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Diffstat (limited to 'config/kernel-bio-rw-discard.m4')
| -rw-r--r-- | config/kernel-bio-rw-discard.m4 | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/config/kernel-bio-rw-discard.m4 b/config/kernel-bio-rw-discard.m4 new file mode 100644 index 000000000..0554b9a9d --- /dev/null +++ b/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) + ]) +]) |