netdev - [PATCH v16 17/22] cxl/region: Factor out interleave granularity setup

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Message-ID: <20250514132743.523469-18-alejandro.lucero-palau@amd.com>
Date: Wed, 14 May 2025 14:27:38 +0100
From: <alejandro.lucero-palau@....com>
To: <linux-cxl@...r.kernel.org>, <netdev@...r.kernel.org>,
	<dan.j.williams@...el.com>, <edward.cree@....com>, <davem@...emloft.net>,
	<kuba@...nel.org>, <pabeni@...hat.com>, <edumazet@...gle.com>,
	<dave.jiang@...el.com>
CC: Alejandro Lucero <alucerop@....com>, Zhi Wang <zhiw@...dia.com>, "Jonathan
 Cameron" <Jonathan.Cameron@...wei.com>, Ben Cheatham
	<benjamin.cheatham@....com>
Subject: [PATCH v16 17/22] cxl/region: Factor out interleave granularity setup

From: Alejandro Lucero <alucerop@....com>

Region creation based on Type3 devices is triggered from user space
allowing memory combination through interleaving.

In preparation for kernel driven region creation, that is Type2 drivers
triggering region creation backed with its advertised CXL memory, factor
out a common helper from the user-sysfs region setup forinterleave
granularity.

Signed-off-by: Alejandro Lucero <alucerop@....com>
Reviewed-by: Zhi Wang <zhiw@...dia.com>
Reviewed-by: Dave Jiang <dave.jiang@...el.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Reviewed-by: Ben Cheatham <benjamin.cheatham@....com>
---
 drivers/cxl/core/region.c | 39 +++++++++++++++++++++++----------------
 1 file changed, 23 insertions(+), 16 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 0f61c9e9b954..4113ee6daec9 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -540,21 +540,14 @@ static ssize_t interleave_granularity_show(struct device *dev,
 	return rc;
 }
 
-static ssize_t interleave_granularity_store(struct device *dev,
-					    struct device_attribute *attr,
-					    const char *buf, size_t len)
+static int set_interleave_granularity(struct cxl_region *cxlr, int val)
 {
-	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev->parent);
+	struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(cxlr->dev.parent);
 	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
-	struct cxl_region *cxlr = to_cxl_region(dev);
 	struct cxl_region_params *p = &cxlr->params;
-	int rc, val;
+	int rc;
 	u16 ig;
 
-	rc = kstrtoint(buf, 0, &val);
-	if (rc)
-		return rc;
-
 	rc = granularity_to_eig(val, &ig);
 	if (rc)
 		return rc;
@@ -570,16 +563,30 @@ static ssize_t interleave_granularity_store(struct device *dev,
 	if (cxld->interleave_ways > 1 && val != cxld->interleave_granularity)
 		return -EINVAL;
 
+	lockdep_assert_held_write(&cxl_region_rwsem);
+	if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE)
+		return -EBUSY;
+
+	p->interleave_granularity = val;
+	return 0;
+}
+
+static ssize_t interleave_granularity_store(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t len)
+{
+	struct cxl_region *cxlr = to_cxl_region(dev);
+	int rc, val;
+
+	rc = kstrtoint(buf, 0, &val);
+	if (rc)
+		return rc;
+
 	rc = down_write_killable(&cxl_region_rwsem);
 	if (rc)
 		return rc;
-	if (p->state >= CXL_CONFIG_INTERLEAVE_ACTIVE) {
-		rc = -EBUSY;
-		goto out;
-	}
 
-	p->interleave_granularity = val;
-out:
+	rc = set_interleave_granularity(cxlr, val);
 	up_write(&cxl_region_rwsem);
 	if (rc)
 		return rc;
-- 
2.34.1