X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=fs%2Ffile_table.c;h=bcea1998b4de48b56fed18334159c34b2559d6c5;hb=1e624196f43c3a62122959e15c5f03572cdadb5d;hp=c3a5e2fd663b772d7eeb997171d6b052b82d680c;hpb=7079060f3e86ea4c1d4e9c1e356592ef9dcaaa1f;p=powerpc.git diff --git a/fs/file_table.c b/fs/file_table.c index c3a5e2fd66..bcea1998b4 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -5,6 +5,7 @@ * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu) */ +#include #include #include #include @@ -16,54 +17,70 @@ #include #include #include +#include #include #include +#include +#include + +#include /* sysctl tunables... */ struct files_stat_struct files_stat = { .max_files = NR_FILE }; -EXPORT_SYMBOL(files_stat); /* Needed by unix.o */ - /* public. Not pretty! */ - __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); +__cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); -static DEFINE_SPINLOCK(filp_count_lock); +static struct percpu_counter nr_files __cacheline_aligned_in_smp; -/* slab constructors and destructors are called from arbitrary - * context and must be fully threaded - use a local spinlock - * to protect files_stat.nr_files - */ -void filp_ctor(void *objp, struct kmem_cache *cachep, unsigned long cflags) +static inline void file_free_rcu(struct rcu_head *head) { - if ((cflags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == - SLAB_CTOR_CONSTRUCTOR) { - unsigned long flags; - spin_lock_irqsave(&filp_count_lock, flags); - files_stat.nr_files++; - spin_unlock_irqrestore(&filp_count_lock, flags); - } + struct file *f = container_of(head, struct file, f_u.fu_rcuhead); + kmem_cache_free(filp_cachep, f); } -void filp_dtor(void *objp, struct kmem_cache *cachep, unsigned long dflags) +static inline void file_free(struct file *f) { - unsigned long flags; - spin_lock_irqsave(&filp_count_lock, flags); - files_stat.nr_files--; - spin_unlock_irqrestore(&filp_count_lock, flags); + percpu_counter_dec(&nr_files); + call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); } -static inline void file_free_rcu(struct rcu_head *head) +/* + * Return the total number of open files in the system + */ +static int get_nr_files(void) { - struct file *f = container_of(head, struct file, f_u.fu_rcuhead); - kmem_cache_free(filp_cachep, f); + return percpu_counter_read_positive(&nr_files); } -static inline void file_free(struct file *f) +/* + * Return the maximum number of open files in the system + */ +int get_max_files(void) { - call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); + return files_stat.max_files; } +EXPORT_SYMBOL_GPL(get_max_files); + +/* + * Handle nr_files sysctl + */ +#if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) +int proc_nr_files(ctl_table *table, int write, struct file *filp, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + files_stat.nr_files = get_nr_files(); + return proc_dointvec(table, write, filp, buffer, lenp, ppos); +} +#else +int proc_nr_files(ctl_table *table, int write, struct file *filp, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + return -ENOSYS; +} +#endif /* Find an unused file structure and return a pointer to it. * Returns NULL, if there are no more free file structures or @@ -71,39 +88,47 @@ static inline void file_free(struct file *f) */ struct file *get_empty_filp(void) { + struct task_struct *tsk; static int old_max; struct file * f; /* * Privileged users can go above max_files */ - if (files_stat.nr_files >= files_stat.max_files && - !capable(CAP_SYS_ADMIN)) - goto over; + if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) { + /* + * percpu_counters are inaccurate. Do an expensive check before + * we go and fail. + */ + if (percpu_counter_sum(&nr_files) >= files_stat.max_files) + goto over; + } f = kmem_cache_alloc(filp_cachep, GFP_KERNEL); if (f == NULL) goto fail; + percpu_counter_inc(&nr_files); memset(f, 0, sizeof(*f)); if (security_file_alloc(f)) goto fail_sec; - eventpoll_init_file(f); + tsk = current; + INIT_LIST_HEAD(&f->f_u.fu_list); atomic_set(&f->f_count, 1); - f->f_uid = current->fsuid; - f->f_gid = current->fsgid; rwlock_init(&f->f_owner.lock); + f->f_uid = tsk->fsuid; + f->f_gid = tsk->fsgid; + eventpoll_init_file(f); /* f->f_version: 0 */ - INIT_LIST_HEAD(&f->f_u.fu_list); return f; over: /* Ran out of filps - report that */ - if (files_stat.nr_files > old_max) { + if (get_nr_files() > old_max) { printk(KERN_INFO "VFS: file-max limit %d reached\n", - files_stat.max_files); - old_max = files_stat.nr_files; + get_max_files()); + old_max = get_nr_files(); } goto fail; @@ -117,7 +142,7 @@ EXPORT_SYMBOL(get_empty_filp); void fastcall fput(struct file *file) { - if (rcuref_dec_and_test(&file->f_count)) + if (atomic_dec_and_test(&file->f_count)) __fput(file); } @@ -166,7 +191,7 @@ struct file fastcall *fget(unsigned int fd) rcu_read_lock(); file = fcheck_files(files, fd); if (file) { - if (!rcuref_inc_lf(&file->f_count)) { + if (!atomic_inc_not_zero(&file->f_count)) { /* File object ref couldn't be taken */ rcu_read_unlock(); return NULL; @@ -198,7 +223,7 @@ struct file fastcall *fget_light(unsigned int fd, int *fput_needed) rcu_read_lock(); file = fcheck_files(files, fd); if (file) { - if (rcuref_inc_lf(&file->f_count)) + if (atomic_inc_not_zero(&file->f_count)) *fput_needed = 1; else /* Didn't get the reference, someone's freed */ @@ -213,7 +238,7 @@ struct file fastcall *fget_light(unsigned int fd, int *fput_needed) void put_filp(struct file *file) { - if (rcuref_dec_and_test(&file->f_count)) { + if (atomic_dec_and_test(&file->f_count)) { security_file_free(file); file_kill(file); file_free(file); @@ -275,4 +300,5 @@ void __init files_init(unsigned long mempages) if (files_stat.max_files < NR_FILE) files_stat.max_files = NR_FILE; files_defer_init(); + percpu_counter_init(&nr_files); }