From 80347cd515ca149f1da31786ec9a59b0dfd1e579 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 4 Aug 2023 09:58:53 +0200 Subject: [PATCH] x86/microcode: Remove microcode_mutex microcode_mutex is only used by reload_store(). It has a comment saying "to synchronize with each other". Other user of this mutex have been removed in the commits 181b6f40e9ea8 ("x86/microcode: Rip out the OLD_INTERFACE"). b6f86689d5b74 ("x86/microcode: Rip out the subsys interface gunk") The sysfs interface does not need additional synchronisation vs itself because it is provided as kernfs_ops::mutex which is acquired in kernfs_fop_write_iter(). Remove the superfluous microcode_mutex. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Sohil Mehta Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230804075853.JF_n6GXC@linutronix.de --- arch/x86/kernel/cpu/common.c | 3 +-- arch/x86/kernel/cpu/microcode/core.c | 6 ------ 2 files changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 52683fddafaf4..06015f304cb8e 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -2276,8 +2276,7 @@ void store_cpu_caps(struct cpuinfo_x86 *curr_info) * @prev_info: CPU capabilities stored before an update. * * The microcode loader calls this upon late microcode load to recheck features, - * only when microcode has been updated. Caller holds microcode_mutex and CPU - * hotplug lock. + * only when microcode has been updated. Caller holds and CPU hotplug lock. * * Return: None */ diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index 192adf5f948e3..c9a53e330df35 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -54,15 +54,12 @@ LIST_HEAD(microcode_cache); * * All non cpu-hotplug-callback call sites use: * - * - microcode_mutex to synchronize with each other; * - cpus_read_lock/unlock() to synchronize with * the cpu-hotplug-callback call sites. * * We guarantee that only a single cpu is being * updated at any particular moment of time. */ -static DEFINE_MUTEX(microcode_mutex); - struct ucode_cpu_info ucode_cpu_info[NR_CPUS]; struct cpu_info_ctx { @@ -488,10 +485,7 @@ static ssize_t reload_store(struct device *dev, if (tmp_ret != UCODE_NEW) goto put; - mutex_lock(µcode_mutex); ret = microcode_reload_late(); - mutex_unlock(µcode_mutex); - put: cpus_read_unlock(); -- 2.30.2