linux-kernel - [PATCH v5 3/7] cxl/region: Skip decoder reset on detach for autodiscovered regions

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Message-ID: <20260122045543.218194-4-Smita.KoralahalliChannabasappa@amd.com>
Date: Thu, 22 Jan 2026 04:55:39 +0000
From: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
To: <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<nvdimm@...ts.linux.dev>, <linux-fsdevel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>
CC: Ard Biesheuvel <ardb@...nel.org>, Alison Schofield
	<alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>, "Ira
 Weiny" <ira.weiny@...el.com>, Dan Williams <dan.j.williams@...el.com>,
	Jonathan Cameron <jonathan.cameron@...wei.com>, Yazen Ghannam
	<yazen.ghannam@....com>, Dave Jiang <dave.jiang@...el.com>, Davidlohr Bueso
	<dave@...olabs.net>, Matthew Wilcox <willy@...radead.org>, Jan Kara
	<jack@...e.cz>, "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown
	<len.brown@...el.com>, Pavel Machek <pavel@...nel.org>, Li Ming
	<ming.li@...omail.com>, Jeff Johnson <jeff.johnson@....qualcomm.com>, "Ying
 Huang" <huang.ying.caritas@...il.com>, Yao Xingtao <yaoxt.fnst@...itsu.com>,
	Peter Zijlstra <peterz@...radead.org>, Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>, Nathan Fontenot <nathan.fontenot@....com>,
	Terry Bowman <terry.bowman@....com>, Robert Richter <rrichter@....com>,
	Benjamin Cheatham <benjamin.cheatham@....com>, Zhijian Li
	<lizhijian@...itsu.com>, Borislav Petkov <bp@...en8.de>, Smita Koralahalli
	<Smita.KoralahalliChannabasappa@....com>, Tomasz Wolski
	<tomasz.wolski@...itsu.com>
Subject: [PATCH v5 3/7] cxl/region: Skip decoder reset on detach for autodiscovered regions

__cxl_decoder_detach() currently resets decoder programming whenever a
region is detached if cxl_config_state is beyond CXL_CONFIG_ACTIVE. For
autodiscovered regions, this can incorrectly tear down decoder state
that may be relied upon by other consumers or by subsequent ownership
decisions.

Skip cxl_region_decode_reset() during detach when CXL_REGION_F_AUTO is
set.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
---
 drivers/cxl/core/region.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index ae899f68551f..45ee598daf95 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2178,7 +2178,9 @@ __cxl_decoder_detach(struct cxl_region *cxlr,
 		cxled->part = -1;
 
 	if (p->state > CXL_CONFIG_ACTIVE) {
-		cxl_region_decode_reset(cxlr, p->interleave_ways);
+		if (!test_bit(CXL_REGION_F_AUTO, &cxlr->flags))
+			cxl_region_decode_reset(cxlr, p->interleave_ways);
+
 		p->state = CXL_CONFIG_ACTIVE;
 	}
 
-- 
2.17.1