From 86ef5c9a8edd78e6bf92879f32329d89b2d55b5a Mon Sep 17 00:00:00 2001 From: Gautham R Shenoy Date: Fri, 25 Jan 2008 21:08:02 +0100 Subject: cpu-hotplug: replace lock_cpu_hotplug() with get_online_cpus() Replace all lock_cpu_hotplug/unlock_cpu_hotplug from the kernel and use get_online_cpus and put_online_cpus instead as it highlights the refcount semantics in these operations. The new API guarantees protection against the cpu-hotplug operation, but it doesn't guarantee serialized access to any of the local data structures. Hence the changes needs to be reviewed. In case of pseries_add_processor/pseries_remove_processor, use cpu_maps_update_begin()/cpu_maps_update_done() as we're modifying the cpu_present_map there. Signed-off-by: Gautham R Shenoy Signed-off-by: Ingo Molnar --- arch/mips/kernel/mips-mt-fpaff.c | 10 +++++----- arch/powerpc/platforms/pseries/hotplug-cpu.c | 8 ++++---- arch/powerpc/platforms/pseries/rtasd.c | 8 ++++---- arch/x86/kernel/cpu/mtrr/main.c | 8 ++++---- arch/x86/kernel/microcode.c | 16 ++++++++-------- 5 files changed, 25 insertions(+), 25 deletions(-) (limited to 'arch') diff --git a/arch/mips/kernel/mips-mt-fpaff.c b/arch/mips/kernel/mips-mt-fpaff.c index 892665bb12b..bb4f00c0cbe 100644 --- a/arch/mips/kernel/mips-mt-fpaff.c +++ b/arch/mips/kernel/mips-mt-fpaff.c @@ -58,13 +58,13 @@ asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len, if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask))) return -EFAULT; - lock_cpu_hotplug(); + get_online_cpus(); read_lock(&tasklist_lock); p = find_process_by_pid(pid); if (!p) { read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); + put_online_cpus(); return -ESRCH; } @@ -106,7 +106,7 @@ asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len, out_unlock: put_task_struct(p); - unlock_cpu_hotplug(); + put_online_cpus(); return retval; } @@ -125,7 +125,7 @@ asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len, if (len < real_len) return -EINVAL; - lock_cpu_hotplug(); + get_online_cpus(); read_lock(&tasklist_lock); retval = -ESRCH; @@ -140,7 +140,7 @@ asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len, out_unlock: read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); + put_online_cpus(); if (retval) return retval; if (copy_to_user(user_mask_ptr, &mask, real_len)) diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index 412e6b42986..c4ad54e0f28 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -153,7 +153,7 @@ static int pseries_add_processor(struct device_node *np) for (i = 0; i < nthreads; i++) cpu_set(i, tmp); - lock_cpu_hotplug(); + cpu_maps_update_begin(); BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map)); @@ -190,7 +190,7 @@ static int pseries_add_processor(struct device_node *np) } err = 0; out_unlock: - unlock_cpu_hotplug(); + cpu_maps_update_done(); return err; } @@ -211,7 +211,7 @@ static void pseries_remove_processor(struct device_node *np) nthreads = len / sizeof(u32); - lock_cpu_hotplug(); + cpu_maps_update_begin(); for (i = 0; i < nthreads; i++) { for_each_present_cpu(cpu) { if (get_hard_smp_processor_id(cpu) != intserv[i]) @@ -225,7 +225,7 @@ static void pseries_remove_processor(struct device_node *np) printk(KERN_WARNING "Could not find cpu to remove " "with physical id 0x%x\n", intserv[i]); } - unlock_cpu_hotplug(); + cpu_maps_update_done(); } static int pseries_smp_notifier(struct notifier_block *nb, diff --git a/arch/powerpc/platforms/pseries/rtasd.c b/arch/powerpc/platforms/pseries/rtasd.c index 73401c82011..e3078ce4151 