1 files changed, 108 insertions, 21 deletions

diff --git a/tests/i915/sysfs_clients.c b/tests/i915/sysfs_clients.c
index a3a1f81e..e936bd48 100644
--- a/tests/i915/sysfs_clients.c
+++ b/tests/i915/sysfs_clients.c
@@ -8,6 +8,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
+#include <limits.h>
 #include <math.h>
 #include <sched.h>
 #include <sys/socket.h>
@@ -47,6 +48,8 @@
 #define assert_within_epsilon(x, ref, tolerance) \
 	__assert_within_epsilon(x, ref, tolerance / 100., tolerance / 100.)
 
+#define BUFSZ 280
+
 #define MI_BATCH_BUFFER_START (0x31 << 23)
 #define MI_BATCH_BUFFER_END (0xa << 23)
 #define MI_ARB_CHECK (0x5 << 23)
@@ -75,7 +78,7 @@ static void pidname(int i915, int clients)
 {
 	struct dirent *de;
 	int sv[2], rv[2];
-	char buf[280];
+	char buf[BUFSZ];
 	int me = -1;
 	long count;
 	pid_t pid;
@@ -180,7 +183,7 @@ static long count_clients(int clients)
 {
 	struct dirent *de;
 	long count = 0;
-	char buf[280];
+	char buf[BUFSZ];
 	DIR *dir;
 
 	dir = fdopendir(dup(clients));
@@ -229,32 +232,113 @@ static void create(int i915, int clients)
 	igt_assert_eq(count_clients(clients), 1);
 }
 
+static const char *find_client(int clients, pid_t pid, char *buf)
+{
+	DIR *dir = fdopendir(dup(clients));
+
+	/* Reading a dir as it changes does not appear to be stable, SEP */
+	for (int pass = 0; pass < 3; pass++) {
+		struct dirent *de;
+
+		rewinddir(dir);
+		fsync(dirfd(dir));
+		while ((de = readdir(dir))) {
+			if (!isdigit(de->d_name[0]))
+				continue;
+
+			snprintf(buf, BUFSZ, "%s/pid", de->d_name);
+			igt_sysfs_read(clients, buf, buf, sizeof(buf));
+			if (atoi(buf) != pid)
+				continue;
+
+			strncpy(buf, de->d_name, BUFSZ);
+			goto out;
+		}
+	}
+	*buf = '\0';
+out:
+	closedir(dir);
+	return buf;
+}
+
 static int find_me(int clients, pid_t pid)
 {
-	struct dirent *de;
-	char buf[280];
-	int me = -1;
-	DIR *dir;
+	char buf[BUFSZ];
 
-	dir = fdopendir(dup(clients));
-	igt_assert(dir);
-	rewinddir(dir);
+	return openat(clients,
+		      find_client(clients, pid, buf),
+		      O_DIRECTORY | O_RDONLY);
+}
 
-	while ((de = readdir(dir))) {
-		if (!isdigit(de->d_name[0]))
-			continue;
+static int reopen_directory(int fd)
+{
+	char buf[BUFSZ];
+	int dir;
 
-		snprintf(buf, sizeof(buf), "%s/pid", de->d_name);
-		igt_sysfs_read(clients, buf, buf, sizeof(buf));
-		if (atoi(buf) != pid)
-			continue;
+	snprintf(buf, sizeof(buf), "/proc/self/fd/%d", fd);
+	dir = open(buf, O_DIRECTORY | O_RDONLY);
+	igt_assert_fd(dir);
 
-		me = openat(clients, de->d_name, O_DIRECTORY | O_RDONLY);
-		break;
+	return dir;
+}
+
+static unsigned long my_id(int clients, pid_t pid)
+{
+	char buf[BUFSZ];
+
+	return strtoul(find_client(clients, pid, buf), NULL, 0);
+}
+
+static unsigned long recycle_client(int i915, int clients)
+{
+	unsigned long client;
+	int device;
+
+	device = gem_reopen_driver(i915);
+	client = my_id(clients, getpid());
+	close(device);
+
+	igt_assert(client != 0);
+	return client;
+}
+
+static void recycle(int i915, int clients)
+{
+	const int ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+
+	/*
+	 * As we open and close clients, we do not expect to reuse old ids,
+	 * i.e. we use a cyclic ida. This reduces the likelihood of userspace
+	 * watchers becoming confused and mistaking the new client as a
+	 * continuation of the old.
+	 */
+	igt_assert(my_id(clients, getpid()));
+
+	igt_fork(child, 2 * ncpus) {
+		unsigned long client, last;
+
+		/* Reopen the directory fd for each client */
+		clients = reopen_directory(clients);
+
+		last = recycle_client(i915, clients);
+		igt_info("Child[%d] first client:%lu\n", getpid(), last);
+		igt_until_timeout(5) {
+			client = recycle_client(i915, clients);
+			igt_assert((long)(client - last) > 0);
+			last = client;
+		}
+		igt_info("Child[%d] last client:%lu\n", getpid(), last);
 	}
+	igt_waitchildren();
 
-	closedir(dir);
-	return me;
+	/* Cleanup delayed behind rcu */
+	igt_until_timeout(30) {
+		sched_yield();
+		if (count_clients(clients) == 1)
+			break;
+		usleep(10000);
+	}
+	igt_assert_eq(count_clients(clients), 1);
 }
 
 static int64_t read_runtime(int client, int class)
@@ -719,7 +803,7 @@ sema(int i915, int clients, const struct intel_execution_engine2 *e, int f)
 static int read_all(int clients, pid_t pid, int class, uint64_t *runtime)
 {
 	struct dirent *de;
-	char buf[280];
+	char buf[BUFSZ];
 	int count = 0;
 	DIR *dir;
 
@@ -958,6 +1042,9 @@ igt_main
 	igt_subtest("create")
 		create(i915, clients);
 
+	igt_subtest("recycle")
+		recycle(i915, clients);
+
 	igt_subtest_group
 		test_busy(i915, clients);