tail(&rq->queuelist, &q->queue_head);
+ break;
+
case ELEVATOR_INSERT_BACK:
rq->cmd_flags |= REQ_SOFTBARRIER;
elv_drain_elevator(q);
@@ -662,36 +664,6 @@ void elv_insert(struct request_queue *q,
q->elevator->ops->elevator_add_req_fn(q, rq);
break;
- case ELEVATOR_INSERT_REQUEUE:
- /*
- * If ordered flush isn't in progress, we do front
- * insertion; otherwise, requests should be requeued
- * in ordseq order.
- */
- rq->cmd_flags |= REQ_SOFTBARRIER;
-
- /*
- * Most requeues happen because of a busy condition,
- * don't force unplug of the queue for that case.
- */
- unplug_it = 0;
-
- if (q->ordseq == 0) {
- list_add(&rq->queuelist, &q->queue_head);
- break;
- }
-
- ordseq = blk_ordered_req_seq(rq);
-
- list_for_each(pos, &q->queue_head) {
- struct request *pos_rq = list_entry_rq(pos);
- if (ordseq <= blk_ordered_req_seq(pos_rq))
- break;
- }
-
- list_add_tail(&rq->queuelist, pos);
- break;
-
default:
printk(KERN_ERR "%s: bad insertion point %d\n",
__func__, where);
@@ -710,33 +682,15 @@ void elv_insert(struct request_queue *q,
void __elv_add_request(struct request_queue *q, struct request *rq, int where,
int plug)
{
- if (q->ordcolor)
- rq->cmd_flags |= REQ_ORDERED_COLOR;
-
if (rq->cmd_flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
- /*
- * toggle ordered color
- */
- if (rq->cmd_flags & REQ_HARDBARRIER)
- q->ordcolor ^= 1;
-
- /*
- * barriers implicitly indicate back insertion
- */
- if (where == ELEVATOR_INSERT_SORT)
- where = ELEVATOR_INSERT_BACK;
-
- /*
- * this request is scheduling boundary, update
- * end_sector
- */
+ /* barriers are scheduling boundary, update end_sector */
if (rq->cmd_type == REQ_TYPE_FS ||
(rq->cmd_flags & REQ_DISCARD)) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
} else if (!(rq->cmd_flags & REQ_ELVPRIV) &&
- where == ELEVATOR_INSERT_SORT)
+ where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
if (plug)
@@ -849,24 +803,6 @@ void elv_completed_request(struct reques
e->ops->elevator_completed_req_fn)
e->ops->elevator_completed_req_fn(q, rq);
}
-
- /*
- * Check if the queue is waiting for fs requests to be
- * drained for flush sequence.
- */
- if (unlikely(q->ordseq)) {
- struct request *next = NULL;
-
- if (!list_empty(&q->queue_head))
- next = list_entry_rq(q->queue_head.next);
-
- if (!queue_in_flight(q) &&
- blk_ordered_cur_seq(q) == QUEUE_ORDSEQ_DRAIN &&
- (!next || blk_ordered_req_seq(next) > QUEUE_ORDSEQ_DRAIN)) {
- blk_ordered_complete_seq(q, QUEUE_ORDSEQ_DRAIN, 0);
- __blk_run_queue(q);
- }
- }
}
#define to_elv(atr) container_of((atr), struct elv_fs_entry, attr)
Index: linux-2.6/block/blk.h
===================================================================
--- linux-2.6.orig/block/blk.h 2010-08-07 12:53:23.762479189 -0400
+++ linux-2.6/block/blk.h 2010-08-07 12:53:53.171479190 -0400
@@ -51,6 +51,8 @@ static inline void blk_clear_rq_complete
*/
#define ELV_ON_HASH(rq) (!hlist_unhashed(&(rq)->hash))
+struct request *blk_do_ordered(struct request_queue *q, struct request *rq);
+
static inline struct request *__elv_next_request(struct request_queue *q)
{
struct request *rq;
@@ -58,7 +60,8 @@ static inline struct request *__elv_next
while (1) {
while (!list_empty(&q->queue_head)) {
rq = list_entry_rq(q->queue_head.next);
