[PATCH 2/8] arm: Remove sentinel elem from ctl_table arrays

From: Joel Granados via B4 Relay <devnull+j.granados.samsung.com@kernel.org>
Date: 2023-09-06 10:04:33
Also in: b4-sent, linux-fsdevel, linux-riscv, linux-s390, linuxppc-dev, lkml
Subsystem: arm pmu profiling and debugging, arm port, arm64 port (aarch64 architecture), the rest · Maintainers: Will Deacon, Mark Rutland, Russell King, Catalin Marinas, Linus Torvalds

From: Joel Granados <redacted>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/ (local))

Removed the sentinel as well as the explicit size from ctl_isa_vars. The
size is redundant as the initialization sets it.
Changed insn_emulation->sysctl from a 2 element array of struct
ctl_table to a simple struct. This has no consequence for the sysctl
registration as it is forwarded as a pointer.
Removed sentinel from sve_defatul_vl_table, sme_default_vl_table,
tagged_addr_sysctl_table and armv8_pmu_sysctl_table.

Signed-off-by: Joel Granados <redacted>
---
 arch/arm/kernel/isa.c                | 4 ++--
 arch/arm64/kernel/armv8_deprecated.c | 8 +++-----
 arch/arm64/kernel/fpsimd.c           | 6 ++----
 arch/arm64/kernel/process.c          | 3 +--
 drivers/perf/arm_pmuv3.c             | 3 +--
 5 files changed, 9 insertions(+), 15 deletions(-)

diff --git a/arch/arm/kernel/isa.c b/arch/arm/kernel/isa.c
index 20218876bef2..0b9c28077092 100644
--- a/arch/arm/kernel/isa.c
+++ b/arch/arm/kernel/isa.c

@@ -16,7 +16,7 @@
 
 static unsigned int isa_membase, isa_portbase, isa_portshift;
 
-static struct ctl_table ctl_isa_vars[4] = {
+static struct ctl_table ctl_isa_vars[] = {
 	{
 		.procname	= "membase",
 		.data		= &isa_membase,

@@ -35,7 +35,7 @@ static struct ctl_table ctl_isa_vars[4] = {
 		.maxlen		= sizeof(isa_portshift),
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
-	}, {}
+	}
 };
 
 static struct ctl_table_header *isa_sysctl_header;

diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index e459cfd33711..dd6ce86d4332 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c

@@ -52,10 +52,8 @@ struct insn_emulation {
 	int min;
 	int max;
 
-	/*
-	 * sysctl for this emulation + a sentinal entry.
-	 */
-	struct ctl_table sysctl[2];
+	/* sysctl for this emulation */
+	struct ctl_table sysctl;
 };
 
 #define ARM_OPCODE_CONDTEST_FAIL   0

@@ -558,7 +556,7 @@ static void __init register_insn_emulation(struct insn_emulation *insn)
 	update_insn_emulation_mode(insn, INSN_UNDEF);
 
 	if (insn->status != INSN_UNAVAILABLE) {
-		sysctl = &insn->sysctl[0];
+		sysctl = &insn->sysctl;
 
 		sysctl->mode = 0644;
 		sysctl->maxlen = sizeof(int);

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 91e44ac7150f..db3ad1ba8272 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c

@@ -588,8 +588,7 @@ static struct ctl_table sve_default_vl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= vec_proc_do_default_vl,
 		.extra1		= &vl_info[ARM64_VEC_SVE],
-	},
-	{ }
+	}
 };
 
 static int __init sve_sysctl_init(void)

@@ -612,8 +611,7 @@ static struct ctl_table sme_default_vl_table[] = {
 		.mode		= 0644,
 		.proc_handler	= vec_proc_do_default_vl,
 		.extra1		= &vl_info[ARM64_VEC_SME],
-	},
-	{ }
+	}
 };
 
 static int __init sme_sysctl_init(void)

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 0fcc4eb1a7ab..48861cdc3aae 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c

@@ -723,8 +723,7 @@ static struct ctl_table tagged_addr_sysctl_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
-	},
-	{ }
+	}
 };
 
 static int __init tagged_addr_init(void)

diff --git a/drivers/perf/arm_pmuv3.c b/drivers/perf/arm_pmuv3.c
index e5a2ac4155f6..c4aa6a8d1b05 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c

@@ -1172,8 +1172,7 @@ static struct ctl_table armv8_pmu_sysctl_table[] = {
 		.proc_handler	= armv8pmu_proc_user_access_handler,
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
-	},
-	{ }
+	}
 };
 
 static void armv8_pmu_register_sysctl_table(void)

-- 
2.30.2


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