linux-kernel - [PATCH 5/8] cxl/region: Add helper function to determine memory is online

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Message-ID: <20250227223816.2036-6-shiju.jose@huawei.com>
Date: Thu, 27 Feb 2025 22:38:12 +0000
From: <shiju.jose@...wei.com>
To: <linux-cxl@...r.kernel.org>, <dan.j.williams@...el.com>,
	<dave@...olabs.net>, <jonathan.cameron@...wei.com>, <dave.jiang@...el.com>,
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	<ira.weiny@...el.com>, <david@...hat.com>, <Vilas.Sridharan@....com>
CC: <linux-edac@...r.kernel.org>, <linux-acpi@...r.kernel.org>,
	<linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>, <bp@...en8.de>,
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Subject: [PATCH 5/8] cxl/region: Add helper function to determine memory is online

From: Shiju Jose <shiju.jose@...wei.com>

Add helper function to determine a CXL memory is online.

Use case: certain memory operations are permitted when the memory
is offline only, for eg. some memory repair operations.

Co-developed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: Shiju Jose <shiju.jose@...wei.com>
---
 drivers/cxl/core/core.h   |  9 +++++++++
 drivers/cxl/core/region.c | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 6c83f6f18122..386e36b18c19 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -32,8 +32,17 @@ int cxl_get_poison_by_endpoint(struct cxl_port *port);
 struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa);
 u64 cxl_dpa_to_hpa(struct cxl_region *cxlr, const struct cxl_memdev *cxlmd,
 		   u64 dpa);
+bool cxl_are_decoders_committed(const struct cxl_memdev *cxlmd);
 
 #else
+static inline bool cxl_are_decoders_committed(const struct cxl_memdev *cxlmd)
+{
+	/*
+	 * If no driver, in absence of a way to check, assume decoders are committed.
+	 */
+	return true;
+}
+
 static inline u64 cxl_dpa_to_hpa(struct cxl_region *cxlr,
 				 const struct cxl_memdev *cxlmd, u64 dpa)
 {
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 9e7b716296d7..3fd14cb0c470 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -2864,6 +2864,16 @@ struct cxl_region *cxl_dpa_to_region(const struct cxl_memdev *cxlmd, u64 dpa)
 	return ctx.cxlr;
 }
 
+bool cxl_are_decoders_committed(const struct cxl_memdev *cxlmd)
+{
+	struct cxl_port *port = cxlmd->endpoint;
+
+	if (port && is_cxl_endpoint(port) && cxl_num_decoders_committed(port))
+		return true;
+
+	return false;
+}
+
 static bool cxl_is_hpa_in_chunk(u64 hpa, struct cxl_region *cxlr, int pos)
 {
 	struct cxl_region_params *p = &cxlr->params;
-- 
2.43.0