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block: deprecate barrier and replace blk_queue_ordered() with blk_queue_flush()

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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>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Tejun Heo 2010-09-03 11:56:16 +02:00 committed by Jens Axboe
parent 6958f14545
commit 4913efe456
15 changed files with 67 additions and 102 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

29
block/blk-barrier.c
View file

@ -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\n", ordered);
return -EINVAL;
}
q->ordered = ordered;
q->next_ordered = ordered;
return 0;
}
EXPORT_SYMBOL(blk_queue_ordered);
/*
* Cache flushing for ordered writes handling
*/

6
block/blk-core.c
View file

@ -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\n")) {
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

20
block/blk-settings.c
View file

@ -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;

1
drivers/block/brd.c
View file

@ -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);

2
drivers/block/loop.c
View file

@ -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);

2
drivers/block/osdblk.c
View file

@ -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;

2
drivers/block/ps3disk.c
View file

@ -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);

25
drivers/block/virtio_blk.c
View file

@ -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))

43
drivers/block/xen-blkfront.c
View file

@ -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\n",
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\n",
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) {

13
drivers/ide/ide-disk.c
View file

@ -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;
}

2
drivers/md/dm.c
View file

@ -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);

1
drivers/mmc/card/queue.c
View file

@ -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);

1
drivers/s390/block/dasd.c
View file

@ -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);
}
/*

16
drivers/scsi/sd.c
View file

@ -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\n"));
@ -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);

6
include/linux/blkdev.h
View file

@ -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 *);