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Old 08-12-2010, 12:41 PM
Tejun Heo
 
Default block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush()

Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with
-EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
blk_queue_flush().

blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a
device has write cache and can flush it, it should set REQ_FLUSH. If
the device can handle FUA writes, it should also set REQ_FUA.

All blk_queue_ordered() users are converted.

* ORDERED_DRAIN is mapped to 0 which is the default value.
* ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH.
* ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Stefan Weinhuber <wein@de.ibm.com>
---
block/blk-barrier.c | 29 ----------------------------
block/blk-core.c | 6 +++-
block/blk-settings.c | 20 +++++++++++++++++++
drivers/block/brd.c | 1 -
drivers/block/loop.c | 2 +-
drivers/block/osdblk.c | 2 +-
drivers/block/ps3disk.c | 2 +-
drivers/block/virtio_blk.c | 25 ++++++++---------------
drivers/block/xen-blkfront.c | 43 +++++++++++------------------------------
drivers/ide/ide-disk.c | 13 +++++------
drivers/md/dm.c | 2 +-
drivers/mmc/card/queue.c | 1 -
drivers/s390/block/dasd.c | 1 -
drivers/scsi/sd.c | 16 +++++++-------
include/linux/blkdev.h | 6 +++-
15 files changed, 67 insertions(+), 102 deletions(-)

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index c807e9c..ed0aba5 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -9,35 +9,6 @@

#include "blk.h"

-/**
- * 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.
- *
- **/
-int blk_queue_ordered(struct request_queue *q, unsigned ordered)
-{
- if (ordered != QUEUE_ORDERED_NONE &&
- ordered != QUEUE_ORDERED_DRAIN &&
- ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
- ordered != QUEUE_ORDERED_DRAIN_FUA) {
- printk(KERN_ERR "blk_queue_ordered: bad value %d
", ordered);
- return -EINVAL;
- }
-
- q->ordered = ordered;
- q->next_ordered = ordered;
-
- return 0;
-}
-EXPORT_SYMBOL(blk_queue_ordered);
-
/*
* Cache flushing for ordered writes handling
*/
diff --git a/block/blk-core.c b/block/blk-core.c
index 5ab3ac2..3f802dd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1203,11 +1203,13 @@ static int __make_request(struct request_queue *q, struct bio *bio)
const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
int rw_flags;

- if ((bio->bi_rw & REQ_HARDBARRIER) &&
- (q->next_ordered == QUEUE_ORDERED_NONE)) {
+ /* REQ_HARDBARRIER is no more */
+ if (WARN_ONCE(bio->bi_rw & REQ_HARDBARRIER,
+ "block: HARDBARRIER is deprecated, use FLUSH/FUA instead
")) {
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
diff --git a/block/blk-settings.c b/block/blk-settings.c
index a234f4b..9b18afc 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -794,6 +794,26 @@ void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
}
EXPORT_SYMBOL(blk_queue_update_dma_alignment);

+/**
+ * blk_queue_flush - configure queue's cache flush capability
+ * @q: the request queue for the device
+ * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
+ *
+ * Tell block layer cache flush capability of @q. If it supports
+ * flushing, REQ_FLUSH should be set. If it supports bypassing
+ * write cache for individual writes, REQ_FUA should be set.
+ */
+void blk_queue_flush(struct request_queue *q, unsigned int flush)
+{
+ WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
+
+ if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
+ flush &= ~REQ_FUA;
+
+ q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
+}
+EXPORT_SYMBOL_GPL(blk_queue_flush);
+
static int __init blk_settings_init(void)
{
blk_max_low_pfn = max_low_pfn - 1;
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 47a4127..fa33f97 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -482,7 +482,6 @@ static struct brd_device *brd_alloc(int i)
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_DRAIN);
blk_queue_max_hw_sectors(brd->brd_queue, 1024);
blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY);

