Linux 5.11 compat: bio_start_io_acct() / bio_end_io_acct()

The generic IO accounting functions have been removed in favor of the
bio_start_io_acct() and bio_end_io_acct() functions which provide a
better interface.  These new functions were introduced in the 5.8
kernels but it wasn't until the 5.11 kernel that the previous generic
IO accounting interfaces were removed.

This commit updates the blk_generic_*_io_acct() wrappers to provide
and interface similar to the updated kernel interface.  It's slightly
different because for older kernels we need to pass the request queue
as well as the bio.

Reviewed-by: Rafael Kitover <[email protected]>
Reviewed-by: Coleman Kane <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Closes #11387
Closes #11390

3 files changed, 92 insertions, 39 deletions

diff --git a/config/kernel-generic_io_acct.m4 b/config/kernel-generic_io_acct.m4
index 423b3e5a3..e4ab503d5 100644
--- a/config/kernel-generic_io_acct.m4
+++ b/config/kernel-generic_io_acct.m4
@@ -2,6 +2,16 @@ dnl #
 dnl # Check for generic io accounting interface.
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_GENERIC_IO_ACCT], [
+	ZFS_LINUX_TEST_SRC([bio_io_acct], [
+		#include <linux/blkdev.h>
+	], [
+		struct bio *bio = NULL;
+		unsigned long start_time;
+
+		start_time = bio_start_io_acct(bio);
+		bio_end_io_acct(bio, start_time);
+	])
+
 	ZFS_LINUX_TEST_SRC([generic_acct_3args], [
 		#include <linux/bio.h>
 
@@ -29,36 +39,49 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_GENERIC_IO_ACCT], [
 
 AC_DEFUN([ZFS_AC_KERNEL_GENERIC_IO_ACCT], [
 	dnl #
-	dnl # 3.19 API addition
+	dnl # 5.7 API,
 	dnl #
-	dnl # torvalds/linux@394ffa50 allows us to increment iostat
-	dnl # counters without generic_make_request().
+	dnl # Added bio_start_io_acct() and bio_end_io_acct() helpers.
 	dnl #
-	AC_MSG_CHECKING([whether generic IO accounting wants 3 args])
-	ZFS_LINUX_TEST_RESULT_SYMBOL([generic_acct_3args],
-	    [generic_start_io_acct], [block/bio.c], [
+	AC_MSG_CHECKING([whether generic bio_*_io_acct() are available])
+	ZFS_LINUX_TEST_RESULT([bio_io_acct], [
 		AC_MSG_RESULT(yes)
-		AC_DEFINE(HAVE_GENERIC_IO_ACCT_3ARG, 1,
-		    [generic_start_io_acct()/generic_end_io_acct() available])
+		AC_DEFINE(HAVE_BIO_IO_ACCT, 1, [bio_*_io_acct() available])
 	], [
 		AC_MSG_RESULT(no)
 
