[PATCH 41/42] block: use QUEUE flags instead of flush_flags to test for flush support

From: mchristi
Date: Wed Apr 13 2016 - 15:38:17 EST

From: Mike Christie <mchristi@xxxxxxxxxx>

The last patch added a REQ_OP_FLUSH for request_fn drivers
and the next patch renames REQ_FLUSH to REQ_PREFLUSH which
will be used by file systems and make_request_fn drivers so
they can send a write/flush combo.

Jens's cleanup in:

block: add ability to flag write back caching on a device
93e9d8e836cb1a9a58b33eb6643bf061c6119ef2

also added QUEUE flags that can be used to get the same info
as flush_flags.

This patch has drivers check the QUEUE_FLAG bits, so we do not
have to have the extra REQ_FLUSH definition.

Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx>
---
block/blk-core.c | 3 ++-
block/blk-flush.c | 12 +++++-----
block/blk-settings.c | 11 ++++-----
drivers/block/xen-blkback/xenbus.c | 2 +-
drivers/block/xen-blkfront.c | 48 +++++++++++++++++++------------------
drivers/md/dm-table.c | 20 +++++++++++-----
drivers/md/raid5-cache.c | 3 ++-
drivers/target/target_core_iblock.c | 6 ++---
include/linux/blkdev.h | 3 ++-
9 files changed, 59 insertions(+), 49 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 71ba3a9..ef69d04 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1969,7 +1969,8 @@ 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)) &&
+ !(blk_queue_flush(q) || blk_queue_fua(q))) {
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 af0c805..7682680 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(struct request *rq)
{
+ struct request_queue *q = rq->q;
unsigned int policy = 0;

if (blk_rq_sectors(rq))
policy |= REQ_FSEQ_DATA;

- if (fflags & REQ_FLUSH) {
+ if (blk_queue_flush(q)) {
if (rq->cmd_flags & REQ_FLUSH)
policy |= REQ_FSEQ_PREFLUSH;
- if (!(fflags & REQ_FUA) && (rq->cmd_flags & REQ_FUA))
+ if (!blk_queue_fua(q) && (rq->cmd_flags & REQ_FUA))
policy |= REQ_FSEQ_POSTFLUSH;
}
return policy;
@@ -385,8 +386,7 @@ 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 int policy = blk_flush_policy(fflags, rq);
+ unsigned int policy = blk_flush_policy(rq);
struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx);

/*
@@ -394,7 +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 (!blk_queue_fua(q))
rq->cmd_flags &= ~REQ_FUA;

/*
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 80d9327..51bc002 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -837,16 +837,13 @@ 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 26aa080..1291c35 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 && (blk_queue_flush(q) || blk_queue_fua(q)))
vbd->flush_support = true;

if (q && blk_queue_secdiscard(q))
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index f01691a..a0651f3 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -196,6 +196,7 @@ struct blkfront_info
unsigned int nr_ring_pages;
struct request_queue *rq;
unsigned int feature_flush;
+ unsigned int feature_fua;
unsigned int feature_discard:1;
unsigned int feature_secdiscard:1;
unsigned int discard_granularity;
@@ -763,19 +764,15 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
* implement it the same way. (It's also a FLUSH+FUA,
* since it is guaranteed ordered WRT previous writes.)
*/
- switch (info->feature_flush &
- ((REQ_FLUSH|REQ_FUA))) {
- case REQ_FLUSH|REQ_FUA:
+ if (blk_queue_flush(info->rq) &&
+ blk_queue_fua(info->rq))
ring_req->operation =
BLKIF_OP_WRITE_BARRIER;
- break;
- case REQ_FLUSH:
+ else if (blk_queue_flush(info->rq))
ring_req->operation =
BLKIF_OP_FLUSH_DISKCACHE;
- break;
- default:
+ else
ring_req->operation = 0;
- }
}
ring_req->u.rw.nr_segments = num_grant;
if (unlikely(require_extra_req)) {
@@ -866,9 +863,9 @@ static inline bool blkif_request_flush_invalid(struct request *req,
{
return ((req->cmd_type != REQ_TYPE_FS) ||
((req->op == REQ_OP_FLUSH) &&
- !(info->feature_flush & REQ_FLUSH)) ||
+ !(blk_queue_flush(info->rq))) ||
((req->cmd_flags & REQ_FUA) &&
- !(info->feature_flush & REQ_FUA)));
+ !(blk_queue_fua(info->rq))));
}

static int blkif_queue_rq(struct blk_mq_hw_ctx *hctx,
@@ -985,24 +982,22 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size,
return 0;
}

