Fix gcc configure warnings

Newer versions of gcc are getting smart enough to detect the sloppy
syntax used for the autoconf tests.  It is now generating warnings
for unused/undeclared variables.  Newer version of gcc even have
the -Wunused-but-set-variable option set by default.  This isn't a
problem except when -Werror is set and they get promoted to an error.
In this case the autoconf test will return an incorrect result which
will result in a build failure latter on.

To handle this I'm tightening up many of the autoconf tests to
explicitly mark variables as unused to suppress the gcc warning.
Remember, all of the autoconf code can never actually be run we
just want to get a clean build error to detect which APIs are
available.  Never using a variable is absolutely fine for this.

Closes #176

diff --git a/config/kernel-bio-end-io-t-args.m4 b/config/kernel-bio-end-io-t-args.m4
index ea69bdb..ced4861 100644 (file)
--- a/config/kernel-bio-end-io-t-args.m4
+++ b/config/kernel-bio-end-io-t-args.m4
@@ -15,7 +15,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_END_IO_T_ARGS], [
                #include <linux/bio.h>
        ],[
                void (*wanted_end_io)(struct bio *, int) = NULL;
-               bio_end_io_t *local_end_io;
+               bio_end_io_t *local_end_io __attribute__ ((unused));
 
                local_end_io = wanted_end_io;
        ],[

diff --git a/config/kernel-bio-failfast.m4 b/config/kernel-bio-failfast.m4
index c45175b..6b9a526 100644 (file)
--- a/config/kernel-bio-failfast.m4
+++ b/config/kernel-bio-failfast.m4
@@ -9,7 +9,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_FAILFAST], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = (1 << BIO_RW_FAILFAST);
        ],[
                AC_MSG_RESULT(yes)
@@ -25,7 +25,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_FAILFAST_DTD], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = ((1 << BIO_RW_FAILFAST_DEV) |
                         (1 << BIO_RW_FAILFAST_TRANSPORT) |
                         (1 << BIO_RW_FAILFAST_DRIVER));
@@ -43,7 +43,7 @@ AC_DEFUN([ZFS_AC_KERNEL_REQ_FAILFAST_MASK], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_FAILFAST_MASK;
        ],[
                AC_MSG_RESULT(yes)

diff --git a/config/kernel-bio-rw-syncio.m4 b/config/kernel-bio-rw-syncio.m4
index 6f8b5b5..4bff80a 100644 (file)
--- a/config/kernel-bio-rw-syncio.m4
+++ b/config/kernel-bio-rw-syncio.m4
@@ -9,7 +9,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_RW_SYNC], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNC;
        ],[
                AC_MSG_RESULT(yes)
@@ -24,7 +24,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BIO_RW_SYNCIO], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNCIO;
        ],[
                AC_MSG_RESULT(yes)
@@ -39,7 +39,7 @@ AC_DEFUN([ZFS_AC_KERNEL_REQ_SYNC], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/bio.h>
        ],[
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_SYNC;
        ],[
                AC_MSG_RESULT(yes)

diff --git a/config/kernel-evict-inode.m4 b/config/kernel-evict-inode.m4
index 3cf5a36..f748898 100644 (file)
--- a/config/kernel-evict-inode.m4
+++ b/config/kernel-evict-inode.m4
@@ -9,7 +9,7 @@ AC_DEFUN([ZFS_AC_KERNEL_EVICT_INODE], [
                #include <linux/fs.h>
        ],[
                void (*evict_inode) (struct inode *) = NULL;
-               struct super_operations sops;
+               struct super_operations sops __attribute__ ((unused));
 
                sops.evict_inode = evict_inode;
        ],[

diff --git a/config/kernel-fmode-t.m4 b/config/kernel-fmode-t.m4
index cf25d81..4a23c39 100644 (file)
--- a/config/kernel-fmode-t.m4
+++ b/config/kernel-fmode-t.m4
@@ -7,7 +7,7 @@ AC_DEFUN([ZFS_AC_KERNEL_TYPE_FMODE_T],
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/types.h>
        ],[
-               fmode_t *ptr;
+               fmode_t *ptr __attribute__ ((unused));
        ],[
                AC_MSG_RESULT([yes])
                AC_DEFINE(HAVE_FMODE_T, 1,

