drbd/0024-compat-test-and-patch-for-queue_limits.features.patch

From 3c18af1a3e8d67833e3ea8a2d38408501c9ee6be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christoph=20B=C3=B6hmwalder?=
 <christoph.boehmwalder@linbit.com>
Date: Thu, 5 Sep 2024 13:05:59 +0200
Subject: [PATCH 24/32] compat: test and patch for queue_limits.features

And fixup compat patches that rely on blk_queue_write_cache being there.
Match to disk->private_data = ... instead.
---
 .../blk_queue_make_request__yes_present.cocci |  3 ++-
 .../blk_queue_merge_bvec__yes_present.cocci   | 21 +++++++++++-----
 .../cocci/congested_fn__yes_present.cocci     |  3 ++-
 .../queue_limits_features__no_present.cocci   | 25 +++++++++++++++++++
 drbd/drbd-kernel-compat/gen_patch_names.c     | 15 ++++++-----
 .../tests/queue_limits_has_features.c         |  8 ++++++
 6 files changed, 61 insertions(+), 14 deletions(-)
 create mode 100644 drbd/drbd-kernel-compat/cocci/queue_limits_features__no_present.cocci
 create mode 100644 drbd/drbd-kernel-compat/tests/queue_limits_has_features.c

diff --git a/drbd/drbd-kernel-compat/cocci/blk_queue_make_request__yes_present.cocci b/drbd/drbd-kernel-compat/cocci/blk_queue_make_request__yes_present.cocci
index 63c65d21cb32..665e10cbaa1a 100644
--- a/drbd/drbd-kernel-compat/cocci/blk_queue_make_request__yes_present.cocci
+++ b/drbd/drbd-kernel-compat/cocci/blk_queue_make_request__yes_present.cocci
@@ -5,12 +5,13 @@ identifier make_request_fn;
 + blk_alloc_queue(GFP_KERNEL)
 
 @@
+struct gendisk *disk;
 identifier rm_blk_alloc_queue.make_request_fn;
 @@
 drbd_create_device(...)
 {
 	...
+	disk->private_data = ...;
 +	blk_queue_make_request(q, make_request_fn);
-	blk_queue_write_cache(...);
 	...
 }
diff --git a/drbd/drbd-kernel-compat/cocci/blk_queue_merge_bvec__yes_present.cocci b/drbd/drbd-kernel-compat/cocci/blk_queue_merge_bvec__yes_present.cocci
index d4c0d85810e8..bedb09f8b375 100644
--- a/drbd/drbd-kernel-compat/cocci/blk_queue_merge_bvec__yes_present.cocci
+++ b/drbd/drbd-kernel-compat/cocci/blk_queue_merge_bvec__yes_present.cocci
@@ -1,10 +1,10 @@
-@@
+@ add_drbd_merge_bvec_definition @
 identifier ws;
 @@
 +extern int drbd_merge_bvec(struct request_queue *, struct bvec_merge_data *, struct bio_vec *);
 extern void do_submit(struct work_struct *ws);
 
-@@
+@ add_drbd_merge_bvec @
 @@
 +/* This is called by bio_add_page().
 + *
@@ -44,9 +44,10 @@ extern void do_submit(struct work_struct *ws);
 do_submit(...)
 { ... }
 
-@@
+@ add_blk_queue_merge_bvec @
 symbol true;
 identifier q, resource, dev;
+struct gendisk *disk;
 @@
 drbd_create_device(...)
 {
@@ -68,9 +69,17 @@ struct request_queue *q;
 // also want to store it in queuedata for the compat.
 dev->rq_queue = q;
 + q->queuedata = dev;
-<...
-blk_queue_write_cache(q, true, true);
+...
+disk->private_data = ...;
 + blk_queue_merge_bvec(q, drbd_merge_bvec);
-...>
+...
 }
 
+@ script:python depends on !(add_drbd_merge_bvec_definition && add_drbd_merge_bvec && add_blk_queue_merge_bvec) @
+@@
+import sys
+print('ERROR: A rule making an essential change was not executed! (blk_queue_merge_bvec)', file=sys.stderr)
+print('ERROR: This would not show up as a compiler error, but would still break DRBD.', file=sys.stderr)
+print('ERROR: As a precaution, the build will be aborted here.', file=sys.stderr)
+sys.exit(1)
+
diff --git a/drbd/drbd-kernel-compat/cocci/congested_fn__yes_present.cocci b/drbd/drbd-kernel-compat/cocci/congested_fn__yes_present.cocci
index d0b55c3dffbf..a697311af6bd 100644
--- a/drbd/drbd-kernel-compat/cocci/congested_fn__yes_present.cocci
+++ b/drbd/drbd-kernel-compat/cocci/congested_fn__yes_present.cocci
@@ -63,14 +63,15 @@ drbd_cleanup(...)
 
