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becc717f61
On some architectures ZERO_PAGE is unavailable because it references
a GPL exported symbol of empty_zero_page. Originally e08b993 removed
the call to PAGE_ZERO(0) for assignment to the abd_zero_page. However,
a simple check can be done to avoid a kernel allocation and free for
the abd_zero_page if ZERO_PAGE is available.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Brian Atkinson <batkinson@lanl.gov>
Closes #13199
28 lines
657 B
Plaintext
28 lines
657 B
Plaintext
dnl #
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dnl # ZERO_PAGE() is an alias for emtpy_zero_page. On certain architectures
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dnl # this is a GPL exported variable.
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dnl #
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dnl #
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dnl # Checking if ZERO_PAGE is exported GPL-only
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dnl #
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AC_DEFUN([ZFS_AC_KERNEL_SRC_ZERO_PAGE], [
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ZFS_LINUX_TEST_SRC([zero_page], [
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#include <asm/pgtable.h>
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], [
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struct page *p __attribute__ ((unused));
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p = ZERO_PAGE(0);
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], [], [ZFS_META_LICENSE])
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])
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AC_DEFUN([ZFS_AC_KERNEL_ZERO_PAGE], [
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AC_MSG_CHECKING([whether ZERO_PAGE() is GPL-only])
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ZFS_LINUX_TEST_RESULT([zero_page_license], [
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AC_MSG_RESULT(no)
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], [
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AC_MSG_RESULT(yes)
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AC_DEFINE(HAVE_ZERO_PAGE_GPL_ONLY, 1,
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[ZERO_PAGE() is GPL-only])
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])
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])
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