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Subject[PATCH] ipmi_si: use smi_num for init_name
Date
From: Tony Camuso <tcamuso@redhat.com>

Commit 1abf71e moved the creation of new_smi->dev to earlier in the init
sequence in order to provide infrastructure for log printing.

However, the init_name was created with a hard-coded value of zero. This
presents a problem in systems with more than one interface, producing a
call trace in dmesg.

To correct the problem, simply use smi_num instead of the hard-coded
value of zero.

Tested on a lenovo x3950.

Signed-off-by: Tony Camuso <tcamuso@redhat.com>

There was actually a more general problem, the platform device wasn't
being set correctly, either, and there was a possible (though extremely
unlikely) race on smi_num. Add locks to clean up the race and use the
proper value for the platform device, too.

Tested on qemu in various configurations.

Signed-off-by: Corey Minyard <cminyard@mvista.com>
---

I reworked this a bit, I think I've covered all the problems with
smi_num. Tony, does this work for you?

Thanks

drivers/char/ipmi/ipmi_si_intf.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 2a7c425..b2b618f 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -1954,7 +1954,9 @@ static int hotmod_handler(const char *val, struct kernel_param *kp)
kfree(info);
goto out;
}
+ mutex_lock(&smi_infos_lock);
rv = try_smi_init(info);
+ mutex_unlock(&smi_infos_lock);
if (rv) {
cleanup_one_si(info);
goto out;
@@ -2042,8 +2044,10 @@ static int hardcode_find_bmc(void)
info->slave_addr = slave_addrs[i];

if (!add_smi(info)) {
+ mutex_lock(&smi_infos_lock);
if (try_smi_init(info))
cleanup_one_si(info);
+ mutex_unlock(&smi_infos_lock);
ret = 0;
} else {
kfree(info);
@@ -3492,6 +3496,11 @@ static int add_smi(struct smi_info *new_smi)
return rv;
}

+/*
+ * Try to start up an interface. Must be called with smi_infos_lock
+ * held, primarily to keep smi_num consistent, we only one to do these
+ * one at a time.
+ */
static int try_smi_init(struct smi_info *new_smi)
{
int rv = 0;
@@ -3524,9 +3533,12 @@ static int try_smi_init(struct smi_info *new_smi)
goto out_err;
}

+ new_smi->intf_num = smi_num;
+
/* Do this early so it's available for logs. */
if (!new_smi->dev) {
- init_name = kasprintf(GFP_KERNEL, "ipmi_si.%d", 0);
+ init_name = kasprintf(GFP_KERNEL, "ipmi_si.%d",
+ new_smi->intf_num);

/*
* If we don't already have a device from something
@@ -3593,8 +3605,6 @@ static int try_smi_init(struct smi_info *new_smi)

new_smi->interrupt_disabled = true;
atomic_set(&new_smi->need_watch, 0);
- new_smi->intf_num = smi_num;
- smi_num++;

rv = try_enable_event_buffer(new_smi);
if (rv == 0)
@@ -3661,6 +3671,9 @@ static int try_smi_init(struct smi_info *new_smi)
goto out_err_stop_timer;
}

+ /* Don't increment till we know we have succeeded. */
+ smi_num++;
+
dev_info(new_smi->dev, "IPMI %s interface initialized\n",
si_to_str[new_smi->si_type]);

--
2.7.4
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