UBUNTU: SAUCE: (noup) Update spl to 0.6.5.9-1, zfs to 0.6.5.9-2

[mirror_ubuntu-artful-kernel.git] / zfs / config / kernel-bio-rw-discard.m4

diff --git a/zfs/config/kernel-bio-rw-discard.m4 b/zfs/config/kernel-bio-rw-discard.m4
new file mode 100644 (file)
index 0000000..0554b9a
--- /dev/null
+++ b/zfs/config/kernel-bio-rw-discard.m4
@@ -0,0 +1,25 @@
+dnl #
+dnl # Interface for issuing a discard bio:
+dnl # 2.6.28-2.6.35: BIO_RW_DISCARD
+dnl # 2.6.36-3.x:    REQ_DISCARD
+dnl #
+
+dnl # Since REQ_DISCARD is a preprocessor definition, there is no need for an
+dnl # autotools check for it. Also, REQ_DISCARD existed in the request layer
+dnl # until torvalds/linux@7b6d91daee5cac6402186ff224c3af39d79f4a0e unified the
+dnl # request layer and bio layer flags, so it would be wrong to assume that
+dnl # the APIs are mutually exclusive contrary to the typical case.
+AC_DEFUN([ZFS_AC_KERNEL_BIO_RW_DISCARD], [
+       AC_MSG_CHECKING([whether BIO_RW_DISCARD is defined])
+       ZFS_LINUX_TRY_COMPILE([
+               #include <linux/bio.h>
+       ],[
+               int flags __attribute__ ((unused));
+               flags = BIO_RW_DISCARD;
+       ],[
+               AC_MSG_RESULT(yes)
+               AC_DEFINE(HAVE_BIO_RW_DISCARD, 1, [BIO_RW_DISCARD is defined])
+       ],[
+               AC_MSG_RESULT(no)
+       ])
+])