 		dnl #
-		dnl # Linux 4.14 API,
+		dnl # 4.14 API,
 		dnl #
 		dnl # generic_start_io_acct/generic_end_io_acct now require
 		dnl # request_queue to be provided. No functional changes,
 		dnl # but preparation for inflight accounting.
 		dnl #
-		AC_MSG_CHECKING([whether generic IO accounting wants 4 args])
+		AC_MSG_CHECKING([whether generic_*_io_acct wants 4 args])
 		ZFS_LINUX_TEST_RESULT_SYMBOL([generic_acct_4args],
 		    [generic_start_io_acct], [block/bio.c], [
 			AC_MSG_RESULT(yes)
 			AC_DEFINE(HAVE_GENERIC_IO_ACCT_4ARG, 1,
-			    [generic_start_io_acct()/generic_end_io_acct() ]
-			    [4 arg available])
+			    [generic_*_io_acct() 4 arg available])
 		], [
 			AC_MSG_RESULT(no)
+
+			dnl #
+			dnl # 3.19 API addition
+			dnl #
+			dnl # torvalds/linux@394ffa50 allows us to increment
+			dnl # iostat counters without generic_make_request().
+			dnl #
+			AC_MSG_CHECKING(
+			    [whether generic_*_io_acct wants 3 args])
+			ZFS_LINUX_TEST_RESULT_SYMBOL([generic_acct_3args],
+			    [generic_start_io_acct], [block/bio.c], [
+				AC_MSG_RESULT(yes)
+				AC_DEFINE(HAVE_GENERIC_IO_ACCT_3ARG, 1,
+				    [generic_*_io_acct() 3 arg available])
+			], [
+				AC_MSG_RESULT(no)
+			])
 		])
 	])
 ])
diff --git a/include/os/linux/kernel/linux/blkdev_compat.h b/include/os/linux/kernel/linux/blkdev_compat.h
index 4d84900be..e1270cb25 100644
--- a/include/os/linux/kernel/linux/blkdev_compat.h
+++ b/include/os/linux/kernel/linux/blkdev_compat.h
@@ -523,25 +523,38 @@ blk_queue_discard_secure(struct request_queue *q)
  */
 #define	VDEV_HOLDER			((void *)0x2401de7)
 
-static inline void
-blk_generic_start_io_acct(struct request_queue *q, int rw,
-    unsigned long sectors, struct hd_struct *part)
+static inline unsigned long
+blk_generic_start_io_acct(struct request_queue *q __attribute__((unused)),
+    struct gendisk *disk __attribute__((unused)),
+    int rw __attribute__((unused)), struct bio *bio)
 {
-#if defined(HAVE_GENERIC_IO_ACCT_3ARG)
-	generic_start_io_acct(rw, sectors, part);
+#if defined(HAVE_BIO_IO_ACCT)
+	return (bio_start_io_acct(bio));
+#elif defined(HAVE_GENERIC_IO_ACCT_3ARG)
+	unsigned long start_time = jiffies;
+	generic_start_io_acct(rw, bio_sectors(bio), &disk->part0);
+	return (start_time);
 #elif defined(HAVE_GENERIC_IO_ACCT_4ARG)
-	generic_start_io_acct(q, rw, sectors, part);
+	unsigned long start_time = jiffies;
+	generic_start_io_acct(q, rw, bio_sectors(bio), &disk->part0);
+	return (start_time);
+#else
+	/* Unsupported */
+	return (0);
 #endif
 }
 
 static inline void
-blk_generic_end_io_acct(struct request_queue *q, int rw,
-    struct hd_struct *part, unsigned long start_time)
+blk_generic_end_io_acct(struct request_queue *q __attribute__((unused)),
+    struct gendisk *disk __attribute__((unused)),
+    int rw __attribute__((unused)), struct bio *bio, unsigned long start_time)
 {
-#if defined(HAVE_GENERIC_IO_ACCT_3ARG)
-	generic_end_io_acct(rw, part, start_time);
+#if defined(HAVE_BIO_IO_ACCT)
+	bio_end_io_acct(bio, start_time);
+#elif defined(HAVE_GENERIC_IO_ACCT_3ARG)
+	generic_end_io_acct(rw, &disk->part0, start_time);
 #elif defined(HAVE_GENERIC_IO_ACCT_4ARG)
-	generic_end_io_acct(q, rw, part, start_time);
+	generic_end_io_acct(q, rw, &disk->part0, start_time);
 #endif
 }
 
diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
index 29ad67368..9a9a721ce 100644
--- a/module/os/linux/zfs/zvol_os.c
+++ b/module/os/linux/zfs/zvol_os.c
@@ -106,10 +106,14 @@ zvol_write(void *arg)
 		return;
 	}
 
