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>
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

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
*/

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

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;

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);

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);

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;

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);

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))

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) {

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;
}

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);

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);

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);
}
/*

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);

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 *);