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c3a4a2e..953d1e1 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -832,7 +832,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
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_FLUSH);
+ blk_queue_flush(lo->lo_queue, REQ_FLUSH);

set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
index 2284b4f..72d6246 100644
--- a/drivers/block/osdblk.c
+++ b/drivers/block/osdblk.c
@@ -439,7 +439,7 @@ static int osdblk_init_disk(struct osdblk_device *osdev)
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_flush(q, REQ_FLUSH);

disk->queue = q;

diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index e9da874..4911f9e 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -468,7 +468,7 @@ static int __devinit ps3disk_probe(struct ps3_system_bus_device *_dev)
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_flush(queue, REQ_FLUSH);

blk_queue_max_segments(queue, -1);
blk_queue_max_segment_size(queue, dev->bounce_size);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 7965280..d10b635 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -388,22 +388,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
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 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 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; otherwise, we must assume
+ * that the host does not perform any kind of volatile write
+ * caching.
+ */
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
+ blk_queue_flush(q, REQ_FLUSH);

/* If disk is read-only in the host, the guest should obey */
if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 25ffbf9..1d48f3a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -95,7 +95,7 @@ struct blkfront_info
struct gnttab_free_callback callback;
struct blk_shadow shadow[BLK_RING_SIZE];
unsigned long shadow_free;
- int feature_barrier;
+ unsigned int feature_flush;
int is_ready;
};

@@ -418,25 +418,12 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
}


-static int xlvbd_barrier(struct blkfront_info *info)
+static void xlvbd_flush(struct blkfront_info *info)
{
- int err;
- const char *barrier;
-
- switch (info->feature_barrier) {
- case QUEUE_ORDERED_DRAIN: barrier = "enabled"; break;
- case QUEUE_ORDERED_NONE: barrier = "disabled"; break;
- default: return -EINVAL;
- }
-
- err = blk_queue_ordered(info->rq, info->feature_barrier);
-
- if (err)
- return err;
-
+ blk_queue_flush(info->rq, info->feature_flush);
printk(KERN_INFO "blkfront: %s: barriers %s
",
- info->gd->disk_name, barrier);
- return 0;
+ info->gd->disk_name,
+ info->feature_flush ? "enabled" : "disabled");
}


@@ -515,7 +502,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
info->rq = gd->queue;
info->gd = gd;

- xlvbd_barrier(info);
+ xlvbd_flush(info);

if (vdisk_info & VDISK_READONLY)
set_disk_ro(gd, 1);
@@ -661,8 +648,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
printk(KERN_WARNING "blkfront: %s: write barrier op failed
",
info->gd->disk_name);
error = -EOPNOTSUPP;
- info->feature_barrier = QUEUE_ORDERED_NONE;
- xlvbd_barrier(info);
+ info->feature_flush = 0;
+ xlvbd_flush(info);
}
/* fall through */
case BLKIF_OP_READ:
@@ -1075,19 +1062,13 @@ static void blkfront_connect(struct blkfront_info *info)
/*
* 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.
+ * synchronously; nothing to do.
*
* If there are barriers, then we use flush.
- *
- * 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_DRAIN_FLUSH;
- else
- info->feature_barrier = QUEUE_ORDERED_NONE;
+ info->feature_flush = 0;
+ if (!err && barrier)
+ info->feature_flush = REQ_FLUSH;

err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 7433e07..7c5b01c 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -516,10 +516,10 @@ static int ide_do_setfeature(ide_drive_t *drive, u8 feature, u8 nsect)
return ide_no_data_taskfile(drive, &cmd);
}

-static void update_ordered(ide_drive_t *drive)
+static void update_flush(ide_drive_t *drive)
{
u16 *id = drive->id;
- unsigned ordered = QUEUE_ORDERED_NONE;
+ unsigned flush = 0;

if (drive->dev_flags & IDE_DFLAG_WCACHE) {
unsigned long long capacity;
@@ -543,13 +543,12 @@ static void update_ordered(ide_drive_t *drive)
drive->name, barrier ? "" : "not ");

if (barrier) {
- ordered = QUEUE_ORDERED_DRAIN_FLUSH;
+ flush = REQ_FLUSH;
blk_queue_prep_rq(drive->queue, idedisk_prep_fn);
}
- } else
- ordered = QUEUE_ORDERED_DRAIN;
+ }

