1 files changed, 90 insertions, 18 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 6f0e62ecfddd..a04bdd81c11c 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>
@@ -32,7 +34,8 @@ struct files_stat_struct files_stat = {
         .max_files = NR_FILE
 };
 
-static __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;
@@ -336,30 +339,98 @@ void put_filp(struct file *file)
         }
 }
 
+static inline int file_list_cpu(struct file *file)
+{
+#ifdef CONFIG_SMP
+        return file->f_sb_list_cpu;
+#else
+        return smp_processor_id();
+#endif
+}
+
+/* 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)
 {
-        spin_lock(&files_lock);
-        BUG_ON(!list_empty(&file->f_u.fu_list));
-        list_add(&file->f_u.fu_list, &sb->s_files);
-        spin_unlock(&files_lock);
+        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)) {
-                spin_lock(&files_lock);
+                lg_local_lock_cpu(files_lglock, file_list_cpu(file));
                 list_del_init(&file->f_u.fu_list);
-                spin_unlock(&files_lock);
+                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. */
-        spin_lock(&files_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? */
@@ -369,11 +440,11 @@ 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;
-        }
-        spin_unlock(&files_lock);
+        } while_file_list_for_each_entry;
+        lg_global_unlock(files_lglock);
         return 1; /* Tis' cool bro. */
 too_bad:
-        spin_unlock(&files_lock);
+        lg_global_unlock(files_lglock);
         return 0;
 }
 
@@ -389,8 +460,8 @@ void mark_files_ro(struct super_block *sb)
         struct file *f;
 
 retry:
-        spin_lock(&files_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;
@@ -406,12 +477,12 @@ retry:
                 file_release_write(f);
                 mnt = mntget(f->f_path.mnt);
                 /* This can sleep, so we can't hold the spinlock. */
-                spin_unlock(&files_lock);
+                lg_global_unlock(files_lglock);
                 mnt_drop_write(mnt);
                 mntput(mnt);
                 goto retry;
-        }
-        spin_unlock(&files_lock);
+        } while_file_list_for_each_entry;
+        lg_global_unlock(files_lglock);
 }
 
 void __init files_init(unsigned long mempages)
@@ -431,5 +502,6 @@ void __init files_init(unsigned long mempages)
         if (files_stat.max_files < NR_FILE)
                 files_stat.max_files = NR_FILE;
         files_defer_init();
+        lg_lock_init(files_lglock);
         percpu_counter_init(&nr_files, 0);
 }