This patch added a function tcmu_execute_pr_register() which
can help to handle Persistent Reservation register operation
for TCMU devices.
Signed-off-by: Zhu Lingshan <lszhu@xxxxxxxx>
---
drivers/target/target_core_user.c | 138 ++++++++++++++++++++++++++++++
1 file changed, 138 insertions(+)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 559e0d40d63b..c3adff826163 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -2691,6 +2691,144 @@ static int tcmu_pr_info_replace(struct tcmu_dev *udev,
return 0;
}
+static sense_reason_t
+tcmu_execute_pr_register(struct se_cmd *cmd, u64 old_key,
+ u64 new_key, bool aptpl, bool all_tg_pt,
+ bool spec_i_pt, bool ignore_existing)
+{
+ struct se_device *dev = cmd->se_dev;
+ char nexus_buf[TCMU_PR_IT_NEXUS_MAXLEN];
+ struct tcmu_pr_info *pr_info;
+ struct tcmu_pr_reg *reg;
+ struct tcmu_pr_reg *existing_reg;
+ char *pr_xattr;
+ int pr_xattr_len;
+ int rc;
+ sense_reason_t ret;
+ int retries = 0;
+ char *pr_buf_ptr = NULL;
+ struct tcmu_dev *udev = TCMU_DEV(dev);
+
+ mutex_lock(&udev->pr_info.pr_info_lock);
+ udev->pr_info.pr_info_buf = kzalloc(TCMU_PR_INFO_XATTR_MAX_SIZE,
+ GFP_KERNEL);
+ pr_buf_ptr = udev->pr_info.pr_info_buf;
+ if (!pr_buf_ptr) {
+ ret = TCM_OUT_OF_RESOURCES;
+ goto err_out;
+ }
+
+ if (!cmd->se_sess || !cmd->se_lun) {
+ pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_out;
+ }
+
+ if (!aptpl) {
+ /*
+ * Currently unsupported by block layer API (hch):
+ * reservations not persistent through a power loss are
+ * basically useless, so I decided to force them on in the API.
+ */
+ pr_warn("PR register with aptpl unset. Treating as aptpl=1\n");
+ aptpl = true;
+ }
+
+ if (all_tg_pt || spec_i_pt) {
+ pr_err("failing PR register with all_tg_pt=%d spec_i_pt=%d\n",
+ all_tg_pt, spec_i_pt);
+ ret = TCM_INVALID_CDB_FIELD;
+ goto err_out;
+ }
+
+ rc = tcmu_gen_it_nexus(cmd->se_sess, nexus_buf, ARRAY_SIZE(nexus_buf));
+ if (rc < 0) {
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_out;
+ }
+
+ pr_debug("generated nexus: %s\n", nexus_buf);
+
+retry:
+ pr_info = NULL;
+ pr_xattr = NULL;
+ pr_xattr_len = 0;
+ rc = tcmu_pr_info_get(udev, &pr_info, &pr_xattr, &pr_xattr_len);
+ if ((rc == -ENODATA) && (retries == 0)) {
+ pr_warn("PR info not present, initializing\n");
+ rc = tcmu_pr_info_init(udev, &pr_info, &pr_xattr,
+ &pr_xattr_len);
+ }
+ if (rc < 0) {
+ pr_err("failed to obtain PR info\n");
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_out;
+ }
+
+ /* check for an existing registration */
+ existing_reg = NULL;
+ list_for_each_entry(reg, &pr_info->regs, regs_node) {
+ if (!strncmp(reg->it_nexus, nexus_buf, ARRAY_SIZE(nexus_buf))) {
+ pr_err("found existing PR reg for %s\n", nexus_buf);
+ existing_reg = reg;
+ break;
+ }
+ }
+
+ if (!existing_reg) {
+ ret = tcmu_execute_pr_register_new(pr_info, old_key, new_key,
+ nexus_buf, ignore_existing);
+ } else {
+ ret = tcmu_execute_pr_register_existing(pr_info, old_key,
+ new_key, nexus_buf,
+ existing_reg,
+ ignore_existing);
+ }
+ if (ret)
+ goto err_out;
+
+ /*
+ * The Persistent Reservations Generation (PRGENERATION) field shall
+ * contain the value of a 32-bit wrapping counter that the device server
+ * shall update (e.g., increment) during the processing of any
+ * PERSISTENT RESERVE OUT command as described in table 216 (see
+ * 6.16.2). The PRgeneration value shall not be updated by a PERSISTENT
+ * RESERVE IN command or by a PERSISTENT RESERVE OUT command that is
+ * terminated due to an error or reservation conflict.
+ */
+ pr_info->gen++;
+
+ rc = tcmu_pr_info_replace(udev, pr_xattr, pr_xattr_len, pr_info);
+ if (rc == -ECANCELED) {
+ int pr_xattr_changed_len = 0;
+ /* PR info has changed since we read it */
+ rc = tcmu_get_dev_pr_info(udev, &pr_xattr_changed_len);
+ pr_warn("atomic PR info update failed due to parallel,");
+ pr_warn("change, expected(%d) %s, now(%d) %s\n",
+ pr_xattr_len, pr_xattr, pr_xattr_changed_len,
+ pr_buf_ptr);
+ retries++;
+ if (retries <= TCMU_PR_REG_MAX_RETRIES) {
+ tcmu_pr_info_free(pr_info);
+ kfree(pr_xattr);
+ goto retry;
+ }
+ }
+ if (rc < 0) {
+ pr_err("atomic PR info update failed: %d\n", rc);
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_out;
+ }
+
+ ret = TCM_NO_SENSE;
+err_out:
+ tcmu_pr_info_free(pr_info);
+ kfree(pr_xattr);
+ kfree(udev->pr_info.pr_info_buf);
+ mutex_unlock(&udev->pr_info.pr_info_lock);
+ return ret;
+}
+
static int tcmu_configure_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
--
2.17.1
