[PATCH] scsi/sata write barrier support
From: Jens Axboe
Date: Thu Jan 27 2005 - 07:07:31 EST
Hi,
For the longest time, only the old PATA drivers supported barrier writes
with journalled file systems. This patch adds support for the same type
of cache flushing barriers that PATA uses for SCSI, to be utilized with
libata. It prepares to support barriers with 'real' SCSI hardware that
can do ordered tags as well, but it isn't done. The remaining work is to
check error handling for reordering on requeue (probably fine), and add
the few lines of support to each hba lld to set ->ordered_tag in the
host template and be able to set the ordered tag bit on commands that
are blk_barrier_rq().
A note on this patch. For write barriers, the PATA drivers issued a pre
and post flush when seeing a barrier write. This ensures that dirty data
in cache is on platter before the barrier, and that later writers don't
go to platter before the barrier. The handling of this was done in
drivers/ide core, which was a little nasty because some of it is a bit
tricky block layer code. This patch moves the handling of this into the
block layer, the only real change needed in drivers (scsi mid layer and
drivers/ide) is to delay completion of the real barrier write until the
post flush has completed. See scsi_io_completion() and
ide_end_request().
So the patch removes a lot of drivers/ide cruft and special casing,
which is always good. It relies on a seperate patch that adds an end_io
function to struct request, it's folded into this one right now. bsg
needs this as well, and the multipath folks need it too. I might submit
that seperately first.
Please test! Patch is against current BK.
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/block/cfq-iosched.c linux-2.6.10/drivers/block/cfq-iosched.c
--- /opt/kernel/linux-2.6.10/drivers/block/cfq-iosched.c 2005-01-26 21:18:37.000000000 +0100
+++ linux-2.6.10/drivers/block/cfq-iosched.c 2005-01-26 21:19:05.000000000 +0100
@@ -1285,19 +1285,19 @@ static int cfq_queue_empty(request_queue
static void cfq_completed_request(request_queue_t *q, struct request *rq)
{
struct cfq_rq *crq = RQ_DATA(rq);
+ struct cfq_queue *cfqq;
if (unlikely(!blk_fs_request(rq)))
return;
- if (crq->in_flight) {
- struct cfq_queue *cfqq = crq->cfq_queue;
+ cfqq = crq->cfq_queue;
+ if (crq->in_flight) {
WARN_ON(!cfqq->in_flight);
cfqq->in_flight--;
-
- cfq_account_completion(cfqq, crq);
}
+ cfq_account_completion(cfqq, crq);
}
static struct request *
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/block/elevator.c linux-2.6.10/drivers/block/elevator.c
--- /opt/kernel/linux-2.6.10/drivers/block/elevator.c 2005-01-26 21:18:37.000000000 +0100
+++ linux-2.6.10/drivers/block/elevator.c 2005-01-26 21:19:05.000000000 +0100
@@ -320,7 +320,21 @@ void elv_add_request(request_queue_t *q,
static inline struct request *__elv_next_request(request_queue_t *q)
{
- return q->elevator->ops->elevator_next_req_fn(q);
+ struct request *rq = q->elevator->ops->elevator_next_req_fn(q);
+
+ /*
+ * if this is a barrier write and the device has to issue a
+ * flush sequence to support it, check how far we are
+ */
+ if (rq && blk_fs_request(rq) && blk_barrier_rq(rq)) {
+ BUG_ON(q->ordered == QUEUE_ORDERED_NONE);
+
+ if (q->ordered == QUEUE_ORDERED_FLUSH &&
+ !blk_barrier_preflush(rq))
+ rq = blk_start_pre_flush(q, rq);
+ }
+
+ return rq;
}
struct request *elv_next_request(request_queue_t *q)
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/block/ll_rw_blk.c linux-2.6.10/drivers/block/ll_rw_blk.c
--- /opt/kernel/linux-2.6.10/drivers/block/ll_rw_blk.c 2005-01-26 21:18:37.000000000 +0100
+++ linux-2.6.10/drivers/block/ll_rw_blk.c 2005-01-27 12:56:17.000000000 +0100
@@ -267,6 +267,24 @@ void blk_queue_make_request(request_queu
EXPORT_SYMBOL(blk_queue_make_request);
+static inline void rq_init(request_queue_t *q, struct request *rq)
+{
+ INIT_LIST_HEAD(&rq->queuelist);
+
+ rq->errors = 0;
+ rq->rq_status = RQ_ACTIVE;
+ rq->bio = rq->biotail = NULL;
+ rq->buffer = NULL;
+ rq->ref_count = 1;
+ rq->q = q;
+ rq->waiting = NULL;
+ rq->special = NULL;
+ rq->data_len = 0;
+ rq->data = NULL;
+ rq->sense = NULL;
+ rq->end_io = NULL;
+}
+
/**
* blk_queue_ordered - does this queue support ordered writes
* @q: the request queue
@@ -281,10 +299,26 @@ EXPORT_SYMBOL(blk_queue_make_request);
**/
void blk_queue_ordered(request_queue_t *q, int flag)
