linux-kernel - [PATCH 1/2] spi: spi-mem: Protect dirmap_create() with spi_mem_access

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Message-ID: <20260115150454.1575970-2-chin-ting_kuo@aspeedtech.com>
Date: Thu, 15 Jan 2026 23:04:53 +0800
From: Chin-Ting Kuo <chin-ting_kuo@...eedtech.com>
To: <clg@...d.org>, <broonie@...nel.org>, <boris.brezillon@...tlin.com>,
	<joel@....id.au>, <andrew@...econstruct.com.au>,
	<linux-aspeed@...ts.ozlabs.org>, <openbmc@...ts.ozlabs.org>,
	<linux-spi@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>, <BMC-SW@...eedtech.com>
Subject: [PATCH 1/2] spi: spi-mem: Protect dirmap_create() with spi_mem_access_start/end

spi_mem_dirmap_create() may reconfigure controller-wide settings,
which can interfere with concurrent transfers to other devices
sharing the same SPI controller but using different chip selects.

Wrap the ->dirmap_create() callback with spi_mem_access_start() and
spi_mem_access_end() to serialize access and prevent cross-CS
interference during dirmap creation.

Signed-off-by: Chin-Ting Kuo <chin-ting_kuo@...eedtech.com>
---
 drivers/spi/spi-mem.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index c8b2add2640e..85702a77b3c8 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -708,9 +708,18 @@ spi_mem_dirmap_create(struct spi_mem *mem,
 
 	desc->mem = mem;
 	desc->info = *info;
-	if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create)
+	if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create) {
+		ret = spi_mem_access_start(mem);
+		if (ret) {
+			kfree(desc);
+			return ERR_PTR(ret);
+		}
+
 		ret = ctlr->mem_ops->dirmap_create(desc);
 
+		spi_mem_access_end(mem);
+	}
+
 	if (ret) {
 		desc->nodirmap = true;
 		if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl))
-- 
2.34.1