- blk_queue_ordered(drive->queue, ordered);
+ blk_queue_flush(drive->queue, flush);
}

ide_devset_get_flag(wcache, IDE_DFLAG_WCACHE);
@@ -572,7 +571,7 @@ static int set_wcache(ide_drive_t *drive, int arg)
}
}

- update_ordered(drive);
+ update_flush(drive);

return err;
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index a3f21dc..b71cc9e 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1908,7 +1908,7 @@ static struct mapped_device *alloc_dev(int minor)
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_flush(md->queue, REQ_FLUSH);

md->disk = alloc_disk(1);
if (!md->disk)
diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index c77eb49..d791772 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -128,7 +128,6 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
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
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 1a84fae..29046b7 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2197,7 +2197,6 @@ static void dasd_setup_queue(struct dasd_block *block)
*/
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);
}

/*
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 05a15b0..7f6aca2 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2109,7 +2109,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
struct scsi_disk *sdkp = scsi_disk(disk);
struct scsi_device *sdp = sdkp->device;
unsigned char *buffer;
- unsigned ordered;
+ unsigned flush = 0;

SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
"sd_revalidate_disk
"));
@@ -2151,15 +2151,15 @@ static int sd_revalidate_disk(struct gendisk *disk)

/*
* We now have all cache related info, determine how we deal
- * with ordered requests.
+ * with flush requests.
*/
- if (sdkp->WCE)
- ordered = sdkp->DPOFUA
- ? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
- else
- ordered = QUEUE_ORDERED_DRAIN;
+ if (sdkp->WCE) {
+ flush |= REQ_FLUSH;
+ if (sdkp->DPOFUA)
+ flush |= REQ_FUA;
+ }

- blk_queue_ordered(sdkp->disk->queue, ordered);
+ blk_queue_flush(sdkp->disk->queue, flush);

set_capacity(disk, sdkp->capacity);
kfree(buffer);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 96ef5f1..6003f7c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -355,8 +355,10 @@ struct request_queue
struct blk_trace *blk_trace;
#endif
/*
- * reserved for flush operations
+ * for flush operations
*/
+ unsigned int flush_flags;
+
unsigned int ordered, next_ordered, ordseq;
int orderr, ordcolor;
struct request pre_flush_rq, bar_rq, post_flush_rq;
@@ -863,8 +865,8 @@ extern void blk_queue_update_dma_alignment(struct request_queue *, int);
extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
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 void blk_queue_flush(struct request_queue *q, unsigned int flush);
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 unsigned blk_ordered_cur_seq(struct request_queue *);
extern unsigned blk_ordered_req_seq(struct request *);
--
1.7.1

--
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https://www.redhat.com/mailman/listinfo/dm-devel
 
Old 08-14-2010, 09:42 AM
"hch@lst.de"
 
Default block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush()

On Fri, Aug 13, 2010 at 06:07:13PM -0700, Jeremy Fitzhardinge wrote:
> On 08/12/2010 05:41 AM, Tejun Heo wrote:
> > Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
> > requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with
> > -EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
> > blk_queue_flush().
> >
> > blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a
> > device has write cache and can flush it, it should set REQ_FLUSH. If
> > the device can handle FUA writes, it should also set REQ_FUA.
>
> Christoph, do these two patches (parts 2 and 3) make xen-blkfront
> correct WRT barriers/flushing as far as your concerned?

If all your backends handle a zero-length BLKIF_OP_WRITE_BARRIER request
it is a fully correct, but rather suboptimal implementation. To get
all the benefit of the new non-draining barriers you'll need a new
If all your backends handle a zero-length BLKIF_OP_FLUSH request that
only flushes the cache, but has no ordering side effects. Note that
the quite suboptimal here means not as good as the new barrier
implementation, but it shouldn't be notiably worse than the old one
for Xen.