{
- if (flag)
- set_bit(QUEUE_FLAG_ORDERED, &q->queue_flags);
- else
- clear_bit(QUEUE_FLAG_ORDERED, &q->queue_flags);
+ switch (flag) {
+ case QUEUE_ORDERED_NONE:
+ if (q->flush_rq)
+ kmem_cache_free(request_cachep, q->flush_rq);
+ q->flush_rq = NULL;
+ q->ordered = flag;
+ break;
+ case QUEUE_ORDERED_TAG:
+ q->ordered = flag;
+ break;
+ case QUEUE_ORDERED_FLUSH:
+ q->ordered = flag;
+ if (!q->flush_rq)
+ q->flush_rq = kmem_cache_alloc(request_cachep,
+ GFP_KERNEL);
+ break;
+ default:
+ printk("blk_queue_ordered: bad value %d\n", flag);
+ break;
+ }
}
EXPORT_SYMBOL(blk_queue_ordered);
@@ -306,6 +340,105 @@ void blk_queue_issue_flush_fn(request_qu
EXPORT_SYMBOL(blk_queue_issue_flush_fn);
+static void blk_pre_flush_end_io(struct request *flush_rq)
+{
+ struct request *rq = flush_rq->end_io_data;
+ request_queue_t *q = rq->q;
+
+ rq->flags |= REQ_BAR_PREFLUSH;
+
+ if (!flush_rq->errors)
+ elv_requeue_request(q, rq);
+ else {
+ q->end_flush_fn(q, flush_rq);
+ clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
+ }
+}
+
+static void blk_post_flush_end_io(struct request *flush_rq)
+{
+ struct request *rq = flush_rq->end_io_data;
+ request_queue_t *q = rq->q;
+
+ rq->flags |= REQ_BAR_POSTFLUSH;
+
+ /*
+ * called from end_that_request_last(), so we know that the queue
+ * lock is held
+ */
+ spin_unlock(q->queue_lock);
+ q->end_flush_fn(q, flush_rq);
+ spin_lock(q->queue_lock);
+
+ clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
+}
+
+struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq)
+{
+ struct request *flush_rq = q->flush_rq;
+
+ rq_init(q, flush_rq);
+ flush_rq->flags = 0;
+ flush_rq->rq_disk = rq->rq_disk;
+
+ if (!q->prepare_flush_fn(q, flush_rq)) {
+ rq->flags |= REQ_BAR_PREFLUSH;
+ return rq;
+ }
+
+ set_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
+
+ /*
+ * some drivers dequeue requests right away, some only after io
+ * completion. make sure the request is dequeued.
+ */
+ if (!list_empty(&rq->queuelist))
+ blkdev_dequeue_request(rq);
+
+ flush_rq->end_io_data = rq;
+ flush_rq->end_io = blk_pre_flush_end_io;
+
+ __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
+ return flush_rq;
+}
+
+EXPORT_SYMBOL(blk_start_pre_flush);
+
+void blk_start_post_flush(request_queue_t *q, struct request *rq)
+{
+ struct request *flush_rq = q->flush_rq;
+
+ rq_init(q, flush_rq);
+ flush_rq->flags = 0;
+ flush_rq->rq_disk = rq->rq_disk;
+
+ if (!q->prepare_flush_fn(q, flush_rq)) {
+ rq->flags |= REQ_BAR_POSTFLUSH;
+
+ end_that_request_first(rq, !rq->errors, rq->hard_nr_sectors);
+ end_that_request_last(rq);
+ } else {
+ flush_rq->end_io_data = rq;
+ flush_rq->end_io = blk_post_flush_end_io;
+
+ __elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
+ q->request_fn(q);
+ }
+}
+
+EXPORT_SYMBOL(blk_start_post_flush);
+
+int blk_check_end_barrier(request_queue_t *q, struct request *rq, int sectors)
+{
+ if (sectors > rq->nr_sectors)
+ sectors = rq->nr_sectors;
+
+ rq->nr_sectors -= sectors;
+ return rq->nr_sectors;
+}
+
+EXPORT_SYMBOL(blk_check_end_barrier);
+
/**
* blk_queue_bounce_limit - set bounce buffer limit for queue
* @q: the request queue for the device
@@ -1428,6 +1561,8 @@ void blk_cleanup_queue(request_queue_t *
if (q->queue_tags)
__blk_queue_free_tags(q);
+ blk_queue_ordered(q, QUEUE_ORDERED_NONE);
+
kmem_cache_free(requestq_cachep, q);
}
@@ -1739,21 +1874,8 @@ rq_starved:
if (ioc_batching(q, ioc))
ioc->nr_batch_requests--;
- INIT_LIST_HEAD(&rq->queuelist);
-
- rq->errors = 0;
- rq->rq_status = RQ_ACTIVE;
- rq->bio = rq->biotail = NULL;
- rq->buffer = NULL;
- rq->ref_count = 1;
- rq->q = q;
+ rq_init(q, rq);
rq->rl = rl;
- rq->waiting = NULL;
- rq->special = NULL;
- rq->data_len = 0;
- rq->data = NULL;
- rq->sense = NULL;
-
out:
put_io_context(ioc);
return rq;
@@ -2018,8 +2140,8 @@ int blk_execute_rq(request_queue_t *q, s
}
rq->flags |= REQ_NOMERGE;
- if (!rq->waiting)
- rq->waiting = &wait;
+ rq->waiting = &wait;
+ rq->end_io = blk_end_sync_rq;
elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 1);
generic_unplug_device(q);
wait_for_completion(rq->waiting);
@@ -2171,7 +2293,7 @@ void disk_round_stats(struct gendisk *di
/*
* queue lock must be held
*/
-void __blk_put_request(request_queue_t *q, struct request *req)
+static void __blk_put_request(request_queue_t *q, struct request *req)
{
struct request_list *rl = req->rl;
