Linux 4.8 compat: submit_bio()

The rw argument has been removed from submit_bio/submit_bio_wait.
Callers are now expected to set bio->bi_rw instead of passing it
in.  See torvalds/linux@4e49ea4a for
complete details.

Signed-off-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue openzfs#4892
Issue openzfs#4899

config/kernel-submit_bio.m4

@@ -0,0 +1,20 @@
+dnl #
+dnl # 4.8 API change
+dnl # The rw argument has been removed from submit_bio/submit_bio_wait.
+dnl # Callers are now expected to set bio->bi_rw instead of passing it in.
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_SUBMIT_BIO], [
+	AC_MSG_CHECKING([whether submit_bio() wants 1 arg])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/bio.h>
+	],[
+		blk_qc_t blk_qc;
+		struct bio *bio = NULL;
+		blk_qc = submit_bio(bio);
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_1ARG_SUBMIT_BIO, 1, [submit_bio() wants 1 arg])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

config/kernel.m4

@@ -8,6 +8,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_CONFIG
 	ZFS_AC_KERNEL_DECLARE_EVENT_CLASS
 	ZFS_AC_KERNEL_CURRENT_BIO_TAIL
+	ZFS_AC_KERNEL_SUBMIT_BIO
 	ZFS_AC_KERNEL_BDEV_BLOCK_DEVICE_OPERATIONS
 	ZFS_AC_KERNEL_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
 	ZFS_AC_KERNEL_TYPE_FMODE_T

module/zfs/vdev_disk.c

@@ -493,18 +493,29 @@ bio_map(struct bio *bio, void *bio_ptr, unsigned int bio_size)
 	return (bio_size);
 }
 
+static inline void
+vdev_submit_bio_impl(int rw, struct bio *bio)
+{
+#ifdef HAVE_1ARG_SUBMIT_BIO
+	bio->bi_rw |= rw;
+	submit_bio(bio);
+#else
+	submit_bio(rw, bio);
+#endif
+}
+
 static inline void
 vdev_submit_bio(int rw, struct bio *bio)
 {
 #ifdef HAVE_CURRENT_BIO_TAIL
 	struct bio **bio_tail = current->bio_tail;
 	current->bio_tail = NULL;
-	submit_bio(rw, bio);
+	vdev_submit_bio_impl(rw, bio);
 	current->bio_tail = bio_tail;
 #else
 	struct bio_list *bio_list = current->bio_list;
 	current->bio_list = NULL;
-	submit_bio(rw, bio);
+	vdev_submit_bio_impl(rw, bio);
 	current->bio_list = bio_list;
 #endif
 }