[PATCH 11/26] scsi: sd: Use the block layer zone append emulation

Damien Le Moal
2024-02-02T07:31:23Z

Set the request queue of a TYPE_ZBC device as needing zone append
emulation by setting the device queue max_zone_append_sectors limit to
0. This enables the block layer generic implementation provided by zone
write plugging. With this, the sd driver will never see a
REQ_OP_ZONE_APPEND request and the zone append emulation code
implemented in sd_zbc.c can be removed.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
drivers/scsi/sd.c | 8 -
drivers/scsi/sd.h | 19 ---
drivers/scsi/sd_zbc.c | 335 ++----------------------------------------
3 files changed, 10 insertions(+), 352 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0833b3e6aa6e..38e4c7cb9e3d 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1233,12 +1233,6 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
}
}

- if (req_op(rq) == REQ_OP_ZONE_APPEND) {
- ret = sd_zbc_prepare_zone_append(cmd, &lba, nr_blocks);
- if (ret)
- goto fail;
- }
-
fua = rq->cmd_flags & REQ_FUA ? 0x8 : 0;
dix = scsi_prot_sg_count(cmd);
dif = scsi_host_dif_capable(cmd->device->host, sdkp->protection_type);
@@ -1321,7 +1315,6 @@ static blk_status_t sd_init_command(struct scsi_cmnd *cmd)
return sd_setup_flush_cmnd(cmd);
case REQ_OP_READ:
case REQ_OP_WRITE:
- case REQ_OP_ZONE_APPEND:
return sd_setup_read_write_cmnd(cmd);
case REQ_OP_ZONE_RESET:
return sd_zbc_setup_zone_mgmt_cmnd(cmd, ZO_RESET_WRITE_POINTER,
@@ -3792,7 +3785,6 @@ static void scsi_disk_release(struct device *dev)
struct scsi_disk *sdkp = to_scsi_disk(dev);

ida_free(&sd_index_ida, sdkp->index);
- sd_zbc_free_zone_info(sdkp);
put_device(&sdkp->device->sdev_gendev);
free_opal_dev(sdkp->opal_dev);

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 409dda5350d1..bba7ad04d1c4 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -104,12 +104,6 @@ struct scsi_disk {
* between zone starting LBAs is constant.
*/
u32 zone_starting_lba_gran;
- u32 *zones_wp_offset;
- spinlock_t zones_wp_offset_lock;
- u32 *rev_wp_offset;
- struct mutex rev_mutex;
- struct work_struct zone_wp_offset_work;
- char *zone_wp_update_buf;
#endif
atomic_t openers;
sector_t capacity; /* size in logical blocks */
@@ -242,7 +236,6 @@ static inline int sd_is_zoned(struct scsi_disk *sdkp)

#ifdef CONFIG_BLK_DEV_ZONED

-void sd_zbc_free_zone_info(struct scsi_disk *sdkp);
int sd_zbc_read_zones(struct scsi_disk *sdkp, u8 buf[SD_BUF_SIZE]);
int sd_zbc_revalidate_zones(struct scsi_disk *sdkp);
blk_status_t sd_zbc_setup_zone_mgmt_cmnd(struct scsi_cmnd *cmd,
@@ -252,13 +245,8 @@ unsigned int sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
int sd_zbc_report_zones(struct gendisk *disk, sector_t sector,
unsigned int nr_zones, report_zones_cb cb, void *data);

-blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd, sector_t *lba,
- unsigned int nr_blocks);
-
#else /* CONFIG_BLK_DEV_ZONED */

-static inline void sd_zbc_free_zone_info(struct scsi_disk *sdkp) {}
-
static inline int sd_zbc_read_zones(struct scsi_disk *sdkp, u8 buf[SD_BUF_SIZE])
{
return 0;
@@ -282,13 +270,6 @@ static inline unsigned int sd_zbc_complete(struct scsi_cmnd *cmd,
return good_bytes;
}

-static inline blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd,
- sector_t *lba,
- unsigned int nr_blocks)
-{
- return BLK_STS_TARGET;
-}
-
#define sd_zbc_report_zones NULL

