target: Allocate aptpl_buf inside update_and_write_aptpl()

Instead of taking the buffer and length, update_and_write_aptpl() will
allocate the buffer as needed, and then free it. Instead, the function
takes an 'aptpl' boolean parameter.

This enables us to remove memory alloc/frees from struct
t10_pr_registration and other spots.

There is a slight loss of functionality because each callsite doesn't get
its own pr_debug any more, but this info can be cleaned via ftrace if
necessary and I think the shorter code is worth it.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 48 insertions, 157 deletions

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index c157b3f7b0e1..915edaab1919 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -606,13 +606,6 @@ static struct t10_pr_registration *__core_scsi3_do_alloc_registration(
                 return NULL;
         }
 
-        pr_reg->pr_aptpl_buf = kzalloc(PR_APTPL_BUF_LEN, GFP_ATOMIC);
-        if (!pr_reg->pr_aptpl_buf) {
-                pr_err("Unable to allocate pr_reg->pr_aptpl_buf\n");
-                kmem_cache_free(t10_pr_reg_cache, pr_reg);
-                return NULL;
-        }
-
         INIT_LIST_HEAD(&pr_reg->pr_reg_list);
         INIT_LIST_HEAD(&pr_reg->pr_reg_abort_list);
         INIT_LIST_HEAD(&pr_reg->pr_reg_aptpl_list);
@@ -803,7 +796,6 @@ int core_scsi3_alloc_aptpl_registration(
                 pr_err("Unable to allocate struct t10_pr_registration\n");
                 return -ENOMEM;
         }
-        pr_reg->pr_aptpl_buf = kzalloc(PR_APTPL_BUF_LEN, GFP_KERNEL);
 
         INIT_LIST_HEAD(&pr_reg->pr_reg_list);
         INIT_LIST_HEAD(&pr_reg->pr_reg_abort_list);
@@ -1272,7 +1264,6 @@ static void __core_scsi3_free_registration(
         if (!preempt_and_abort_list) {
                 pr_reg->pr_reg_deve = NULL;
                 pr_reg->pr_reg_nacl = NULL;
-                kfree(pr_reg->pr_aptpl_buf);
                 kmem_cache_free(t10_pr_reg_cache, pr_reg);
                 return;
         }
@@ -1341,7 +1332,6 @@ void core_scsi3_free_all_registrations(
         list_for_each_entry_safe(pr_reg, pr_reg_tmp, &pr_tmpl->aptpl_reg_list,
                                 pr_reg_aptpl_list) {
                 list_del(&pr_reg->pr_reg_aptpl_list);
-                kfree(pr_reg->pr_aptpl_buf);
                 kmem_cache_free(t10_pr_reg_cache, pr_reg);
         }
         spin_unlock(&pr_tmpl->aptpl_reg_lock);
@@ -1814,7 +1804,6 @@ out:
                         kmem_cache_free(t10_pr_reg_cache, pr_reg_tmp);
                 }
 
-                kfree(dest_pr_reg->pr_aptpl_buf);
                 kmem_cache_free(t10_pr_reg_cache, dest_pr_reg);
 
                 if (dest_local_nexus)
@@ -1840,8 +1829,6 @@ static int core_scsi3_update_aptpl_buf(
         int reg_count = 0;
         int ret = 0;
 
-        memset(buf, 0, pr_aptpl_buf_len);
-
         spin_lock(&dev->dev_reservation_lock);
         spin_lock(&dev->t10_pr.registration_lock);
         /*
@@ -1965,31 +1952,45 @@ static int __core_scsi3_write_aptpl_to_file(
         return ret ? -EIO : 0;
 }
 
-static int
-core_scsi3_update_and_write_aptpl(struct se_device *dev, unsigned char *in_buf,
-                u32 in_pr_aptpl_buf_len)
+/*
+ * Clear the APTPL metadata if APTPL has been disabled, otherwise
+ * write out the updated metadata to struct file for this SCSI device.
+ */
+static int core_scsi3_update_and_write_aptpl(struct se_device *dev, bool aptpl)
 {
-        unsigned char null_buf[64], *buf;
-        int ret;
+        int ret = 0;
 
