BINFMT: fill_elf_header cleanup - use straight memset first

This patch does simplify fill_elf_header function by setting
to zero the whole elf header first. So we fillup the fields
we really need only.

before:
   text    data     bss     dec     hex filename
  11735      80       0   11815    2e27 fs/binfmt_elf.o

after:
   text    data     bss     dec     hex filename
  11710      80       0   11790    2e0e fs/binfmt_elf.o

viola, 25 bytes of text is freed
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/binfmt_elf.c

@@ -1255,26 +1255,23 @@ static int writenote(struct memelfnote *men, struct file *file,
 static void fill_elf_header(struct elfhdr *elf, int segs,
 			    u16 machine, u32 flags, u8 osabi)
 {
+	memset(elf, 0, sizeof(*elf));
+
 	memcpy(elf->e_ident, ELFMAG, SELFMAG);
 	elf->e_ident[EI_CLASS] = ELF_CLASS;
 	elf->e_ident[EI_DATA] = ELF_DATA;
 	elf->e_ident[EI_VERSION] = EV_CURRENT;
 	elf->e_ident[EI_OSABI] = ELF_OSABI;
-	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
 
 	elf->e_type = ET_CORE;
 	elf->e_machine = machine;
 	elf->e_version = EV_CURRENT;
-	elf->e_entry = 0;
 	elf->e_phoff = sizeof(struct elfhdr);
-	elf->e_shoff = 0;
 	elf->e_flags = flags;
 	elf->e_ehsize = sizeof(struct elfhdr);
 	elf->e_phentsize = sizeof(struct elf_phdr);
 	elf->e_phnum = segs;
-	elf->e_shentsize = 0;
-	elf->e_shnum = 0;
-	elf->e_shstrndx = 0;
+
 	return;
 }