Unify /proc/slabinfo configuration

Both SLUB and SLAB really did almost exactly the same thing for
/proc/slabinfo setup, using duplicate code and per-allocator #ifdef's.

This just creates a common CONFIG_SLABINFO that is enabled by both SLUB
and SLAB, and shares all the setup code.  Maybe SLOB will want this some
day too.
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/proc/proc_misc.c

@@ -410,7 +410,7 @@ static const struct file_operations proc_modules_operations = {
 };
 #endif
 
-#ifdef CONFIG_SLAB
+#ifdef CONFIG_SLABINFO
 static int slabinfo_open(struct inode *inode, struct file *file)
 {
 	return seq_open(file, &slabinfo_op);
@@ -451,20 +451,6 @@ static const struct file_operations proc_slabstats_operations = {
 #endif
 #endif
 
-#ifdef CONFIG_SLUB
-static int slabinfo_open(struct inode *inode, struct file *file)
-{
-	return seq_open(file, &slabinfo_op);
-}
-
-static const struct file_operations proc_slabinfo_operations = {
-	.open		= slabinfo_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= seq_release,
-};
-#endif
-
 static int show_stat(struct seq_file *p, void *v)
 {
 	int i;
@@ -742,14 +728,11 @@ void __init proc_misc_init(void)
 #endif
 	create_seq_entry("stat", 0, &proc_stat_operations);
 	create_seq_entry("interrupts", 0, &proc_interrupts_operations);
-#ifdef CONFIG_SLAB
+#ifdef CONFIG_SLABINFO
 	create_seq_entry("slabinfo",S_IWUSR|S_IRUGO,&proc_slabinfo_operations);
 #ifdef CONFIG_DEBUG_SLAB_LEAK
 	create_seq_entry("slab_allocators", 0 ,&proc_slabstats_operations);
 #endif
-#endif
-#ifdef CONFIG_SLUB
-	create_seq_entry("slabinfo", S_IWUSR|S_IRUGO, &proc_slabinfo_operations);
 #endif
 	create_seq_entry("buddyinfo",S_IRUGO, &fragmentation_file_operations);
 	create_seq_entry("pagetypeinfo", S_IRUGO, &pagetypeinfo_file_ops);

include/linux/slab.h

@@ -271,5 +271,10 @@ static inline void *kzalloc(size_t size, gfp_t flags)
 	return kmalloc(size, flags | __GFP_ZERO);
 }
 
+#ifdef CONFIG_SLABINFO
+extern const struct seq_operations slabinfo_op;
+ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
+#endif
+
 #endif	/* __KERNEL__ */
 #endif	/* _LINUX_SLAB_H */

include/linux/slab_def.h

@@ -95,7 +95,4 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 
 #endif	/* CONFIG_NUMA */
 
-extern const struct seq_operations slabinfo_op;
-ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
-
 #endif	/* _LINUX_SLAB_DEF_H */

include/linux/slub_def.h

@@ -200,6 +200,4 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 }
 #endif
 
-extern const struct seq_operations slabinfo_op;
-
 #endif /* _LINUX_SLUB_DEF_H */

init/Kconfig

@@ -658,6 +658,12 @@ endchoice
 
 endmenu		# General setup
 
+config SLABINFO
+	bool
+	depends on PROC_FS
+	depends on SLAB || SLUB
+	default y
+
 config RT_MUTEXES
 	boolean
 	select PLIST

mm/slab.c

@@ -4105,7 +4105,7 @@ static void cache_reap(struct work_struct *w)
 	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
 }
 
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_SLABINFO
 
 static void print_slabinfo_header(struct seq_file *m)
 {

mm/slub.c

@@ -4127,7 +4127,14 @@ __initcall(slab_sysfs_init);
 /*
  * The /proc/slabinfo ABI
  */
-#ifdef CONFIG_PROC_FS
+#ifdef CONFIG_SLABINFO
+
+ssize_t slabinfo_write(struct file *file, const char __user * buffer,
+                       size_t count, loff_t *ppos)
+{
+	return -EINVAL;
+}
+
 
 static void print_slabinfo_header(struct seq_file *m)
 {
@@ -4201,4 +4208,4 @@ const struct seq_operations slabinfo_op = {
 	.show = s_show,
 };
 
-#endif /* CONFIG_PROC_FS */
+#endif /* CONFIG_SLABINFO */