@@ -2219,6 +2341,25 @@ void blk_put_request(struct request *req
EXPORT_SYMBOL(blk_put_request);
/**
+ * blk_end_sync_rq - executes a completion event on a request
+ * @rq: request to complete
+ */
+void blk_end_sync_rq(struct request *rq)
+{
+ struct completion *waiting = rq->waiting;
+
+ rq->waiting = NULL;
+ __blk_put_request(rq->q, rq);
+
+ /*
+ * complete last, if this is a stack request the process (and thus
+ * the rq pointer) could be invalid right after this complete()
+ */
+ complete(waiting);
+}
+EXPORT_SYMBOL(blk_end_sync_rq);
+
+/**
* blk_congestion_wait - wait for a queue to become uncongested
* @rw: READ or WRITE
* @timeout: timeout in jiffies
@@ -2371,7 +2512,7 @@ static int __make_request(request_queue_
spin_lock_prefetch(q->queue_lock);
barrier = bio_barrier(bio);
- if (barrier && !(q->queue_flags & (1 << QUEUE_FLAG_ORDERED))) {
+ if (barrier && (q->ordered == QUEUE_ORDERED_NONE)) {
err = -EOPNOTSUPP;
goto end_io;
}
@@ -2978,7 +3119,9 @@ EXPORT_SYMBOL(end_that_request_chunk);
void end_that_request_last(struct request *req)
{
struct gendisk *disk = req->rq_disk;
- struct completion *waiting = req->waiting;
+
+ if (blk_barrier_rq(req) && !blk_barrier_postflush(req))
+ return;
if (unlikely(laptop_mode) && blk_fs_request(req))
laptop_io_completion();
@@ -2998,10 +3141,10 @@ void end_that_request_last(struct reques
disk_round_stats(disk);
disk->in_flight--;
}
- __blk_put_request(req->q, req);
- /* Do this LAST! The structure may be freed immediately afterwards */
- if (waiting)
- complete(waiting);
+ if (req->end_io)
+ req->end_io(req);
+ else
+ __blk_put_request(req->q, req);
}
EXPORT_SYMBOL(end_that_request_last);
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/block/paride/pd.c linux-2.6.10/drivers/block/paride/pd.c
--- /opt/kernel/linux-2.6.10/drivers/block/paride/pd.c 2005-01-26 21:18:36.000000000 +0100
+++ linux-2.6.10/drivers/block/paride/pd.c 2005-01-26 21:19:05.000000000 +0100
@@ -743,6 +743,7 @@ static int pd_special_command(struct pd_
rq.rq_disk = disk->gd;
rq.ref_count = 1;
rq.waiting = &wait;
+ rq.end_io = blk_end_sync_rq;
blk_insert_request(disk->gd->queue, &rq, 0, func, 0);
wait_for_completion(&wait);
rq.waiting = NULL;
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/ide/ide-disk.c linux-2.6.10/drivers/ide/ide-disk.c
--- /opt/kernel/linux-2.6.10/drivers/ide/ide-disk.c 2005-01-26 21:18:38.000000000 +0100
+++ linux-2.6.10/drivers/ide/ide-disk.c 2005-01-26 21:19:05.000000000 +0100
@@ -701,18 +701,54 @@ static ide_proc_entry_t idedisk_proc[] =
#endif /* CONFIG_PROC_FS */
-static int idedisk_issue_flush(request_queue_t *q, struct gendisk *disk,
- sector_t *error_sector)
+static void idedisk_end_flush(request_queue_t *q, struct request *flush_rq)
+{
+ ide_drive_t *drive = q->queuedata;
+ struct request *rq = flush_rq->end_io_data;
+ int good_sectors = rq->hard_nr_sectors;
+ int bad_sectors;
+ sector_t sector;
+
+ if (flush_rq->errors & ABRT_ERR) {
+ printk(KERN_ERR "%s: barrier support doesn't work\n", drive->name);
+ blk_queue_ordered(drive->queue, QUEUE_ORDERED_NONE);
+ blk_queue_issue_flush_fn(drive->queue, NULL);
+ good_sectors = 0;
+ } else if (flush_rq->errors) {
+ sector = ide_get_error_location(drive, flush_rq->buffer);
+ if ((sector >= rq->hard_sector) &&
+ (sector < rq->hard_sector + rq->hard_nr_sectors))
+ good_sectors = sector - rq->hard_sector;
+ else
+ good_sectors = 0;
+ }
+
+ if (flush_rq->errors)
+ printk(KERN_ERR "%s: failed barrier write: "
+ "sector=%Lx(good=%d/bad=%d)\n",
+ drive->name, (unsigned long long)rq->sector,
+ good_sectors,
+ (int) (rq->hard_nr_sectors-good_sectors));
+
+ bad_sectors = rq->hard_nr_sectors - good_sectors;
+
+ spin_lock(&ide_lock);
+
+ if (good_sectors)
+ __ide_end_request(drive, rq, 1, good_sectors);
+ if (bad_sectors)
+ __ide_end_request(drive, rq, 0, bad_sectors);
+
+ spin_unlock(&ide_lock);
+}
+
+static int idedisk_prepare_flush(request_queue_t *q, struct request *rq)
{
ide_drive_t *drive = q->queuedata;
- struct request *rq;
- int ret;
if (!drive->wcache)
return 0;
- rq = blk_get_request(q, WRITE, __GFP_WAIT);
-
memset(rq->cmd, 0, sizeof(rq->cmd));
if (ide_id_has_flush_cache_ext(drive->id) &&
@@ -724,6 +760,22 @@ static int idedisk_issue_flush(request_q
rq->flags |= REQ_DRIVE_TASK | REQ_SOFTBARRIER;
rq->buffer = rq->cmd;
+ return 1;
+}
+
+static int idedisk_issue_flush(request_queue_t *q, struct gendisk *disk,
+ sector_t *error_sector)