-        /*
-         * Can be called with a NULL pointer from PROUT service action CLEAR
-         */
-        if (!in_buf) {
-                snprintf(null_buf, 64, "No Registrations or Reservations\n");
-                buf = null_buf;
+        if (!aptpl) {
+                char *null_buf = "No Registrations or Reservations\n";
+
+                ret = __core_scsi3_write_aptpl_to_file(dev, null_buf);
+                dev->t10_pr.pr_aptpl_active = 0;
+                pr_debug("SPC-3 PR: Set APTPL Bit Deactivated\n");
         } else {
-                ret = core_scsi3_update_aptpl_buf(dev, in_buf, in_pr_aptpl_buf_len);
-                if (ret != 0)
+                int ret;
+                unsigned char *buf;
+
+                buf = kzalloc(PR_APTPL_BUF_LEN, GFP_KERNEL);
+                if (!buf)
+                        return -ENOMEM;
+
+                ret = core_scsi3_update_aptpl_buf(dev, buf, PR_APTPL_BUF_LEN);
+                if (ret < 0) {
+                        kfree(buf);
                         return ret;
-                buf = in_buf;
+                }
+
+                ret = __core_scsi3_write_aptpl_to_file(dev, buf);
+                if (ret != 0) {
+                        pr_err("SPC-3 PR: Could not update APTPL\n");
+                } else {
+                        dev->t10_pr.pr_aptpl_active = 1;
+                        pr_debug("SPC-3 PR: Set APTPL Bit Activated\n");
+                }
+                kfree(buf);
         }
 
-        /*
-         * __core_scsi3_write_aptpl_to_file() will call strlen()
-         * on the passed buf to determine pr_aptpl_buf_len.
-         */
-        return __core_scsi3_write_aptpl_to_file(dev, buf);
+        return ret;
 }
 
 static sense_reason_t
@@ -2003,8 +2004,6 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
         struct se_portal_group *se_tpg;
         struct t10_pr_registration *pr_reg, *pr_reg_p, *pr_reg_tmp, *pr_reg_e;
         struct t10_reservation *pr_tmpl = &dev->t10_pr;
-        /* Used for APTPL metadata w/ UNREGISTER */
-        unsigned char *pr_aptpl_buf = NULL;
         unsigned char isid_buf[PR_REG_ISID_LEN], *isid_ptr = NULL;
         sense_reason_t ret = TCM_NO_SENSE;
         int pr_holder = 0, type;
@@ -2066,31 +2065,8 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
                         if (ret != 0)
                                 return ret;
                 }
-                /*
-                 * Nothing left to do for the APTPL=0 case.
-                 */
-                if (!aptpl) {
-                        pr_tmpl->pr_aptpl_active = 0;
-                        core_scsi3_update_and_write_aptpl(cmd->se_dev, NULL, 0);
-                        pr_debug("SPC-3 PR: Set APTPL Bit Deactivated for"
-                                        " REGISTER\n");
-                        return 0;
-                }
-                /*
-                 * Locate the newly allocated local I_T Nexus *pr_reg, and
-                 * update the APTPL metadata information using its
-                 * preallocated *pr_reg->pr_aptpl_buf.
-                 */
-                pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev,
-                                se_sess->se_node_acl, se_sess);
-
-                if (core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                                pr_reg->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_tmpl->pr_aptpl_active = 1;
-                        pr_debug("SPC-3 PR: Set APTPL Bit Activated for REGISTER\n");
-                }
 
-                goto out_put_pr_reg;
+                return core_scsi3_update_and_write_aptpl(dev, aptpl);
         }
 
         /*
@@ -2131,19 +2107,6 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
         }
 
