On Wed, Apr 13 2016, Jens Axboe wrote:
> On Wed, Apr 13 2016, Ming Lei wrote:
> > > +static ssize_t queue_wc_store(struct request_queue *q, const char *page,
> > > + size_t count)
> > > +{
> > > + int set = -1;
> > > +
> > > + if (!strncmp(page, "write back", 10))
> > > + set = 1;
> > > + else if (!strncmp(page, "write through", 13) ||
> > > + !strncmp(page, "none", 4))
> > > + set = 0;
> > > +
> > > + if (set == -1)
> > > + return -EINVAL;
> > > +
> > > + spin_lock_irq(q->queue_lock);
> > > + if (set)
> > > + queue_flag_set(QUEUE_FLAG_WC, q);
> > > + else
> > > + queue_flag_clear(QUEUE_FLAG_WC, q);
> > > + spin_unlock_irq(q->queue_lock);
> >
> > When the write cache (queue)flag is changed, I guess we need to change
> > q->flush_flags via blk_queue_write_cache() too? Otherwise, the change
> > on write cache flag can't affect block flush behaviour.
> >
> > BTW, looks the flush_flags has been redundant after this patch, can
> > we just kill it in the future?
>
> How about we fold both those concerns into one? Kill off ->flush_flags,
> and that then fixes the other part as well. Like the below, untested.
Minor screwup in target_core_iblock.c and a missing unsigned -> long
conversion in dm. Also changed the dm part to pass by value, not
reference.
diff --git a/block/blk-core.c b/block/blk-core.c
index c50227796a26..2475b1c72773 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1964,7 +1964,8 @@ generic_make_request_checks(struct bio *bio)
* drivers without flush support don't have to worry
* about them.
*/
- if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) {
+ if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) &&
+ !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) {
bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA);
if (!nr_sectors) {
err = 0;
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 9c423e53324a..b1c91d229e5e 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -95,17 +95,18 @@ enum {
static bool blk_kick_flush(struct request_queue *q,
struct blk_flush_queue *fq);
-static unsigned int blk_flush_policy(unsigned int fflags, struct request *rq)
+static unsigned int blk_flush_policy(unsigned long fflags, struct request *rq)
{
unsigned int policy = 0;
if (blk_rq_sectors(rq))
policy |= REQ_FSEQ_DATA;
- if (fflags & REQ_FLUSH) {
+ if (fflags & (1UL << QUEUE_FLAG_WC)) {
if (rq->cmd_flags & REQ_FLUSH)
policy |= REQ_FSEQ_PREFLUSH;
- if (!(fflags & REQ_FUA) && (rq->cmd_flags & REQ_FUA))
+ if (!(fflags & (1UL << QUEUE_FLAG_FUA)) &&
+ (rq->cmd_flags & REQ_FUA))
policy |= REQ_FSEQ_POSTFLUSH;
}
return policy;
@@ -384,7 +385,7 @@ static void mq_flush_data_end_io(struct request *rq, int error)
void blk_insert_flush(struct request *rq)
{
struct request_queue *q = rq->q;
- unsigned int fflags = q->flush_flags; /* may change, cache */
+ unsigned long fflags = q->queue_flags; /* may change, cache */
unsigned int policy = blk_flush_policy(fflags, rq);
struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx);
@@ -393,7 +394,7 @@ void blk_insert_flush(struct request *rq)
* REQ_FLUSH and FUA for the driver.