--
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Old 09-03-2010, 10:29 AM
Tejun Heo
 
Default block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush()

Barrier is deemed too heavy and will soon be replaced by FLUSH/FUA
requests. Deprecate barrier. All REQ_HARDBARRIERs are failed with
-EOPNOTSUPP and blk_queue_ordered() is replaced with simpler
blk_queue_flush().

blk_queue_flush() takes combinations of REQ_FLUSH and FUA. If a
device has write cache and can flush it, it should set REQ_FLUSH. If
the device can handle FUA writes, it should also set REQ_FUA.

All blk_queue_ordered() users are converted.

* ORDERED_DRAIN is mapped to 0 which is the default value.
* ORDERED_DRAIN_FLUSH is mapped to REQ_FLUSH.
* ORDERED_DRAIN_FLUSH_FUA is mapped to REQ_FLUSH | REQ_FUA.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: Stefan Weinhuber <wein@de.ibm.com>
---
block/blk-barrier.c | 29 ----------------------------
block/blk-core.c | 6 +++-
block/blk-settings.c | 20 +++++++++++++++++++
drivers/block/brd.c | 1 -
drivers/block/loop.c | 2 +-
drivers/block/osdblk.c | 2 +-
drivers/block/ps3disk.c | 2 +-
drivers/block/virtio_blk.c | 25 ++++++++---------------
drivers/block/xen-blkfront.c | 43 +++++++++++------------------------------
drivers/ide/ide-disk.c | 13 +++++------
drivers/md/dm.c | 2 +-
drivers/mmc/card/queue.c | 1 -
drivers/s390/block/dasd.c | 1 -
drivers/scsi/sd.c | 16 +++++++-------
include/linux/blkdev.h | 6 +++-
15 files changed, 67 insertions(+), 102 deletions(-)

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index c807e9c..ed0aba5 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -9,35 +9,6 @@

#include "blk.h"

-/**
- * 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.
- *
- **/
-int blk_queue_ordered(struct request_queue *q, unsigned ordered)
-{
- if (ordered != QUEUE_ORDERED_NONE &&
- ordered != QUEUE_ORDERED_DRAIN &&
- ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
- ordered != QUEUE_ORDERED_DRAIN_FUA) {
- printk(KERN_ERR "blk_queue_ordered: bad value %d
", ordered);
- return -EINVAL;
- }
-
- q->ordered = ordered;
- q->next_ordered = ordered;
-
- return 0;
-}
-EXPORT_SYMBOL(blk_queue_ordered);
-
/*
* Cache flushing for ordered writes handling
*/
diff --git a/block/blk-core.c b/block/blk-core.c
index ee1a1e7..f063541 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1203,11 +1203,13 @@ static int __make_request(struct request_queue *q, struct bio *bio)
const unsigned int ff = bio->bi_rw & REQ_FAILFAST_MASK;
int rw_flags;

- if ((bio->bi_rw & REQ_HARDBARRIER) &&
- (q->next_ordered == QUEUE_ORDERED_NONE)) {
+ /* REQ_HARDBARRIER is no more */
+ if (WARN_ONCE(bio->bi_rw & REQ_HARDBARRIER,
+ "block: HARDBARRIER is deprecated, use FLUSH/FUA instead
")) {
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
diff --git a/block/blk-settings.c b/block/blk-settings.c
index a234f4b..9b18afc 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -794,6 +794,26 @@ void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
}
EXPORT_SYMBOL(blk_queue_update_dma_alignment);

