Seagate drives report a SAME code of 0 due to having:
  - Zones of different types (CMR zones at the low LBA space).
  - Zones of different size (A terminating 'runt' zone in the high
    lba space).

Support loading the zone topology into the zone cache.

Signed-off-by: Shaun Tancheff <shaun.tanch...@seagate.com>
---
 drivers/scsi/sd.c      |  22 +++---
 drivers/scsi/sd.h      |  20 ++++--
 drivers/scsi/sd_zbc.c  | 183 +++++++++++++++++++++++++++++++++++--------------
 include/linux/blkdev.h |  16 +++--
 4 files changed, 170 insertions(+), 71 deletions(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 059a57f..7903e21 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -693,8 +693,13 @@ static void sd_config_discard(struct scsi_disk *sdkp, 
unsigned int mode)
                break;
 
        case SD_ZBC_RESET_WP:
-               max_blocks = sdkp->unmap_granularity;
                q->limits.discard_zeroes_data = 1;
+               q->limits.discard_granularity =
+                       sd_zbc_discard_granularity(sdkp);
+
+               max_blocks = min_not_zero(sdkp->unmap_granularity,
+                                         q->limits.discard_granularity >>
+                                               ilog2(logical_block_size));
                break;
 
        case SD_LBP_ZERO:
@@ -1955,13 +1960,12 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                        good_bytes = blk_rq_bytes(req);
                        scsi_set_resid(SCpnt, 0);
                } else {
-#ifdef CONFIG_SCSI_ZBC
                        if (op == ZBC_OUT)
                                /* RESET WRITE POINTER failed */
                                sd_zbc_update_zones(sdkp,
                                                    blk_rq_pos(req),
-                                                   512, true);
-#endif
+                                                   512, SD_ZBC_RESET_WP_ERR);
+
                        good_bytes = 0;
                        scsi_set_resid(SCpnt, blk_rq_bytes(req));
                }
@@ -2034,7 +2038,6 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                                good_bytes = blk_rq_bytes(req);
                                scsi_set_resid(SCpnt, 0);
                        }
-#ifdef CONFIG_SCSI_ZBC
                        /*
                         * ZBC: Unaligned write command.
                         * Write did not start a write pointer position.
@@ -2042,8 +2045,7 @@ static int sd_done(struct scsi_cmnd *SCpnt)
                        if (sshdr.ascq == 0x04)
                                sd_zbc_update_zones(sdkp,
                                                    blk_rq_pos(req),
-                                                   512, true);
-#endif
+                                                   512, SD_ZBC_WRITE_ERR);
                }
                break;
        default:
@@ -2270,7 +2272,7 @@ static void sd_read_zones(struct scsi_disk *sdkp, 
unsigned char *buffer)
         * supports equal zone sizes.
         */
        same = buffer[4] & 0xf;
-       if (same == 0 || same > 3) {
+       if (same > 3) {
                sd_printk(KERN_WARNING, sdkp,
                          "REPORT ZONES SAME type %d not supported\n", same);
                return;
@@ -2282,9 +2284,9 @@ static void sd_read_zones(struct scsi_disk *sdkp, 
unsigned char *buffer)
        sdkp->unmap_granularity = zone_len;
        blk_queue_chunk_sectors(sdkp->disk->queue,
                                logical_to_sectors(sdkp->device, zone_len));
-       sd_config_discard(sdkp, SD_ZBC_RESET_WP);
 
-       sd_zbc_setup(sdkp, buffer, SD_BUF_SIZE);
+       sd_zbc_setup(sdkp, zone_len, buffer, SD_BUF_SIZE);
+       sd_config_discard(sdkp, SD_ZBC_RESET_WP);
 }
 
 static void read_capacity_error(struct scsi_disk *sdkp, struct scsi_device 
*sdp,
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 6ae4505..ef6c132 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -283,19 +283,24 @@ static inline void sd_dif_complete(struct scsi_cmnd *cmd, 
unsigned int a)
 
