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Date: Wed, 24 Mar 2010 20:33:06 +0300
From: Dmitry Monakhov <dmonakhov@...nvz.org>
To: linux-kernel@...r.kernel.org
Cc: jens.axboe@...cle.com, hch@...radead.org, mkp@....net,
Dmitry Monakhov <dmonakhov@...nvz.org>
Subject: [PATCH 3/5] blkdev: add blkdev_issue helper functions
Move blkdev_issue_discard from blk-barrier.c because it is not barrier
related.
Add new helper functions:
__blkdev_issue_zeroout: Explicitly zero given range via zeroed write request.
blkdev_issue_clear: zero given range, user discard if possible.
Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
---
block/Makefile | 2 +-
block/blk-barrier.c | 103 -------------------
block/blk-lib.c | 255 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/blkdev.h | 5 +-
4 files changed, 260 insertions(+), 105 deletions(-)
create mode 100644 block/blk-lib.c
diff --git a/block/Makefile b/block/Makefile
index cb2d515..0bb499a 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -5,7 +5,7 @@
obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
- blk-iopoll.o ioctl.o genhd.o scsi_ioctl.o
+ blk-iopoll.o blk-lib.o ioctl.o genhd.o scsi_ioctl.o
obj-$(CONFIG_BLK_DEV_BSG) += bsg.o
obj-$(CONFIG_BLK_CGROUP) += blk-cgroup.o
diff --git a/block/blk-barrier.c b/block/blk-barrier.c
index 56254b1..1242bdd 100644
--- a/block/blk-barrier.c
+++ b/block/blk-barrier.c
@@ -347,106 +347,3 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
}
EXPORT_SYMBOL(blkdev_issue_flush);
-static void blkdev_discard_end_io(struct bio *bio, int err)
-{
- if (err) {
- if (err == -EOPNOTSUPP)
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
- }
-
- if (bio->bi_private)
- complete(bio->bi_private);
- __free_page(bio_page(bio));
-
- bio_put(bio);
-}
-
-/**
- * blkdev_issue_discard - queue a discard
- * @bdev: blockdev to issue discard for
- * @sector: start sector
- * @nr_sects: number of sectors to discard
- * @gfp_mask: memory allocation flags (for bio_alloc)
- * @flags: BLKDEV_IFL_* flags to control behaviour
- *
- * Description:
- * Issue a discard request for the sectors in question.
- */
-int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
- sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
-{
- DECLARE_COMPLETION_ONSTACK(wait);
- struct request_queue *q = bdev_get_queue(bdev);
- int type = flags & BLKDEV_IFL_BARRIER ?
- DISCARD_BARRIER : DISCARD_NOBARRIER;
- struct bio *bio;
- struct page *page;
- int ret = 0;
-
- if (!q)
- return -ENXIO;
-
- if (!blk_queue_discard(q))
- return -EOPNOTSUPP;
-
- while (nr_sects && !ret) {
- unsigned int sector_size = q->limits.logical_block_size;
- unsigned int max_discard_sectors =
- min(q->limits.max_discard_sectors, UINT_MAX >> 9);
-
- bio = bio_alloc(gfp_mask, 1);
- if (!bio)
- goto out;
- bio->bi_sector = sector;
- bio->bi_end_io = blkdev_discard_end_io;
- bio->bi_bdev = bdev;
- if (flags & BLKDEV_IFL_BARRIER)
- bio->bi_private = &wait;
-
- /*
- * Add a zeroed one-sector payload as that's what
- * our current implementations need. If we'll ever need
- * more the interface will need revisiting.
- */
- page = alloc_page(gfp_mask | __GFP_ZERO);
- if (!page)
- goto out_free_bio;
- if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
- goto out_free_page;
-
- /*
- * And override the bio size - the way discard works we
- * touch many more blocks on disk than the actual payload
- * length.