- if (blk_do_ordered(q, &rq))
+ rq = blk_do_ordered(q, rq);
+ if (rq)
return rq;
}
Index: linux-2.6/drivers/block/xen-blkfront.c
===================================================================
--- linux-2.6.orig/drivers/block/xen-blkfront.c 2010-08-07 12:53:23.807479189 -0400
+++ linux-2.6/drivers/block/xen-blkfront.c 2010-08-07 14:44:39.564479189 -0400
@@ -417,30 +417,6 @@ static int xlvbd_init_blk_queue(struct g
return 0;
}
-
-static int xlvbd_barrier(struct blkfront_info *info)
-{
- int err;
- const char *barrier;
-
- switch (info->feature_barrier) {
- case QUEUE_ORDERED_DRAIN: barrier = "enabled (drain)"; break;
- case QUEUE_ORDERED_TAG: barrier = "enabled (tag)"; break;
- case QUEUE_ORDERED_NONE: barrier = "disabled"; break;
- default: return -EINVAL;
- }
-
- err = blk_queue_ordered(info->rq, info->feature_barrier);
-
- if (err)
- return err;
-
- printk(KERN_INFO "blkfront: %s: barriers %s\n",
- info->gd->disk_name, barrier);
- return 0;
-}
-
-
static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
struct blkfront_info *info,
u16 vdisk_info, u16 sector_size)
@@ -516,8 +492,6 @@ static int xlvbd_alloc_gendisk(blkif_sec
info->rq = gd->queue;
info->gd = gd;
- xlvbd_barrier(info);
-
if (vdisk_info & VDISK_READONLY)
set_disk_ro(gd, 1);
@@ -662,8 +636,6 @@ static irqreturn_t blkif_interrupt(int i
printk(KERN_WARNING "blkfront: %s: write barrier op failed\n",
info->gd->disk_name);
error = -EOPNOTSUPP;
- info->feature_barrier = QUEUE_ORDERED_NONE;
- xlvbd_barrier(info);
}
/* fall through */
case BLKIF_OP_READ:
@@ -1073,24 +1045,6 @@ static void blkfront_connect(struct blkf
"feature-barrier", "%lu", &barrier,
NULL);
- /*
- * If there's no "feature-barrier" defined, then it means
- * we're dealing with a very old backend which writes
- * synchronously; draining will do what needs to get done.
- *
- * If there are barriers, then we can do full queued writes
- * with tagged barriers.
- *
- * If barriers are not supported, then there's no much we can
- * do, so just set ordering to NONE.
- */
- if (err)
- info->feature_barrier = QUEUE_ORDERED_DRAIN;
- else if (barrier)
- info->feature_barrier = QUEUE_ORDERED_TAG;
- else
- info->feature_barrier = QUEUE_ORDERED_NONE;
-
err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
xenbus_dev_fatal(info->xbdev, err, "xlvbd_add at %s",
Index: linux-2.6/drivers/ide/ide-disk.c
===================================================================
--- linux-2.6.orig/drivers/ide/ide-disk.c 2010-08-07 12:53:23.889479189 -0400
+++ linux-2.6/drivers/ide/ide-disk.c 2010-08-07 15:00:30.215479189 -0400
@@ -518,12 +518,13 @@ static int ide_do_setfeature(ide_drive_t
static void update_ordered(ide_drive_t *drive)
{
- u16 *id = drive->id;
- unsigned ordered = QUEUE_ORDERED_NONE;
+ unsigned ordered = 0;
if (drive->dev_flags & IDE_DFLAG_WCACHE) {
+ u16 *id = drive->id;
unsigned long long capacity;
int barrier;
+
/*
* We must avoid issuing commands a drive does not
* understand or we may crash it. We check flush cache
@@ -543,13 +544,18 @@ static void update_ordered(ide_drive_t *
drive->name, barrier ? "" : "not ");
if (barrier) {
- ordered = QUEUE_ORDERED_DRAIN_FLUSH;
+ printk(KERN_INFO "%s: cache flushes supported\n",
+ drive->name);