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
+
+#define SD_ZBC_INIT            0
+#define SD_ZBC_RESET_WP_ERR    1
+#define SD_ZBC_WRITE_ERR       2
+
 #ifdef CONFIG_SCSI_ZBC
 
 extern int sd_zbc_report_zones(struct scsi_disk *, unsigned char *, int,
                               sector_t, enum zbc_zone_reporting_options, bool);
-extern int sd_zbc_setup(struct scsi_disk *, char *, int);
+extern int sd_zbc_setup(struct scsi_disk *, u64 zlen, char *buf, int buf_len);
 extern void sd_zbc_remove(struct scsi_disk *);
 extern void sd_zbc_reset_zones(struct scsi_disk *);
 extern int sd_zbc_setup_discard(struct scsi_disk *, struct request *,
                                sector_t, unsigned int);
 extern int sd_zbc_setup_read_write(struct scsi_disk *, struct request *,
                                   sector_t, unsigned int *);
-extern void sd_zbc_update_zones(struct scsi_disk *, sector_t, int, bool);
-extern void sd_zbc_refresh_zone_work(struct work_struct *);
+extern void sd_zbc_update_zones(struct scsi_disk *, sector_t, int, int reason);
+extern unsigned int sd_zbc_discard_granularity(struct scsi_disk *sdkp);
 
 #else /* CONFIG_SCSI_ZBC */
 
@@ -308,7 +313,7 @@ static inline int sd_zbc_report_zones(struct scsi_disk 
*sdkp,
        return -EOPNOTSUPP;
 }
 
-static inline int sd_zbc_setup(struct scsi_disk *sdkp,
+static inline int sd_zbc_setup(struct scsi_disk *sdkp, u64 zlen,
                               unsigned char *buf, int buf_len)
 {
        return 0;
@@ -328,6 +333,13 @@ static inline int sd_zbc_setup_read_write(struct scsi_disk 
*sdkp,
        return BLKPREP_OK;
 }
 
+static inline unsigned int sd_zbc_discard_granularity(struct scsi_disk *sdkp)
+{
+       return sdkp->device->sector_size;
+}
+
+static inline void sd_zbc_update_zones(struct scsi_disk *sdkp, sector_t s,
+                                      int buf_sz, int reason) {}
 static inline void sd_zbc_remove(struct scsi_disk *sdkp) {}
 #endif /* CONFIG_SCSI_ZBC */
 
diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index f953d16..17414fb 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -36,17 +36,6 @@
 #include "sd.h"
 #include "scsi_priv.h"
 
-enum zbc_zone_cond {
-       ZBC_ZONE_COND_NO_WP,
-       ZBC_ZONE_COND_EMPTY,
-       ZBC_ZONE_COND_IMPLICIT_OPEN,
-       ZBC_ZONE_COND_EXPLICIT_OPEN,
-       ZBC_ZONE_COND_CLOSED,
-       ZBC_ZONE_COND_READONLY = 0xd,
-       ZBC_ZONE_COND_FULL,
-       ZBC_ZONE_COND_OFFLINE,
-};
-
 #define SD_ZBC_BUF_SIZE 524288
 
 #define sd_zbc_debug(sdkp, fmt, args...)                               \
@@ -69,10 +58,10 @@ struct zbc_update_work {
        char            zone_buf[0];
 };
 
+static
 struct blk_zone *zbc_desc_to_zone(struct scsi_disk *sdkp, unsigned char *rec)
 {
        struct blk_zone *zone;
-       enum zbc_zone_cond zone_cond;
        sector_t wp = (sector_t)-1;
 
        zone = kzalloc(sizeof(struct blk_zone), GFP_KERNEL);
@@ -81,37 +70,27 @@ struct blk_zone *zbc_desc_to_zone(struct scsi_disk *sdkp, 
unsigned char *rec)
 
        spin_lock_init(&zone->lock);
        zone->type = rec[0] & 0xf;
-       zone_cond = (rec[1] >> 4) & 0xf;
+       zone->state = (rec[1] >> 4) & 0xf;
        zone->len = logical_to_sectors(sdkp->device,
                                       get_unaligned_be64(&rec[8]));
        zone->start = logical_to_sectors(sdkp->device,
                                         get_unaligned_be64(&rec[16]));
 