         /*
-         * Allocate APTPL metadata buffer used for UNREGISTER ops
-         */
-        if (aptpl) {
-                pr_aptpl_buf = kzalloc(PR_APTPL_BUF_LEN, GFP_KERNEL);
-                if (!pr_aptpl_buf) {
-                        pr_err("Unable to allocate"
-                                " pr_aptpl_buf\n");
-                        ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
-                        goto out_put_pr_reg;
-                }
-        }
-
-        /*
          * sa_res_key=0 Unregister Reservation Key for registered I_T
          * Nexus sa_res_key=1 Change Reservation Key for registered I_T
          * Nexus.
@@ -2152,7 +2115,6 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
                 pr_holder = core_scsi3_check_implict_release(
                                 cmd->se_dev, pr_reg);
                 if (pr_holder < 0) {
-                        kfree(pr_aptpl_buf);
                         ret = TCM_RESERVATION_CONFLICT;
                         goto out_put_pr_reg;
                 }
@@ -2214,21 +2176,8 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
                 }
                 spin_unlock(&pr_tmpl->registration_lock);
 
-                if (!aptpl) {
-                        pr_tmpl->pr_aptpl_active = 0;
-                        core_scsi3_update_and_write_aptpl(dev, NULL, 0);
-                        pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
-                                        " for UNREGISTER\n");
-                        return 0;
-                }
-
-                if (!core_scsi3_update_and_write_aptpl(dev, pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_tmpl->pr_aptpl_active = 1;
-                        pr_debug("SPC-3 PR: Set APTPL Bit Activated"
-                                        " for UNREGISTER\n");
-                }
-
-                goto out_free_aptpl_buf;
+                ret = core_scsi3_update_and_write_aptpl(dev, aptpl);
+                goto out_put_pr_reg;
         }
 
         /*
@@ -2245,24 +2194,8 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
                 pr_reg->pr_reg_nacl->initiatorname,
                 pr_reg->pr_res_key, pr_reg->pr_res_generation);
 
-        if (!aptpl) {
-                pr_tmpl->pr_aptpl_active = 0;
-                core_scsi3_update_and_write_aptpl(dev, NULL, 0);
-                pr_debug("SPC-3 PR: Set APTPL Bit Deactivated"
-                                " for REGISTER\n");
-                ret = 0;
-                goto out_put_pr_reg;
-        }
+        ret = core_scsi3_update_and_write_aptpl(dev, aptpl);
 
-        if (!core_scsi3_update_and_write_aptpl(dev, pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                pr_tmpl->pr_aptpl_active = 1;
-                pr_debug("SPC-3 PR: Set APTPL Bit Activated"
-                        " for REGISTER\n");
-        }
-
-out_free_aptpl_buf:
-        kfree(pr_aptpl_buf);
-        ret = 0;
 out_put_pr_reg:
         core_scsi3_put_pr_reg(pr_reg);
         return ret;
@@ -2437,13 +2370,8 @@ core_scsi3_pro_reserve(struct se_cmd *cmd, int type, int scope, u64 res_key)
                         i_buf);
         spin_unlock(&dev->dev_reservation_lock);
 
-        if (pr_tmpl->pr_aptpl_active) {
-                if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                                pr_reg->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_debug("SPC-3 PR: Updated APTPL metadata"
-                                        " for RESERVE\n");
-                }
-        }
+        if (pr_tmpl->pr_aptpl_active)
+                core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
 
         ret = 0;
 out_put_pr_reg:
@@ -2657,12 +2585,9 @@ core_scsi3_emulate_pro_release(struct se_cmd *cmd, int type, int scope,
         spin_unlock(&pr_tmpl->registration_lock);
 
 write_aptpl:
-        if (pr_tmpl->pr_aptpl_active) {
-                if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                        pr_reg->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_debug("SPC-3 PR: Updated APTPL metadata for RELEASE\n");
-                }
-        }
+        if (pr_tmpl->pr_aptpl_active)
+                core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
+
 out_put_pr_reg:
         core_scsi3_put_pr_reg(pr_reg);
         return ret;
@@ -2746,11 +2671,7 @@ core_scsi3_emulate_pro_clear(struct se_cmd *cmd, u64 res_key)
         pr_debug("SPC-3 PR [%s] Service Action: CLEAR complete\n",
                 cmd->se_tfo->get_fabric_name());
 
