From: Wang Weidong <wangweidong1@xxxxxxxxxx>
On 2013/12/16 21:48, Neil Horman wrote:
On Mon, Dec 16, 2013 at 10:47:00AM +0800, Wang Weidong wrote:
On 2013/12/13 20:26, Neil Horman wrote:
On Fri, Dec 13, 2013 at 11:00:10AM +0800, Wang Weidong wrote:
when I modprobe sctp_probe, it failed with "FATAL: ". I found that
sctp should load before sctp_probe register jprobe. So I add a
sctp_setup_jprobe for loading 'sctp' when first failed to register
jprobe, just do this similar to dccp_probe.
v2: add MODULE_SOFTDEP and check of request_module, as suggested by Neil
Signed-off-by: Wang Weidong <wangweidong1@xxxxxxxxxx>
---
net/sctp/probe.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/net/sctp/probe.c b/net/sctp/probe.c
index 53c452e..5e68b94 100644
--- a/net/sctp/probe.c
+++ b/net/sctp/probe.c
@@ -38,6 +38,7 @@
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
+MODULE_SOFTDEP("pre: sctp");
MODULE_AUTHOR("Wei Yongjun <yjwei@xxxxxxxxxxxxxx>");
MODULE_DESCRIPTION("SCTP snooper");
MODULE_LICENSE("GPL");
@@ -182,6 +183,20 @@ static struct jprobe sctp_recv_probe = {
.entry = jsctp_sf_eat_sack,
};
+static __init int sctp_setup_jprobe(void)
+{
+ int ret = register_jprobe(&sctp_recv_probe);
+
+ if (ret) {
+ if (request_module("sctp"))
+ goto out;
+ ret = register_jprobe(&sctp_recv_probe);
+ }
+
+out:
+ return ret;
+}
+
static __init int sctpprobe_init(void)
{
int ret = -ENOMEM;
@@ -202,7 +217,7 @@ static __init int sctpprobe_init(void)
&sctpprobe_fops))
goto free_kfifo;
- ret = register_jprobe(&sctp_recv_probe);
+ ret = sctp_setup_jprobe();
You don't need to create your own function for this, you can collapse it down to
a call to try_then_request_module(regitser_jprobe(...), "sctp");
Neil
Hi Neil,
I try to use try_then_request_module(!regitser_jprobe(...), "sctp"); I found that if
I used this, I couldn't get the ture value which returned by register_jprobe(). Is the
returned value not important? The problem("if sctp.ko doesn't exist") you had pointed out
is exist as well.
Regards.
Wang
Not sure I follow. There appear to be lots of examples in the kernel where
I do this just like the dccp/probe.c do. So I think it can be an example.
exactly what you are trying to do is done. try_then_request_module calls your
requested method, and if it returns non-zero, calls request_module, then calls
No actually. Just look the definition:
#define try_then_request_module(x, mod...) \
((x) ?: (__request_module(true, mod), (x)))
if x return non-zero, it will return the value, not call request_module.
your requested method again, returning the final result. What problem are you
running into?
Neil
So I only can use it like this:
try_then_request_module(!regitser_jprobe(...), "sctp");
when register_jprobe return 0 indicates success, I get the value is 1. It is OK.
when register_jprobe is non-zero indicates failed, then calls request_module,
and last calls register_jprobe. Here,
1)maybe it will failed return non-zero, what I get the value is !register_jprobe
is 0 with losing the value.
2)request_module failed with the sctp is not exist, it will do the register_jprobe
as well.
Is there I am wrong somewhere?
Regards.
Wang
if (ret)
goto remove_proc;
.
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