[PATCH v2 04/20] scsi: Add support for block PR read keys/reservation.

[Mike Christie]

This adds support in sd.c for the block PR read keys and read reservation
callouts.

Signed-off-by: Mike Christie <michael.christie at oracle.com>
---
 drivers/scsi/sd.c         | 88 +++++++++++++++++++++++++++++++++++++++
 include/scsi/scsi_proto.h |  5 +++
 2 files changed, 93 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 88ce1464527c..f1d4d0568075 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1683,6 +1683,92 @@ static int sd_get_unique_id(struct gendisk *disk, u8 id[16],
 	return ret;
 }
 
+static int sd_pr_in_command(struct block_device *bdev, u8 sa,
+			    unsigned char *data, int data_len)
+{
+	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
+	struct scsi_device *sdev = sdkp->device;
+	struct scsi_sense_hdr sshdr;
+	u8 cmd[10] = { 0, };
+	int result;
+
+	cmd[0] = PERSISTENT_RESERVE_IN;
+	cmd[1] = sa;
+	put_unaligned_be16(data_len, &cmd[7]);
+
+	result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, data, data_len,
+				  &sshdr, SD_TIMEOUT, sdkp->max_retries, NULL);
+	if (scsi_status_is_check_condition(result) &&
+	    scsi_sense_valid(&sshdr)) {
+		sdev_printk(KERN_INFO, sdev, "PR command failed: %d\n", result);
+		scsi_print_sense_hdr(sdev, NULL, &sshdr);
+	}
+
+	return result;
+}
+
+static int sd_pr_read_keys(struct block_device *bdev, struct pr_keys *keys_info,
+			   u32 keys_len)
+{
+	int result, i, data_offset, num_copy_keys;
+	int data_len = keys_len + 8;
+	u8 *data;
+
+	data = kzalloc(data_len, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	result = sd_pr_in_command(bdev, READ_KEYS, data, data_len);
+	if (result)
+		goto free_data;
+
+	keys_info->generation = get_unaligned_be32(&data[0]);
+	keys_info->num_keys = get_unaligned_be32(&data[4]) / 8;
+
+	data_offset = 8;
+	num_copy_keys = min(keys_len / 8, keys_info->num_keys);
+
+	for (i = 0; i < num_copy_keys; i++) {
+		keys_info->keys[i] = get_unaligned_be64(&data[data_offset]);
+		data_offset += 8;
+	}
+
+free_data:
+	kfree(data);
+	return result;
+}
+
+static int sd_pr_read_reservation(struct block_device *bdev,
+				  struct pr_held_reservation *rsv)
+{
+	struct scsi_disk *sdkp = scsi_disk(bdev->bd_disk);
+	struct scsi_device *sdev = sdkp->device;
+	u8 data[24] = { 0, };
+	int result, len;
+
+	result = sd_pr_in_command(bdev, READ_RESERVATION, data, sizeof(data));
+	if (result)
+		return result;
+
+	memset(rsv, 0, sizeof(*rsv));
+	len = get_unaligned_be32(&data[4]);
+	if (!len)
+		return result;
+
+	/* Make sure we have at least the key and type */
+	if (len < 14) {
+		sdev_printk(KERN_INFO, sdev,
+			    "READ RESERVATION failed due to short return buffer of %d bytes\n",
+			    len);
+		return -EINVAL;
+	}
+
+	rsv->generation = get_unaligned_be32(&data[0]);
+	rsv->key = get_unaligned_be64(&data[8]);
+	rsv->type = scsi_pr_type_to_block(data[21] & 0x0f);
+	return 0;
+}
+
 static int sd_pr_out_command(struct block_device *bdev, u8 sa,
 		u64 key, u64 sa_key, u8 type, u8 flags)
 {
@@ -1757,6 +1843,8 @@ static const struct pr_ops sd_pr_ops = {
 	.pr_release	= sd_pr_release,
 	.pr_preempt	= sd_pr_preempt,
 	.pr_clear	= sd_pr_clear,
+	.pr_read_keys	= sd_pr_read_keys,
+	.pr_read_reservation = sd_pr_read_reservation,
 };
 
 static void scsi_disk_free_disk(struct gendisk *disk)
diff --git a/include/scsi/scsi_proto.h b/include/scsi/scsi_proto.h
index c03e35fc382c..0fd6e295375a 100644
--- a/include/scsi/scsi_proto.h
+++ b/include/scsi/scsi_proto.h
@@ -151,6 +151,11 @@
 #define ZO_FINISH_ZONE	      0x02
 #define ZO_OPEN_ZONE	      0x03
 #define ZO_RESET_WRITE_POINTER 0x04
+/* values for PR in service action */
+#define READ_KEYS             0x00
+#define READ_RESERVATION      0x01
+#define REPORT_CAPABILITES    0x02
+#define READ_FULL_STATUS      0x03
 /* values for variable length command */
 #define XDREAD_32	      0x03
 #define XDWRITE_32	      0x04
-- 
2.18.2