[dm-devel] [PATCH 4/4] block: Generically handle report zones buffer
Damien Le Moal
damien.lemoal at wdc.com
Thu Oct 24 06:50:06 UTC 2019
Instead of relying on a zoned block device driver to allocate a buffer
for every execution of a report zones command execution, rely on the
block layer use of the device zone report queue limits to allocate a
buffer and keep it around when the device report_zones method is
executed in a loop, e.g. as in blk_revalidate_disk_zones().
This simplifies the code in the scsi sd_zbc driver as well as simplify
the addition of zone supports for upcoming new zoned device drivers.
Signed-off-by: Damien Le Moal <damien.lemoal at wdc.com>
---
block/blk-zoned.c | 99 ++++++++++++++++++++--------------
drivers/block/null_blk.h | 6 ++-
drivers/block/null_blk_zoned.c | 3 +-
drivers/md/dm.c | 3 +-
drivers/scsi/sd.h | 3 +-
drivers/scsi/sd_zbc.c | 61 ++++++---------------
include/linux/blkdev.h | 8 +--
7 files changed, 88 insertions(+), 95 deletions(-)
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 43bfd1be0985..6bddaa505df0 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -97,6 +97,29 @@ unsigned int blkdev_nr_zones(struct block_device *bdev)
}
EXPORT_SYMBOL_GPL(blkdev_nr_zones);
+/*
+ * Allocate a buffer to execute report zones.
+ */
+static void *blk_alloc_report_buffer(struct request_queue *q,
+ unsigned int *nr_zones, size_t *buflen)
+{
+ unsigned int nrz = *nr_zones;
+ size_t bufsize = nrz * q->limits.zone_descriptor_size;
+ void *buf;
+
+ if (q->limits.zones_report_granularity)
+ bufsize = roundup(bufsize, q->limits.zones_report_granularity);
+ bufsize = min_t(size_t, bufsize, q->limits.max_zones_report_size);
+ buf = vzalloc(bufsize);
+ if (buf) {
+ *buflen = bufsize;
+ *nr_zones = min_t(unsigned int, nrz,
+ bufsize / q->limits.zone_descriptor_size);
+ }
+
+ return buf;
+}
+
/*
* Check that a zone report belongs to this partition, and if yes, fix its start
* sector and write pointer and return true. Return false otherwise.
@@ -140,7 +163,10 @@ int blkdev_report_zones(struct block_device *bdev, sector_t sector,
{
struct request_queue *q = bdev_get_queue(bdev);
struct gendisk *disk = bdev->bd_disk;
- unsigned int i, nrz;
+ unsigned int i, nrz = *nr_zones;
+ sector_t capacity = bdev->bd_part->nr_sects;
+ size_t buflen = 0;
+ void *buf = NULL;
int ret;
if (!blk_queue_is_zoned(q))
@@ -154,27 +180,33 @@ int blkdev_report_zones(struct block_device *bdev, sector_t sector,
if (WARN_ON_ONCE(!disk->fops->report_zones))
return -EOPNOTSUPP;
- if (!*nr_zones || sector >= bdev->bd_part->nr_sects) {
+ if (!nrz || sector >= capacity) {
*nr_zones = 0;
return 0;
}
- nrz = min(*nr_zones,
- __blkdev_nr_zones(q, bdev->bd_part->nr_sects - sector));
- ret = disk->fops->report_zones(disk, get_start_sect(bdev) + sector,
- zones, &nrz);
+ nrz = min(nrz, __blkdev_nr_zones(q, capacity - sector));
+ if (q->limits.zone_descriptor_size) {
+ buf = blk_alloc_report_buffer(q, &nrz, &buflen);
+ if (!buf)
+ return -ENOMEM;
+ }
+
+ ret = disk->fops->report_zones(disk, sector, zones, &nrz, buf, buflen);
if (ret)
- return ret;
+ goto out;
for (i = 0; i < nrz; i++) {
if (!blkdev_report_zone(bdev, zones))
break;
zones++;
}
-
*nr_zones = i;
- return 0;
+out:
+ kvfree(buf);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(blkdev_report_zones);
@@ -384,31 +416,6 @@ static inline unsigned long *blk_alloc_zone_bitmap(int node,
GFP_NOIO, node);
}
-/*
- * Allocate an array of struct blk_zone to get nr_zones zone information.
