diff mbox series

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

Message ID 20220809000419.10674-5-michael.christie@oracle.com
State New
Headers show
Series Use block pr_ops in LIO | expand

Commit Message

Mike Christie Aug. 9, 2022, 12:04 a.m. UTC 
This adds support in sd.c for the block PR read keys and read reservation
callouts.

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

Comments

Bart Van Assche Aug. 9, 2022, 7:26 p.m. UTC | #1 
On 8/8/22 17:04, Mike Christie wrote:
> +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;

Isn't "{ }" instead of "{ 0, }" the preferred way to zero-initialize a 
data structure?

> +
> +	cmd[0] = PERSISTENT_RESERVE_IN;
> +	cmd[1] = sa;

Can the above two assignments be moved into the initializer of cmd[]?

Thanks,

Bart.
Mike Christie Aug. 10, 2022, 3:28 a.m. UTC | #2 
On 8/9/22 2:26 PM, Bart Van Assche wrote:
> On 8/8/22 17:04, Mike Christie wrote:
>> +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;
> 
> Isn't "{ }" instead of "{ 0, }" the preferred way to zero-initialize a data structure?

The original code used { 0, } and that seems common sd.c. { } was not used in sd.c.

I didn't see anything in coding-style.rst. It does not make any difference to me
other than it's better to be consistent unless we are supposed to be transitioning
to a new style.

> 
>> +
>> +    cmd[0] = PERSISTENT_RESERVE_IN;
>> +    cmd[1] = sa;
> 
> Can the above two assignments be moved into the initializer of cmd[]?
> 

Yes, but it was like the first comment. The original code didn't do
that and it seemed more common to not do it. Do we want to switch
or are we transitioning? It does not matter to me. Both are simple changes.
diff mbox series

Patch

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