freebsd-dev/config/kernel-bio-end-io-t-args.m4
Brian Behlendorf 79713039a2 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
2011-04-19 10:10:47 -07:00

30 lines
921 B
Plaintext

dnl #
dnl # 2.6.24 API change
dnl # Size argument dropped from bio_endio and bi_end_io, because the
dnl # bi_end_io is only called once now when the request is complete.
dnl # There is no longer any need for a size argument. This also means
dnl # that partial IO's are no longer possibe and the end_io callback
dnl # should not check bi->bi_size. Finally, the return type was updated
dnl # to void.
dnl #
AC_DEFUN([ZFS_AC_KERNEL_BIO_END_IO_T_ARGS], [
AC_MSG_CHECKING([whether bio_end_io_t wants 2 args])
tmp_flags="$EXTRA_KCFLAGS"
EXTRA_KCFLAGS="-Werror"
ZFS_LINUX_TRY_COMPILE([
#include <linux/bio.h>
],[
void (*wanted_end_io)(struct bio *, int) = NULL;
bio_end_io_t *local_end_io __attribute__ ((unused));
local_end_io = wanted_end_io;
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_2ARGS_BIO_END_IO_T, 1,
[bio_end_io_t wants 2 args])
],[
AC_MSG_RESULT(no)
])
EXTRA_KCFLAGS="$tmp_flags"
])