- */
- if (nr_sects > max_discard_sectors) {
- bio->bi_size = max_discard_sectors << 9;
- nr_sects -= max_discard_sectors;
- sector += max_discard_sectors;
- } else {
- bio->bi_size = nr_sects << 9;
- nr_sects = 0;
- }
-
- bio_get(bio);
- submit_bio(type, bio);
-
- if (flags & BLKDEV_IFL_BARRIER)
- wait_for_completion(&wait);
-
- if (bio_flagged(bio, BIO_EOPNOTSUPP))
- ret = -EOPNOTSUPP;
- else if (!bio_flagged(bio, BIO_UPTODATE))
- ret = -EIO;
- bio_put(bio);
- }
- return ret;
-out_free_page:
- __free_page(page);
-out_free_bio:
- bio_put(bio);
-out:
- return -ENOMEM;
-}
-EXPORT_SYMBOL(blkdev_issue_discard);
diff --git a/block/blk-lib.c b/block/blk-lib.c
new file mode 100644
index 0000000..67b641e
--- /dev/null
+++ b/block/blk-lib.c
@@ -0,0 +1,255 @@
+/*
+ * Functions related to generic helpers functions
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/scatterlist.h>
+
+#include "blk.h"
+
+struct bio_batch
+{
+ atomic_t done;
+ unsigned long flags;
+ struct completion *wait;
+ bio_end_io_t *end_io;
+};
+
+static void bio_batch_end_io(struct bio *bio, int err)
+{
+ struct bio_batch *bb = bio->bi_private;
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ set_bit(BIO_EOPNOTSUPP, &bb->flags);
+ else
+ clear_bit(BIO_UPTODATE, &bb->flags);
+ }
+ if (bb) {
+ if (bb->end_io)
+ bb->end_io(bio, err);
+ atomic_inc(&bb->done);
+ complete(bb->wait);
+ }
+ bio_put(bio);
+}
+
+/**
+ * __blkdev_issue_zeroout generate number of zero filed write bios
+ * @bdev: blockdev to issue
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @flags: BLKDEV_IFL_* flags to control behaviour
+ *
+ * Description:
+ * Generate and issue number of bios with zerofiled pages.
+ * Send barrier at the beginning and at the end if requested. This guarantie
+ * correct request ordering. Empty barrier allow us to avoid post queue flush.
+ */
+
+int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
+{
+ int ret = 0;
+ struct bio *bio;
+ struct bio_batch bb;
+ unsigned int sz, issued = 0;
+ DECLARE_COMPLETION_ONSTACK(wait);
+
+ atomic_set(&bb.done, 0);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+ bb.end_io = NULL;
+
+ if (flags & BLKDEV_IFL_BARRIER) {
+ /* issue async barrier before the data */
+ ret = blkdev_issue_flush(bdev, gfp_mask, NULL, 0);
+ if (ret)
+ return ret;
+ }
+submit:
+ while (nr_sects != 0) {
+ bio = bio_alloc(gfp_mask,
+ min(nr_sects, (sector_t)BIO_MAX_PAGES));
+ if (!bio)
+ break;
+
+ bio->bi_sector = sector;
+ bio->bi_bdev = bdev;
+ bio->bi_end_io = bio_batch_end_io;
+ if (flags & BLKDEV_IFL_WAIT)
+ bio->bi_private = &bb;
+
+ while(nr_sects != 0) {
+ sz = min(PAGE_SIZE >> 9 , nr_sects);
+ if (sz == 0)
+ /* bio has maximum size possible */
+ break;
+ ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
+ nr_sects -= ret >> 9;
+ sector += ret >> 9;
+ if (ret < (sz << 9))
+ break;
+ }
+ issued++;
+ submit_bio(WRITE, bio);
+ }
+ /*
+ * When all data bios are in flight. Send final barrier if requeted.
+ */
+ if (nr_sects == 0 && flags & BLKDEV_IFL_BARRIER)
+ ret = blkdev_issue_flush(bdev, gfp_mask, NULL,
+ flags & BLKDEV_IFL_WAIT);
+
+
+ if (flags & BLKDEV_IFL_WAIT)
+ /* Wait for bios in-flight */
+ while ( issued != atomic_read(&bb.done))
+ wait_for_completion(&wait);
+
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ /* One of bios in the batch was completed with error.*/
+ ret = -EIO;
+
+ if (ret)
+ goto out;
+
+ if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
+ ret = -EOPNOTSUPP;
+ goto out;
+ }
+ if (nr_sects != 0)
+ goto submit;
+out:
+ return ret;
+}
+EXPORT_SYMBOL(__blkdev_issue_zeroout);
+
+static void blkdev_discard_end_io(struct bio *bio, int err)
+{
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ }
+
+ if (bio->bi_private)
+ complete(bio->bi_private);
+ __free_page(bio_page(bio));
+
+ bio_put(bio);
+}
+
+/**
+ * blkdev_issue_discard - queue a discard
+ * @bdev: blockdev to issue discard for
+ * @sector: start sector
+ * @nr_sects: number of sectors to discard
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ * @flags: BLKDEV_IFL_* flags to control behaviour
+ *
+ * Description:
+ * Issue a discard request for the sectors in question.
