sd: Implement support for ZBC devices

Implement ZBC support functions to setup zoned disks, both
host-managed and host-aware models. Only zoned disks that satisfy
the following conditions are supported:
1) All zones are the same size, with the exception of an eventual
   last smaller runt zone.
2) For host-managed disks, reads are unrestricted (reads are not
   failed due to zone or write pointer alignement constraints).
Zoned disks that do not satisfy these 2 conditions are setup with
a capacity of 0 to prevent their use.

The function sd_zbc_read_zones, called from sd_revalidate_disk,
checks that the device satisfies the above two constraints. This
function may also change the disk capacity previously set by
sd_read_capacity for devices reporting only the capacity of
conventional zones at the beginning of the LBA range (i.e. devices
reporting rc_basis set to 0).

The capacity message output was moved out of sd_read_capacity into
a new function sd_print_capacity to include this eventual capacity
change by sd_zbc_read_zones. This new function also includes a call
to sd_zbc_print_zones to display the number of zones and zone size
of the device.

Signed-off-by: Hannes Reinecke <hare@suse.de>

[Damien: * Removed zone cache support
         * Removed mapping of discard to reset write pointer command
         * Modified sd_zbc_read_zones to include checks that the
           device satisfies the kernel constraints
         * Implemeted REPORT ZONES setup and post-processing based
           on code from Shaun Tancheff <shaun.tancheff@seagate.com>
         * Removed confusing use of 512B sector units in functions
           interface]
Signed-off-by: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Tested-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index c8d986368da9..4dac35e96a75 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -64,6 +64,15 @@ struct scsi_disk {
 	struct scsi_device *device;
 	struct device	dev;
 	struct gendisk	*disk;
+#ifdef CONFIG_BLK_DEV_ZONED
+	unsigned int	nr_zones;
+	unsigned int	zone_blocks;
+	unsigned int	zone_shift;
+	unsigned long	*zones_wlock;
+	unsigned int	zones_optimal_open;
+	unsigned int	zones_optimal_nonseq;
+	unsigned int	zones_max_open;
+#endif
 	atomic_t	openers;
 	sector_t	capacity;	/* size in logical blocks */
 	u32		max_xfer_blocks;
@@ -94,6 +103,9 @@ struct scsi_disk {
 	unsigned	lbpvpd : 1;
 	unsigned	ws10 : 1;
 	unsigned	ws16 : 1;
+	unsigned	rc_basis: 2;
+	unsigned	zoned: 2;
+	unsigned	urswrz : 1;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)
 
@@ -156,6 +168,11 @@ static inline unsigned int logical_to_bytes(struct scsi_device *sdev, sector_t b
 	return blocks * sdev->sector_size;
 }
 
+static inline sector_t sectors_to_logical(struct scsi_device *sdev, sector_t sector)
+{
+	return sector >> (ilog2(sdev->sector_size) - 9);
+}
+
 /*
  * Look up the DIX operation based on whether the command is read or
  * write and whether dix and dif are enabled.
@@ -239,4 +256,57 @@ static inline void sd_dif_complete(struct scsi_cmnd *cmd, unsigned int a)
 
 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 
+static inline int sd_is_zoned(struct scsi_disk *sdkp)
+{
+	return sdkp->zoned == 1 || sdkp->device->type == TYPE_ZBC;
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+
+extern int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buffer);
+extern void sd_zbc_remove(struct scsi_disk *sdkp);
+extern void sd_zbc_print_zones(struct scsi_disk *sdkp);
+extern int sd_zbc_setup_write_cmnd(struct scsi_cmnd *cmd);
+extern void sd_zbc_cancel_write_cmnd(struct scsi_cmnd *cmd);
+extern int sd_zbc_setup_report_cmnd(struct scsi_cmnd *cmd);
+extern int sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd);
+extern void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
+			    struct scsi_sense_hdr *sshdr);
+
+#else /* CONFIG_BLK_DEV_ZONED */
+
+static inline int sd_zbc_read_zones(struct scsi_disk *sdkp,
+				    unsigned char *buf)
+{
+	return 0;
+}
+
+static inline void sd_zbc_remove(struct scsi_disk *sdkp) {}
+
+static inline void sd_zbc_print_zones(struct scsi_disk *sdkp) {}
+
+static inline int sd_zbc_setup_write_cmnd(struct scsi_cmnd *cmd)
+{
+	/* Let the drive fail requests */
+	return BLKPREP_OK;
+}
+
+static inline void sd_zbc_cancel_write_cmnd(struct scsi_cmnd *cmd) {}
+
+static inline int sd_zbc_setup_report_cmnd(struct scsi_cmnd *cmd)
+{
+	return BLKPREP_INVALID;
+}
+
+static inline int sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd)
+{
+	return BLKPREP_INVALID;
+}
+
+static inline void sd_zbc_complete(struct scsi_cmnd *cmd,
+				   unsigned int good_bytes,
+				   struct scsi_sense_hdr *sshdr) {}
+
+#endif /* CONFIG_BLK_DEV_ZONED */
+
 #endif /* _SCSI_DISK_H */