#endif /* CONFIG_BLK_DEV_ZONED */
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 26af5ab7d7c1..d0ead9858954 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -23,36 +23,6 @@
#define CREATE_TRACE_POINTS
#include "sd_trace.h"

-/**
- * sd_zbc_get_zone_wp_offset - Get zone write pointer offset.
- * @zone: Zone for which to return the write pointer offset.
- *
- * Return: offset of the write pointer from the start of the zone.
- */
-static unsigned int sd_zbc_get_zone_wp_offset(struct blk_zone *zone)
-{
- if (zone->type == ZBC_ZONE_TYPE_CONV)
- return 0;
-
- switch (zone->cond) {
- case BLK_ZONE_COND_IMP_OPEN:
- case BLK_ZONE_COND_EXP_OPEN:
- case BLK_ZONE_COND_CLOSED:
- return zone->wp - zone->start;
- case BLK_ZONE_COND_FULL:
- return zone->len;
- case BLK_ZONE_COND_EMPTY:
- case BLK_ZONE_COND_OFFLINE:
- case BLK_ZONE_COND_READONLY:
- default:
- /*
- * Offline and read-only zones do not have a valid
- * write pointer. Use 0 as for an empty zone.
- */
- return 0;
- }
-}
-
/* Whether or not a SCSI zone descriptor describes a gap zone. */
static bool sd_zbc_is_gap_zone(const u8 buf[64])
{
@@ -121,9 +91,6 @@ static int sd_zbc_parse_report(struct scsi_disk *sdkp, const u8 buf[64],
if (ret)
return ret;

- if (sdkp->rev_wp_offset)
- sdkp->rev_wp_offset[idx] = sd_zbc_get_zone_wp_offset(&zone);
-
return 0;
}

@@ -347,123 +314,6 @@ static blk_status_t sd_zbc_cmnd_checks(struct scsi_cmnd *cmd)
return BLK_STS_OK;
}

