[PATCH 07/33] TCMU PR: add functions to handle SCSI2 Reservation

[Zhu Lingshan]

This patch added two functions: tcmu_pr_info_scsi2_rsv_encode()
and tcmu_pr_info_scsi2_rsv_decode() to encode and decode SCSI2
Reservations.

Signed-off-by: Zhu Lingshan <ls...@suse.com>
---
 drivers/target/target_core_user.c | 65 +++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/drivers/target/target_core_user.c 
b/drivers/target/target_core_user.c
index ccb1607edd0a..50723ac0ed22 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -94,6 +94,9 @@
 #define TCMU_GLOBAL_MAX_BLOCKS_DEF (512 * 1024)
 
 #define TCMU_PR_INFO_XATTR_VERS                1
+#define TCMU_PR_INFO_XATTR_VAL_SCSI2_RSV_ABSENT                "No SPC-2 
Reservation holder"
+
+#define TCMU_PR_IT_NEXUS_MAXLEN                484
 
 static u8 tcmu_kern_cmd_reply_supported;
 
@@ -200,6 +203,14 @@ struct tcmu_cmd {
 #define TCMU_CMD_BIT_EXPIRED 0
        unsigned long flags;
 };
+
+/*
+ * I-T nexus for SCSI2 (RESERVE/RELEASE) reservation.
+ */
+struct tcmu_scsi2_rsv {
+       char it_nexus[TCMU_PR_IT_NEXUS_MAXLEN];
+       };
+
 /*
  * To avoid dead lock the mutex lock order should always be:
  *
@@ -1875,6 +1886,60 @@ tcmu_pr_info_vers_decode(char *str, u32 *vers)
        return 0;
 }
 
+static int
+tcmu_pr_info_scsi2_rsv_decode(char *str, struct tcmu_scsi2_rsv **_scsi2_rsv)
+{
+       struct tcmu_scsi2_rsv *scsi2_rsv;
+
+       if (!_scsi2_rsv) {
+               WARN_ON(1);
+               return -EINVAL;
+       }
+       if (!strncmp(str, TCMU_PR_INFO_XATTR_VAL_SCSI2_RSV_ABSENT,
+                    sizeof(TCMU_PR_INFO_XATTR_VAL_SCSI2_RSV_ABSENT))) {
+               scsi2_rsv = NULL;
+       } else {
+               size_t n;
+
+               scsi2_rsv = kzalloc(sizeof(*scsi2_rsv), GFP_KERNEL);
+               if (!scsi2_rsv)
+                       return -ENOMEM;
+
+               n = strlcpy(scsi2_rsv->it_nexus, str,
+                           TCMU_PR_IT_NEXUS_MAXLEN);
+               if (n >= TCMU_PR_IT_NEXUS_MAXLEN) {
+                       kfree(scsi2_rsv);
+                       return -EINVAL;
+               }
+       }
+
+       pr_debug("processed pr_info SCSI2 rsv: %s\n", str);
+
+       *_scsi2_rsv = scsi2_rsv;
+       return 0;
+}
+
+static int
+tcmu_pr_info_scsi2_rsv_encode(char *buf, size_t buf_remain,
+                             struct tcmu_scsi2_rsv *scsi2_rsv)
+{
+       int rc;
+
+       if (!scsi2_rsv) {
+               /* no reservation */
+               rc = snprintf(buf, buf_remain, "%s\n",
+                             TCMU_PR_INFO_XATTR_VAL_SCSI2_RSV_ABSENT);
+       } else {
+               rc = snprintf(buf, buf_remain, "%s\n", scsi2_rsv->it_nexus);
+       }
+       if ((rc < 0) || (rc >= buf_remain)) {
+               pr_err("failed to encode SCSI2 reservation\n");
+               return -EINVAL;
+       }
+
+       return rc;
+}
+
 static int tcmu_configure_device(struct se_device *dev)
 {
        struct tcmu_dev *udev = TCMU_DEV(dev);
-- 
2.17.1