-       if (blk_zone_is_smr(zone)) {
+       if (blk_zone_is_smr(zone))
                wp = logical_to_sectors(sdkp->device,
                                        get_unaligned_be64(&rec[24]));
-               if (zone_cond == ZBC_ZONE_COND_READONLY) {
-                       zone->state = BLK_ZONE_READONLY;
-               } else if (zone_cond == ZBC_ZONE_COND_OFFLINE) {
-                       zone->state = BLK_ZONE_OFFLINE;
-               } else {
-                       zone->state = BLK_ZONE_OPEN;
-               }
-       } else
-               zone->state = BLK_ZONE_NO_WP;
-
        zone->wp = wp;
        /*
         * Fixup block zone state
         */
-       if (zone_cond == ZBC_ZONE_COND_EMPTY &&
+       if (zone->state == BLK_ZONE_EMPTY &&
            zone->wp != zone->start) {
                sd_zbc_debug(sdkp,
                             "zone %zu state EMPTY wp %zu: adjust wp\n",
                             zone->start, zone->wp);
                zone->wp = zone->start;
        }
-       if (zone_cond == ZBC_ZONE_COND_FULL &&
+       if (zone->state == BLK_ZONE_FULL &&
            zone->wp != zone->start + zone->len) {
                sd_zbc_debug(sdkp,
                             "zone %zu state FULL wp %zu: adjust wp\n",
@@ -122,7 +101,8 @@ struct blk_zone *zbc_desc_to_zone(struct scsi_disk *sdkp, 
unsigned char *rec)
        return zone;
 }
 
-sector_t zbc_parse_zones(struct scsi_disk *sdkp, unsigned char *buf,
+static
+sector_t zbc_parse_zones(struct scsi_disk *sdkp, u64 zlen, unsigned char *buf,
                         unsigned int buf_len)
 {
        struct request_queue *q = sdkp->disk->queue;
@@ -149,6 +129,11 @@ sector_t zbc_parse_zones(struct scsi_disk *sdkp, unsigned 
char *buf,
                if (!this)
                        break;
 
+               if (same == 0 && this->len != zlen) {
+                       next_sector = this->start + this->len;
+                       break;
+               }
+
                next_sector = this->start + this->len;
                old = blk_insert_zone(q, this);
                if (old) {
@@ -171,29 +156,58 @@ sector_t zbc_parse_zones(struct scsi_disk *sdkp, unsigned 
char *buf,
        return next_sector;
 }
 
-void sd_zbc_refresh_zone_work(struct work_struct *work)
+static void sd_zbc_refresh_zone_work(struct work_struct *work)
 {
        struct zbc_update_work *zbc_work =
                container_of(work, struct zbc_update_work, zone_work);
        struct scsi_disk *sdkp = zbc_work->sdkp;
        struct request_queue *q = sdkp->disk->queue;
-       unsigned int zone_buflen;
+       unsigned char *zone_buf = zbc_work->zone_buf;
+       unsigned int zone_buflen = zbc_work->zone_buflen;
        int ret;
+       u8 same;
+       u64 zlen = 0;
        sector_t last_sector;
        sector_t capacity = logical_to_sectors(sdkp->device, sdkp->capacity);
 
-       zone_buflen = zbc_work->zone_buflen;
-       ret = sd_zbc_report_zones(sdkp, zbc_work->zone_buf, zone_buflen,
+       ret = sd_zbc_report_zones(sdkp, zone_buf, zone_buflen,
                                  zbc_work->zone_sector,
                                  ZBC_ZONE_REPORTING_OPTION_ALL, true);
        if (ret)
                goto done_free;
 