blk_queue_prep_rq(drive->queue, idedisk_prep_fn);
+ ordered |= QUEUE_HAS_FLUSH;
+ } else {
+ printk(KERN_INFO
+ "%s: WARNING: cache flushes not supported\n",
+ drive->name);
}
- } else
- ordered = QUEUE_ORDERED_DRAIN;
+ }
- blk_queue_ordered(drive->queue, ordered);
+ blk_queue_cache_features(drive->queue, ordered);
}
ide_devset_get_flag(wcache, IDE_DFLAG_WCACHE);
Index: linux-2.6/drivers/md/dm.c
===================================================================
--- linux-2.6.orig/drivers/md/dm.c 2010-08-07 12:53:23.905479189 -0400
+++ linux-2.6/drivers/md/dm.c 2010-08-07 14:51:38.240479189 -0400
@@ -1908,7 +1908,7 @@ static struct mapped_device *alloc_dev(i
blk_queue_softirq_done(md->queue, dm_softirq_done);
blk_queue_prep_rq(md->queue, dm_prep_fn);
blk_queue_lld_busy(md->queue, dm_lld_busy);
- blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN_FLUSH);
+ blk_queue_cache_features(md->queue, QUEUE_HAS_FLUSH);
md->disk = alloc_disk(1);
if (!md->disk)
Index: linux-2.6/drivers/mmc/card/queue.c
===================================================================
--- linux-2.6.orig/drivers/mmc/card/queue.c 2010-08-07 12:53:23.927479189 -0400
+++ linux-2.6/drivers/mmc/card/queue.c 2010-08-07 14:30:09.666479189 -0400
@@ -128,7 +128,6 @@ int mmc_init_queue(struct mmc_queue *mq,
mq->req = NULL;
blk_queue_prep_rq(mq->queue, mmc_prep_request);
- blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
#ifdef CONFIG_MMC_BLOCK_BOUNCE
Index: linux-2.6/drivers/s390/block/dasd.c
===================================================================
--- linux-2.6.orig/drivers/s390/block/dasd.c 2010-08-07 12:53:23.939479189 -0400
+++ linux-2.6/drivers/s390/block/dasd.c 2010-08-07 14:30:13.307479189 -0400
@@ -2197,7 +2197,6 @@ static void dasd_setup_queue(struct dasd
*/
blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
- blk_queue_ordered(block->request_queue, QUEUE_ORDERED_DRAIN);
}
/*
Index: linux-2.6/include/linux/elevator.h
===================================================================
--- linux-2.6.orig/include/linux/elevator.h 2010-08-07 12:53:23.781479189 -0400
+++ linux-2.6/include/linux/elevator.h 2010-08-07 12:53:53.208479190 -0400
@@ -162,9 +162,9 @@ extern struct request *elv_rb_find(struc
* Insertion selection
*/
#define ELEVATOR_INSERT_FRONT 1
-#define ELEVATOR_INSERT_BACK 2
-#define ELEVATOR_INSERT_SORT 3
-#define ELEVATOR_INSERT_REQUEUE 4
+#define ELEVATOR_INSERT_ORDERED 2
+#define ELEVATOR_INSERT_BACK 3
+#define ELEVATOR_INSERT_SORT 4
/*
* return values from elevator_may_queue_fn
Index: linux-2.6/drivers/block/pktcdvd.c
===================================================================
--- linux-2.6.orig/drivers/block/pktcdvd.c 2010-08-07 12:53:23.815479189 -0400
+++ linux-2.6/drivers/block/pktcdvd.c 2010-08-07 12:53:53.211479190 -0400
@@ -753,7 +753,6 @@ static int pkt_generic_packet(struct pkt
rq->timeout = 60*HZ;
rq->cmd_type = REQ_TYPE_BLOCK_PC;
- rq->cmd_flags |= REQ_HARDBARRIER;
if (cgc->quiet)
rq->cmd_flags |= REQ_QUIET;
Index: linux-2.6/drivers/block/brd.c
===================================================================
--- linux-2.6.orig/drivers/block/brd.c 2010-08-07 12:53:23.825479189 -0400
+++ linux-2.6/drivers/block/brd.c 2010-08-07 14:26:12.293479191 -0400