- * The allocated array may be smaller than nr_zones.
- */
-static struct blk_zone *blk_alloc_zones(unsigned int *nr_zones)
-{
- struct blk_zone *zones;
- size_t nrz = min(*nr_zones, BLK_ZONED_REPORT_MAX_ZONES);
-
- /*
- * GFP_KERNEL here is meaningless as the caller task context has
- * the PF_MEMALLOC_NOIO flag set in blk_revalidate_disk_zones()
- * with memalloc_noio_save().
- */
- zones = kvcalloc(nrz, sizeof(struct blk_zone), GFP_KERNEL);
- if (!zones) {
- *nr_zones = 0;
- return NULL;
- }
-
- *nr_zones = nrz;
-
- return zones;
-}
-
void blk_queue_free_zone_bitmaps(struct request_queue *q)
{
kfree(q->seq_zones_bitmap);
@@ -482,10 +489,12 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
struct request_queue *q = disk->queue;
unsigned int nr_zones = __blkdev_nr_zones(q, get_capacity(disk));
unsigned long *seq_zones_wlock = NULL, *seq_zones_bitmap = NULL;
- unsigned int i, rep_nr_zones = 0, z = 0, nrz;
+ unsigned int i, rep_nr_zones, z = 0, nrz;
struct blk_zone *zones = NULL;
unsigned int noio_flag;
sector_t sector = 0;
+ size_t buflen = 0;
+ void *buf = NULL;
int ret = 0;
/*
@@ -518,17 +527,28 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
goto out;
/*
- * Get zone information to check the zones and initialize
- * seq_zones_bitmap.
+ * Allocate a report buffer for the driver execution of report zones
+ * and an array of zones to get the report back.
*/
rep_nr_zones = nr_zones;
- zones = blk_alloc_zones(&rep_nr_zones);
+ if (q->limits.zone_descriptor_size) {
+ buf = blk_alloc_report_buffer(q, &rep_nr_zones, &buflen);
+ if (!buf)
+ goto out;
+ }
+
+ zones = kvcalloc(rep_nr_zones, sizeof(struct blk_zone), GFP_KERNEL);
if (!zones)
goto out;
+ /*
+ * Get zone information to check the zones and initialize
+ * seq_zones_bitmap.
+ */
while (z < nr_zones) {
nrz = min(nr_zones - z, rep_nr_zones);
- ret = disk->fops->report_zones(disk, sector, zones, &nrz);
+ ret = disk->fops->report_zones(disk, sector, zones, &nrz,
+ buf, buflen);
if (ret)
goto out;
if (!nrz)
@@ -565,6 +585,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk)
memalloc_noio_restore(noio_flag);
kvfree(zones);
+ kvfree(buf);
kfree(seq_zones_wlock);
kfree(seq_zones_bitmap);
diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
index 93c2a3d403da..6bd0482ec683 100644
--- a/drivers/block/null_blk.h
+++ b/drivers/block/null_blk.h
@@ -92,7 +92,8 @@ struct nullb {
int null_zone_init(struct nullb_device *dev);
void null_zone_exit(struct nullb_device *dev);
int null_zone_report(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones);
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen);
blk_status_t null_handle_zoned(struct nullb_cmd *cmd,
enum req_opf op, sector_t sector,
sector_t nr_sectors);
@@ -107,7 +108,8 @@ static inline int null_zone_init(struct nullb_device *dev)
static inline void null_zone_exit(struct nullb_device *dev) {}
static inline int null_zone_report(struct gendisk *disk, sector_t sector,
struct blk_zone *zones,
- unsigned int *nr_zones)
+ unsigned int *nr_zones,
+ void *buf, size_t buflen)
{
return -EOPNOTSUPP;
}
diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
index 4e56b17ed3ef..446e083be240 100644
--- a/drivers/block/null_blk_zoned.c
+++ b/drivers/block/null_blk_zoned.c
@@ -67,7 +67,8 @@ void null_zone_exit(struct nullb_device *dev)
}
int null_zone_report(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones)
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen)
{
struct nullb *nullb = disk->private_data;
struct nullb_device *dev = nullb->dev;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 647aa5b0233b..5d5a297ceeb1 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -441,7 +441,8 @@ static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
}
static int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones)
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen)
{
#ifdef CONFIG_BLK_DEV_ZONED
struct mapped_device *md = disk->private_data;
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 1eab779f812b..b948656b6882 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -213,7 +213,8 @@ extern blk_status_t sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd, bool all);
extern void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
struct scsi_sense_hdr *sshdr);
extern int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones);
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen);
#else /* CONFIG_BLK_DEV_ZONED */
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 8dc96f4ea920..228522c4338f 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -104,35 +104,6 @@ static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
return 0;
}
-/**
- * Allocate a buffer for report zones reply.
