[PATCH v3 2/7] arm: Remove now superfluous sentinel elem from ctl_table arrays

From: Joel Granados via B4 Relay <devnull+j.granados.samsung.com@kernel.org>
To: Luis Chamberlain <mcgrof@kernel.org>,
	willy@infradead.org,  josh@joshtriplett.org,
	Kees Cook <keescook@chromium.org>,
	 Iurii Zaikin <yzaikin@google.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	 Vasily Gorbik <gor@linux.ibm.com>,
	 Alexander Gordeev <agordeev@linux.ibm.com>,
	 Christian Borntraeger <borntraeger@linux.ibm.com>,
	 Sven Schnelle <svens@linux.ibm.com>,
	 Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
	 Russell King <linux@armlinux.org.uk>,
	 Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	 Mark Rutland <mark.rutland@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	 Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org,  "H. Peter Anvin" <hpa@zytor.com>,
	Andy Lutomirski <luto@kernel.org>,
	 Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	 Christophe Leroy <christophe.leroy@csgroup.eu>,
	Guo Ren <guoren@kernel.org>,  Alexey Gladkov <legion@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, linux-s390@vger.kernel.org,
	 linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	 linux-riscv@lists.infradead.org, linuxppc-dev@lists.ozlabs.org,
	 linux-ia64@vger.kernel.org, linux-csky@vger.kernel.org,
	 Joel Granados <j.granados@samsung.com>
Subject: [PATCH v3 2/7] arm: Remove now superfluous sentinel elem from ctl_table arrays
Date: Mon, 02 Oct 2023 13:30:37 +0200	[thread overview]
Message-ID: <20231002-jag-sysctl_remove_empty_elem_arch-v3-2-606da2840a7a@samsung.com> (raw)
In-Reply-To: <20231002-jag-sysctl_remove_empty_elem_arch-v3-0-606da2840a7a@samsung.com>

From: Joel Granados <j.granados@samsung.com>

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/)

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.

This removal is safe because register_sysctl_sz and register_sysctl use
the array size in addition to checking for the sentinel.

Signed-off-by: Joel Granados <j.granados@samsung.com>
---
 arch/arm/kernel/isa.c                | 4 ++--
 arch/arm64/kernel/armv8_deprecated.c | 8 +++-----
 arch/arm64/kernel/fpsimd.c           | 2 --
 arch/arm64/kernel/process.c          | 1 -
 drivers/perf/arm_pmuv3.c             | 1 -
 5 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/arm/kernel/isa.c b/arch/arm/kernel/isa.c
index 20218876bef2..905b1b191546 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..9afd0eb0cf88 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -589,7 +589,6 @@ static struct ctl_table sve_default_vl_table[] = {
 		.proc_handler	= vec_proc_do_default_vl,
 		.extra1		= &vl_info[ARM64_VEC_SVE],
 	},
-	{ }
 };
 
 static int __init sve_sysctl_init(void)
@@ -613,7 +612,6 @@ static struct ctl_table sme_default_vl_table[] = {
 		.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..610e13c3d41b 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -724,7 +724,6 @@ static struct ctl_table tagged_addr_sysctl_table[] = {
 		.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 8fcaa26f0f8a..c0307b9181c3 100644
--- a/drivers/perf/arm_pmuv3.c
+++ b/drivers/perf/arm_pmuv3.c
@@ -1175,7 +1175,6 @@ static struct ctl_table armv8_pmu_sysctl_table[] = {
 		.extra1		= SYSCTL_ZERO,
 		.extra2		= SYSCTL_ONE,
 	},
-	{ }
 };
 
 static void armv8_pmu_register_sysctl_table(void)

-- 
2.30.2


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