e191b54ecf
Certain versions of gcc generate an 'unrecognized command
line option' error message when -Wunused-but-set-variable
is used unconditionally. This in turn can cause several
of the autoconf tests to misdetect an interface.
Now, the use of -Wunused-but-set-variable in the autoconf
tests was introduced by commit b9c59ec8 to address a gcc
4.6 compatibility problem. So we really only need to pass
this option for version of gcc which are known to support it.
Therefore, the tests have been updated to use the result of
the existing ZFS_AC_CONFIG_ALWAYS_NO_UNUSED_BUT_SET_VARIABLE
which determines if gcc supports this option.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1004
26 lines
766 B
Plaintext
26 lines
766 B
Plaintext
dnl #
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dnl # 2.6.27 API change
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dnl # The blk_queue_nonrot() function and QUEUE_FLAG_NONROT flag were
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dnl # added so non-rotational devices could be identified. These devices
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dnl # have no seek time which the higher level elevator uses to optimize
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dnl # how the I/O issued to the device.
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dnl #
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AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_NONROT], [
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AC_MSG_CHECKING([whether blk_queue_nonrot() is available])
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tmp_flags="$EXTRA_KCFLAGS"
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EXTRA_KCFLAGS="${NO_UNUSED_BUT_SET_VARIABLE}"
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ZFS_LINUX_TRY_COMPILE([
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#include <linux/blkdev.h>
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],[
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struct request_queue *q = NULL;
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(void) blk_queue_nonrot(q);
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],[
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AC_MSG_RESULT(yes)
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AC_DEFINE(HAVE_BLK_QUEUE_NONROT, 1,
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[blk_queue_nonrot() is available])
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],[
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AC_MSG_RESULT(no)
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])
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EXTRA_KCFLAGS="$tmp_flags"
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])
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