 @@
 identifier dev;
+struct gendisk *disk;
 @@
 drbd_create_device(...)
 {
 ...
 	struct drbd_device *dev;
 ...
+	disk->private_data = ...;
 +	q->backing_dev_info->congested_fn = drbd_congested;
 +	q->backing_dev_info->congested_data = dev;
-	blk_queue_write_cache(...);
 ...
 }
diff --git a/drbd/drbd-kernel-compat/cocci/queue_limits_features__no_present.cocci b/drbd/drbd-kernel-compat/cocci/queue_limits_features__no_present.cocci
new file mode 100644
index 000000000000..b9017351302b
--- /dev/null
+++ b/drbd/drbd-kernel-compat/cocci/queue_limits_features__no_present.cocci
@@ -0,0 +1,25 @@
+// NOTE this actually encompasses three patches:
+// 1122c0c1 block: move cache control settings out of queue->flags
+// bd4a633b block: move the nonrot flag to queue_limits
+// 1a02f3a7 block: move the stable_writes flag to queue_limits
+//
+// They add "BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA", "BLK_FEAT_ROTATIONAL", and
+// "BLK_FEAT_STABLE_WRITES", respectively.
+// Since these commits are all from the same series, just patch them together.
+@@
+expression e;
+struct gendisk *disk;
+identifier lim;
+@@
+-struct queue_limits lim = {
+-	.features = e,
+-};
+...
+blk_alloc_disk(
+-	&lim
++	NULL
+	, ...)
+...
+disk->private_data = ...;
++ blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES, disk->queue);
++ blk_queue_write_cache(disk->queue, true, true);
diff --git a/drbd/drbd-kernel-compat/gen_patch_names.c b/drbd/drbd-kernel-compat/gen_patch_names.c
index 5abc32725daf..cc3bad2d84e4 100644
--- a/drbd/drbd-kernel-compat/gen_patch_names.c
+++ b/drbd/drbd-kernel-compat/gen_patch_names.c
@@ -153,6 +153,9 @@ int main(int argc, char **argv)
 	patch(1, "blk_cleanup_disk", false, true,
 	      COMPAT_HAVE_BLK_CLEANUP_DISK, "present");
 
+	patch(1, "queue_limits_features", true, false,
+	      COMPAT_QUEUE_LIMITS_HAS_FEATURES, "present");
+
 	patch(1, "blk_alloc_disk", true, false,
 	      COMPAT_BLK_ALLOC_DISK_TAKES_QUEUE_LIMITS, "takes_queue_limits");
 #if !defined(COMPAT_BLK_ALLOC_DISK_TAKES_QUEUE_LIMITS)
@@ -267,13 +270,13 @@ int main(int argc, char **argv)
 	patch(1, "security_netlink_recv", false, true,
 	      COMPAT_HAVE_SECURITY_NETLINK_RECV, "present");
 
-#if defined(COMPAT_HAVE_QUEUE_FLAG_STABLE_WRITES)
-	/* in versions >=5.9, there is QUEUE_FLAG_STABLE_WRITES */
-#else
-	/* for <5.9 but >=3.9, fall back to BDI_CAP_STABLE_WRITES */
+	/*
+	 * >= 6.10:  BLK_FEAT_STABLE_WRITES
+	 * 5.9-6.10: QUEUE_FLAG_STABLE_WRITES
+	 * <5.9:     BDI_CAP_STABLE_WRITES
+	 */
 	patch(1, "queue_flag_stable_writes", true, false,
-	      NO, "present");
-#endif
+	      COMPAT_HAVE_QUEUE_FLAG_STABLE_WRITES, "present");
 
 	patch(1, "queue_flag_discard", false, true,
 	      COMPAT_HAVE_QUEUE_FLAG_DISCARD, "present");
diff --git a/drbd/drbd-kernel-compat/tests/queue_limits_has_features.c b/drbd/drbd-kernel-compat/tests/queue_limits_has_features.c
new file mode 100644
index 000000000000..e566a34bdda6
--- /dev/null
+++ b/drbd/drbd-kernel-compat/tests/queue_limits_has_features.c
@@ -0,0 +1,8 @@
+/* { "version": "v6.10", "commit": "1122c0c1cc71f740fa4d5f14f239194e06a1d5e7", "comment": "features field was introduced", "author": "Christoph Hellwig <hch@lst.de>", "date": "Mon Jun 17 08:04:40 2024 +0200" } */
+
+#include <linux/blkdev.h>
+
+unsigned int foo(struct queue_limits lim)
+{
+       return lim.features;
+}
-- 
2.35.3