[PATCH] s390: fadvise hint values.

Add special case for the POSIX_FADV_DONTNEED and POSIX_FADV_NOREUSE hint
values for s390-64.  The user space values in the s390-64 glibc headers for
these two defines have always been 6 and 7 instead of 4 and 5.  All 64 bit
applications therefore use the "wrong" values.  To get these applications
working without recompiling the kernel needs to accept the "wrong" values.
Since the values for s390-31 are 4 and 5 the compat wrapper for fadvise64
and fadvise64_64 need to rewrite the values for 31 bit system calls.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/s390/kernel/compat_linux.c b/arch/s390/kernel/compat_linux.c
index 614056222875f86a6210c9d4b8057894b562131f..18610cea03a21d6d59bfb23224ecf1672678c7bc 100644 (file)
--- a/arch/s390/kernel/compat_linux.c
+++ b/arch/s390/kernel/compat_linux.c
@@ -58,6 +58,7 @@
 #include <linux/compat.h>
 #include <linux/vfs.h>
 #include <linux/ptrace.h>
+#include <linux/fadvise.h>
 
 #include <asm/types.h>
 #include <asm/ipc.h>
@@ -1043,3 +1044,40 @@ sys32_timer_create(clockid_t which_clock, struct compat_sigevent *se32,
 
        return ret;
 }
+
+/*
+ * 31 bit emulation wrapper functions for sys_fadvise64/fadvise64_64.
+ * These need to rewrite the advise values for POSIX_FADV_{DONTNEED,NOREUSE}
+ * because the 31 bit values differ from the 64 bit values.
+ */
+
+asmlinkage long
+sys32_fadvise64(int fd, loff_t offset, size_t len, int advise)
+{
+       if (advise == 4)
+               advise = POSIX_FADV_DONTNEED;
+       else if (advise == 5)
+               advise = POSIX_FADV_NOREUSE;
+       return sys_fadvise64(fd, offset, len, advise);
+}
+
+struct fadvise64_64_args {
+       int fd;
+       long long offset;
+       long long len;
+       int advice;
+};
+
+asmlinkage long
+sys32_fadvise64_64(struct fadvise64_64_args __user *args)
+{
+       struct fadvise64_64_args a;
+
+       if ( copy_from_user(&a, args, sizeof(a)) )
+               return -EFAULT;
+       if (a.advice == 4)
+               a.advice = POSIX_FADV_DONTNEED;
+       else if (a.advice == 5)
+               a.advice = POSIX_FADV_NOREUSE;
+       return sys_fadvise64_64(a.fd, a.offset, a.len, a.advice);
+}

diff --git a/arch/s390/kernel/compat_wrapper.S b/arch/s390/kernel/compat_wrapper.S
index bf529739c8ab6a53709b4bf5507ae7c4ca7410f0..799a98eac92d6b18f8e76c971645a0a3269ea919 100644 (file)
--- a/arch/s390/kernel/compat_wrapper.S
+++ b/arch/s390/kernel/compat_wrapper.S
@@ -1251,12 +1251,12 @@ sys32_fadvise64_wrapper:
        or      %r3,%r4                 # get low word of 64bit loff_t
        llgfr   %r4,%r5                 # size_t (unsigned long)
        lgfr    %r5,%r6                 # int
-       jg      sys_fadvise64
+       jg      sys32_fadvise64
 
        .globl  sys32_fadvise64_64_wrapper
 sys32_fadvise64_64_wrapper:
        llgtr   %r2,%r2                 # struct fadvise64_64_args *
-       jg      s390_fadvise64_64
+       jg      sys32_fadvise64_64
 
        .globl  sys32_clock_settime_wrapper
 sys32_clock_settime_wrapper:

diff --git a/include/linux/fadvise.h b/include/linux/fadvise.h
index 6fc656dfb93d8f3dd7d518a3fe9cd776a9b5aad9..e8e747139b9a1483897f8c4b0aa9e8b9f4a49588 100644 (file)
--- a/include/linux/fadvise.h
+++ b/include/linux/fadvise.h
@@ -5,7 +5,17 @@
 #define POSIX_FADV_RANDOM      1 /* Expect random page references.  */
 #define POSIX_FADV_SEQUENTIAL  2 /* Expect sequential page references.  */
 #define POSIX_FADV_WILLNEED    3 /* Will need these pages.  */
+
+/*
+ * The advise values for POSIX_FADV_DONTNEED and POSIX_ADV_NOREUSE
+ * for s390-64 differ from the values for the rest of the world.
+ */
+#if defined(__s390x__)
+#define POSIX_FADV_DONTNEED    6 /* Don't need these pages.  */
+#define POSIX_FADV_NOREUSE     7 /* Data will be accessed once.  */
+#else
 #define POSIX_FADV_DONTNEED    4 /* Don't need these pages.  */
 #define POSIX_FADV_NOREUSE     5 /* Data will be accessed once.  */
+#endif
 
 #endif /* FADVISE_H_INCLUDED */