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authorHelge Deller <deller@gmx.de>2013-02-04 19:39:52 +0000
committerHelge Deller <deller@gmx.de>2013-02-08 20:42:18 +0100
commit4f4ffc3a5398ef9bdbb32db04756d7d34e356fcf (patch)
treeb94869692f876ade9df44a3d550aaff3c157f11b /include
parent124b69b6cc1020fff589312c62fcaf360abd8d12 (diff)
unbreak automounter support on 64-bit kernel with 32-bit userspace (v2)
automount-support is broken on the parisc architecture, because the existing #if list does not include a check for defined(__hppa__). The HPPA (parisc) architecture is similiar to other 64bit Linux targets where we have to define autofs_wqt_t (which is passed back and forth to user space) as int type which has a size of 32bit across 32 and 64bit kernels. During the discussion on the mailing list, H. Peter Anvin suggested to invert the #if list since only specific platforms (specifically those who do not have a 32bit userspace, like IA64 and Alpha) should have autofs_wqt_t as unsigned long type. This suggestion is probably the best way to go, since Arm64 (and maybe others?) seems to have a non-working automounter. So in the long run even for other new upcoming architectures this inverted check seem to be the best solution, since it will not require them to change this #if again (unless they are 64bit only). Signed-off-by: Helge Deller <deller@gmx.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Acked-by: Ian Kent <raven@themaw.net> Acked-by: Catalin Marinas <catalin.marinas@arm.com> CC: James Bottomley <James.Bottomley@HansenPartnership.com> CC: Rolf Eike Beer <eike-kernel@sf-tec.de>
Diffstat (limited to 'include')
-rw-r--r--include/uapi/linux/auto_fs.h25
1 files changed, 8 insertions, 17 deletions
diff --git a/include/uapi/linux/auto_fs.h b/include/uapi/linux/auto_fs.h
index 77cdba9df27..bb991dfe134 100644
--- a/include/uapi/linux/auto_fs.h
+++ b/include/uapi/linux/auto_fs.h
@@ -28,25 +28,16 @@
#define AUTOFS_MIN_PROTO_VERSION AUTOFS_PROTO_VERSION
/*
- * Architectures where both 32- and 64-bit binaries can be executed
- * on 64-bit kernels need this. This keeps the structure format
- * uniform, and makes sure the wait_queue_token isn't too big to be
- * passed back down to the kernel.
- *
- * This assumes that on these architectures:
- * mode 32 bit 64 bit
- * -------------------------
- * int 32 bit 32 bit
- * long 32 bit 64 bit
- *
- * If so, 32-bit user-space code should be backwards compatible.
+ * The wait_queue_token (autofs_wqt_t) is part of a structure which is passed
+ * back to the kernel via ioctl from userspace. On architectures where 32- and
+ * 64-bit userspace binaries can be executed it's important that the size of
+ * autofs_wqt_t stays constant between 32- and 64-bit Linux kernels so that we
+ * do not break the binary ABI interface by changing the structure size.
*/
-
-#if defined(__sparc__) || defined(__mips__) || defined(__x86_64__) \
- || defined(__powerpc__) || defined(__s390__)
-typedef unsigned int autofs_wqt_t;
-#else
+#if defined(__ia64__) || defined(__alpha__) /* pure 64bit architectures */
typedef unsigned long autofs_wqt_t;
+#else
+typedef unsigned int autofs_wqt_t;
#endif
/* Packet types */