From: Adam Michalski <a.michalski2@partner.samsung.com>
Date: Mon, 25 Jul 2022 14:50:48 +0000 (+0200)
Subject: Add `volatile` specifier for the mapped memory area pointer to give
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c1ce626859d650a9274f4e9df56aad30edfdfb03;p=platform%2Fcore%2Fsystem%2Fdbus-tools.git

Add `volatile` specifier for the mapped memory area pointer to give
a hint to the compiler that it cannot optimize any checks to it

Without this hint the compiler tends to optimize the synchronization
barrier as it thinks that if a variable is unchanged in the parent
process, it can optimize access to it and not perform the check each
time during the `while` loop which leads to deadlock (endless waiting).

Change-Id: I0a316b4e0d1546bc6864737c20c86601635fff2a
---

diff --git a/benchmark/gdbus.c b/benchmark/gdbus.c
index b9a02f7..5c281ef 100644
--- a/benchmark/gdbus.c
+++ b/benchmark/gdbus.c
@@ -256,7 +256,7 @@ void Measure_bandwidth(void)
 	int returnp[nprocs/2][2];
 	int pids[nprocs];
 	int ready_fd;
-	char *ready_ptr;
+	volatile char *ready_ptr;
 
 	ready_fd = shm_open("isready", O_CREAT | O_TRUNC | O_RDWR, 0666);
 	if(ready_fd == -1)
@@ -359,7 +359,7 @@ void Measure_bandwidth(void)
 
 		waitpid(pids[child], NULL, 0);
 	}
-	ret = munmap(ready_ptr, sizeof(bool));
+	ret = munmap((void*)ready_ptr, sizeof(bool));
 	if (ret != 0) {
 		perror("munmap");
 		exit(1);
diff --git a/benchmark/libdbus.c b/benchmark/libdbus.c
index 84f1df7..2efa631 100644
--- a/benchmark/libdbus.c
+++ b/benchmark/libdbus.c
@@ -213,7 +213,7 @@ void Measure_bandwidth(void)
 	int returnp[nprocs/2][2];
 	int pids[nprocs];
 	int ready_fd;
-	char *ready_ptr;
+	volatile char *ready_ptr;
 
 	ready_fd = shm_open("isready", O_CREAT | O_TRUNC | O_RDWR, 0666);
 	if(ready_fd == -1)
@@ -318,7 +318,7 @@ void Measure_bandwidth(void)
 
 		waitpid(pids[child], NULL, 0);
 	}
-	ret = munmap(ready_ptr, sizeof(bool));
+	ret = munmap((void*)ready_ptr, sizeof(bool));
 	if (ret != 0) {
 		perror("munmap");
 		exit(1);
diff --git a/benchmark/pipe.c b/benchmark/pipe.c
index f0b3907..1d46d8f 100644
--- a/benchmark/pipe.c
+++ b/benchmark/pipe.c
@@ -137,7 +137,7 @@ void Measure_bandwidth(void)
 	int p[nprocs/2][2];
 	int pids[nprocs];
 	int ready_fd;
-	char *ready_ptr;
+	volatile char *ready_ptr;
 
 	ready_fd = shm_open("isready", O_CREAT | O_TRUNC | O_RDWR, 0666);
 	if(ready_fd == -1)
@@ -251,7 +251,7 @@ void Measure_bandwidth(void)
 		waitpid(pids[child], NULL, 0);
 	}
 
-	ret = munmap(ready_ptr, sizeof(bool));
+	ret = munmap((void*)ready_ptr, sizeof(bool));
 	if (ret != 0) {
 		perror("munmap");
 		exit(1);
diff --git a/benchmark/socket.c b/benchmark/socket.c
index 01d24d3..2d3ed7a 100644
--- a/benchmark/socket.c
+++ b/benchmark/socket.c
@@ -137,7 +137,7 @@ void Measure_bandwidth(void)
 	int fd[nprocs/2][2];
 	int pids[nprocs];
 	int ready_fd;
-	char *ready_ptr;
+	volatile char *ready_ptr;
 
 	ready_fd = shm_open("isready", O_CREAT | O_TRUNC | O_RDWR, 0666);
 	if(ready_fd == -1)
@@ -251,7 +251,7 @@ void Measure_bandwidth(void)
 
 		waitpid(pids[child], NULL, 0);
 	}
-	ret = munmap(ready_ptr, sizeof(bool));
+	ret = munmap((void*)ready_ptr, sizeof(bool));
 	if (ret != 0) {
 		perror("munmap");
 		exit(1);