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From: Wu Fengguang on 7 Oct 2009 04:10
For now only pass the non-rotational bit to the queue's bdi.

To support hierarchical dm/md configurations, blk_set_rotational()
shall be expanded to make several iterations of the bdi list and call
its bdi->rotational_fn to pass the bit up. But that would imply we
don's support mixed SSD/HD arrays.

CC: Jens Axboe <jens.axboe(a)oracle.com>
Signed-off-by: Wu Fengguang <fengguang.wu(a)intel.com>
---
block/blk-core.c | 14 ++++++++++++++
block/blk-sysfs.c | 7 +------
drivers/block/nbd.c | 2 +-
drivers/block/xen-blkfront.c | 1 +
drivers/mmc/card/queue.c | 2 +-
drivers/scsi/sd.c | 2 +-
include/linux/backing-dev.h | 8 ++++++++
include/linux/blkdev.h | 1 +
8 files changed, 28 insertions(+), 9 deletions(-)

--- linux.orig/block/blk-sysfs.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/block/blk-sysfs.c 2009-10-06 23:39:26.000000000 +0800
@@ -162,12 +162,7 @@ static ssize_t queue_nonrot_store(struct
unsigned long nm;
ssize_t ret = queue_var_store(&nm, page, count);

- spin_lock_irq(q->queue_lock);
- if (nm)
- queue_flag_clear(QUEUE_FLAG_NONROT, q);
- else
- queue_flag_set(QUEUE_FLAG_NONROT, q);
- spin_unlock_irq(q->queue_lock);
+ blk_set_rotational(q, nm);

return ret;
}
--- linux.orig/include/linux/backing-dev.h 2009-10-06 23:38:44.000000000 +0800
+++ linux/include/linux/backing-dev.h 2009-10-06 23:39:26.000000000 +0800
@@ -29,6 +29,7 @@ enum bdi_state {
BDI_wb_alloc, /* Default embedded wb allocated */
BDI_async_congested, /* The async (write) queue is getting full */
BDI_sync_congested, /* The sync queue is getting full */
+ BDI_non_rotational, /* Underlying device is SSD or virtual */
BDI_registered, /* bdi_register() was done */
BDI_unused, /* Available bits start here */
};
@@ -254,6 +255,8 @@ int bdi_set_max_ratio(struct backing_dev
#define BDI_CAP_NO_ACCT_WB 0x00000080
#define BDI_CAP_SWAP_BACKED 0x00000100

+#define BDI_CAP_NONROT 0x00000200
+
#define BDI_CAP_VMFLAGS \
(BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)

@@ -291,6 +294,11 @@ static inline int can_submit_background_
return !test_and_set_bit(WB_FLAG_BACKGROUND_WORK, &bdi->wb_mask);
}

+static inline bool bdi_nonrot(struct backing_dev_info *bdi)
+{
+ return bdi->state & (1 << BDI_non_rotational);
+}
+
static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
{
if (bdi->congested_fn)
--- linux.orig/block/blk-core.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/block/blk-core.c 2009-10-06 23:39:26.000000000 +0800
@@ -2486,6 +2486,20 @@ free_and_out:
}
EXPORT_SYMBOL_GPL(blk_rq_prep_clone);

+void blk_set_rotational(struct request_queue *q, int rotational)
+{
+ spin_lock_irq(q->queue_lock);
+ if (rotational) {
+ queue_flag_clear(QUEUE_FLAG_NONROT, q);
+ clear_bit(BDI_non_rotational, &q->backing_dev_info.state);
+ } else {
+ queue_flag_set(QUEUE_FLAG_NONROT, q);
+ set_bit(BDI_non_rotational, &q->backing_dev_info.state);
+ }
+ spin_unlock_irq(q->queue_lock);
+}
+EXPORT_SYMBOL(blk_set_rotational);
+
int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
{
return queue_work(kblockd_workqueue, work);
--- linux.orig/include/linux/blkdev.h 2009-10-06 23:37:44.000000000 +0800
+++ linux/include/linux/blkdev.h 2009-10-06 23:39:26.000000000 +0800
@@ -666,6 +666,7 @@ static inline void blk_clear_queue_full(
queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
}

+void blk_set_rotational(struct request_queue *q, int rotational);

/*
* mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
--- linux.orig/drivers/block/nbd.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/drivers/block/nbd.c 2009-10-06 23:39:26.000000000 +0800
@@ -772,7 +772,7 @@ static int __init nbd_init(void)
/*
* Tell the block layer that we are not a rotational device
*/
- queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
+ blk_set_rotational(disk->queue, 0);
}

if (register_blkdev(NBD_MAJOR, "nbd")) {
--- linux.orig/drivers/block/xen-blkfront.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/drivers/block/xen-blkfront.c 2009-10-06 23:39:26.000000000 +0800
@@ -342,6 +342,7 @@ static int xlvbd_init_blk_queue(struct g
return -1;

queue_flag_set_unlocked(QUEUE_FLAG_VIRT, rq);
+ blk_set_rotational(rq, 0);

/* Hard sector size and max sectors impersonate the equiv. hardware. */
blk_queue_logical_block_size(rq, sector_size);
--- linux.orig/drivers/mmc/card/queue.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/drivers/mmc/card/queue.c 2009-10-06 23:39:26.000000000 +0800
@@ -127,7 +127,7 @@ int mmc_init_queue(struct mmc_queue *mq,

blk_queue_prep_rq(mq->queue, mmc_prep_request);
blk_queue_ordered(mq->queue, QUEUE_ORDERED_DRAIN, NULL);
- queue_flag_set_unlocked(QUEUE_FLAG_NONROT, mq->queue);
+ blk_set_rotational(mq->queue, 0);

#ifdef CONFIG_MMC_BLOCK_BOUNCE
if (host->max_hw_segs == 1) {
--- linux.orig/drivers/scsi/sd.c 2009-10-06 23:37:44.000000000 +0800
+++ linux/drivers/scsi/sd.c 2009-10-06 23:39:26.000000000 +0800
@@ -1898,7 +1898,7 @@ static void sd_read_block_characteristic
rot = get_unaligned_be16(&buffer[4]);

if (rot == 1)
- queue_flag_set_unlocked(QUEUE_FLAG_NONROT, sdkp->disk->queue);
+ blk_set_rotational(sdkp->disk->queue, 0);

kfree(buffer);
}


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Prev: [PATCH 03/45] ext4: remove unused parameter wbc from __ext4_journalled_writepage()
Next: [PATCH 01/10] KVM: SVM: Notify nested hypervisor of lost event injections