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

From: Joel Granados via B4 Relay
Date: Mon Oct 02 2023 - 07:29:39 EST


From: Joel Granados <j.granados@xxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxxxxx/)

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@xxxxxxxxxxx>
---
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