- * @sdkp: The target disk
- * @nr_zones: Maximum number of zones to report
- * @buflen: Size of the buffer allocated
- *
- * Try to allocate a reply buffer for the number of requested zones.
- * The size of the buffer allocated may be smaller than requested to
- * satify the device constraint (max_hw_sectors, max_segments, etc).
- *
- * Return the address of the allocated buffer and update @buflen with
- * the size of the allocated buffer.
- */
-static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
- unsigned int nr_zones, size_t *buflen)
-{
- struct request_queue *q = sdkp->disk->queue;
- size_t bufsize;
- void *buf;
-
- bufsize = min_t(size_t, roundup(nr_zones * 64, SECTOR_SIZE),
- q->limits.max_zones_report_size);
- buf = vzalloc(bufsize);
- if (buf)
- *buflen = bufsize;
-
- return buf;
-}
-
/**
* sd_zbc_report_zones - Disk report zones operation.
* @disk: The target disk
@@ -143,40 +114,40 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp,
* Execute a report zones command on the target disk.
*/
int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones)
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen)
{
struct scsi_disk *sdkp = scsi_disk(disk);
unsigned int i, nrz = *nr_zones;
- unsigned char *buf;
- size_t buflen = 0, offset = 0;
- int ret = 0;
+ unsigned char *rep_buf = buf;
+ size_t offset = 0;
+ int ret;
if (!sd_is_zoned(sdkp))
/* Not a zoned device */
return -EOPNOTSUPP;
- buf = sd_zbc_alloc_report_buffer(sdkp, nrz, &buflen);
- if (!buf)
- return -ENOMEM;
-
- ret = sd_zbc_do_report_zones(sdkp, buf, buflen,
+ /*
+ * The buffer prepared by the block layer may be too large for the
+ * number of zones requested. Tune it here to avoid requesting too
+ * many zones than necessary.
+ */
+ buflen = min_t(size_t, roundup((nrz + 1) * 64, SECTOR_SIZE), buflen);
+ ret = sd_zbc_do_report_zones(sdkp, rep_buf, buflen,
sectors_to_logical(sdkp->device, sector), true);
if (ret)
- goto out;
+ return ret;
- nrz = min(nrz, get_unaligned_be32(&buf[0]) / 64);
+ nrz = min(nrz, get_unaligned_be32(&rep_buf[0]) / 64);
for (i = 0; i < nrz; i++) {
offset += 64;
- sd_zbc_parse_report(sdkp, buf + offset, zones);
+ sd_zbc_parse_report(sdkp, rep_buf + offset, zones);
zones++;
}
*nr_zones = nrz;
-out:
- kvfree(buf);
-
- return ret;
+ return 0;
}
/**
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1c76d71fc232..f04927a7fb40 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -355,11 +355,6 @@ struct queue_limits {
#ifdef CONFIG_BLK_DEV_ZONED
-/*
- * Maximum number of zones to report with a single report zones command.
- */
-#define BLK_ZONED_REPORT_MAX_ZONES 8192U
-
extern unsigned int blkdev_nr_zones(struct block_device *bdev);
extern int blkdev_report_zones(struct block_device *bdev,
sector_t sector, struct blk_zone *zones,
@@ -1713,7 +1708,8 @@ struct block_device_operations {
/* this callback is with swap_lock and sometimes page table lock held */
void (*swap_slot_free_notify) (struct block_device *, unsigned long);
int (*report_zones)(struct gendisk *, sector_t sector,
- struct blk_zone *zones, unsigned int *nr_zones);
+ struct blk_zone *zones, unsigned int *nr_zones,
+ void *buf, size_t buflen);
struct module *owner;
const struct pr_ops *pr_ops;
};
--
2.21.0
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