100644 --- a/arch/powerpc/platforms/pseries/rtasd.c +++ b/arch/powerpc/platforms/pseries/rtasd.c @@ -382,7 +382,7 @@ static void do_event_scan_all_cpus(long delay) { int cpu; - lock_cpu_hotplug(); + get_online_cpus(); cpu = first_cpu(cpu_online_map); for (;;) { set_cpus_allowed(current, cpumask_of_cpu(cpu)); @@ -390,15 +390,15 @@ static void do_event_scan_all_cpus(long delay) set_cpus_allowed(current, CPU_MASK_ALL); /* Drop hotplug lock, and sleep for the specified delay */ - unlock_cpu_hotplug(); + put_online_cpus(); msleep_interruptible(delay); - lock_cpu_hotplug(); + get_online_cpus(); cpu = next_cpu(cpu, cpu_online_map); if (cpu == NR_CPUS) break; } - unlock_cpu_hotplug(); + put_online_cpus(); } static int rtasd(void *unused) diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c index 3b20613325d..beb45c9c083 100644 --- a/arch/x86/kernel/cpu/mtrr/main.c +++ b/arch/x86/kernel/cpu/mtrr/main.c @@ -349,7 +349,7 @@ int mtrr_add_page(unsigned long base, unsigned long size, replace = -1; /* No CPU hotplug when we change MTRR entries */ - lock_cpu_hotplug(); + get_online_cpus(); /* Search for existing MTRR */ mutex_lock(&mtrr_mutex); for (i = 0; i < num_var_ranges; ++i) { @@ -405,7 +405,7 @@ int mtrr_add_page(unsigned long base, unsigned long size, error = i; out: mutex_unlock(&mtrr_mutex); - unlock_cpu_hotplug(); + put_online_cpus(); return error; } @@ -495,7 +495,7 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size) max = num_var_ranges; /* No CPU hotplug when we change MTRR entries */ - lock_cpu_hotplug(); + get_online_cpus(); mutex_lock(&mtrr_mutex); if (reg < 0) { /* Search for existing MTRR */ @@ -536,7 +536,7 @@ int mtrr_del_page(int reg, unsigned long base, unsigned long size) error = reg; out: mutex_unlock(&mtrr_mutex); - unlock_cpu_hotplug(); + put_online_cpus(); return error; } /** diff --git a/arch/x86/kernel/microcode.c b/arch/x86/kernel/microcode.c index 09c315214a5..40cfd548871 100644 --- a/arch/x86/kernel/microcode.c +++ b/arch/x86/kernel/microcode.c @@ -436,7 +436,7 @@ static ssize_t microcode_write (struct file *file, const char __user *buf, size_ return -EINVAL; } - lock_cpu_hotplug(); + get_online_cpus(); mutex_lock(µcode_mutex); user_buffer = (void __user *) buf; @@ -447,7 +447,7 @@ static ssize_t microcode_write (struct file *file, const char __user *buf, size_ ret = (ssize_t)len; mutex_unlock(µcode_mutex); - unlock_cpu_hotplug(); + put_online_cpus(); return ret; } @@ -658,14 +658,14 @@ static ssize_t reload_store(struct sys_device *dev, const char *buf, size_t sz) old = current->cpus_allowed; - lock_cpu_hotplug(); + get_online_cpus(); set_cpus_allowed(current, cpumask_of_cpu(cpu)); mutex_lock(µcode_mutex); if (uci->valid) err = cpu_request_microcode(cpu); mutex_unlock(µcode_mutex); - unlock_cpu_hotplug(); + put_online_cpus(); set_cpus_allowed(current, old); } if (err) @@ -817,9 +817,9 @@ static int __init microcode_init (void) return PTR_ERR(microcode_pdev); } - lock_cpu_hotplug(); + get_online_cpus(); error = sysdev_driver_register(&cpu_sysdev_class, &mc_sysdev_driver); - unlock_cpu_hotplug(); + put_online_cpus(); if (error) { microcode_dev_exit(); platform_device_unregister(microcode_pdev); @@ -839,9 +839,9 @@ static void __exit microcode_exit (void) unregister_hotcpu_notifier(&mc_cpu_notifier); - lock_cpu_hotplug(); + get_online_cpus(); sysdev_driver_unregister(&cpu_sysdev_class, &mc_sysdev_driver); - unlock_cpu_hotplug(); + put_online_cpus(); platform_device_unregister(microcode_pdev); } -- cgit v1.2.3