+{
+ ide_drive_t *drive = q->queuedata;
+ struct request *rq;
+ int ret;
+
+ if (!drive->wcache)
+ return 0;
+
+ rq = blk_get_request(q, WRITE, __GFP_WAIT);
+
+ idedisk_prepare_flush(q, rq);
ret = blk_execute_rq(q, disk, rq);
@@ -1101,10 +1153,15 @@ static void idedisk_setup (ide_drive_t *
barrier = 0;
}
- printk(KERN_DEBUG "%s: cache flushes %ssupported\n",
+ if (!strncmp(drive->name, "hdc", 3))
+ barrier = 1;
+
+ printk(KERN_INFO "%s: cache flushes %ssupported\n",
drive->name, barrier ? "" : "not ");
if (barrier) {
- blk_queue_ordered(drive->queue, 1);
+ blk_queue_ordered(drive->queue, QUEUE_ORDERED_FLUSH);
+ drive->queue->prepare_flush_fn = idedisk_prepare_flush;
+ drive->queue->end_flush_fn = idedisk_end_flush;
blk_queue_issue_flush_fn(drive->queue, idedisk_issue_flush);
}
}
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/ide/ide-io.c linux-2.6.10/drivers/ide/ide-io.c
--- /opt/kernel/linux-2.6.10/drivers/ide/ide-io.c 2005-01-26 21:18:38.000000000 +0100
+++ linux-2.6.10/drivers/ide/ide-io.c 2005-01-26 21:19:05.000000000 +0100
@@ -55,62 +55,8 @@
#include <asm/io.h>
#include <asm/bitops.h>
-static void ide_fill_flush_cmd(ide_drive_t *drive, struct request *rq)
-{
- char *buf = rq->cmd;
-
- /*
- * reuse cdb space for ata command
- */
- memset(buf, 0, sizeof(rq->cmd));
-
- rq->flags |= REQ_DRIVE_TASK | REQ_STARTED;
- rq->buffer = buf;
- rq->buffer[0] = WIN_FLUSH_CACHE;
-
- if (ide_id_has_flush_cache_ext(drive->id) &&
- (drive->capacity64 >= (1UL << 28)))
- rq->buffer[0] = WIN_FLUSH_CACHE_EXT;
-}
-
-/*
- * preempt pending requests, and store this cache flush for immediate
- * execution
- */
-static struct request *ide_queue_flush_cmd(ide_drive_t *drive,
- struct request *rq, int post)
-{
- struct request *flush_rq = &HWGROUP(drive)->wrq;
-
- /*
- * write cache disabled, clear the barrier bit and treat it like
- * an ordinary write
- */
- if (!drive->wcache) {
- rq->flags |= REQ_BAR_PREFLUSH;
- return rq;
- }
-
- ide_init_drive_cmd(flush_rq);
- ide_fill_flush_cmd(drive, flush_rq);
-
- flush_rq->special = rq;
- flush_rq->nr_sectors = rq->nr_sectors;
-
- if (!post) {
- drive->doing_barrier = 1;
- flush_rq->flags |= REQ_BAR_PREFLUSH;
- blkdev_dequeue_request(rq);
- } else
- flush_rq->flags |= REQ_BAR_POSTFLUSH;
-
- __elv_add_request(drive->queue, flush_rq, ELEVATOR_INSERT_FRONT, 0);
- HWGROUP(drive)->rq = NULL;
- return flush_rq;
-}
-
-static int __ide_end_request(ide_drive_t *drive, struct request *rq,
- int uptodate, int nr_sectors)
+int __ide_end_request(ide_drive_t *drive, struct request *rq, int uptodate,
+ int nr_sectors)
{
int ret = 1;
@@ -148,6 +94,23 @@ static int __ide_end_request(ide_drive_t
}
return ret;
}
+EXPORT_SYMBOL(__ide_end_request);
+
+static int ide_barrier_io_completion(ide_drive_t *drive, struct request *rq,
+ int sectors, int *ret)
+{
+ if (!blk_fs_request(rq) || !blk_barrier_rq(rq))
+ return 0;
+ if (blk_barrier_postflush(rq))
+ return 0;
+
+ if (!blk_check_end_barrier(drive->queue, rq, sectors)) {
+ blk_start_post_flush(drive->queue, rq);
+ *ret = 0;
+ }
+
+ return 1;
+}
/**
* ide_end_request - complete an IDE I/O
@@ -172,17 +135,8 @@ int ide_end_request (ide_drive_t *drive,
if (!nr_sectors)
nr_sectors = rq->hard_cur_sectors;
- if (!blk_barrier_rq(rq) || !drive->wcache)
+ if (!ide_barrier_io_completion(drive, rq, nr_sectors, &ret))
ret = __ide_end_request(drive, rq, uptodate, nr_sectors);
- else {
- struct request *flush_rq = &HWGROUP(drive)->wrq;
-
- flush_rq->nr_sectors -= nr_sectors;
- if (!flush_rq->nr_sectors) {
- ide_queue_flush_cmd(drive, rq, 1);
- ret = 0;
- }
- }
spin_unlock_irqrestore(&ide_lock, flags);
return ret;
@@ -252,79 +206,6 @@ u64 ide_get_error_location(ide_drive_t *
}
EXPORT_SYMBOL(ide_get_error_location);
-static void ide_complete_barrier(ide_drive_t *drive, struct request *rq,
- int error)
-{
- struct request *real_rq = rq->special;
- int good_sectors, bad_sectors;
- sector_t sector;
-
- if (!error) {
- if (blk_barrier_postflush(rq)) {
- /*
- * this completes the barrier write
- */
- __ide_end_request(drive, real_rq, 1, real_rq->hard_nr_sectors);
- drive->doing_barrier = 0;
- } else {
- /*
- * just indicate that we did the pre flush
- */
- real_rq->flags |= REQ_BAR_PREFLUSH;
- elv_requeue_request(drive->queue, real_rq);
- }
- /*
- * all is fine, return
- */
- return;
- }
-
- /*
- * we need to end real_rq, but it's not on the queue currently.
