x86/intel_rdt: Add diagnostics when making directories

Mostly this is about running out of RMIDs or CLOSIDs. Other
errors are various internal errors.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/027cf1ffb3a3695f2d54525813a1d644887353cf.1506382469.git.tony.luck@intel.com

diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
index 6e0ee7c..abd220b 100644 (file)
--- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
+++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
@@ -1593,8 +1593,10 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
        int ret;
 
        prdtgrp = rdtgroup_kn_lock_live(prgrp_kn);
+       rdt_last_cmd_clear();
        if (!prdtgrp) {
                ret = -ENODEV;
+               rdt_last_cmd_puts("directory was removed\n");
                goto out_unlock;
        }
 
@@ -1602,6 +1604,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
        rdtgrp = kzalloc(sizeof(*rdtgrp), GFP_KERNEL);
        if (!rdtgrp) {
                ret = -ENOSPC;
+               rdt_last_cmd_puts("kernel out of memory\n");
                goto out_unlock;
        }
        *r = rdtgrp;
@@ -1613,6 +1616,7 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
        kn = kernfs_create_dir(parent_kn, name, mode, rdtgrp);
        if (IS_ERR(kn)) {
                ret = PTR_ERR(kn);
+               rdt_last_cmd_puts("kernfs create error\n");
                goto out_free_rgrp;
        }
        rdtgrp->kn = kn;
@@ -1626,24 +1630,32 @@ static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,
        kernfs_get(kn);
 
        ret = rdtgroup_kn_set_ugid(kn);
-       if (ret)
+       if (ret) {
+               rdt_last_cmd_puts("kernfs perm error\n");
                goto out_destroy;
+       }
 
        files = RFTYPE_BASE | RFTYPE_CTRL;
        files = RFTYPE_BASE | BIT(RF_CTRLSHIFT + rtype);
        ret = rdtgroup_add_files(kn, files);
-       if (ret)
+       if (ret) {
+               rdt_last_cmd_puts("kernfs fill error\n");
                goto out_destroy;
+       }
 
        if (rdt_mon_capable) {
                ret = alloc_rmid();
-               if (ret < 0)
+               if (ret < 0) {
+                       rdt_last_cmd_puts("out of RMIDs\n");
                        goto out_destroy;
+               }
                rdtgrp->mon.rmid = ret;
 
                ret = mkdir_mondata_all(kn, rdtgrp, &rdtgrp->mon.mon_data_kn);
-               if (ret)
+               if (ret) {
+                       rdt_last_cmd_puts("kernfs subdir error\n");
                        goto out_idfree;
+               }
        }
        kernfs_activate(kn);
 
@@ -1721,8 +1733,10 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
 
        kn = rdtgrp->kn;
        ret = closid_alloc();
-       if (ret < 0)
+       if (ret < 0) {
+               rdt_last_cmd_puts("out of CLOSIDs\n");
                goto out_common_fail;
+       }
        closid = ret;
 
        rdtgrp->closid = closid;
@@ -1734,8 +1748,10 @@ static int rdtgroup_mkdir_ctrl_mon(struct kernfs_node *parent_kn,
                 * of tasks and cpus to monitor.
                 */
                ret = mongroup_create_dir(kn, NULL, "mon_groups", NULL);
-               if (ret)
+               if (ret) {
+                       rdt_last_cmd_puts("kernfs subdir error\n");
                        goto out_id_free;
+               }
        }
 
        goto out_unlock;