-       last_sector = zbc_parse_zones(sdkp, zbc_work->zone_buf, zone_buflen);
+       /* this whole path is unlikely so extra reports shouldn't be a
+        * large impact */
+       same = zone_buf[4] & 0xf;
+       if (same == 0) {
+               unsigned char *desc = &zone_buf[64];
+               unsigned int blen = zone_buflen;
+
+               /* just pull the first zone */
+               if (blen > 512)
+                       blen = 512;
+               ret = sd_zbc_report_zones(sdkp, zone_buf, blen, 0,
+                                         ZBC_ZONE_REPORTING_OPTION_ALL, true);
+               if (ret)
+                       goto done_free;
+
+               /* Read the zone length from the first zone descriptor */
+               zlen = logical_to_sectors(sdkp->device,
+                                         get_unaligned_be64(&desc[8]));
+
+               ret = sd_zbc_report_zones(sdkp, zone_buf, zone_buflen,
+                                         zbc_work->zone_sector,
+                                         ZBC_ZONE_REPORTING_OPTION_ALL, true);
+               if (ret)
+                       goto done_free;
+       }
+
+       last_sector = zbc_parse_zones(sdkp, zlen, zone_buf, zone_buflen);
+       capacity = logical_to_sectors(sdkp->device, sdkp->capacity);
        if (last_sector != -1 && last_sector < capacity) {
                if (test_bit(SD_ZBC_ZONE_RESET, &sdkp->zone_flags)) {
                        sd_zbc_debug(sdkp,
-                                    "zones in reset, cancelling refresh\n");
+                                    "zones in reset, canceling refresh\n");
                        ret = -EAGAIN;
                        goto done_free;
                }
@@ -207,7 +221,7 @@ done_free:
        kfree(zbc_work);
        if (test_and_clear_bit(SD_ZBC_ZONE_INIT, &sdkp->zone_flags) && ret) {
                sd_zbc_debug(sdkp,
-                            "Cancelling zone initialisation\n");
+                            "Canceling zone initialization\n");
        }
 done_start_queue:
        if (q->mq_ops)
@@ -226,10 +240,10 @@ done_start_queue:
  * @sdkp: SCSI disk for which the zone information needs to be updated
  * @sector: sector to be updated
  * @bufsize: buffersize to be allocated
- * @update: true if existing zones should be updated
+ * @reason: non-zero if existing zones should be updated
  */
 void sd_zbc_update_zones(struct scsi_disk *sdkp, sector_t sector, int bufsize,
-                        bool update)
+                        int reason)
 {
        struct request_queue *q = sdkp->disk->queue;
        struct zbc_update_work *zbc_work;
@@ -240,13 +254,24 @@ void sd_zbc_update_zones(struct scsi_disk *sdkp, sector_t 
sector, int bufsize,
 
        if (test_bit(SD_ZBC_ZONE_RESET, &sdkp->zone_flags)) {
                sd_zbc_debug(sdkp,
-                            "zones in reset, not starting update\n");
+                            "zones in reset, not starting reason\n");
                return;
        }
 
+       if (reason != SD_ZBC_INIT) {
+               /* lookup sector, is zone pref? then ignore */
+               struct blk_zone *zone = blk_lookup_zone(q, sector);
+
+               if (reason == SD_ZBC_RESET_WP)
+                       sd_zbc_debug(sdkp, "RESET WP failed %lx\n", sector);
+
+               if (zone && blk_zone_is_seq_pref(zone))
+                       return;
+       }
+
 retry:
        zbc_work = kzalloc(sizeof(struct zbc_update_work) + bufsize,
-                          update ? GFP_NOWAIT : GFP_KERNEL);
+                          reason != SD_ZBC_INIT ? GFP_NOWAIT : GFP_KERNEL);
        if (!zbc_work) {
                if (bufsize > 512) {
                        sd_zbc_debug(sdkp,
@@ -256,7 +281,7 @@ retry:
                }
                sd_zbc_debug(sdkp,
                             "failed to allocate %d bytes\n", bufsize);
-               if (!update)
+               if (reason == SD_ZBC_INIT)
                        clear_bit(SD_ZBC_ZONE_INIT, &sdkp->zone_flags);
                return;
        }
@@ -269,7 +294,7 @@ retry:
        /*
         * Mark zones under update as BUSY
         */
-       if (update) {
+       if (reason != SD_ZBC_INIT) {
                for (node = rb_first(&q->zones); node; node = rb_next(node)) {
                        unsigned long flags;
 
