coredump: move dump_write() and dump_seek() into a header file

My next patch will replace ELF_CORE_EXTRA_* macros by functions, putting
them into other newly created *.c files.  Then, each files will contain
dump_write(), where each pair of binfmt_*.c and elfcore.c should be the
same.  So, this patch moves them into a header file with dump_seek().
Also, the patch deletes confusing DUMP_WRITE macros in each files.

Signed-off-by: Daisuke HATAYAMA <d.hatayama@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c
index d2f8872..15d80bb 100644
--- a/fs/binfmt_aout.c
+++ b/fs/binfmt_aout.c
@@ -24,6 +24,7 @@
 #include <linux/binfmts.h>
 #include <linux/personality.h>
 #include <linux/init.h>
+#include <linux/coredump.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -60,42 +61,6 @@
 }
 
 /*
- * These are the only things you should do on a core-file: use only these
- * macros to write out all the necessary info.
- */
-
-static int dump_write(struct file *file, const void *addr, int nr)
-{
-	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
-}
-
-static int dump_seek(struct file *file, loff_t off)
-{
-	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
-		if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
-			return 0;
-	} else {
-		char *buf = (char *)get_zeroed_page(GFP_KERNEL);
-		if (!buf)
-			return 0;
-		while (off > 0) {
-			unsigned long n = off;
-			if (n > PAGE_SIZE)
-				n = PAGE_SIZE;
-			if (!dump_write(file, buf, n))
-				return 0;
-			off -= n;
-		}
-		free_page((unsigned long)buf);
-	}
-	return 1;
-}
-
-#define DUMP_WRITE(addr, nr)	\
-	if (!dump_write(file, (void *)(addr), (nr))) \
-		goto end_coredump;
-
-/*
  * Routine writes a core dump image in the current directory.
  * Currently only a stub-function.
  *
@@ -146,7 +111,8 @@
 
 	set_fs(KERNEL_DS);
 /* struct user */
-	DUMP_WRITE(&dump,sizeof(dump));
+	if (!dump_write(file, &dump, sizeof(dump)))
+		goto end_coredump;
 /* Now dump all of the user data.  Include malloced stuff as well */
 	if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump)))
 		goto end_coredump;
@@ -156,17 +122,20 @@
 	if (dump.u_dsize != 0) {
 		dump_start = START_DATA(dump);
 		dump_size = dump.u_dsize << PAGE_SHIFT;
-		DUMP_WRITE(dump_start,dump_size);
+		if (!dump_write(file, dump_start, dump_size))
+			goto end_coredump;
 	}
 /* Now prepare to dump the stack area */
 	if (dump.u_ssize != 0) {
 		dump_start = START_STACK(dump);
 		dump_size = dump.u_ssize << PAGE_SHIFT;
-		DUMP_WRITE(dump_start,dump_size);
+		if (!dump_write(file, dump_start, dump_size))
+			goto end_coredump;
 	}
 /* Finally dump the task struct.  Not be used by gdb, but could be useful */
 	set_fs(KERNEL_DS);
-	DUMP_WRITE(current,sizeof(*current));
+	if (!dump_write(file, current, sizeof(*current)))
+		goto end_coredump;
 end_coredump:
 	set_fs(fs);
 	return has_dumped;