-static const char *flush_info(unsigned int feature_flush)
+static const char *flush_info(struct blkfront_info *info)
{
- switch (feature_flush & ((REQ_FLUSH | REQ_FUA))) {
- case REQ_FLUSH|REQ_FUA:
+ if (blk_queue_flush(info->rq) && blk_queue_fua(info->rq))
return "barrier: enabled;";
- case REQ_FLUSH:
+ else if (blk_queue_flush(info->rq))
return "flush diskcache: enabled;";
- default:
+ else
return "barrier or flush: disabled;";
- }
}

static void xlvbd_flush(struct blkfront_info *info)
{
- blk_queue_write_cache(info->rq, info->feature_flush & REQ_FLUSH,
- info->feature_flush & REQ_FUA);
+ blk_queue_write_cache(info->rq, info->feature_flush ? true : false,
+ info->feature_flush ? true : false);
pr_info("blkfront: %s: %s %s %s %s %s\n",
- info->gd->disk_name, flush_info(info->feature_flush),
+ info->gd->disk_name, flush_info(info),
"persistent grants:", info->feature_persistent ?
"enabled;" : "disabled;", "indirect descriptors:",
info->max_indirect_segments ? "enabled;" : "disabled;");
@@ -1621,6 +1616,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
if (unlikely(error)) {
if (error == -EOPNOTSUPP)
error = 0;
+ info->feature_fua = 0;
info->feature_flush = 0;
xlvbd_flush(info);
}
@@ -2315,6 +2311,7 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
unsigned int indirect_segments;

info->feature_flush = 0;
+ info->feature_fua = 0;

err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"feature-barrier", "%d", &barrier,
@@ -2327,8 +2324,11 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
*
* If there are barriers, then we use flush.
*/
- if (!err && barrier)
- info->feature_flush = REQ_FLUSH | REQ_FUA;
+ if (!err && barrier) {
+ info->feature_flush = 1;
+ info->feature_fua = 1;
+ }
+
/*
* And if there is "feature-flush-cache" use that above
* barriers.
@@ -2337,8 +2337,10 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
"feature-flush-cache", "%d", &flush,
NULL);

- if (!err && flush)
- info->feature_flush = REQ_FLUSH;
+ if (!err && flush) {
+ info->feature_flush = 1;
+ info->feature_fua = 0;
+ }

err = xenbus_gather(XBT_NIL, info->xbdev->otherend,
"feature-discard", "%d", &discard,
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4b1ffc0..a47884b 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1348,13 +1348,21 @@ 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);
struct request_queue *q = bdev_get_queue(dev->bdev);

- return q && (q->flush_flags & flush);
+ return q && blk_queue_flush(q);
}

-static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
+static int device_fua_capable(struct dm_target *ti, struct dm_dev *dev,
+ sector_t start, sector_t len, void *data)
+{
+ struct request_queue *q = bdev_get_queue(dev->bdev);
+
+ return q && blk_queue_fua(q);
+}
+
+static bool dm_table_supports_flush(struct dm_table *t,
+ iterate_devices_callout_fn callout_fn)
{
struct dm_target *ti;
unsigned i = 0;
@@ -1375,7 +1383,7 @@ 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, callout_fn, NULL))
return true;
}

@@ -1518,9 +1526,9 @@ 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, device_flush_capable)) {
wc = true;
- if (dm_table_supports_flush(t, REQ_FUA))
+ if (dm_table_supports_flush(t, device_fua_capable))
fua = true;
}
blk_queue_write_cache(q, wc, fua);
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index da07670..3d88b55 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -1196,6 +1196,7 @@ ioerr:

int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
{
+ struct request_queue *q = rdev->bdev->bd_disk->queue;
struct r5l_log *log;

if (PAGE_SIZE != 4096)
@@ -1205,7 +1206,7 @@ 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 = (blk_queue_flush(q) || blk_queue_fua(q));

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 fb1543b..733a61a 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -691,11 +691,11 @@ 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 (blk_queue_fua(q)) {
if (cmd->se_cmd_flags & SCF_FUA) {
op = REQ_OP_WRITE;
op_flags = WRITE_FUA;
- } else if (!(q->flush_flags & REQ_FLUSH)) {
+ } else if (!blk_queue_flush(q)) {
op = REQ_OP_WRITE;
op_flags = WRITE_FUA;
} else {
@@ -844,7 +844,7 @@ 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 blk_queue_flush(q);
}

static const struct target_backend_ops iblock_ops = {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 4fdea8e..ed33156 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -434,7 +434,6 @@ struct request_queue {
/*
* for flush operations
*/
- unsigned int flush_flags;
unsigned int flush_not_queueable:1;
struct blk_flush_queue *fq;

@@ -583,6 +582,8 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
#define blk_queue_discard(q) test_bit(QUEUE_FLAG_DISCARD, &(q)->queue_flags)
#define blk_queue_secdiscard(q) (blk_queue_discard(q) && \
test_bit(QUEUE_FLAG_SECDISCARD, &(q)->queue_flags))
+#define blk_queue_flush(q) test_bit(QUEUE_FLAG_WC, &(q)->queue_flags)
+#define blk_queue_fua(q) test_bit(QUEUE_FLAG_FUA, &(q)->queue_flags)

#define blk_noretry_request(rq) \
((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
--
2.7.2