@@ -333,8 +358,7 @@ int sd_zbc_report_zones(struct scsi_disk *sdkp, unsigned 
char *buffer,
        if (!scsi_device_online(sdp))
                return -ENODEV;
 
-       sd_zbc_debug(sdkp, "REPORT ZONES lba %zu len %d\n",
-                    start_lba, bufflen);
+       sd_zbc_debug(sdkp, "REPORT ZONES lba %zu len %d\n", start_lba, bufflen);
 
        memset(cmd, 0, 16);
        cmd[0] = ZBC_IN;
@@ -460,9 +484,37 @@ int sd_zbc_setup_read_write(struct scsi_disk *sdkp, struct 
request *rq,
                goto out;
        }
 
-       if (req_op(rq) == REQ_OP_WRITE || req_op(rq) == REQ_OP_WRITE_SAME) {
-               if (zone->type != BLK_ZONE_TYPE_SEQWRITE_REQ)
-                       goto out;
+       if (blk_zone_is_cmr(zone))
+               goto out;
+
+       if (blk_zone_is_seq_pref(zone)) {
+               if (op_is_write(req_op(rq))) {
+                       u64 nwp = sector + sectors;
+
+                       while (nwp > (zone->start + zone->len)) {
+                               struct rb_node *node = rb_next(&zone->node);
+
+                               zone->wp = zone->start + zone->len;
+                               sector = zone->wp;
+                               sectors = nwp - zone->wp;
+                               spin_unlock_irqrestore(&zone->lock, flags);
+
+                               if (!node)
+                                       return BLKPREP_OK;
+                               zone = rb_entry(node, struct blk_zone, node);
+                               if (!zone)
+                                       return BLKPREP_OK;
+
+                               spin_lock_irqsave(&zone->lock, flags);
+                               nwp = sector + sectors;
+                       }
+                       if (nwp > zone->wp)
+                               zone->wp = nwp;
+               }
+               goto out;
+       }
+
+       if (op_is_write(req_op(rq))) {
                if (zone->state == BLK_ZONE_READONLY)
                        goto out;
                if (blk_zone_is_full(zone)) {
@@ -480,8 +532,7 @@ int sd_zbc_setup_read_write(struct scsi_disk *sdkp, struct 
request *rq,
                        goto out;
                }
                zone->wp += sectors;
-       } else if (zone->type == BLK_ZONE_TYPE_SEQWRITE_REQ &&
-                  zone->wp <= sector + sectors) {
+       } else if (zone->wp <= sector + sectors) {
                if (zone->wp <= sector) {
                        /* Read beyond WP: clear request buffer */
                        struct req_iterator iter;
@@ -513,14 +564,18 @@ out:
        return ret;
 }
 
-int sd_zbc_setup(struct scsi_disk *sdkp, char *buf, int buf_len)
+/**
+ * sd_zbc_setup - Load zones of matching zlen size into rb tree.
+ *
+ */
+int sd_zbc_setup(struct scsi_disk *sdkp, u64 zlen, char *buf, int buf_len)
 {
        sector_t capacity = logical_to_sectors(sdkp->device, sdkp->capacity);
        sector_t last_sector;
 
        if (test_and_set_bit(SD_ZBC_ZONE_INIT, &sdkp->zone_flags)) {
                sdev_printk(KERN_WARNING, sdkp->device,
-                           "zone initialisation already running\n");
+                           "zone initialization already running\n");
                return 0;
        }
 