diff --git a/config/kernel-fsync.m4 b/config/kernel-fsync.m4
index 2733dba..3f93842 100644 (file)
--- a/config/kernel-fsync.m4
+++ b/config/kernel-fsync.m4
@@ -8,7 +8,7 @@ AC_DEFUN([ZFS_AC_KERNEL_FSYNC_2ARGS], [
                #include <linux/fs.h>
        ],[
                int (*fsync) (struct file *, int datasync) = NULL;
-               struct file_operations fops;
+               struct file_operations fops __attribute__ ((unused));
 
                fops.fsync = fsync;
        ],[

diff --git a/config/kernel-invalidate-bdev-args.m4 b/config/kernel-invalidate-bdev-args.m4
index c768f62..09c2ebf 100644 (file)
--- a/config/kernel-invalidate-bdev-args.m4
+++ b/config/kernel-invalidate-bdev-args.m4
@@ -7,7 +7,7 @@ AC_DEFUN([ZFS_AC_KERNEL_INVALIDATE_BDEV_ARGS], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/buffer_head.h>
        ],[
-               struct block_device *bdev;
+               struct block_device *bdev = NULL;
                invalidate_bdev(bdev);
        ],[
                AC_MSG_RESULT(yes)

diff --git a/config/kernel-kobj-name-len.m4 b/config/kernel-kobj-name-len.m4
index 5363a41..37999fa 100644 (file)
--- a/config/kernel-kobj-name-len.m4
+++ b/config/kernel-kobj-name-len.m4
@@ -9,7 +9,7 @@ AC_DEFUN([ZFS_AC_KERNEL_KOBJ_NAME_LEN], [
        ZFS_LINUX_TRY_COMPILE([
                #include <linux/kobject.h>
        ],[
-               int val;
+               int val __attribute__ ((unused));
                val = KOBJ_NAME_LEN;
        ],[
                AC_MSG_RESULT([yes])

diff --git a/config/kernel-xattr-handler.m4 b/config/kernel-xattr-handler.m4
index 1ebe1f0..325c960 100644 (file)
--- a/config/kernel-xattr-handler.m4
+++ b/config/kernel-xattr-handler.m4
@@ -19,7 +19,7 @@ AC_DEFUN([ZFS_AC_KERNEL_CONST_XATTR_HANDLER],
                        &xattr_test_handler,
                };
        ],[
-               struct super_block sb;
+               struct super_block sb __attribute__ ((unused));
 
                sb.s_xattr = xattr_handlers;
        ],[
@@ -43,7 +43,7 @@ AC_DEFUN([ZFS_AC_KERNEL_XATTR_HANDLER_GET], [
        ],[
                int (*get)(struct dentry *dentry, const char *name,
                    void *buffer, size_t size, int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.get = get;
        ],[
@@ -68,7 +68,7 @@ AC_DEFUN([ZFS_AC_KERNEL_XATTR_HANDLER_SET], [
                int (*set)(struct dentry *dentry, const char *name,
                    const void *buffer, size_t size, int flags,
                    int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.set = set;
        ],[

diff --git a/configure b/configure
index 8815554..feffaae 100755 (executable)
--- a/configure
+++ b/configure
@@ -12372,7 +12372,7 @@ int
 main (void)
 {
 
-               fmode_t *ptr;
+               fmode_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -12437,7 +12437,7 @@ int
 main (void)
 {
 
-               int val;
+               int val __attribute__ ((unused));
                val = KOBJ_NAME_LEN;
 
   ;
@@ -12583,7 +12583,7 @@ int
 main (void)
 {
 
-               struct block_device *bdev;
+               struct block_device *bdev = NULL;
                invalidate_bdev(bdev);
 
   ;
@@ -12782,7 +12782,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = (1 << BIO_RW_FAILFAST);
 
   ;
@@ -12848,7 +12848,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = ((1 << BIO_RW_FAILFAST_DEV) |
                         (1 << BIO_RW_FAILFAST_TRANSPORT) |
                         (1 << BIO_RW_FAILFAST_DRIVER));
@@ -12916,7 +12916,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_FAILFAST_MASK;
 
   ;
@@ -12985,7 +12985,7 @@ main (void)
 {
 
                void (*wanted_end_io)(struct bio *, int) = NULL;
-               bio_end_io_t *local_end_io;
+               bio_end_io_t *local_end_io __attribute__ ((unused));
 
                local_end_io = wanted_end_io;
 