- * put it back on the queue, so we don't have to special case
- * anything else for completing it
- */
- if (!blk_barrier_postflush(rq))
- elv_requeue_request(drive->queue, real_rq);
-
- /*
- * drive aborted flush command, assume FLUSH_CACHE_* doesn't
- * work and disable barrier support
- */
- if (error & ABRT_ERR) {
- printk(KERN_ERR "%s: barrier support doesn't work\n", drive->name);
- __ide_end_request(drive, real_rq, -EOPNOTSUPP, real_rq->hard_nr_sectors);
- blk_queue_ordered(drive->queue, 0);
- blk_queue_issue_flush_fn(drive->queue, NULL);
- } else {
- /*
- * find out what part of the request failed
- */
- good_sectors = 0;
- if (blk_barrier_postflush(rq)) {
- sector = ide_get_error_location(drive, rq->buffer);
-
- if ((sector >= real_rq->hard_sector) &&
- (sector < real_rq->hard_sector + real_rq->hard_nr_sectors))
- good_sectors = sector - real_rq->hard_sector;
- } else
- sector = real_rq->hard_sector;
-
- bad_sectors = real_rq->hard_nr_sectors - good_sectors;
- if (good_sectors)
- __ide_end_request(drive, real_rq, 1, good_sectors);
- if (bad_sectors)
- __ide_end_request(drive, real_rq, 0, bad_sectors);
-
- printk(KERN_ERR "%s: failed barrier write: "
- "sector=%Lx(good=%d/bad=%d)\n",
- drive->name, (unsigned long long)sector,
- good_sectors, bad_sectors);
- }
-
- drive->doing_barrier = 0;
-}
-
/**
* ide_end_drive_cmd - end an explicit drive command
* @drive: command
@@ -416,11 +297,8 @@ void ide_end_drive_cmd (ide_drive_t *dri
spin_lock_irqsave(&ide_lock, flags);
blkdev_dequeue_request(rq);
-
- if (blk_barrier_preflush(rq) || blk_barrier_postflush(rq))
- ide_complete_barrier(drive, rq, err);
-
HWGROUP(drive)->rq = NULL;
+ rq->errors = err;
end_that_request_last(rq);
spin_unlock_irqrestore(&ide_lock, flags);
}
@@ -961,7 +839,7 @@ repeat:
* though that is 3 requests, it must be seen as a single transaction.
* we must not preempt this drive until that is complete
*/
- if (drive->doing_barrier) {
+ if (blk_queue_flush(drive->queue)) {
/*
* small race where queue could get replugged during
* the 3-request flush cycle, just yank the plug since
@@ -1124,13 +1002,6 @@ static void ide_do_request (ide_hwgroup_
}
/*
- * if rq is a barrier write, issue pre cache flush if not
- * already done
- */
- if (blk_barrier_rq(rq) && !blk_barrier_preflush(rq))
- rq = ide_queue_flush_cmd(drive, rq, 0);
-
- /*
* Sanity: don't accept a request that isn't a PM request
* if we are currently power managed. This is very important as
* blk_stop_queue() doesn't prevent the elv_next_request()
@@ -1604,6 +1475,7 @@ int ide_do_drive_cmd (ide_drive_t *drive
if (must_wait) {
rq->ref_count++;
rq->waiting = &wait;
+ rq->end_io = blk_end_sync_rq;
}
spin_lock_irqsave(&ide_lock, flags);
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/ide/ide-tape.c linux-2.6.10/drivers/ide/ide-tape.c
--- /opt/kernel/linux-2.6.10/drivers/ide/ide-tape.c 2005-01-26 21:18:38.000000000 +0100
+++ linux-2.6.10/drivers/ide/ide-tape.c 2005-01-26 21:19:05.000000000 +0100
@@ -2720,6 +2720,7 @@ static void idetape_wait_for_request (id
}
#endif /* IDETAPE_DEBUG_BUGS */
rq->waiting = &wait;
+ rq->end_io = blk_end_sync_rq;
spin_unlock_irq(&tape->spinlock);
wait_for_completion(&wait);
/* The stage and its struct request have been deallocated */
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/ahci.c linux-2.6.10/drivers/scsi/ahci.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/ahci.c 2005-01-26 21:18:33.000000000 +0100
+++ linux-2.6.10/drivers/scsi/ahci.c 2005-01-26 21:40:57.000000000 +0100
@@ -198,6 +198,7 @@ static Scsi_Host_Template ahci_sht = {
.dma_boundary = AHCI_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations ahci_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/ata_piix.c linux-2.6.10/drivers/scsi/ata_piix.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/ata_piix.c 2005-01-26 21:18:35.000000000 +0100
+++ linux-2.6.10/drivers/scsi/ata_piix.c 2005-01-26 21:42:19.000000000 +0100
@@ -121,6 +121,7 @@ static Scsi_Host_Template piix_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations piix_pata_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/hosts.c linux-2.6.10/drivers/scsi/hosts.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/hosts.c 2005-01-26 21:18:33.000000000 +0100
+++ linux-2.6.10/drivers/scsi/hosts.c 2005-01-26 21:19:05.000000000 +0100
@@ -258,6 +258,16 @@ struct Scsi_Host *scsi_host_alloc(struct
shost->cmd_per_lun = sht->cmd_per_lun;
shost->unchecked_isa_dma = sht->unchecked_isa_dma;
shost->use_clustering = sht->use_clustering;
+ shost->ordered_flush = sht->ordered_flush;
+ shost->ordered_tag = sht->ordered_tag;
+
+ /*
+ * hosts/devices that do queueing must support ordered tags
+ */
+ if (shost->can_queue > 1 && shost->ordered_flush) {
+ printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