+/**
+ * blk_queue_flush - configure queue's cache flush capability
+ * @q: the request queue for the device
+ * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
+ *
+ * Tell block layer cache flush capability of @q. If it supports
+ * flushing, REQ_FLUSH should be set. If it supports bypassing
+ * write cache for individual writes, REQ_FUA should be set.
+ */
+void blk_queue_flush(struct request_queue *q, unsigned int flush)
+{
+ WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
+
+ if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
+ flush &= ~REQ_FUA;
+
+ q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
+}
+EXPORT_SYMBOL_GPL(blk_queue_flush);
+
static int __init blk_settings_init(void)
{
blk_max_low_pfn = max_low_pfn - 1;
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 47a4127..fa33f97 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -482,7 +482,6 @@ static struct brd_device *brd_alloc(int i)
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_DRAIN);
blk_queue_max_hw_sectors(brd->brd_queue, 1024);
blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY);

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c3a4a2e..953d1e1 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -832,7 +832,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
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_FLUSH);
+ blk_queue_flush(lo->lo_queue, REQ_FLUSH);

set_capacity(lo->lo_disk, size);
bd_set_size(bdev, size << 9);
diff --git a/drivers/block/osdblk.c b/drivers/block/osdblk.c
index 2284b4f..72d6246 100644
--- a/drivers/block/osdblk.c
+++ b/drivers/block/osdblk.c
@@ -439,7 +439,7 @@ static int osdblk_init_disk(struct osdblk_device *osdev)
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_flush(q, REQ_FLUSH);

disk->queue = q;

diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index e9da874..4911f9e 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -468,7 +468,7 @@ static int __devinit ps3disk_probe(struct ps3_system_bus_device *_dev)
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_flush(queue, REQ_FLUSH);

blk_queue_max_segments(queue, -1);
blk_queue_max_segment_size(queue, dev->bounce_size);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 7965280..d10b635 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -388,22 +388,15 @@ static int __devinit virtblk_probe(struct virtio_device *vdev)
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 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 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; otherwise, we must assume
+ * that the host does not perform any kind of volatile write
+ * caching.
+ */
+ if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH))
+ blk_queue_flush(q, REQ_FLUSH);

/* If disk is read-only in the host, the guest should obey */
if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8341862..f2ffc46 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -95,7 +95,7 @@ struct blkfront_info
struct gnttab_free_callback callback;
struct blk_shadow shadow[BLK_RING_SIZE];
unsigned long shadow_free;
- int feature_barrier;
+ unsigned int feature_flush;
int is_ready;
};

@@ -418,25 +418,12 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
}


-static int xlvbd_barrier(struct blkfront_info *info)
+static void xlvbd_flush(struct blkfront_info *info)
{
- int err;
- const char *barrier;
-
- switch (info->feature_barrier) {
- case QUEUE_ORDERED_DRAIN: barrier = "enabled"; break;
- case QUEUE_ORDERED_NONE: barrier = "disabled"; break;
- default: return -EINVAL;
- }
-
- err = blk_queue_ordered(info->rq, info->feature_barrier);
-
- if (err)
- return err;
-
+ blk_queue_flush(info->rq, info->feature_flush);
printk(KERN_INFO "blkfront: %s: barriers %s
",
- info->gd->disk_name, barrier);
- return 0;
+ info->gd->disk_name,
+ info->feature_flush ? "enabled" : "disabled");
}


@@ -515,7 +502,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
info->rq = gd->queue;
info->gd = gd;

- xlvbd_barrier(info);
+ xlvbd_flush(info);

if (vdisk_info & VDISK_READONLY)
set_disk_ro(gd, 1);
@@ -661,8 +648,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
printk(KERN_WARNING "blkfront: %s: write barrier op failed
",
info->gd->disk_name);
error = -EOPNOTSUPP;
- info->feature_barrier = QUEUE_ORDERED_NONE;
- xlvbd_barrier(info);
+ info->feature_flush = 0;
+ xlvbd_flush(info);
}
/* fall through */
case BLKIF_OP_READ:
@@ -1075,19 +1062,13 @@ static void blkfront_connect(struct blkfront_info *info)
/*
* 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.
+ * synchronously; nothing to do.
*
* If there are barriers, then we use flush.
- *
- * 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_DRAIN_FLUSH;
- else
- info->feature_barrier = QUEUE_ORDERED_NONE;
+ info->feature_flush = 0;
+ if (!err && barrier)
+ info->feature_flush = REQ_FLUSH;

err = xlvbd_alloc_gendisk(sectors, info, binfo, sector_size);
if (err) {
diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index 7433e07..7c5b01c 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -516,10 +516,10 @@ static int ide_do_setfeature(ide_drive_t *drive, u8 feature, u8 nsect)
return ide_no_data_taskfile(drive, &cmd);
}