@@ -13053,7 +13053,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNC;
 
   ;
@@ -13119,7 +13119,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNCIO;
 
   ;
@@ -13185,7 +13185,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_SYNC;
 
   ;
@@ -13994,7 +13994,7 @@ int
 main (void)
 {
 
-               struct super_block sb;
+               struct super_block sb __attribute__ ((unused));
 
                sb.s_xattr = xattr_handlers;
 
@@ -14063,7 +14063,7 @@ main (void)
 
                int (*get)(struct dentry *dentry, const char *name,
                    void *buffer, size_t size, int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.get = get;
 
@@ -14133,7 +14133,7 @@ main (void)
                int (*set)(struct dentry *dentry, const char *name,
                    const void *buffer, size_t size, int flags,
                    int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.set = set;
 
@@ -14201,7 +14201,7 @@ main (void)
 {
 
                int (*fsync) (struct file *, int datasync) = NULL;
-               struct file_operations fops;
+               struct file_operations fops __attribute__ ((unused));
 
                fops.fsync = fsync;
 
@@ -14269,7 +14269,7 @@ main (void)
 {
 
                void (*evict_inode) (struct inode *) = NULL;
-               struct super_operations sops;
+               struct super_operations sops __attribute__ ((unused));
 
                sops.evict_inode = evict_inode;
 
@@ -16417,7 +16417,7 @@ int
 main (void)
 {
 
-               fmode_t *ptr;
+               fmode_t *ptr __attribute__ ((unused));
 
   ;
   return 0;
@@ -16482,7 +16482,7 @@ int
 main (void)
 {
 
-               int val;
+               int val __attribute__ ((unused));
                val = KOBJ_NAME_LEN;
 
   ;
@@ -16628,7 +16628,7 @@ int
 main (void)
 {
 
-               struct block_device *bdev;
+               struct block_device *bdev = NULL;
                invalidate_bdev(bdev);
 
   ;
@@ -16827,7 +16827,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = (1 << BIO_RW_FAILFAST);
 
   ;
@@ -16893,7 +16893,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = ((1 << BIO_RW_FAILFAST_DEV) |
                         (1 << BIO_RW_FAILFAST_TRANSPORT) |
                         (1 << BIO_RW_FAILFAST_DRIVER));
@@ -16961,7 +16961,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_FAILFAST_MASK;
 
   ;
@@ -17030,7 +17030,7 @@ main (void)
 {
 
                void (*wanted_end_io)(struct bio *, int) = NULL;
-               bio_end_io_t *local_end_io;
+               bio_end_io_t *local_end_io __attribute__ ((unused));
 
                local_end_io = wanted_end_io;
 
@@ -17098,7 +17098,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNC;
 
   ;
@@ -17164,7 +17164,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = BIO_RW_SYNCIO;
 
   ;
@@ -17230,7 +17230,7 @@ int
 main (void)
 {
 
-               int flags;
+               int flags __attribute__ ((unused));
                flags = REQ_SYNC;
 
   ;
@@ -18039,7 +18039,7 @@ int
 main (void)
 {
 
-               struct super_block sb;
+               struct super_block sb __attribute__ ((unused));
 
                sb.s_xattr = xattr_handlers;
 
@@ -18108,7 +18108,7 @@ main (void)
 
                int (*get)(struct dentry *dentry, const char *name,
                    void *buffer, size_t size, int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.get = get;
 
@@ -18178,7 +18178,7 @@ main (void)
                int (*set)(struct dentry *dentry, const char *name,
                    const void *buffer, size_t size, int flags,
                    int handler_flags) = NULL;
-               struct xattr_handler xops;
+               struct xattr_handler xops __attribute__ ((unused));
 
                xops.set = set;
 
@@ -18246,7 +18246,7 @@ main (void)
 {
 
                int (*fsync) (struct file *, int datasync) = NULL;
-               struct file_operations fops;
+               struct file_operations fops __attribute__ ((unused));
 
                fops.fsync = fsync;
 
@@ -18314,7 +18314,7 @@ main (void)
 {
 
                void (*evict_inode) (struct inode *) = NULL;
-               struct super_operations sops;
+               struct super_operations sops __attribute__ ((unused));
 
                sops.evict_inode = evict_inode;