FAILED: patch "[PATCH] cxl: Fix match_region_by_range() to use" failed to apply to 6.17-stable tree

The patch below does not apply to the 6.17-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y
git checkout FETCH_HEAD
git cherry-pick -x f4d027921c811ff7fc16e4d03c6bbbf4347cf37a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025102001-outsmart-slackness-607a@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f4d027921c811ff7fc16e4d03c6bbbf4347cf37a Mon Sep 17 00:00:00 2001
From: Dave Jiang <[email protected]>
Date: Fri, 10 Oct 2025 13:57:55 -0700
Subject: [PATCH] cxl: Fix match_region_by_range() to use
region_res_match_cxl_range()

match_region_by_range() is not using the helper function that also takes extended linear cache size into account when comparing regions. This causes a x2 region to show up as 2 partial incomplete regions rather than a single CXL region with extended linear cache support. Replace the open coded compare logic with the proper helper function for comparison. User visible impact is that when 'cxl list' is issued, no activa CXL region(s) are shown. There may be multiple idle regions present. No actual active CXL region is present in the kernel.

[dj: Fix stable address]

index 858d4678628d..57ed85e332d3 100644
@@ -3398,10 +3398,7 @@ static int match_region_by_range(struct device *dev, const void *data)
 	p = &cxlr->params;
 
 	guard(rwsem_read)(&cxl_rwsem.region);
-	if (p->res && p->res->start == r->start && p->res->end == r->end)
-		return 1;
-
-	return 0;
+	return region_res_match_cxl_range(p, r);
 }
 
 static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,

From: Dave Jiang <[email protected]>

[ Upstream commit f4d027921c811ff7fc16e4d03c6bbbf4347cf37a ]

match_region_by_range() is not using the helper function that also takes extended linear cache size into account when comparing regions. This causes a x2 region to show up as 2 partial incomplete regions rather than a single CXL region with extended linear cache support. Replace the open coded compare logic with the proper helper function for comparison. User visible impact is that when 'cxl list' is issued, no activa CXL region(s) are shown. There may be multiple idle regions present. No actual active CXL region is present in the kernel.

[dj: Fix stable address]

---
 drivers/cxl/core/region.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

index 71cc42d052481..be45211843282 100644
@@ -831,7 +831,7 @@ static int match_free_decoder(struct device *dev, const void *data)
 }
 
 static bool region_res_match_cxl_range(const struct cxl_region_params *p,
-				       struct range *range)
+				       const struct range *range)
 {
 	if (!p->res)
 		return false;

@@ -3287,10 +3287,7 @@ static int match_region_by_range(struct device *dev, const void *data)
 	p = &cxlr->params;
 
 	guard(rwsem_read)(&cxl_rwsem.region);
-	if (p->res && p->res->start == r->start && p->res->end == r->end)
-		return 1;
-
-	return 0;
+	return region_res_match_cxl_range(p, r);
 }
 
 static int cxl_extended_linear_cache_resize(struct cxl_region *cxlr,

2.51.0