+ */
+int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q = bdev_get_queue(bdev);
+ int type = flags & BLKDEV_IFL_BARRIER ?
+ DISCARD_BARRIER : DISCARD_NOBARRIER;
+ struct bio *bio;
+ struct page *page;
+ int ret = 0;
+
+ if (!q)
+ return -ENXIO;
+
+ if (!blk_queue_discard(q))
+ return -EOPNOTSUPP;
+
+ while (nr_sects && !ret) {
+ unsigned int sector_size = q->limits.logical_block_size;
+ unsigned int max_discard_sectors =
+ min(q->limits.max_discard_sectors, UINT_MAX >> 9);
+
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio)
+ goto out;
+ bio->bi_sector = sector;
+ bio->bi_end_io = blkdev_discard_end_io;
+ bio->bi_bdev = bdev;
+ if (flags & BLKDEV_IFL_BARRIER)
+ bio->bi_private = &wait;
+
+ /*
+ * Add a zeroed one-sector payload as that's what
+ * our current implementations need. If we'll ever need
+ * more the interface will need revisiting.
+ */
+ page = alloc_page(gfp_mask | __GFP_ZERO);
+ if (!page)
+ goto out_free_bio;
+ if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
+ goto out_free_page;
+
+ /*
+ * And override the bio size - the way discard works we
+ * touch many more blocks on disk than the actual payload
+ * length.
+ */
+ if (nr_sects > max_discard_sectors) {
+ bio->bi_size = max_discard_sectors << 9;
+ nr_sects -= max_discard_sectors;
+ sector += max_discard_sectors;
+ } else {
+ bio->bi_size = nr_sects << 9;
+ nr_sects = 0;
+ }
+
+ bio_get(bio);
+ submit_bio(type, bio);
+
+ if (flags & BLKDEV_IFL_BARRIER)
+ wait_for_completion(&wait);
+
+ if (bio_flagged(bio, BIO_EOPNOTSUPP))
+ ret = -EOPNOTSUPP;
+ else if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+ bio_put(bio);
+ }
+ return ret;
+out_free_page:
+ __free_page(page);
+out_free_bio:
+ bio_put(bio);
+out:
+ return -ENOMEM;
+}
+EXPORT_SYMBOL(blkdev_issue_discard);
+
+/**
+ * blkdev_issue_clear : Clear a given region with zeros, use DISCARD if
+ * supported.
+ * @bdev: blockdev to issue
+ * @sector: start sector
+ * @nr_sects: number of sectors to write
+ * @gfp: memory allocation flags (for bio_alloc)
+ * @fl: BLKDEV_IFL_* flags to control behaviour
+ */
+int blkdev_issue_clear(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp, unsigned long fl)
+{
+ int ret = 0;
+ struct request_queue *q = bdev_get_queue(bdev)
+ if (blk_queue_discard(q) && q->limits.discard_zeroes_data)
+ ret = blkdev_issue_discard(bdev, sector, nr_sects, gfp, fl);
+ else
+ ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp, fl);
+ return ret;
+}
+
+EXPORT_SYMBOL(blkdev_issue_clear);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 84ec105..78180b7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1022,7 +1022,10 @@ extern int blkdev_issue_flush(struct block_device *, gfp_t, sector_t *,
unsigned long);
extern int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
-
+extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
+extern int blkdev_issue_clear(struct block_device *bdev, sector_t sector,
+ sector_t nr_sects, gfp_t gfp, unsigned long fl);
static inline int sb_issue_discard(struct super_block *sb,
sector_t block, sector_t nr_blocks)
{
--
1.6.6.1
--
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