scsi: Move sense handling routines to scsi_common

Sense data handling is also done in the target stack.
Hence, move sense handling routines to scsi_common so
the target will be able to use them as well.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 98 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_common.c b/drivers/scsi/scsi_common.c
index 2ff092252b76..41432c10dda2 100644
--- a/drivers/scsi/scsi_common.c
+++ b/drivers/scsi/scsi_common.c
@@ -5,6 +5,7 @@
 #include <linux/bug.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
+#include <asm/unaligned.h>
 #include <scsi/scsi_common.h>
 
 /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
@@ -176,3 +177,100 @@ bool scsi_normalize_sense(const u8 *sense_buffer, int sb_len,
 	return true;
 }
 EXPORT_SYMBOL(scsi_normalize_sense);
+
+/**
+ * scsi_sense_desc_find - search for a given descriptor type in	descriptor sense data format.
+ * @sense_buffer:	byte array of descriptor format sense data
+ * @sb_len:		number of valid bytes in sense_buffer
+ * @desc_type:		value of descriptor type to find
+ *			(e.g. 0 -> information)
+ *
+ * Notes:
+ *	only valid when sense data is in descriptor format
+ *
+ * Return value:
+ *	pointer to start of (first) descriptor if found else NULL
+ */
+const u8 * scsi_sense_desc_find(const u8 * sense_buffer, int sb_len,
+				int desc_type)
+{
+	int add_sen_len, add_len, desc_len, k;
+	const u8 * descp;
+
+	if ((sb_len < 8) || (0 == (add_sen_len = sense_buffer[7])))
+		return NULL;
+	if ((sense_buffer[0] < 0x72) || (sense_buffer[0] > 0x73))
+		return NULL;
+	add_sen_len = (add_sen_len < (sb_len - 8)) ?
+			add_sen_len : (sb_len - 8);
+	descp = &sense_buffer[8];
+	for (desc_len = 0, k = 0; k < add_sen_len; k += desc_len) {
+		descp += desc_len;
+		add_len = (k < (add_sen_len - 1)) ? descp[1]: -1;
+		desc_len = add_len + 2;
+		if (descp[0] == desc_type)
+			return descp;
+		if (add_len < 0) // short descriptor ??
+			break;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL(scsi_sense_desc_find);
+
+/**
+ * scsi_build_sense_buffer - build sense data in a buffer
+ * @desc:	Sense format (non zero == descriptor format,
+ *              0 == fixed format)
+ * @buf:	Where to build sense data
+ * @key:	Sense key
+ * @asc:	Additional sense code
+ * @ascq:	Additional sense code qualifier
+ *
+ **/
+void scsi_build_sense_buffer(int desc, u8 *buf, u8 key, u8 asc, u8 ascq)
+{
+	if (desc) {
+		buf[0] = 0x72;	/* descriptor, current */
+		buf[1] = key;
+		buf[2] = asc;
+		buf[3] = ascq;
+		buf[7] = 0;
+	} else {
+		buf[0] = 0x70;	/* fixed, current */
+		buf[2] = key;
+		buf[7] = 0xa;
+		buf[12] = asc;
+		buf[13] = ascq;
+	}
+}
+EXPORT_SYMBOL(scsi_build_sense_buffer);
+
+/**
+ * scsi_set_sense_information - set the information field in a
+ *		formatted sense data buffer
+ * @buf:	Where to build sense data
+ * @info:	64-bit information value to be set
+ *
+ **/
+void scsi_set_sense_information(u8 *buf, u64 info)
+{
+	if ((buf[0] & 0x7f) == 0x72) {
+		u8 *ucp, len;
+
+		len = buf[7];
+		ucp = (char *)scsi_sense_desc_find(buf, len + 8, 0);
+		if (!ucp) {
+			buf[7] = len + 0xa;
+			ucp = buf + 8 + len;
+		}
+		ucp[0] = 0;
+		ucp[1] = 0xa;
+		ucp[2] = 0x80; /* Valid bit */
+		ucp[3] = 0;
+		put_unaligned_be64(info, &ucp[4]);
+	} else if ((buf[0] & 0x7f) == 0x70) {
+		buf[0] |= 0x80;
+		put_unaligned_be64(info, &buf[3]);
+	}
+}
+EXPORT_SYMBOL(scsi_set_sense_information);