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Subject: [PATCH v5 2/2] x86/resctrl: Remove arch_has_empty_bitmaps
From:   Babu Moger <babu.moger@amd.com>
To:     <corbet@lwn.net>, <reinette.chatre@intel.com>,
        <tglx@linutronix.de>, <mingo@redhat.com>, <bp@alien8.de>
CC:     <fenghua.yu@intel.com>, <dave.hansen@linux.intel.com>,
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Date:   Tue, 27 Sep 2022 15:16:36 -0500
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The field arch_has_empty_bitmaps is not required anymore. The field=0A=
min_cbm_bits is enough to validate the CBM (capacity bit mask) if the=0A=
architecture can support the zero CBM or not.=0A=
=0A=
Suggested-by: Reinette Chatre <reinette.chatre@intel.com>=0A=
Signed-off-by: Babu Moger <babu.moger@amd.com>=0A=
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>=0A=
---=0A=
 arch/x86/kernel/cpu/resctrl/core.c        |    2 --=0A=
 arch/x86/kernel/cpu/resctrl/ctrlmondata.c |    3 +--=0A=
 include/linux/resctrl.h                   |    6 +++---=0A=
 3 files changed, 4 insertions(+), 7 deletions(-)=0A=
=0A=
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resct=
rl/core.c=0A=
index a5c51a14fbce..c2657754672e 100644=0A=
--- a/arch/x86/kernel/cpu/resctrl/core.c=0A=
+++ b/arch/x86/kernel/cpu/resctrl/core.c=0A=
@@ -869,7 +869,6 @@ static __init void rdt_init_res_defs_intel(void)=0A=
 		if (r->rid =3D=3D RDT_RESOURCE_L3 ||=0A=
 		    r->rid =3D=3D RDT_RESOURCE_L2) {=0A=
 			r->cache.arch_has_sparse_bitmaps =3D false;=0A=
-			r->cache.arch_has_empty_bitmaps =3D false;=0A=
 			r->cache.arch_has_per_cpu_cfg =3D false;=0A=
 			r->cache.min_cbm_bits =3D 1;=0A=
 		} else if (r->rid =3D=3D RDT_RESOURCE_MBA) {=0A=
@@ -890,7 +889,6 @@ static __init void rdt_init_res_defs_amd(void)=0A=
 		if (r->rid =3D=3D RDT_RESOURCE_L3 ||=0A=
 		    r->rid =3D=3D RDT_RESOURCE_L2) {=0A=
 			r->cache.arch_has_sparse_bitmaps =3D true;=0A=
-			r->cache.arch_has_empty_bitmaps =3D true;=0A=
 			r->cache.arch_has_per_cpu_cfg =3D true;=0A=
 			r->cache.min_cbm_bits =3D 0;=0A=
 		} else if (r->rid =3D=3D RDT_RESOURCE_MBA) {=0A=
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cp=
u/resctrl/ctrlmondata.c=0A=
index 87666275eed9..7f38c8bd8429 100644=0A=
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c=0A=
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c=0A=
@@ -98,8 +98,7 @@ static bool cbm_validate(char *buf, u32 *data, struct rdt=
_resource *r)=0A=
 		return false;=0A=
 	}=0A=
 =0A=
-	if ((!r->cache.arch_has_empty_bitmaps && val =3D=3D 0) ||=0A=
-	    val > r->default_ctrl) {=0A=
+	if ((r->cache.min_cbm_bits > 0 && val =3D=3D 0) || val > r->default_ctrl)=
 {=0A=
 		rdt_last_cmd_puts("Mask out of range\n");=0A=
 		return false;=0A=
 	}=0A=
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h=0A=
index 21deb5212bbd..46ed8589857c 100644=0A=
--- a/include/linux/resctrl.h=0A=
+++ b/include/linux/resctrl.h=0A=
@@ -72,11 +72,12 @@ struct rdt_domain {=0A=
 /**=0A=
  * struct resctrl_cache - Cache allocation related data=0A=
  * @cbm_len:		Length of the cache bit mask=0A=
- * @min_cbm_bits:	Minimum number of consecutive bits to be set=0A=
+ * @min_cbm_bits:	Minimum number of consecutive bits to be set.=0A=
+ *			The value 0 means the architecture can support=0A=
+ *			zero CBM.=0A=
  * @shareable_bits:	Bitmask of shareable resource with other=0A=
  *			executing entities=0A=
  * @arch_has_sparse_bitmaps:	True if a bitmap like f00f is valid.=0A=
- * @arch_has_empty_bitmaps:	True if the '0' bitmap is valid.=0A=
  * @arch_has_per_cpu_cfg:	True if QOS_CFG register for this cache=0A=
  *				level has CPU scope.=0A=
  */=0A=
@@ -85,7 +86,6 @@ struct resctrl_cache {=0A=
 	unsigned int	min_cbm_bits;=0A=
 	unsigned int	shareable_bits;=0A=
 	bool		arch_has_sparse_bitmaps;=0A=
-	bool		arch_has_empty_bitmaps;=0A=
 	bool		arch_has_per_cpu_cfg;=0A=
 };=0A=
 =0A=
=0A=