Linux 6.11: get backing_dev_info through queue gendisk

It's no longer available directly on the request queue, but its easy to
get from the attached disk.

Reviewed-by: Tony Hutter <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Rob Norris <[email protected]>
Sponsored-by: https://despairlabs.com/sponsor/
Closes #16400

config/kernel-blk-queue.m4

@@ -25,6 +25,8 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_PLUG], [
 dnl #
 dnl # 2.6.32 - 4.11: statically allocated bdi in request_queue
 dnl # 4.12: dynamically allocated bdi in request_queue
+dnl # 6.11: bdi no longer available through request_queue, so get it from
+dnl #       the gendisk attached to the queue
 dnl #
 AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_BDI], [
 	ZFS_LINUX_TEST_SRC([blk_queue_bdi], [
@@ -47,6 +49,30 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_BDI], [
 	])
 ])
 
+AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISK_BDI], [
+	ZFS_LINUX_TEST_SRC([blk_queue_disk_bdi], [
+		#include <linux/blkdev.h>
+		#include <linux/backing-dev.h>
+	], [
+		struct request_queue q;
+		struct gendisk disk;
+		struct backing_dev_info bdi __attribute__ ((unused));
+		q.disk = &disk;
+		q.disk->bdi = &bdi;
+	])
+])
+
+AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE_DISK_BDI], [
+	AC_MSG_CHECKING([whether backing_dev_info is available through queue gendisk])
+	ZFS_LINUX_TEST_RESULT([blk_queue_disk_bdi], [
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(HAVE_BLK_QUEUE_DISK_BDI, 1,
+		    [backing_dev_info is available through queue gendisk])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])
+
 dnl #
 dnl # 5.9: added blk_queue_update_readahead(),
 dnl # 5.15: renamed to disk_update_readahead()
@@ -407,6 +433,7 @@ AC_DEFUN([ZFS_AC_KERNEL_BLK_MQ], [
 AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE], [
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_PLUG
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_BDI
+	ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISK_BDI
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_UPDATE_READAHEAD
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_DISCARD
 	ZFS_AC_KERNEL_SRC_BLK_QUEUE_SECURE_ERASE
@@ -421,6 +448,7 @@ AC_DEFUN([ZFS_AC_KERNEL_SRC_BLK_QUEUE], [
 AC_DEFUN([ZFS_AC_KERNEL_BLK_QUEUE], [
 	ZFS_AC_KERNEL_BLK_QUEUE_PLUG
 	ZFS_AC_KERNEL_BLK_QUEUE_BDI
+	ZFS_AC_KERNEL_BLK_QUEUE_DISK_BDI
 	ZFS_AC_KERNEL_BLK_QUEUE_UPDATE_READAHEAD
 	ZFS_AC_KERNEL_BLK_QUEUE_DISCARD
 	ZFS_AC_KERNEL_BLK_QUEUE_SECURE_ERASE

include/os/linux/kernel/linux/blkdev_compat.h

@@ -133,8 +133,10 @@ blk_queue_set_read_ahead(struct request_queue *q, unsigned long ra_pages)
 {
 #if !defined(HAVE_BLK_QUEUE_UPDATE_READAHEAD) && \
 	!defined(HAVE_DISK_UPDATE_READAHEAD)
-#ifdef HAVE_BLK_QUEUE_BDI_DYNAMIC
+#if defined(HAVE_BLK_QUEUE_BDI_DYNAMIC)
 	q->backing_dev_info->ra_pages = ra_pages;
+#elif defined(HAVE_BLK_QUEUE_DISK_BDI)
+	q->disk->bdi->ra_pages = ra_pages;
 #else
 	q->backing_dev_info.ra_pages = ra_pages;
 #endif