*/
rq->cmd_flags &= ~REQ_FLUSH;
- if (!(fflags & REQ_FUA))
+ if (!(fflags & (1UL << QUEUE_FLAG_FUA)))
rq->cmd_flags &= ~REQ_FUA;
/*
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 80d9327a214b..f679ae122843 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -822,7 +822,12 @@ EXPORT_SYMBOL(blk_queue_update_dma_alignment);
void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
{
- q->flush_not_queueable = !queueable;
+ spin_lock_irq(q->queue_lock);
+ if (queueable)
+ clear_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
+ else
+ set_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
+ spin_unlock_irq(q->queue_lock);
}
EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
@@ -837,16 +842,13 @@ EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
spin_lock_irq(q->queue_lock);
- if (wc) {
+ if (wc)
queue_flag_set(QUEUE_FLAG_WC, q);
- q->flush_flags = REQ_FLUSH;
- } else
+ else
queue_flag_clear(QUEUE_FLAG_WC, q);
- if (fua) {
- if (wc)
- q->flush_flags |= REQ_FUA;
+ if (fua)
queue_flag_set(QUEUE_FLAG_FUA, q);
- } else
+ else
queue_flag_clear(QUEUE_FLAG_FUA, q);
spin_unlock_irq(q->queue_lock);
}
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 26aa080e243c..3355f1cdd4e5 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -477,7 +477,7 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
vbd->type |= VDISK_REMOVABLE;
q = bdev_get_queue(bdev);
- if (q && q->flush_flags)
+ if (q && test_bit(QUEUE_FLAG_WC, &q->queue_flags))
vbd->flush_support = true;
if (q && blk_queue_secdiscard(q))
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4b1ffc0abe11..626a5ec04466 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1348,13 +1348,13 @@ static void dm_table_verify_integrity(struct dm_table *t)
static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
- unsigned flush = (*(unsigned *)data);
+ unsigned long flush = (unsigned long) data;
struct request_queue *q = bdev_get_queue(dev->bdev);
- return q && (q->flush_flags & flush);
+ return q && (q->queue_flags & flush);
}
-static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
+static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
{
struct dm_target *ti;
unsigned i = 0;
@@ -1375,7 +1375,7 @@ static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
return true;
if (ti->type->iterate_devices &&
- ti->type->iterate_devices(ti, device_flush_capable, &flush))
+ ti->type->iterate_devices(ti, device_flush_capable, (void *) flush))
return true;
}
@@ -1518,9 +1518,9 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
else
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
- if (dm_table_supports_flush(t, REQ_FLUSH)) {
+ if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
wc = true;
- if (dm_table_supports_flush(t, REQ_FUA))
+ if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
fua = true;
}
blk_queue_write_cache(q, wc, fua);
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 9531f5f05b93..26f14970a858 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1188,6 +1188,7 @@ ioerr:
int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
{
+ struct request_queue *q = bdev_get_queue(rdev->bdev);
struct r5l_log *log;
if (PAGE_SIZE != 4096)
@@ -1197,7 +1198,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
return -ENOMEM;
log->rdev = rdev;
- log->need_cache_flush = (rdev->bdev->bd_disk->queue->flush_flags != 0);
+ log->need_cache_flush = test_bit(QUEUE_FLAG_WC, &q->queue_flags) != 0;
log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
sizeof(rdev->mddev->uuid));
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 026a758e5778..7c4efb4417b0 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -687,10 +687,10 @@ iblock_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
* Force writethrough using WRITE_FUA if a volatile write cache
* is not enabled, or if initiator set the Force Unit Access bit.
*/
- if (q->flush_flags & REQ_FUA) {
+ if (test_bit(QUEUE_FLAG_FUA, &q->queue_flags)) {
if (cmd->se_cmd_flags & SCF_FUA)
rw = WRITE_FUA;
- else if (!(q->flush_flags & REQ_FLUSH))
+ else if (!test_bit(QUEUE_FLAG_WC, &q->queue_flags))
rw = WRITE_FUA;
else
rw = WRITE;
@@ -836,7 +836,7 @@ static bool iblock_get_write_cache(struct se_device *dev)
struct block_device *bd = ib_dev->ibd_bd;
struct request_queue *q = bdev_get_queue(bd);
- return q->flush_flags & REQ_FLUSH;
+ return test_bit(QUEUE_FLAG_WC, &q->queue_flags);
}
static const struct target_backend_ops iblock_ops = {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f3f232fa505d..57c085917da6 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -433,8 +433,6 @@ struct request_queue {
/*
* for flush operations
*/
- unsigned int flush_flags;
- unsigned int flush_not_queueable:1;
struct blk_flush_queue *fq;
struct list_head requeue_list;
@@ -493,6 +491,7 @@ struct request_queue {
#define QUEUE_FLAG_POLL 22 /* IO polling enabled if set */
#define QUEUE_FLAG_WC 23 /* Write back caching */
#define QUEUE_FLAG_FUA 24 /* device supports FUA writes */
+#define QUEUE_FLAG_FLUSH_NQ 25 /* flush not queueuable */
#define QUEUE_FLAG_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_STACKABLE) | \
@@ -1365,7 +1364,7 @@ static inline unsigned int block_size(struct block_device *bdev)
static inline bool queue_flush_queueable(struct request_queue *q)
{
- return !q->flush_not_queueable;
+ return !test_bit(QUEUE_FLAG_FLUSH_NQ, &q->queue_flags);
}
typedef struct {struct page *v;} Sector;
--
Jens Axboe
--
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