-static void update_ordered(ide_drive_t *drive)
+static void update_flush(ide_drive_t *drive)
{
u16 *id = drive->id;
- unsigned ordered = QUEUE_ORDERED_NONE;
+ unsigned flush = 0;

if (drive->dev_flags & IDE_DFLAG_WCACHE) {
unsigned long long capacity;
@@ -543,13 +543,12 @@ static void update_ordered(ide_drive_t *drive)
drive->name, barrier ? "" : "not ");

if (barrier) {
- ordered = QUEUE_ORDERED_DRAIN_FLUSH;
+ flush = REQ_FLUSH;
blk_queue_prep_rq(drive->queue, idedisk_prep_fn);
}
- } else
- ordered = QUEUE_ORDERED_DRAIN;
+ }

- blk_queue_ordered(drive->queue, ordered);
+ blk_queue_flush(drive->queue, flush);
}

ide_devset_get_flag(wcache, IDE_DFLAG_WCACHE);
@@ -572,7 +571,7 @@ static int set_wcache(ide_drive_t *drive, int arg)
}
}

- update_ordered(drive);
+ update_flush(drive);

return err;
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ac384b2..b1d92be 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2245,7 +2245,7 @@ static int dm_init_request_based_queue(struct mapped_device *md)
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_flush(md->queue, REQ_FLUSH);

elv_register_queue(md->queue);

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index e876678..9c0b42b 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -128,7 +128,6 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card, spinlock_t *lock
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);
if (mmc_can_erase(card)) {
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mq->queue);
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 8373ca0..9b106d8 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2197,7 +2197,6 @@ static void dasd_setup_queue(struct dasd_block *block)
*/
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);
}

/*
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index cdfc51a..63bd01a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2109,7 +2109,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
struct scsi_disk *sdkp = scsi_disk(disk);
struct scsi_device *sdp = sdkp->device;
unsigned char *buffer;
- unsigned ordered;
+ unsigned flush = 0;

SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp,
"sd_revalidate_disk
"));
@@ -2151,15 +2151,15 @@ static int sd_revalidate_disk(struct gendisk *disk)

/*
* We now have all cache related info, determine how we deal
- * with ordered requests.
+ * with flush requests.
*/
- if (sdkp->WCE)
- ordered = sdkp->DPOFUA
- ? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
- else
- ordered = QUEUE_ORDERED_DRAIN;
+ if (sdkp->WCE) {
+ flush |= REQ_FLUSH;
+ if (sdkp->DPOFUA)
+ flush |= REQ_FUA;
+ }

- blk_queue_ordered(sdkp->disk->queue, ordered);
+ blk_queue_flush(sdkp->disk->queue, flush);

set_capacity(disk, sdkp->capacity);
kfree(buffer);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7077bc0..e97911d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -355,8 +355,10 @@ struct request_queue
struct blk_trace *blk_trace;
#endif
/*
- * reserved for flush operations
+ * for flush operations
*/
+ unsigned int flush_flags;
+
unsigned int ordered, next_ordered, ordseq;
int orderr, ordcolor;
struct request pre_flush_rq, bar_rq, post_flush_rq;
@@ -865,8 +867,8 @@ extern void blk_queue_update_dma_alignment(struct request_queue *, int);
extern void blk_queue_softirq_done(struct request_queue *, softirq_done_fn *);
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 void blk_queue_flush(struct request_queue *q, unsigned int flush);
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 unsigned blk_ordered_cur_seq(struct request_queue *);
extern unsigned blk_ordered_req_seq(struct request *);
--
1.7.1

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