-#define SD_ZBC_INVALID_WP_OFST (~0u)
-#define SD_ZBC_UPDATING_WP_OFST (SD_ZBC_INVALID_WP_OFST - 1)
-
-static int sd_zbc_update_wp_offset_cb(struct blk_zone *zone, unsigned int idx,
- void *data)
-{
- struct scsi_disk *sdkp = data;
-
- lockdep_assert_held(&sdkp->zones_wp_offset_lock);
-
- sdkp->zones_wp_offset[idx] = sd_zbc_get_zone_wp_offset(zone);
-
- return 0;
-}
-
-/*
- * An attempt to append a zone triggered an invalid write pointer error.
- * Reread the write pointer of the zone(s) in which the append failed.
- */
-static void sd_zbc_update_wp_offset_workfn(struct work_struct *work)
-{
- struct scsi_disk *sdkp;
- unsigned long flags;
- sector_t zno;
- int ret;
-
- sdkp = container_of(work, struct scsi_disk, zone_wp_offset_work);
-
- spin_lock_irqsave(&sdkp->zones_wp_offset_lock, flags);
- for (zno = 0; zno < sdkp->zone_info.nr_zones; zno++) {
- if (sdkp->zones_wp_offset[zno] != SD_ZBC_UPDATING_WP_OFST)
- continue;
-
- spin_unlock_irqrestore(&sdkp->zones_wp_offset_lock, flags);
- ret = sd_zbc_do_report_zones(sdkp, sdkp->zone_wp_update_buf,
- SD_BUF_SIZE,
- zno * sdkp->zone_info.zone_blocks, true);
- spin_lock_irqsave(&sdkp->zones_wp_offset_lock, flags);
- if (!ret)
- sd_zbc_parse_report(sdkp, sdkp->zone_wp_update_buf + 64,
- zno, sd_zbc_update_wp_offset_cb,
- sdkp);
- }
- spin_unlock_irqrestore(&sdkp->zones_wp_offset_lock, flags);
-
- scsi_device_put(sdkp->device);
-}
-
-/**
- * sd_zbc_prepare_zone_append() - Prepare an emulated ZONE_APPEND command.
- * @cmd: the command to setup
- * @lba: the LBA to patch
- * @nr_blocks: the number of LBAs to be written
- *
- * Called from sd_setup_read_write_cmnd() for REQ_OP_ZONE_APPEND.
- * @sd_zbc_prepare_zone_append() handles the necessary zone wrote locking and
- * patching of the lba for an emulated ZONE_APPEND command.
- *
- * In case the cached write pointer offset is %SD_ZBC_INVALID_WP_OFST it will
- * schedule a REPORT ZONES command and return BLK_STS_IOERR.
- */
-blk_status_t sd_zbc_prepare_zone_append(struct scsi_cmnd *cmd, sector_t *lba,
- unsigned int nr_blocks)
-{
- struct request *rq = scsi_cmd_to_rq(cmd);
- struct scsi_disk *sdkp = scsi_disk(rq->q->disk);
- unsigned int wp_offset, zno = blk_rq_zone_no(rq);
- unsigned long flags;
- blk_status_t ret;
-
- ret = sd_zbc_cmnd_checks(cmd);
- if (ret != BLK_STS_OK)
- return ret;
-
- if (!blk_rq_zone_is_seq(rq))
- return BLK_STS_IOERR;
-
- /* Unlock of the write lock will happen in sd_zbc_complete() */
- if (!blk_req_zone_write_trylock(rq))
- return BLK_STS_ZONE_RESOURCE;
-
- spin_lock_irqsave(&sdkp->zones_wp_offset_lock, flags);
- wp_offset = sdkp->zones_wp_offset[zno];
- switch (wp_offset) {
- case SD_ZBC_INVALID_WP_OFST:
- /*
- * We are about to schedule work to update a zone write pointer
- * offset, which will cause the zone append command to be
- * requeued. So make sure that the scsi device does not go away
- * while the work is being processed.
- */
- if (scsi_device_get(sdkp->device)) {
- ret = BLK_STS_IOERR;
- break;
- }
- sdkp->zones_wp_offset[zno] = SD_ZBC_UPDATING_WP_OFST;
- schedule_work(&sdkp->zone_wp_offset_work);
- fallthrough;
- case SD_ZBC_UPDATING_WP_OFST:
- ret = BLK_STS_DEV_RESOURCE;
- break;
- default:
- wp_offset = sectors_to_logical(sdkp->device, wp_offset);
- if (wp_offset + nr_blocks > sdkp->zone_info.zone_blocks) {
- ret = BLK_STS_IOERR;
- break;
- }
-
- trace_scsi_prepare_zone_append(cmd, *lba, wp_offset);
- *lba += wp_offset;
- }
- spin_unlock_irqrestore(&sdkp->zones_wp_offset_lock, flags);
- if (ret)
- blk_req_zone_write_unlock(rq);
- return ret;
-}
-
/**
* sd_zbc_setup_zone_mgmt_cmnd - Prepare a zone ZBC_OUT command. The operations
* can be RESET WRITE POINTER, OPEN, CLOSE or FINISH.
@@ -504,96 +354,6 @@ blk_status_t sd_zbc_setup_zone_mgmt_cmnd(struct scsi_cmnd *cmd,
return BLK_STS_OK;
}

