[ovs-dev] [PATCH 1/2] dpif-linux: Fail earlier if OVS kernel module isn't loaded
Justin Pettit
jpettit at nicira.com
Fri Oct 2 22:32:04 UTC 2009
When the kernel module isn't loaded, the bridge tries to open all the
possible minor devices, regardless. This change first checks that there
is a major device number for Open vSwitch and only then tries to open the
minor devices.
This change also removes the assumption that there's a default Open vSwitch
major device number, since the kernel module always attempts to get a
dynamic one. Maybe one day we'll have one...
Bug #1179
---
lib/dpif-linux.c | 46 ++++++++++++++++++++++++++++++++--------------
1 files changed, 32 insertions(+), 14 deletions(-)
diff --git a/lib/dpif-linux.c b/lib/dpif-linux.c
index a1a666b..2d9c47e 100644
--- a/lib/dpif-linux.c
+++ b/lib/dpif-linux.c
@@ -61,6 +61,7 @@ static struct vlog_rate_limit error_rl = VLOG_RATE_LIMIT_INIT(9999, 5);
static int do_ioctl(const struct dpif *, int cmd, const void *arg);
static int lookup_minor(const char *name, int *minor);
static int finish_open(struct dpif *, const char *local_ifname);
+static int get_openvswitch_major(void);
static int create_minor(const char *name, int minor, struct dpif **dpifp);
static int open_minor(int minor, struct dpif **dpifp);
static int make_openvswitch_device(int minor, char **fnp);
@@ -77,9 +78,19 @@ dpif_linux_cast(const struct dpif *dpif)
static int
dpif_linux_enumerate(struct svec *all_dps)
{
+ int major;
int error;
int i;
+ /* Check that the Open vSwitch module is loaded. */
+ major = get_openvswitch_major();
+ if (major < 0) {
+ error = -major;
+ VLOG_WARN_RL(&error_rl, "could not find openvswitch major device (%s)",
+ strerror(error));
+ return error;
+ }
+
error = 0;
for (i = 0; i < ODP_MAX; i++) {
struct dpif *dpif;
@@ -472,7 +483,7 @@ const struct dpif_class dpif_linux_class = {
};
static int get_openvswitch_major(void);
-static int get_major(const char *target, int default_major);
+static int get_major(const char *target);
static int
do_ioctl(const struct dpif *dpif_, int cmd, const void *arg)
@@ -541,11 +552,21 @@ error:
static int
make_openvswitch_device(int minor, char **fnp)
{
- dev_t dev = makedev(get_openvswitch_major(), minor);
const char dirname[] = "/dev/net";
+ int major;
+ dev_t dev;
struct stat s;
char fn[128];
+ major = get_openvswitch_major();
+ if (major < 0) {
+ int error = -major;
+ VLOG_WARN_RL(&error_rl, "could not find openvswitch major device (%s)",
+ strerror(error));
+ return error;
+ }
+ dev = makedev(major, minor);
+
*fnp = NULL;
sprintf(fn, "%s/dp%d", dirname, minor);
if (!stat(fn, &s)) {
@@ -597,20 +618,20 @@ success:
return 0;
}
-
+/* Return the major device number of the Open vSwitch device. If it
+ * cannot be determined, a negative errno is returned. */
static int
get_openvswitch_major(void)
{
- static unsigned int openvswitch_major;
- if (!openvswitch_major) {
- enum { DEFAULT_MAJOR = 248 };
- openvswitch_major = get_major("openvswitch", DEFAULT_MAJOR);
+ static int openvswitch_major = -1;
+ if (openvswitch_major < 0) {
+ openvswitch_major = get_major("openvswitch");
}
return openvswitch_major;
}
static int
-get_major(const char *target, int default_major)
+get_major(const char *target)
{
const char fn[] = "/proc/devices";
char line[128];
@@ -620,7 +641,7 @@ get_major(const char *target, int default_major)
file = fopen(fn, "r");
if (!file) {
VLOG_ERR("opening %s failed (%s)", fn, strerror(errno));
- goto error;
+ return -errno;
}
for (ln = 1; fgets(line, sizeof line, file); ln++) {
@@ -646,11 +667,8 @@ get_major(const char *target, int default_major)
}
}
- VLOG_ERR("%s: %s major not found (is the module loaded?), using "
- "default major %d", fn, target, default_major);
-error:
- VLOG_INFO("using default major %d for %s", default_major, target);
- return default_major;
+ VLOG_ERR("%s: %s major not found (is the module loaded?)", fn, target);
+ return -ENODEV;
}
static int
--
1.5.5
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