Merge branch 'zvol'

Performance improvements for zvols.

Signed-off-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #3720

config/kernel-bio-rw-barrier.m4

@@ -0,0 +1,25 @@
+dnl #
+dnl # Interface for issuing a discard bio:
+dnl # 2.6.28-2.6.35: BIO_RW_BARRIER
+dnl # 2.6.36-3.x:    REQ_BARRIER
+dnl #
+
+dnl # Since REQ_BARRIER is a preprocessor definition, there is no need for an
+dnl # autotools check for it. Also, REQ_BARRIER 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_BARRIER], [
+	AC_MSG_CHECKING([whether BIO_RW_BARRIER is defined])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/bio.h>
+	],[
+		int flags __attribute__ ((unused));
+		flags = BIO_RW_BARRIER;
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BIO_RW_BARRIER, 1, [BIO_RW_BARRIER is defined])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

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)
+	])
+])

config/kernel-current_bio_tail.m4

@@ -0,0 +1,33 @@
+dnl #
+dnl # 2.6.34 API change
+dnl # current->bio_tail and current->bio_list were struct bio pointers prior to
+dnl # Linux 2.6.34. They were refactored into a struct bio_list pointer called
+dnl # current->bio_list in Linux 2.6.34.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_CURRENT_BIO_TAIL], [
+	AC_MSG_CHECKING([whether current->bio_tail exists])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/sched.h>
+	],[
+		current->bio_tail = (struct bio **) NULL;
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_CURRENT_BIO_TAIL, 1,
+		    [current->bio_tail exists])
+	],[
+		AC_MSG_RESULT(no)
+		AC_MSG_CHECKING([whether current->bio_list exists])
+		ZFS_LINUX_TRY_COMPILE([
+			#include <linux/sched.h>
+		],[
+			current->bio_list = (struct bio_list *) NULL;
+		],[
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(HAVE_CURRENT_BIO_LIST, 1,
+			    [current->bio_list exists])
+		],[
+			AC_MSG_ERROR(no - Please file a bug report at
+			    https://github.com/zfsonlinux/zfs/issues/new)
+		])
+	])
+])

config/kernel-mk-request-fn.m4

@@ -0,0 +1,43 @@
+dnl #
+dnl # Linux 3.2 API Change
+dnl # make_request_fn returns void instead of int.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_MAKE_REQUEST_FN], [
+	AC_MSG_CHECKING([whether make_request_fn() returns int])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/blkdev.h>
+
+		int make_request(struct request_queue *q, struct bio *bio)
+		{
+			return (0);
+		}
+	],[
+		blk_queue_make_request(NULL, &make_request);
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(MAKE_REQUEST_FN_RET, int,
+		    [make_request_fn() returns int])
+		AC_DEFINE(HAVE_MAKE_REQUEST_FN_RET_INT, 1,
+		    [Noting that make_request_fn() returns int])
+	],[
+		AC_MSG_RESULT(no)
+		AC_MSG_CHECKING([whether make_request_fn() returns void])
+		ZFS_LINUX_TRY_COMPILE([
+			#include <linux/blkdev.h>
+
+			void make_request(struct request_queue *q, struct bio *bio)
+			{
+				return;
+			}
+		],[
+			blk_queue_make_request(NULL, &make_request);
+		],[
+			AC_MSG_RESULT(yes)
+			AC_DEFINE(MAKE_REQUEST_FN_RET, void,
+			    [make_request_fn() returns void])
+		],[
+			AC_MSG_ERROR(no - Please file a bug report at
+			    https://github.com/zfsonlinux/zfs/issues/new)
+		])
+	])
+])