Merge tag 'x86_cache_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 resource control updates from Borislav Petkov:

 - Add return value descriptions to several internal functions,
   addressing kernel-doc complaints

 - Add the x86 maintainer mailing list to the resctrl section so they
   are automatically included in patch submissions, and reference the
   applicable contribution rules document

 - Allow users to apply a single Capacity Bitmask to all cache domains
   at once using '*' as a shorthand, instead of having to specify each
   domain individually. This is particularly user-friendly on high
   core-count systems with many cache clusters

 - When a user provides a non-existent domain ID while configuring cache
   allocation, ensure the failure reason is properly reported to the
   user rather than silently returning an error with a misleading "ok"
   status

* tag 'x86_cache_for_v7.1_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  fs/resctrl: Add missing return value descriptions
  MAINTAINERS: Update resctrl entry
  fs/resctrl: Add "*" shorthand to set io_alloc CBM for all domains
  fs/resctrl: Report invalid domain ID when parsing io_alloc_cbm

5 files changed, 36 insertions, 4 deletions

diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst
index ba609f8d4de5..b003bed339fd 100644
--- a/Documentation/filesystems/resctrl.rst
+++ b/Documentation/filesystems/resctrl.rst
@@ -215,6 +215,14 @@ related to allocation:
 			# cat /sys/fs/resctrl/info/L3/io_alloc_cbm
 			0=00ff;1=000f
 
+		An ID of "*" configures all domains with the provided CBM.
+
+		Example on a system that does not require a minimum number of consecutive bits in the mask::
+
+			# echo "*=0" > /sys/fs/resctrl/info/L3/io_alloc_cbm
+			# cat /sys/fs/resctrl/info/L3/io_alloc_cbm
+			0=0;1=0
+
 		When CDP is enabled "io_alloc_cbm" associated with the CDP_DATA and CDP_CODE
 		resources may reflect the same values. For example, values read from and
 		written to /sys/fs/resctrl/info/L3DATA/io_alloc_cbm may be reflected by
diff --git a/MAINTAINERS b/MAINTAINERS
index dda161bc695c..20752c1e1672 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22178,11 +22178,13 @@ F:	tools/testing/selftests/net/rds/
 RDT - RESOURCE ALLOCATION
 M:	Tony Luck <tony.luck@intel.com>
 M:	Reinette Chatre <reinette.chatre@intel.com>
+M:	x86@kernel.org
 R:	Dave Martin <Dave.Martin@arm.com>
 R:	James Morse <james.morse@arm.com>
 R:	Babu Moger <babu.moger@amd.com>
 L:	linux-kernel@vger.kernel.org
 S:	Supported
+P:	Documentation/process/maintainer-tip.rst
 F:	Documentation/filesystems/resctrl.rst
 F:	arch/x86/include/asm/resctrl.h
 F:	arch/x86/kernel/cpu/resctrl/
diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index cc4237c57cbe..9a7dfc48cb2e 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -954,25 +954,34 @@ static int resctrl_io_alloc_parse_line(char *line,  struct rdt_resource *r,
 				       struct resctrl_schema *s, u32 closid)
 {
 	enum resctrl_conf_type peer_type;
+	unsigned long dom_id = ULONG_MAX;
 	struct rdt_parse_data data;
 	struct rdt_ctrl_domain *d;
+	bool update_all = false;
 	char *dom = NULL, *id;
-	unsigned long dom_id;
 
 next:
 	if (!line || line[0] == '\0')
 		return 0;
 
+	if (update_all) {
+		rdt_last_cmd_puts("Configurations after global '*'\n");
+		return -EINVAL;
+	}
+
 	dom = strsep(&line, ";");
 	id = strsep(&dom, "=");
-	if (!dom || kstrtoul(id, 10, &dom_id)) {
+
+	if (dom && !strcmp(id, "*")) {
+		update_all = true;
+	} else if (!dom || kstrtoul(id, 10, &dom_id)) {
 		rdt_last_cmd_puts("Missing '=' or non-numeric domain\n");
 		return -EINVAL;
 	}
 
 	dom = strim(dom);
 	list_for_each_entry(d, &r->ctrl_domains, hdr.list) {
-		if (d->hdr.id == dom_id) {
+		if (update_all || d->hdr.id == dom_id) {
 			data.buf = dom;
 			data.mode = RDT_MODE_SHAREABLE;
 			data.closid = closid;
@@ -988,10 +997,15 @@ next:
 				       &d->staged_config[s->conf_type],
 				       sizeof(d->staged_config[0]));
 			}
-			goto next;
+			if (!update_all)
+				goto next;
 		}
 	}
 
+	if (update_all)
+		goto next;
+
+	rdt_last_cmd_printf("Invalid domain %lu\n", dom_id);
 	return -EINVAL;
 }
 
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 49f3f6b846b2..9fd901c78dc6 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -234,6 +234,8 @@ static struct rmid_entry *resctrl_find_free_rmid(u32 closid)
  *
  * When the CLOSID and RMID are independent numbers, the first free CLOSID will
  * be returned.
+ *
+ * Return: Free CLOSID on success, < 0 on failure.
  */
 int resctrl_find_cleanest_closid(void)
 {
diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c
index 5da305bd36c9..5dfdaa6f9d8f 100644
--- a/fs/resctrl/rdtgroup.c
+++ b/fs/resctrl/rdtgroup.c
@@ -1519,6 +1519,8 @@ out:
  *
  * @cbm is unsigned long, even if only 32 bits are used to make the
  * bitmap functions work correctly.
+ *
+ * Return: Size (in bytes) of cache portion represented by CBM, 0 on failure.
  */
 unsigned int rdtgroup_cbm_to_size(struct rdt_resource *r,
 				  struct rdt_ctrl_domain *d, unsigned long cbm)
@@ -3102,6 +3104,8 @@ static void rmdir_all_sub(void)
  * @mevt:   The type of event file being created.
  * @do_sum: Whether SNC summing monitors are being created. Only set
  *	    when @rid == RDT_RESOURCE_L3.
+ *
+ * Return: Pointer to mon_data private data of the event, NULL on failure.
  */
 static struct mon_data *mon_get_kn_priv(enum resctrl_res_level rid, int domid,
 					struct mon_evt *mevt,
@@ -3496,6 +3500,8 @@ out_destroy:
  * resource group is initialized. The user can follow this with a
  * modification to the CBM if the default does not satisfy the
  * requirements.
+ *
+ * Return: A CBM that is valid for resource @r.
  */
 static u32 cbm_ensure_valid(u32 _val, struct rdt_resource *r)
 {