+	struct request_queue *q = zv->zv_zso->zvo_queue;
+	struct gendisk *disk = zv->zv_zso->zvo_disk;
 	ssize_t start_resid = uio.uio_resid;
-	unsigned long start_jif = jiffies;
-	blk_generic_start_io_acct(zv->zv_zso->zvo_queue, WRITE,
-	    bio_sectors(bio), &zv->zv_zso->zvo_disk->part0);
+	unsigned long start_time;
+
+	boolean_t acct = blk_queue_io_stat(q);
+	if (acct)
+		start_time = blk_generic_start_io_acct(q, disk, WRITE, bio);
 
 	boolean_t sync =
 	    bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
@@ -153,8 +157,10 @@ zvol_write(void *arg)
 		zil_commit(zv->zv_zilog, ZVOL_OBJ);
 
 	rw_exit(&zv->zv_suspend_lock);
-	blk_generic_end_io_acct(zv->zv_zso->zvo_queue,
-	    WRITE, &zv->zv_zso->zvo_disk->part0, start_jif);
+
+	if (acct)
+		blk_generic_end_io_acct(q, disk, WRITE, bio, start_time);
+
 	BIO_END_IO(bio, -error);
 	kmem_free(zvr, sizeof (zv_request_t));
 }
@@ -171,15 +177,18 @@ zvol_discard(void *arg)
 	boolean_t sync;
 	int error = 0;
 	dmu_tx_t *tx;
-	unsigned long start_jif;
 
 	ASSERT3P(zv, !=, NULL);
 	ASSERT3U(zv->zv_open_count, >, 0);
 	ASSERT3P(zv->zv_zilog, !=, NULL);
 
-	start_jif = jiffies;
-	blk_generic_start_io_acct(zv->zv_zso->zvo_queue, WRITE,
-	    bio_sectors(bio), &zv->zv_zso->zvo_disk->part0);
+	struct request_queue *q = zv->zv_zso->zvo_queue;
+	struct gendisk *disk = zv->zv_zso->zvo_disk;
+	unsigned long start_time;
+
+	boolean_t acct = blk_queue_io_stat(q);
+	if (acct)
+		start_time = blk_generic_start_io_acct(q, disk, WRITE, bio);
 
 	sync = bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
 
@@ -224,8 +233,10 @@ zvol_discard(void *arg)
 
 unlock:
 	rw_exit(&zv->zv_suspend_lock);
-	blk_generic_end_io_acct(zv->zv_zso->zvo_queue, WRITE,
-	    &zv->zv_zso->zvo_disk->part0, start_jif);
+
+	if (acct)
+		blk_generic_end_io_acct(q, disk, WRITE, bio, start_time);
+
 	BIO_END_IO(bio, -error);
 	kmem_free(zvr, sizeof (zv_request_t));
 }
@@ -244,10 +255,14 @@ zvol_read(void *arg)
 	ASSERT3P(zv, !=, NULL);
 	ASSERT3U(zv->zv_open_count, >, 0);
 
+	struct request_queue *q = zv->zv_zso->zvo_queue;
+	struct gendisk *disk = zv->zv_zso->zvo_disk;
 	ssize_t start_resid = uio.uio_resid;
-	unsigned long start_jif = jiffies;
-	blk_generic_start_io_acct(zv->zv_zso->zvo_queue, READ, bio_sectors(bio),
-	    &zv->zv_zso->zvo_disk->part0);
+	unsigned long start_time;
+
+	boolean_t acct = blk_queue_io_stat(q);
+	if (acct)
+		start_time = blk_generic_start_io_acct(q, disk, READ, bio);
 
 	zfs_locked_range_t *lr = zfs_rangelock_enter(&zv->zv_rangelock,
 	    uio.uio_loffset, uio.uio_resid, RL_READER);
@@ -275,8 +290,10 @@ zvol_read(void *arg)
 	task_io_account_read(nread);
 
 	rw_exit(&zv->zv_suspend_lock);
-	blk_generic_end_io_acct(zv->zv_zso->zvo_queue, READ,
-	    &zv->zv_zso->zvo_disk->part0, start_jif);
+
+	if (acct)
+		blk_generic_end_io_acct(q, disk, READ, bio, start_time);
+
 	BIO_END_IO(bio, -error);
 	kmem_free(zvr, sizeof (zv_request_t));
 }