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>

1 files changed, 14 insertions, 38 deletions

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index fd5b2ea5d299..0bcfbb05c32d 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -31,6 +31,7 @@
 #include <linux/random.h>
 #include <linux/elf.h>
 #include <linux/utsname.h>
+#include <linux/coredump.h>
 #include <asm/uaccess.h>
 #include <asm/param.h>
 #include <asm/page.h>
@@ -1085,36 +1086,6 @@ out:
  * Modelled on fs/exec.c:aout_core_dump()
  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
  */
-/*
- * These are the only things you should do on a core-file: use only these
- * functions 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;
-}
 
 /*
  * Decide what to dump of a segment, part, all or none.
@@ -1249,11 +1220,6 @@ static int writenote(struct memelfnote *men, struct file *file,
 }
 #undef DUMP_WRITE
 
-#define DUMP_WRITE(addr, nr)                            \
-        if ((size += (nr)) > cprm->limit ||             \
-            !dump_write(cprm->file, (addr), (nr)))      \
-                goto end_coredump;
-
 static void fill_elf_header(struct elfhdr *elf, int segs,
                             u16 machine, u32 flags, u8 osabi)
 {
@@ -1934,7 +1900,10 @@ static int elf_core_dump(struct coredump_params *cprm)
         fs = get_fs();
         set_fs(KERNEL_DS);
 
-        DUMP_WRITE(elf, sizeof(*elf));
+        size += sizeof(*elf);
+        if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
+                goto end_coredump;
+
         offset += sizeof(*elf);                         /* Elf header */
         offset += (segs + 1) * sizeof(struct elf_phdr); /* Program headers */
         foffset = offset;
@@ -1948,7 +1917,11 @@ static int elf_core_dump(struct coredump_params *cprm)
 
                 fill_elf_note_phdr(&phdr, sz, offset);
                 offset += sz;
-                DUMP_WRITE(&phdr, sizeof(phdr));
+
+                size += sizeof(phdr);
+                if (size > cprm->limit
+                    || !dump_write(cprm->file, &phdr, sizeof(phdr)))
+                        goto end_coredump;
         }
 
         dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
@@ -1979,7 +1952,10 @@ static int elf_core_dump(struct coredump_params *cprm)
                         phdr.p_flags |= PF_X;
                 phdr.p_align = ELF_EXEC_PAGESIZE;
 
-                DUMP_WRITE(&phdr, sizeof(phdr));
+                size += sizeof(phdr);
+                if (size > cprm->limit
+                    || !dump_write(cprm->file, &phdr, sizeof(phdr)))
+                        goto end_coredump;
         }
 
 #ifdef ELF_CORE_WRITE_EXTRA_PHDRS