Re: [PATCH V8 6/7] sd_zbc: Initialize device request queue zoned data

[Martin K. Petersen]

Damien,

> Initialize the seq_zones_bitmap, seq_zones_wlock and nr_zones fields
> of the disk request queue on disk revalidate. As the seq_zones_bitmap
> and seq_zones_wlock allocations are identical, introduce the helper
> sd_zbc_alloc_zone_bitmap(). Using this helper, reallocate the bitmaps
> whenever the disk capacity (number of zones) changes.

Reviewed-by: Martin K. Petersen 

-- 
Martin K. Petersen  Oracle Linux Engineering

[PATCH V8 6/7] sd_zbc: Initialize device request queue zoned data

[Damien Le Moal]

Initialize the seq_zones_bitmap, seq_zones_wlock and nr_zones fields of
the disk request queue on disk revalidate. As the seq_zones_bitmap
and seq_zones_wlock allocations are identical, introduce the helper
sd_zbc_alloc_zone_bitmap(). Using this helper, reallocate the bitmaps
whenever the disk capacity (number of zones) changes.

Signed-off-by: Damien Le Moal 
---
 drivers/scsi/sd_zbc.c | 152 +++---
 1 file changed, 144 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 27793b9f54c0..c715b8363ce0 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -586,8 +586,123 @@ static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
return 0;
 }
 
+/**
+ * sd_zbc_alloc_zone_bitmap - Allocate a zone bitmap (one bit per zone).
+ * @sdkp: The disk of the bitmap
+ */
+static inline unsigned long *sd_zbc_alloc_zone_bitmap(struct scsi_disk *sdkp)
+{
+   struct request_queue *q = sdkp->disk->queue;
+
+   return kzalloc_node(BITS_TO_LONGS(sdkp->nr_zones)
+   * sizeof(unsigned long),
+   GFP_KERNEL, q->node);
+}
+
+/**
+ * sd_zbc_get_seq_zones - Parse report zones reply to identify sequential zones
+ * @sdkp: disk used
+ * @buf: report reply buffer
+ * @seq_zone_bitamp: bitmap of sequential zones to set
+ *
+ * Parse reported zone descriptors in @buf to identify sequential zones and
+ * set the reported zone bit in @seq_zones_bitmap accordingly.
+ * Since read-only and offline zones cannot be written, do not
+ * mark them as sequential in the bitmap.
+ * Return the LBA after the last zone reported.
+ */
+static sector_t sd_zbc_get_seq_zones(struct scsi_disk *sdkp, unsigned char 
*buf,
+unsigned int buflen,
+unsigned long *seq_zones_bitmap)
+{
+   sector_t lba, next_lba = sdkp->capacity;
+   unsigned int buf_len, list_length;
+   unsigned char *rec;
+   u8 type, cond;
+
+   list_length = get_unaligned_be32([0]) + 64;
+   buf_len = min(list_length, buflen);
+   rec = buf + 64;
+
+   while (rec < buf + buf_len) {
+   type = rec[0] & 0x0f;
+   cond = (rec[1] >> 4) & 0xf;
+   lba = get_unaligned_be64([16]);
+   if (type != ZBC_ZONE_TYPE_CONV &&
+   cond != ZBC_ZONE_COND_READONLY &&
+   cond != ZBC_ZONE_COND_OFFLINE)
+   set_bit(lba >> sdkp->zone_shift, seq_zones_bitmap);
+   next_lba = lba + get_unaligned_be64([8]);
+   rec += 64;
+   }
+
+   return next_lba;
+}
+
+/**
+ * sd_zbc_setup_seq_zones_bitmap - Initialize the disk seq zone bitmap.
+ * @sdkp: target disk
+ *
+ * Allocate a zone bitmap and initialize it by identifying sequential zones.
+ */
+static int sd_zbc_setup_seq_zones_bitmap(struct scsi_disk *sdkp)
+{
+   struct request_queue *q = sdkp->disk->queue;
+   unsigned long *seq_zones_bitmap;
+   sector_t lba = 0;
+   unsigned char *buf;
+   int ret = -ENOMEM;
+
+   seq_zones_bitmap = sd_zbc_alloc_zone_bitmap(sdkp);
+   if (!seq_zones_bitmap)
+   return -ENOMEM;
+
+   buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
+   if (!buf)
+   goto out;
+
+   while (lba < sdkp->capacity) {
+   ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, lba);
+   if (ret)
+   goto out;
+   lba = sd_zbc_get_seq_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
+  seq_zones_bitmap);
+   }
+
+   if (lba != sdkp->capacity) {
+   /* Something went wrong */
+   ret = -EIO;
+   }
+
+out:
+   kfree(buf);
+   if (ret) {
+   kfree(seq_zones_bitmap);
+   return ret;
+   }
+
+   q->seq_zones_bitmap = seq_zones_bitmap;
+
+   return 0;
+}
+
+static void sd_zbc_cleanup(struct scsi_disk *sdkp)
+{
+   struct request_queue *q = sdkp->disk->queue;
+
+   kfree(q->seq_zones_bitmap);
+   q->seq_zones_bitmap = NULL;
+
+   kfree(q->seq_zones_wlock);
+   q->seq_zones_wlock = NULL;
+
+   q->nr_zones = 0;
+}
+
 static int sd_zbc_setup(struct scsi_disk *sdkp)
 {
+   struct request_queue *q = sdkp->disk->queue;
+   int ret;
 
/* READ16/WRITE16 is mandatory for ZBC disks */
sdkp->device->use_16_for_rw = 1;
@@ -599,15 +714,36 @@ static int sd_zbc_setup(struct scsi_disk *sdkp)
sdkp->nr_zones =
round_up(sdkp->capacity, sdkp->zone_blocks) >> sdkp->zone_shift;
 
-   if (!sdkp->zones_wlock) {
-   sdkp->zones_wlock = kcalloc(BITS_TO_LONGS(sdkp->nr_zones),
-   sizeof(unsigned long),
-   GFP_KERNEL);
-   if (!sdkp->zones_wlock)
-   return -ENOMEM;