kmemtrace, fs: uninline simple_transaction_set()

Impact: cleanup

We want to remove percpu.h from rcupdate.h (for upcoming kmemtrace
changes), but this is not possible currently without breaking the
build because fs.h has an implicit include file depedency: it
uses PAGE_SIZE but does not include asm/page.h which defines it.

This problem gets masked in practice because most fs.h using sites
use rcupreempt.h (and other headers) which includes percpu.h which
brings in asm/page.h indirectly.

We cannot add asm/page.h to asm/fs.h because page.h is not an
exported header.

Move simple_transaction_set() to the other simple-transaction
file helpers in fs/libfs.c.

This removes the include file hell and also reduces
kernel size a bit.
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Cc: paulmck@linux.vnet.ibm.com
LKML-Reference: <1237898630.25315.83.camel@penberg-laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

fs/libfs.c

@@ -575,6 +575,21 @@ ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
  * possibly a read which collects the result - which is stored in a
  * file-local buffer.
  */
+
+void simple_transaction_set(struct file *file, size_t n)
+{
+	struct simple_transaction_argresp *ar = file->private_data;
+
+	BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
+
+	/*
+	 * The barrier ensures that ar->size will really remain zero until
+	 * ar->data is ready for reading.
+	 */
+	smp_mb();
+	ar->size = n;
+}
+
 char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
 {
 	struct simple_transaction_argresp *ar;
@@ -820,6 +835,7 @@ EXPORT_SYMBOL(simple_sync_file);
 EXPORT_SYMBOL(simple_unlink);
 EXPORT_SYMBOL(simple_read_from_buffer);
 EXPORT_SYMBOL(memory_read_from_buffer);
+EXPORT_SYMBOL(simple_transaction_set);
 EXPORT_SYMBOL(simple_transaction_get);
 EXPORT_SYMBOL(simple_transaction_read);
 EXPORT_SYMBOL(simple_transaction_release);

include/linux/fs.h

@@ -2323,19 +2323,7 @@ ssize_t simple_transaction_read(struct file *file, char __user *buf,
 				size_t size, loff_t *pos);
 int simple_transaction_release(struct inode *inode, struct file *file);
 
-static inline void simple_transaction_set(struct file *file, size_t n)
-{
-	struct simple_transaction_argresp *ar = file->private_data;
-
-	BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
-
-	/*
-	 * The barrier ensures that ar->size will really remain zero until
-	 * ar->data is ready for reading.
-	 */
-	smp_mb();
-	ar->size = n;
-}
+void simple_transaction_set(struct file *file, size_t n);
 
 /*
  * simple attribute files