+ shost->ordered_flush = 0;
+ }
if (sht->max_host_blocked)
shost->max_host_blocked = sht->max_host_blocked;
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_nv.c linux-2.6.10/drivers/scsi/sata_nv.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_nv.c 2005-01-26 21:18:33.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_nv.c 2005-01-26 21:41:14.000000000 +0100
@@ -194,6 +194,7 @@ static Scsi_Host_Template nv_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations nv_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_promise.c linux-2.6.10/drivers/scsi/sata_promise.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_promise.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_promise.c 2005-01-26 21:41:18.000000000 +0100
@@ -102,6 +102,7 @@ static Scsi_Host_Template pdc_ata_sht =
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations pdc_ata_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_sil.c linux-2.6.10/drivers/scsi/sata_sil.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_sil.c 2005-01-26 21:18:33.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_sil.c 2005-01-26 21:41:22.000000000 +0100
@@ -123,6 +123,7 @@ static Scsi_Host_Template sil_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations sil_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_sis.c linux-2.6.10/drivers/scsi/sata_sis.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_sis.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_sis.c 2005-01-26 21:41:27.000000000 +0100
@@ -90,6 +90,7 @@ static Scsi_Host_Template sis_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations sis_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_svw.c linux-2.6.10/drivers/scsi/sata_svw.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_svw.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_svw.c 2005-01-26 21:41:32.000000000 +0100
@@ -288,6 +288,7 @@ static Scsi_Host_Template k2_sata_sht =
.proc_info = k2_sata_proc_info,
#endif
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_sx4.c linux-2.6.10/drivers/scsi/sata_sx4.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_sx4.c 2005-01-26 21:18:32.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_sx4.c 2005-01-26 21:41:37.000000000 +0100
@@ -188,6 +188,7 @@ static Scsi_Host_Template pdc_sata_sht =
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations pdc_20621_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_uli.c linux-2.6.10/drivers/scsi/sata_uli.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_uli.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_uli.c 2005-01-26 21:41:41.000000000 +0100
@@ -82,6 +82,7 @@ static Scsi_Host_Template uli_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations uli_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_via.c linux-2.6.10/drivers/scsi/sata_via.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_via.c 2005-01-26 21:18:33.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_via.c 2005-01-26 21:41:52.000000000 +0100
@@ -95,6 +95,7 @@ static Scsi_Host_Template svia_sht = {
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
static struct ata_port_operations svia_sata_ops = {
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sata_vsc.c linux-2.6.10/drivers/scsi/sata_vsc.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sata_vsc.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sata_vsc.c 2005-01-26 21:41:56.000000000 +0100
@@ -204,6 +204,7 @@ static Scsi_Host_Template vsc_sata_sht =
.dma_boundary = ATA_DMA_BOUNDARY,
.slave_configure = ata_scsi_slave_config,
.bios_param = ata_std_bios_param,
+ .ordered_flush = 1,
};
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/scsi_lib.c linux-2.6.10/drivers/scsi/scsi_lib.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/scsi_lib.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/scsi_lib.c 2005-01-26 21:19:05.000000000 +0100
@@ -659,6 +659,29 @@ static void scsi_release_buffers(struct
cmd->request_bufflen = 0;
}
+static int scsi_barrier_io_completion(struct scsi_cmnd *cmd, int sectors)
+{
+ request_queue_t *q = cmd->device->request_queue;
+ struct request *req = cmd->request;
+
+ if (q->ordered != QUEUE_ORDERED_FLUSH)
+ return 0;
+ if (!blk_fs_request(req) || !blk_barrier_rq(req))
+ return 0;
+ if (blk_barrier_postflush(req))
+ return 0;
+
+ if (!blk_check_end_barrier(q, req, sectors)) {
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_start_post_flush(q, req);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
+
+ return 1;
+}
+
/*
* Function: scsi_io_completion()
*
@@ -697,6 +720,9 @@ void scsi_io_completion(struct scsi_cmnd
int clear_errors = 1;
struct scsi_sense_hdr sshdr;
+ if (scsi_barrier_io_completion(cmd, good_bytes << 9))
+ return;
+
/*
* Free up any indirection buffers we allocated for DMA purposes.
