[PATCH] sys_fadvise64_64

Alas, both POSIX and I got the fadvise() interface wrong.  It needs to take a
64-bit length, not a 32-bit one.  Because fadvise(POSIX_FADV_DONTNEED) on a
4TB file will require 1000 syscalls.  Silly.

There are glibc's in the wild which use the existing syscall, so we must
make a new one.

arch/i386/kernel/entry.S

@@ -878,5 +878,6 @@ ENTRY(sys_call_table)
 	.long sys_fstatfs64	
 	.long sys_tgkill	/* 270 */
 	.long sys_utimes
+ 	.long sys_fadvise64_64
 
 nr_syscalls=(.-sys_call_table)/4

include/asm-i386/unistd.h

@@ -277,8 +277,9 @@
 #define __NR_fstatfs64		269
 #define __NR_tgkill		270
 #define __NR_utimes		271
+#define __NR_fadvise64_64	272
 
-#define NR_syscalls 272
+#define NR_syscalls 273
 
 /* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
 

mm/fadvise.c

@@ -20,7 +20,7 @@
  * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
  * deactivate the pages and clear PG_Referenced.
  */
-long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
+long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
 {
 	struct file *file = fget(fd);
 	struct inode *inode;
@@ -79,3 +79,9 @@ long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
 	fput(file);
 	return ret;
 }
+
+long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
+{
+	return sys_fadvise64_64(fd, offset, len, advice);
+}
+