1 files changed, 116 insertions, 44 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 5c7d10ead4ad..c3dee381f1b4 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -20,7 +20,9 @@
 #include <linux/cdev.h>
 #include <linux/fsnotify.h>
 #include <linux/sysctl.h>
+#include <linux/lglock.h>
 #include <linux/percpu_counter.h>
+#include <linux/percpu.h>
 #include <linux/ima.h>
 
 #include <asm/atomic.h>
@@ -32,8 +34,8 @@ struct files_stat_struct files_stat = {
         .max_files = NR_FILE
 };
 
-/* public. Not pretty! */
-__cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock);
+DECLARE_LGLOCK(files_lglock);
+DEFINE_LGLOCK(files_lglock);
 
 /* SLAB cache for file structures */
 static struct kmem_cache *filp_cachep __read_mostly;
@@ -58,7 +60,7 @@ static inline void file_free(struct file *f)
 /*
  * Return the total number of open files in the system
  */
-static int get_nr_files(void)
+static long get_nr_files(void)
 {
         return percpu_counter_read_positive(&nr_files);
 }
@@ -66,7 +68,7 @@ static int get_nr_files(void)
 /*
  * Return the maximum number of open files in the system
  */
-int get_max_files(void)
+unsigned long get_max_files(void)
 {
         return files_stat.max_files;
 }
@@ -80,7 +82,7 @@ int proc_nr_files(ctl_table *table, int write,
                      void __user *buffer, size_t *lenp, loff_t *ppos)
 {
         files_stat.nr_files = get_nr_files();
-        return proc_dointvec(table, write, buffer, lenp, ppos);
+        return proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
 }
 #else
 int proc_nr_files(ctl_table *table, int write,
@@ -103,7 +105,7 @@ int proc_nr_files(ctl_table *table, int write,
 struct file *get_empty_filp(void)
 {
         const struct cred *cred = current_cred();
-        static int old_max;
+        static long old_max;
         struct file * f;
 
         /*
@@ -138,8 +140,7 @@ struct file *get_empty_filp(void)
 over:
         /* Ran out of filps - report that */
         if (get_nr_files() > old_max) {
-                printk(KERN_INFO "VFS: file-max limit %d reached\n",
-                                        get_max_files());
+                pr_info("VFS: file-max limit %lu reached\n", get_max_files());
                 old_max = get_nr_files();
         }
         goto fail;
@@ -249,7 +250,7 @@ static void __fput(struct file *file)
                 cdev_put(inode->i_cdev);
         fops_put(file->f_op);
         put_pid(file->f_owner.pid);
-        file_kill(file);
+        file_sb_list_del(file);
         if (file->f_mode & FMODE_WRITE)
                 drop_file_write_access(file);
         file->f_path.dentry = NULL;
@@ -289,11 +290,20 @@ struct file *fget(unsigned int fd)
 EXPORT_SYMBOL(fget);
 
 /*
- * Lightweight file lookup - no refcnt increment if fd table isn't shared. 
- * You can use this only if it is guranteed that the current task already 
- * holds a refcnt to that file. That check has to be done at fget() only
- * and a flag is returned to be passed to the corresponding fput_light().
- * There must not be a cloning between an fget_light/fput_light pair.
+ * Lightweight file lookup - no refcnt increment if fd table isn't shared.
+ *
+ * You can use this instead of fget if you satisfy all of the following
+ * conditions:
+ * 1) You must call fput_light before exiting the syscall and returning control
+ *    to userspace (i.e. you cannot remember the returned struct file * after
+ *    returning to userspace).
+ * 2) You must not call filp_close on the returned struct file * in between
+ *    calls to fget_light and fput_light.
+ * 3) You must not clone the current task in between the calls to fget_light
+ *    and fput_light.
+ *
+ * The fput_needed flag returned by fget_light should be passed to the
+ * corresponding fput_light.
  */
 struct file *fget_light(unsigned int fd, int *fput_needed)
 {
@@ -319,41 +329,107 @@ struct file *fget_light(unsigned int fd, int *fput_needed)
         return file;
 }
 
-
 void put_filp(struct file *file)
 {
         if (atomic_long_dec_and_test(&file->f_count)) {
                 security_file_free(file);
-                file_kill(file);
+                file_sb_list_del(file);
                 file_free(file);
         }
 }
 
-void file_move(struct file *file, struct list_head *list)
+static inline int file_list_cpu(struct file *file)
 {
-        if (!list)
-                return;
-        file_list_lock();
-        list_move(&file->f_u.fu_list, list);
-        file_list_unlock();
+#ifdef CONFIG_SMP
+        return file->f_sb_list_cpu;
+#else
+        return smp_processor_id();
+#endif
 }
 