@@ -482,7 +482,6 @@ static struct brd_device *brd_alloc(int
if (!brd->brd_queue)
goto out_free_dev;
blk_queue_make_request(brd->brd_queue, brd_make_request);
- blk_queue_ordered(brd->brd_queue, QUEUE_ORDERED_TAG);
blk_queue_max_hw_sectors(brd->brd_queue, 1024);
blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY);
Index: linux-2.6/drivers/block/loop.c
===================================================================
--- linux-2.6.orig/drivers/block/loop.c 2010-08-07 12:53:23.836479189 -0400
+++ linux-2.6/drivers/block/loop.c 2010-08-07 14:51:27.937479189 -0400
@@ -831,8 +831,8 @@ static int loop_set_fd(struct loop_devic
lo->lo_queue->queuedata = lo;
lo->lo_queue->unplug_fn = loop_unplug;
- if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
- blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN);
+ /* XXX(hch): loop can't properly deal with flush requests currently */
+// blk_queue_cache_features(lo->lo_queue, QUEUE_HAS_FLUSH);
set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
Index: linux-2.6/drivers/block/osdblk.c
===================================================================
--- linux-2.6.orig/drivers/block/osdblk.c 2010-08-07 12:53:23.843479189 -0400
+++ linux-2.6/drivers/block/osdblk.c 2010-08-07 14:51:30.091479189 -0400
@@ -439,7 +439,7 @@ static int osdblk_init_disk(struct osdbl
blk_queue_stack_limits(q, osd_request_queue(osdev->osd));
blk_queue_prep_rq(q, blk_queue_start_tag);
- blk_queue_ordered(q, QUEUE_ORDERED_DRAIN_FLUSH);
+ blk_queue_cache_features(q, QUEUE_HAS_FLUSH);
disk->queue = q;
Index: linux-2.6/drivers/block/ps3disk.c
===================================================================
--- linux-2.6.orig/drivers/block/ps3disk.c 2010-08-07 12:53:23.859479189 -0400
+++ linux-2.6/drivers/block/ps3disk.c 2010-08-07 14:51:32.204479189 -0400
@@ -468,7 +468,7 @@ static int __devinit ps3disk_probe(struc
blk_queue_dma_alignment(queue, dev->blk_size-1);
blk_queue_logical_block_size(queue, dev->blk_size);
- blk_queue_ordered(queue, QUEUE_ORDERED_DRAIN_FLUSH);
+ blk_queue_cache_features(queue, QUEUE_HAS_FLUSH);
blk_queue_max_segments(queue, -1);
blk_queue_max_segment_size(queue, dev->bounce_size);
Index: linux-2.6/include/linux/blk_types.h
===================================================================
--- linux-2.6.orig/include/linux/blk_types.h 2010-08-07 12:53:23.793479189 -0400
+++ linux-2.6/include/linux/blk_types.h 2010-08-07 12:53:53.243479190 -0400
@@ -141,7 +141,6 @@ enum rq_flag_bits {
__REQ_FAILED, /* set if the request failed */
__REQ_QUIET, /* don't worry about errors */
__REQ_PREEMPT, /* set for "ide_preempt" requests */
- __REQ_ORDERED_COLOR, /* is before or after barrier */
__REQ_ALLOCED, /* request came from our alloc pool */
__REQ_COPY_USER, /* contains copies of user pages */
__REQ_INTEGRITY, /* integrity metadata has been remapped */
@@ -181,7 +180,6 @@ enum rq_flag_bits {
#define REQ_FAILED (1 << __REQ_FAILED)
#define REQ_QUIET (1 << __REQ_QUIET)
#define REQ_PREEMPT (1 << __REQ_PREEMPT)
-#define REQ_ORDERED_COLOR (1 << __REQ_ORDERED_COLOR)
#define REQ_ALLOCED (1 << __REQ_ALLOCED)
#define REQ_COPY_USER (1 << __REQ_COPY_USER)
#define REQ_INTEGRITY (1 << __REQ_INTEGRITY)
--
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