[PATCH v6 1/4] firmware: stratix10-svc: Add mutex in stratix10 memory management

[Mahesh Rao via B4 Relay <devnull+mahesh.rao.altera.com@kernel.org>]

From: Mahesh Rao <mahesh.rao@altera.com>

Add mutex lock to stratix10_svc_allocate_memory and
stratix10_svc_free_memory for thread safety. This prevents race
conditions and ensures proper synchronization during memory operations.
This is required for parallel communication with the Stratix10 service
channel.

Fixes: 7ca5ce896524f ("firmware: add Intel Stratix10 service layer driver")
Signed-off-by: Mahesh Rao <mahesh.rao@altera.com>
Reviewed-by: Matthew Gerlach <matthew.gerlach@altera.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
---
 drivers/firmware/stratix10-svc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/firmware/stratix10-svc.c b/drivers/firmware/stratix10-svc.c
index e3f990d888d71829f0ab22b8a59aa7af0316bea0..11285df8681bfac71c9bace6b7d39c1848f40f08 100644
--- a/drivers/firmware/stratix10-svc.c
+++ b/drivers/firmware/stratix10-svc.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2017-2018, Intel Corporation
+ * Copyright (C) 2025, Altera Corporation
  */
 
 #include <linux/completion.h>
@@ -172,6 +173,12 @@ struct stratix10_svc_chan {
 static LIST_HEAD(svc_ctrl);
 static LIST_HEAD(svc_data_mem);
 
+/**
+ * svc_mem_lock protects access to the svc_data_mem list for
+ * concurrent multi-client operations
+ */
+static DEFINE_MUTEX(svc_mem_lock);
+
 /**
  * svc_pa_to_va() - translate physical address to virtual address
  * @addr: to be translated physical address
@@ -184,6 +191,7 @@ static void *svc_pa_to_va(unsigned long addr)
 	struct stratix10_svc_data_mem *pmem;
 
 	pr_debug("claim back P-addr=0x%016x\n", (unsigned int)addr);
+	guard(mutex)(&svc_mem_lock);
 	list_for_each_entry(pmem, &svc_data_mem, node)
 		if (pmem->paddr == addr)
 			return pmem->vaddr;
@@ -990,6 +998,7 @@ int stratix10_svc_send(struct stratix10_svc_chan *chan, void *msg)
 			p_data->flag = ct->flags;
 		}
 	} else {
+		guard(mutex)(&svc_mem_lock);
 		list_for_each_entry(p_mem, &svc_data_mem, node)
 			if (p_mem->vaddr == p_msg->payload) {
 				p_data->paddr = p_mem->paddr;
@@ -1072,6 +1081,7 @@ void *stratix10_svc_allocate_memory(struct stratix10_svc_chan *chan,
 	if (!pmem)
 		return ERR_PTR(-ENOMEM);
 
+	guard(mutex)(&svc_mem_lock);
 	va = gen_pool_alloc(genpool, s);
 	if (!va)
 		return ERR_PTR(-ENOMEM);
@@ -1100,6 +1110,7 @@ EXPORT_SYMBOL_GPL(stratix10_svc_allocate_memory);
 void stratix10_svc_free_memory(struct stratix10_svc_chan *chan, void *kaddr)
 {
 	struct stratix10_svc_data_mem *pmem;
+	guard(mutex)(&svc_mem_lock);
 
 	list_for_each_entry(pmem, &svc_data_mem, node)
 		if (pmem->vaddr == kaddr) {

-- 
2.35.3