* For the case of a READ, we need to copy the data out of the
@@ -964,6 +990,38 @@ static int scsi_init_io(struct scsi_cmnd
return BLKPREP_KILL;
}
+static int scsi_prepare_flush_fn(request_queue_t *q, struct request *rq)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct scsi_driver *drv;
+
+ if (sdev->sdev_state == SDEV_RUNNING) {
+ drv = *(struct scsi_driver **) rq->rq_disk->private_data;
+
+ if (drv->prepare_flush)
+ return drv->prepare_flush(q, rq);
+ }
+
+ return 0;
+}
+
+static void scsi_end_flush_fn(request_queue_t *q, struct request *rq)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct request *flush_rq = rq->end_io_data;
+ struct scsi_driver *drv;
+
+ if (flush_rq->errors) {
+ printk("scsi: barrier error, disabling flush support\n");
+ blk_queue_ordered(q, QUEUE_ORDERED_NONE);
+ }
+
+ if (sdev->sdev_state == SDEV_RUNNING) {
+ drv = *(struct scsi_driver **) rq->rq_disk->private_data;
+ drv->end_flush(q, rq);
+ }
+}
+
static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk,
sector_t *error_sector)
{
@@ -1368,6 +1426,17 @@ struct request_queue *scsi_alloc_queue(s
blk_queue_segment_boundary(q, shost->dma_boundary);
blk_queue_issue_flush_fn(q, scsi_issue_flush_fn);
+ /*
+ * ordered tags are superior to flush ordering
+ */
+ if (shost->ordered_tag)
+ blk_queue_ordered(q, QUEUE_ORDERED_TAG);
+ else if (shost->ordered_flush) {
+ blk_queue_ordered(q, QUEUE_ORDERED_FLUSH);
+ q->prepare_flush_fn = scsi_prepare_flush_fn;
+ q->end_flush_fn = scsi_end_flush_fn;
+ }
+
if (!shost->use_clustering)
clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
return q;
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/drivers/scsi/sd.c linux-2.6.10/drivers/scsi/sd.c
--- /opt/kernel/linux-2.6.10/drivers/scsi/sd.c 2005-01-26 21:18:34.000000000 +0100
+++ linux-2.6.10/drivers/scsi/sd.c 2005-01-26 21:19:05.000000000 +0100
@@ -121,6 +121,8 @@ static void sd_shutdown(struct device *d
static void sd_rescan(struct device *);
static int sd_init_command(struct scsi_cmnd *);
static int sd_issue_flush(struct device *, sector_t *);
+static void sd_end_flush(request_queue_t *, struct request *);
+static int sd_prepare_flush(request_queue_t *, struct request *);
static void sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
struct scsi_request *SRpnt, unsigned char *buffer);
@@ -135,6 +137,8 @@ static struct scsi_driver sd_template =
.rescan = sd_rescan,
.init_command = sd_init_command,
.issue_flush = sd_issue_flush,
+ .prepare_flush = sd_prepare_flush,
+ .end_flush = sd_end_flush,
};
/*
@@ -734,6 +738,33 @@ static int sd_issue_flush(struct device
return sd_sync_cache(sdp);
}
+static void sd_end_flush(request_queue_t *q, struct request *flush_rq)
+{
+ struct request *rq = flush_rq->end_io_data;
+ struct scsi_cmnd *cmd = rq->special;
+ unsigned int bytes = rq->hard_nr_sectors << 9;
+
+ if (!flush_rq->errors)
+ scsi_io_completion(cmd, bytes, 0);
+ else
+ scsi_io_completion(cmd, 0, bytes);
+}
+
+static int sd_prepare_flush(request_queue_t *q, struct request *rq)
+{
+ struct scsi_device *sdev = q->queuedata;
+ struct scsi_disk *sdkp = dev_get_drvdata(&sdev->sdev_gendev);
+
+ if (sdkp->WCE) {
+ memset(rq->cmd, 0, sizeof(rq->cmd));
+ rq->flags = REQ_BLOCK_PC | REQ_SOFTBARRIER;
+ rq->cmd[0] = SYNCHRONIZE_CACHE;
+ return 1;
+ }
+
+ return 0;
+}
+
static void sd_rescan(struct device *dev)
{
struct scsi_disk *sdkp = dev_get_drvdata(dev);
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/include/linux/blkdev.h linux-2.6.10/include/linux/blkdev.h
--- /opt/kernel/linux-2.6.10/include/linux/blkdev.h 2005-01-26 21:18:13.000000000 +0100
+++ linux-2.6.10/include/linux/blkdev.h 2005-01-26 21:19:05.000000000 +0100
@@ -93,6 +93,9 @@ struct io_context *get_io_context(int gf
void copy_io_context(struct io_context **pdst, struct io_context **psrc);
void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
+struct request;
+typedef void (rq_end_io_fn)(struct request *);
+
struct request_list {
int count[2];
int starved[2];
@@ -176,6 +179,12 @@ struct request {
* For Power Management requests
*/
struct request_pm_state *pm;
+
+ /*
+ * completion callback. end_io_data should be folded in with waiting
+ */
+ rq_end_io_fn *end_io;
+ void *end_io_data;
};
/*
@@ -266,6 +275,8 @@ struct bio_vec;
typedef int (merge_bvec_fn) (request_queue_t *, struct bio *, struct bio_vec *);
typedef void (activity_fn) (void *data, int rw);
typedef int (issue_flush_fn) (request_queue_t *, struct gendisk *, sector_t *);
+typedef int (prepare_flush_fn) (request_queue_t *, struct request *);
+typedef void (end_flush_fn) (request_queue_t *, struct request *);
enum blk_queue_state {
Queue_down,
@@ -309,6 +320,8 @@ struct request_queue
merge_bvec_fn *merge_bvec_fn;
activity_fn *activity_fn;
issue_flush_fn *issue_flush_fn;
+ prepare_flush_fn *prepare_flush_fn;
+ end_flush_fn *end_flush_fn;
/*
* Auto-unplugging state
@@ -380,6 +393,18 @@ struct request_queue