@@ -539,15 +594,20 @@ int sd_zbc_setup(struct scsi_disk *sdkp, char *buf, int 
buf_len)
                clear_bit(SD_ZBC_ZONE_RESET, &sdkp->zone_flags);
        }
 
-       last_sector = zbc_parse_zones(sdkp, buf, buf_len);
+       last_sector = zbc_parse_zones(sdkp, zlen, buf, buf_len);
+       capacity = logical_to_sectors(sdkp->device, sdkp->capacity);
        if (last_sector != -1 && last_sector < capacity) {
-               sd_zbc_update_zones(sdkp, last_sector, SD_ZBC_BUF_SIZE, false);
+               sd_zbc_update_zones(sdkp, last_sector,
+                                   SD_ZBC_BUF_SIZE, SD_ZBC_INIT);
        } else
                clear_bit(SD_ZBC_ZONE_INIT, &sdkp->zone_flags);
 
        return 0;
 }
 
+/**
+ * sd_zbc_remove -
+ */
 void sd_zbc_remove(struct scsi_disk *sdkp)
 {
        if (sdkp->zone_work_q) {
@@ -557,3 +617,24 @@ void sd_zbc_remove(struct scsi_disk *sdkp)
                destroy_workqueue(sdkp->zone_work_q);
        }
 }
+/**
+ * sd_zbc_discard_granularity - Determine discard granularity.
+ * @sdkp: SCSI disk used to calculate discard granularity.
+ *
+ * Discard granularity should match the (maximum non-CMR) zone
+ * size reported on the drive.
+ */
+unsigned int sd_zbc_discard_granularity(struct scsi_disk *sdkp)
+{
+       unsigned int bytes = 1;
+       struct request_queue *q = sdkp->disk->queue;
+       struct rb_node *node = rb_first(&q->zones);
+
+       if (node) {
+               struct blk_zone *zone = rb_entry(node, struct blk_zone, node);
+
+               bytes = zone->len;
+       }
+       bytes <<= ilog2(sdkp->device->sector_size);
+       return bytes;
+}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 9084a9e..68198eb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -272,12 +272,16 @@ enum blk_zone_type {
 };
 
 enum blk_zone_state {
-       BLK_ZONE_UNKNOWN,
        BLK_ZONE_NO_WP,
+       BLK_ZONE_EMPTY,
        BLK_ZONE_OPEN,
-       BLK_ZONE_READONLY,
+       BLK_ZONE_OPEN_EXPLICIT,
+       BLK_ZONE_CLOSED,
+       BLK_ZONE_UNKNOWN = 5,
+       BLK_ZONE_READONLY = 0xd,
+       BLK_ZONE_FULL,
        BLK_ZONE_OFFLINE,
-       BLK_ZONE_BUSY,
+       BLK_ZONE_BUSY = 0x20,
 };
 
 struct blk_zone {
@@ -291,9 +295,9 @@ struct blk_zone {
        void *private_data;
 };
 
-#define blk_zone_is_smr(z) ((z)->type == BLK_ZONE_TYPE_SEQWRITE_REQ || \
-                           (z)->type == BLK_ZONE_TYPE_SEQWRITE_PREF)
-
+#define blk_zone_is_seq_req(z) ((z)->type == BLK_ZONE_TYPE_SEQWRITE_REQ)
+#define blk_zone_is_seq_pref(z) ((z)->type == BLK_ZONE_TYPE_SEQWRITE_PREF)
+#define blk_zone_is_smr(z) (blk_zone_is_seq_req(z) || blk_zone_is_seq_pref(z))
 #define blk_zone_is_cmr(z) ((z)->type == BLK_ZONE_TYPE_CONVENTIONAL)
 #define blk_zone_is_full(z) ((z)->wp == (z)->start + (z)->len)
 #define blk_zone_is_empty(z) ((z)->wp == (z)->start)
-- 
2.9.3

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