-void file_kill(struct file *file)
+/* helper for file_sb_list_add to reduce ifdefs */
+static inline void __file_sb_list_add(struct file *file, struct super_block *sb)
+{
+        struct list_head *list;
+#ifdef CONFIG_SMP
+        int cpu;
+        cpu = smp_processor_id();
+        file->f_sb_list_cpu = cpu;
+        list = per_cpu_ptr(sb->s_files, cpu);
+#else
+        list = &sb->s_files;
+#endif
+        list_add(&file->f_u.fu_list, list);
+}
+
+/**
+ * file_sb_list_add - add a file to the sb's file list
+ * @file: file to add
+ * @sb: sb to add it to
+ *
+ * Use this function to associate a file with the superblock of the inode it
+ * refers to.
+ */
+void file_sb_list_add(struct file *file, struct super_block *sb)
+{
+        lg_local_lock(files_lglock);
+        __file_sb_list_add(file, sb);
+        lg_local_unlock(files_lglock);
+}
+
+/**
+ * file_sb_list_del - remove a file from the sb's file list
+ * @file: file to remove
+ * @sb: sb to remove it from
+ *
+ * Use this function to remove a file from its superblock.
+ */
+void file_sb_list_del(struct file *file)
 {
         if (!list_empty(&file->f_u.fu_list)) {
-                file_list_lock();
+                lg_local_lock_cpu(files_lglock, file_list_cpu(file));
                 list_del_init(&file->f_u.fu_list);
-                file_list_unlock();
+                lg_local_unlock_cpu(files_lglock, file_list_cpu(file));
         }
 }
 
+#ifdef CONFIG_SMP
+
+/*
+ * These macros iterate all files on all CPUs for a given superblock.
+ * files_lglock must be held globally.
+ */
+#define do_file_list_for_each_entry(__sb, __file)               \
+{                                                               \
+        int i;                                                  \
+        for_each_possible_cpu(i) {                              \
+                struct list_head *list;                         \
+                list = per_cpu_ptr((__sb)->s_files, i);         \
+                list_for_each_entry((__file), list, f_u.fu_list)
+
+#define while_file_list_for_each_entry                          \
+        }                                                       \
+}
+
+#else
+
+#define do_file_list_for_each_entry(__sb, __file)               \
+{                                                               \
+        struct list_head *list;                                 \
+        list = &(sb)->s_files;                                  \
+        list_for_each_entry((__file), list, f_u.fu_list)
+
+#define while_file_list_for_each_entry                          \
+}
+
+#endif
+
 int fs_may_remount_ro(struct super_block *sb)
 {
         struct file *file;
-
         /* Check that no files are currently opened for writing. */
-        file_list_lock();
-        list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
+        lg_global_lock(files_lglock);
+        do_file_list_for_each_entry(sb, file) {
                 struct inode *inode = file->f_path.dentry->d_inode;
 
                 /* File with pending delete? */
@@ -363,11 +439,11 @@ int fs_may_remount_ro(struct super_block *sb)
                 /* Writeable file? */
                 if (S_ISREG(inode->i_mode) && (file->f_mode & FMODE_WRITE))
                         goto too_bad;
-        }
-        file_list_unlock();
+        } while_file_list_for_each_entry;
+        lg_global_unlock(files_lglock);
         return 1; /* Tis' cool bro. */
 too_bad:
-        file_list_unlock();
+        lg_global_unlock(files_lglock);
         return 0;
 }
 
@@ -383,8 +459,8 @@ void mark_files_ro(struct super_block *sb)
         struct file *f;
 
 retry:
-        file_list_lock();
-        list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
+        lg_global_lock(files_lglock);
+        do_file_list_for_each_entry(sb, f) {
                 struct vfsmount *mnt;
                 if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
                        continue;
@@ -399,21 +475,18 @@ retry:
                         continue;
                 file_release_write(f);
                 mnt = mntget(f->f_path.mnt);
-                file_list_unlock();
-                /*
-                 * This can sleep, so we can't hold
-                 * the file_list_lock() spinlock.
-                 */
+                /* This can sleep, so we can't hold the spinlock. */
+                lg_global_unlock(files_lglock);
                 mnt_drop_write(mnt);
                 mntput(mnt);
                 goto retry;
-        }
-        file_list_unlock();
+        } while_file_list_for_each_entry;
+        lg_global_unlock(files_lglock);
 }
 
 void __init files_init(unsigned long mempages)
 { 
-        int n; 
+        unsigned long n;
 
         filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
                         SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
@@ -424,9 +497,8 @@ void __init files_init(unsigned long mempages)
          */ 
 
         n = (mempages * (PAGE_SIZE / 1024)) / 10;
-        files_stat.max_files = n; 
-        if (files_stat.max_files < NR_FILE)
-                files_stat.max_files = NR_FILE;
+        files_stat.max_files = max_t(unsigned long, n, NR_FILE);
         files_defer_init();
+        lg_lock_init(files_lglock);
         percpu_counter_init(&nr_files, 0);
 }