-static bool sd_zbc_need_zone_wp_update(struct request *rq)
-{
- switch (req_op(rq)) {
- case REQ_OP_ZONE_APPEND:
- case REQ_OP_ZONE_FINISH:
- case REQ_OP_ZONE_RESET:
- case REQ_OP_ZONE_RESET_ALL:
- return true;
- case REQ_OP_WRITE:
- case REQ_OP_WRITE_ZEROES:
- return blk_rq_zone_is_seq(rq);
- default:
- return false;
- }
-}
-
-/**
- * sd_zbc_zone_wp_update - Update cached zone write pointer upon cmd completion
- * @cmd: Completed command
- * @good_bytes: Command reply bytes
- *
- * Called from sd_zbc_complete() to handle the update of the cached zone write
- * pointer value in case an update is needed.
- */
-static unsigned int sd_zbc_zone_wp_update(struct scsi_cmnd *cmd,
- unsigned int good_bytes)
-{
- int result = cmd->result;
- struct request *rq = scsi_cmd_to_rq(cmd);
- struct scsi_disk *sdkp = scsi_disk(rq->q->disk);
- unsigned int zno = blk_rq_zone_no(rq);
- enum req_op op = req_op(rq);
- unsigned long flags;
-
- /*
- * If we got an error for a command that needs updating the write
- * pointer offset cache, we must mark the zone wp offset entry as
- * invalid to force an update from disk the next time a zone append
- * command is issued.
- */
- spin_lock_irqsave(&sdkp->zones_wp_offset_lock, flags);
-
- if (result && op != REQ_OP_ZONE_RESET_ALL) {
- if (op == REQ_OP_ZONE_APPEND) {
- /* Force complete completion (no retry) */
- good_bytes = 0;
- scsi_set_resid(cmd, blk_rq_bytes(rq));
- }
-
- /*
- * Force an update of the zone write pointer offset on
- * the next zone append access.
- */
- if (sdkp->zones_wp_offset[zno] != SD_ZBC_UPDATING_WP_OFST)
- sdkp->zones_wp_offset[zno] = SD_ZBC_INVALID_WP_OFST;
- goto unlock_wp_offset;
- }
-
- switch (op) {
- case REQ_OP_ZONE_APPEND:
- trace_scsi_zone_wp_update(cmd, rq->__sector,
- sdkp->zones_wp_offset[zno], good_bytes);
- rq->__sector += sdkp->zones_wp_offset[zno];
- fallthrough;
- case REQ_OP_WRITE_ZEROES:
- case REQ_OP_WRITE:
- if (sdkp->zones_wp_offset[zno] < sd_zbc_zone_sectors(sdkp))
- sdkp->zones_wp_offset[zno] +=
- good_bytes >> SECTOR_SHIFT;
- break;
- case REQ_OP_ZONE_RESET:
- sdkp->zones_wp_offset[zno] = 0;
- break;
- case REQ_OP_ZONE_FINISH:
- sdkp->zones_wp_offset[zno] = sd_zbc_zone_sectors(sdkp);
- break;
- case REQ_OP_ZONE_RESET_ALL:
- memset(sdkp->zones_wp_offset, 0,
- sdkp->zone_info.nr_zones * sizeof(unsigned int));
- break;
- default:
- break;
- }
-
-unlock_wp_offset:
- spin_unlock_irqrestore(&sdkp->zones_wp_offset_lock, flags);
-
- return good_bytes;
-}
-
/**
* sd_zbc_complete - ZBC command post processing.
* @cmd: Completed command
@@ -619,11 +379,7 @@ unsigned int sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
* so be quiet about the error.
*/
rq->rq_flags |= RQF_QUIET;
- } else if (sd_zbc_need_zone_wp_update(rq))
- good_bytes = sd_zbc_zone_wp_update(cmd, good_bytes);
-
- if (req_op(rq) == REQ_OP_ZONE_APPEND)
- blk_req_zone_write_unlock(rq);
+ }

return good_bytes;
}
@@ -780,46 +536,6 @@ static void sd_zbc_print_zones(struct scsi_disk *sdkp)
sdkp->zone_info.zone_blocks);
}