unsigned int sg_reserved_size;
struct list_head drain_list;
+
+ /*
+ * reserved for flush operations
+ */
+ struct request *flush_rq;
+ unsigned char ordered;
+};
+
+enum {
+ QUEUE_ORDERED_NONE,
+ QUEUE_ORDERED_TAG,
+ QUEUE_ORDERED_FLUSH,
};
#define RQ_INACTIVE (-1)
@@ -396,12 +421,13 @@ struct request_queue
#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
#define QUEUE_FLAG_REENTER 6 /* Re-entrancy avoidance */
#define QUEUE_FLAG_PLUGGED 7 /* queue is plugged */
-#define QUEUE_FLAG_ORDERED 8 /* supports ordered writes */
-#define QUEUE_FLAG_DRAIN 9 /* draining queue for sched switch */
+#define QUEUE_FLAG_DRAIN 8 /* draining queue for sched switch */
+#define QUEUE_FLAG_FLUSH 9 /* doing barrier flush sequence */
#define blk_queue_plugged(q) test_bit(QUEUE_FLAG_PLUGGED, &(q)->queue_flags)
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_flush(q) test_bit(QUEUE_FLAG_FLUSH, &(q)->queue_flags)
#define blk_fs_request(rq) ((rq)->flags & REQ_CMD)
#define blk_pc_request(rq) ((rq)->flags & REQ_BLOCK_PC)
@@ -509,10 +535,10 @@ extern void blk_unregister_queue(struct
extern void register_disk(struct gendisk *dev);
extern void generic_make_request(struct bio *bio);
extern void blk_put_request(struct request *);
+extern void blk_end_sync_rq(struct request *rq);
extern void blk_attempt_remerge(request_queue_t *, struct request *);
extern void __blk_attempt_remerge(request_queue_t *, struct request *);
extern struct request *blk_get_request(request_queue_t *, int, int);
-extern void blk_put_request(struct request *);
extern void blk_insert_request(request_queue_t *, struct request *, int, void *, int);
extern void blk_requeue_request(request_queue_t *, struct request *);
extern void blk_plug_device(request_queue_t *);
@@ -602,6 +628,9 @@ extern struct backing_dev_info *blk_get_
extern void blk_queue_ordered(request_queue_t *, int);
extern void blk_queue_issue_flush_fn(request_queue_t *, issue_flush_fn *);
extern int blkdev_scsi_issue_flush_fn(request_queue_t *, struct gendisk *, sector_t *);
+extern void blk_start_post_flush(request_queue_t *,struct request *);
+extern struct request *blk_start_pre_flush(request_queue_t *, struct request *);
+extern int blk_check_end_barrier(request_queue_t *, struct request *, int);
extern int blk_rq_map_sg(request_queue_t *, struct request *, struct scatterlist *);
extern void blk_dump_rq_flags(struct request *, char *);
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/include/linux/ide.h linux-2.6.10/include/linux/ide.h
--- /opt/kernel/linux-2.6.10/include/linux/ide.h 2005-01-26 21:18:14.000000000 +0100
+++ linux-2.6.10/include/linux/ide.h 2005-01-26 21:19:05.000000000 +0100
@@ -743,7 +743,6 @@ typedef struct ide_drive_s {
u8 sect; /* "real" sectors per track */
u8 bios_head; /* BIOS/fdisk/LILO number of heads */
u8 bios_sect; /* BIOS/fdisk/LILO sectors per track */
- u8 doing_barrier; /* state, 1=currently doing flush */
unsigned int bios_cyl; /* BIOS/fdisk/LILO number of cyls */
unsigned int cyl; /* "real" number of cyls */
@@ -1131,6 +1130,7 @@ extern ide_hwif_t ide_hwifs[]; /* maste
extern int noautodma;
extern int ide_end_request (ide_drive_t *drive, int uptodate, int nrsecs);
+extern int __ide_end_request (ide_drive_t *drive, struct request *rq, int uptodate, int nrsecs);
/*
* This is used on exit from the driver to designate the next irq handler
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/include/scsi/scsi_driver.h linux-2.6.10/include/scsi/scsi_driver.h
--- /opt/kernel/linux-2.6.10/include/scsi/scsi_driver.h 2005-01-26 21:18:15.000000000 +0100
+++ linux-2.6.10/include/scsi/scsi_driver.h 2005-01-26 21:19:05.000000000 +0100
@@ -14,6 +14,8 @@ struct scsi_driver {
int (*init_command)(struct scsi_cmnd *);
void (*rescan)(struct device *);
int (*issue_flush)(struct device *, sector_t *);
+ int (*prepare_flush)(struct request_queue *, struct request *);
+ void (*end_flush)(struct request_queue *, struct request *);
};
#define to_scsi_driver(drv) \
container_of((drv), struct scsi_driver, gendrv)
diff -urp -X /home/axboe/cdrom/exclude /opt/kernel/linux-2.6.10/include/scsi/scsi_host.h linux-2.6.10/include/scsi/scsi_host.h
--- /opt/kernel/linux-2.6.10/include/scsi/scsi_host.h 2005-01-26 21:18:15.000000000 +0100
+++ linux-2.6.10/include/scsi/scsi_host.h 2005-01-26 21:19:05.000000000 +0100
@@ -352,6 +352,12 @@ struct scsi_host_template {
unsigned skip_settle_delay:1;
/*
+ * ordered write support
+ */
+ unsigned ordered_flush:1;
+ unsigned ordered_tag:1;
+
+ /*
* Countdown for host blocking with no commands outstanding
*/
unsigned int max_host_blocked;
@@ -491,6 +497,12 @@ struct Scsi_Host {
unsigned reverse_ordering:1;
/*
+ * ordered write support
+ */
+ unsigned ordered_flush:1;
+ unsigned ordered_tag:1;
+
+ /*
* Host has rejected a command because it was busy.
*/
unsigned int host_blocked;
--
Jens Axboe
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