-        if (pr_tmpl->pr_aptpl_active) {
-                core_scsi3_update_and_write_aptpl(cmd->se_dev, NULL, 0);
-                pr_debug("SPC-3 PR: Updated APTPL metadata"
-                                " for CLEAR\n");
-        }
+        core_scsi3_update_and_write_aptpl(cmd->se_dev, false);
 
         core_scsi3_pr_generation(dev);
         return 0;
@@ -2822,7 +2743,6 @@ static void core_scsi3_release_preempt_and_abort(
 
                 pr_reg->pr_reg_deve = NULL;
                 pr_reg->pr_reg_nacl = NULL;
-                kfree(pr_reg->pr_aptpl_buf);
                 kmem_cache_free(t10_pr_reg_cache, pr_reg);
         }
 }
@@ -2984,14 +2904,8 @@ core_scsi3_pro_preempt(struct se_cmd *cmd, int type, int scope, u64 res_key,
                 }
                 spin_unlock(&dev->dev_reservation_lock);
 
-                if (pr_tmpl->pr_aptpl_active) {
-                        if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                                        pr_reg_n->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                                pr_debug("SPC-3 PR: Updated APTPL"
-                                        " metadata for  PREEMPT%s\n", (preempt_type == PREEMPT_AND_ABORT) ?
-                                        "_AND_ABORT" : "");
-                        }
-                }
+                if (pr_tmpl->pr_aptpl_active)
+                        core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
 
                 core_scsi3_put_pr_reg(pr_reg_n);
                 core_scsi3_pr_generation(cmd->se_dev);
@@ -3119,13 +3033,8 @@ core_scsi3_pro_preempt(struct se_cmd *cmd, int type, int scope, u64 res_key,
                                                 pr_reg_n);
         }
 
-        if (pr_tmpl->pr_aptpl_active) {
-                if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                                pr_reg_n->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_debug("SPC-3 PR: Updated APTPL metadata for PREEMPT"
-                                "%s\n", (preempt_type == PREEMPT_AND_ABORT) ? "_AND_ABORT" : "");
-                }
-        }
+        if (pr_tmpl->pr_aptpl_active)
+                core_scsi3_update_and_write_aptpl(cmd->se_dev, true);
 
         core_scsi3_put_pr_reg(pr_reg_n);
         core_scsi3_pr_generation(cmd->se_dev);
@@ -3552,23 +3461,7 @@ after_iport_check:
         } else
                 core_scsi3_put_pr_reg(pr_reg);
 
-        /*
-         * Clear the APTPL metadata if APTPL has been disabled, otherwise
-         * write out the updated metadata to struct file for this SCSI device.
-         */
-        if (!aptpl) {
-                pr_tmpl->pr_aptpl_active = 0;
-                core_scsi3_update_and_write_aptpl(cmd->se_dev, NULL, 0);
-                pr_debug("SPC-3 PR: Set APTPL Bit Deactivated for"
-                                " REGISTER_AND_MOVE\n");
-        } else {
-                pr_tmpl->pr_aptpl_active = 1;
-                if (!core_scsi3_update_and_write_aptpl(cmd->se_dev,
-                                dest_pr_reg->pr_aptpl_buf, PR_APTPL_BUF_LEN)) {
-                        pr_debug("SPC-3 PR: Set APTPL Bit Activated for"
-                                        " REGISTER_AND_MOVE\n");
-                }
-        }
+        core_scsi3_update_and_write_aptpl(cmd->se_dev, aptpl);
 
         transport_kunmap_data_sg(cmd);
 
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 5976dc3e4066..8952ee9f7cef 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -339,8 +339,6 @@ struct t10_pr_registration {
         /* Used during APTPL metadata reading */
 #define PR_APTPL_MAX_TPORT_LEN                  256
         unsigned char pr_tport[PR_APTPL_MAX_TPORT_LEN];
-        /* For writing out live meta data */
-        unsigned char *pr_aptpl_buf;
         u16 pr_aptpl_rpti;
         u16 pr_reg_tpgt;
         /* Reservation effects all target ports */