-static int sd_zbc_init_disk(struct scsi_disk *sdkp)
-{
- sdkp->zones_wp_offset = NULL;
- spin_lock_init(&sdkp->zones_wp_offset_lock);
- sdkp->rev_wp_offset = NULL;
- mutex_init(&sdkp->rev_mutex);
- INIT_WORK(&sdkp->zone_wp_offset_work, sd_zbc_update_wp_offset_workfn);
- sdkp->zone_wp_update_buf = kzalloc(SD_BUF_SIZE, GFP_KERNEL);
- if (!sdkp->zone_wp_update_buf)
- return -ENOMEM;
-
- return 0;
-}
-
-void sd_zbc_free_zone_info(struct scsi_disk *sdkp)
-{
- if (!sdkp->zone_wp_update_buf)
- return;
-
- /* Serialize against revalidate zones */
- mutex_lock(&sdkp->rev_mutex);
-
- kvfree(sdkp->zones_wp_offset);
- sdkp->zones_wp_offset = NULL;
- kfree(sdkp->zone_wp_update_buf);
- sdkp->zone_wp_update_buf = NULL;
-
- sdkp->early_zone_info = (struct zoned_disk_info){ };
- sdkp->zone_info = (struct zoned_disk_info){ };
-
- mutex_unlock(&sdkp->rev_mutex);
-}
-
-static void sd_zbc_revalidate_zones_cb(struct gendisk *disk)
-{
- struct scsi_disk *sdkp = scsi_disk(disk);
-
- swap(sdkp->zones_wp_offset, sdkp->rev_wp_offset);
-}
-
/*
* Call blk_revalidate_disk_zones() if any of the zoned disk properties have
* changed that make it necessary to call that function. Called by
@@ -831,18 +547,8 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
struct request_queue *q = disk->queue;
u32 zone_blocks = sdkp->early_zone_info.zone_blocks;
unsigned int nr_zones = sdkp->early_zone_info.nr_zones;
- int ret = 0;
unsigned int flags;
-
- /*
- * For all zoned disks, initialize zone append emulation data if not
- * already done.
- */
- if (sd_is_zoned(sdkp) && !sdkp->zone_wp_update_buf) {
- ret = sd_zbc_init_disk(sdkp);
- if (ret)
- return ret;
- }
+ int ret;

/*
* There is nothing to do for regular disks, including host-aware disks
@@ -851,50 +557,32 @@ int sd_zbc_revalidate_zones(struct scsi_disk *sdkp)
if (!blk_queue_is_zoned(q))
return 0;

- /*
- * Make sure revalidate zones are serialized to ensure exclusive
- * updates of the scsi disk data.
- */
- mutex_lock(&sdkp->rev_mutex);
-
if (sdkp->zone_info.zone_blocks == zone_blocks &&
sdkp->zone_info.nr_zones == nr_zones &&
disk->nr_zones == nr_zones)
- goto unlock;
+ return 0;

- flags = memalloc_noio_save();
sdkp->zone_info.zone_blocks = zone_blocks;
sdkp->zone_info.nr_zones = nr_zones;
- sdkp->rev_wp_offset = kvcalloc(nr_zones, sizeof(u32), GFP_KERNEL);
- if (!sdkp->rev_wp_offset) {
- ret = -ENOMEM;
- memalloc_noio_restore(flags);
- goto unlock;
- }

blk_queue_chunk_sectors(q,
logical_to_sectors(sdkp->device, zone_blocks));
- blk_queue_max_zone_append_sectors(q,
- q->limits.max_segments << PAGE_SECTORS_SHIFT);

- ret = blk_revalidate_disk_zones(disk, sd_zbc_revalidate_zones_cb);
+ /* Enable block layer zone append emulation */
+ blk_queue_max_zone_append_sectors(q, 0);

+ flags = memalloc_noio_save();
+ ret = blk_revalidate_disk_zones(disk, NULL);
memalloc_noio_restore(flags);
- kvfree(sdkp->rev_wp_offset);
- sdkp->rev_wp_offset = NULL;
-
if (ret) {
sdkp->zone_info = (struct zoned_disk_info){ };
sdkp->capacity = 0;
- goto unlock;
+ return ret;
}

sd_zbc_print_zones(sdkp);

-unlock:
- mutex_unlock(&sdkp->rev_mutex);
-
- return ret;
+ return 0;
}

/**
@@ -917,10 +605,8 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, u8 buf[SD_BUF_SIZE])
if (!sd_is_zoned(sdkp)) {
/*
* Device managed or normal SCSI disk, no special handling
- * required. Nevertheless, free the disk zone information in
- * case the device type changed.
+ * required.
*/
- sd_zbc_free_zone_info(sdkp);
return 0;
}

@@ -941,7 +627,6 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, u8 buf[SD_BUF_SIZE])

/* The drive satisfies the kernel restrictions: set it up */
blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
- blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);
if (sdkp->zones_max_open == U32_MAX)
disk_set_max_open_zones(disk, 0);
else
--
2.43.0