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 <[email protected]> --- 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
