From: Jean Delvare <jdelvare@suse.de>
Subject: kABI fix for "ipmi: Don't allow device module unload when in use"
References: bsc#1154768
Patch-mainline: Never, kABI breakage workaround

In order to avoid breaking the kABI, we restore the original
ipmi_register_smi() as a wrapper around the new ipmi_add_smi(). We
rename the new ipmi_register_smi macro to ipmi_register_smi_owner
and update the 3 drivers using it accordingly.

If any 3rd party ipmi driver exists then they will call the old
code which does not protect against module removal while in use,
and a warning will be printed to let the user know.
---
 drivers/char/ipmi/ipmi_msghandler.c |   11 +++++++++++
 drivers/char/ipmi/ipmi_powernv.c    |    2 +-
 drivers/char/ipmi/ipmi_si_intf.c    |    8 ++++----
 drivers/char/ipmi/ipmi_ssif.c       |    8 ++++----
 include/linux/ipmi_smi.h            |    7 ++++++-
 5 files changed, 26 insertions(+), 10 deletions(-)

--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -3698,6 +3698,17 @@ int ipmi_add_smi(struct module         *
 }
 EXPORT_SYMBOL(ipmi_add_smi);
 
+/* Compatibility layer to preserve kABI */
+int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
+		      void		    *send_info,
+		      struct device         *si_dev,
+		      unsigned char         slave_addr)
+{
+	pr_warn("Warning: legacy ipmi_register_smi does not protect against module removal\n");
+	return ipmi_add_smi(NULL, handlers, send_info, si_dev, slave_addr);
+}
+EXPORT_SYMBOL(ipmi_register_smi);
+
 static void deliver_smi_err_response(struct ipmi_smi *intf,
 				     struct ipmi_smi_msg *msg,
 				     unsigned char err)
--- a/drivers/char/ipmi/ipmi_powernv.c
+++ b/drivers/char/ipmi/ipmi_powernv.c
@@ -261,7 +261,7 @@ static int ipmi_powernv_probe(struct pla
 		goto err_unregister;
 	}
 
-	rc = ipmi_register_smi(&ipmi_powernv_smi_handlers, ipmi, dev, 0);
+	rc = ipmi_register_smi_owner(&ipmi_powernv_smi_handlers, ipmi, dev, 0);
 	if (rc) {
 		dev_warn(dev, "IPMI SMI registration failed (%d)\n", rc);
 		goto err_free_msg;
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -2076,10 +2076,10 @@ static int try_smi_init(struct smi_info
 
 	dev_set_drvdata(new_smi->io.dev, new_smi);
 
-	rv = ipmi_register_smi(&handlers,
-			       new_smi,
-			       new_smi->io.dev,
-			       new_smi->io.slave_addr);
+	rv = ipmi_register_smi_owner(&handlers,
+				     new_smi,
+				     new_smi->io.dev,
+				     new_smi->io.slave_addr);
 	if (rv) {
 		dev_err(new_smi->io.dev,
 			"Unable to register device: error %d\n",
--- a/drivers/char/ipmi/ipmi_ssif.c
+++ b/drivers/char/ipmi/ipmi_ssif.c
@@ -1753,10 +1753,10 @@ static int ssif_probe(struct i2c_client
 		}
 	}
 
-	rv = ipmi_register_smi(&ssif_info->handlers,
-			       ssif_info,
-			       &ssif_info->client->dev,
-			       slave_addr);
+	rv = ipmi_register_smi_owner(&ssif_info->handlers,
+				     ssif_info,
+				     &ssif_info->client->dev,
+				     slave_addr);
 	 if (rv) {
 		pr_err(PFX "Unable to register device: error %d\n", rv);
 		goto out;
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -226,9 +226,14 @@ int ipmi_add_smi(struct module
 		 struct device            *dev,
 		 unsigned char            slave_addr);
 
-#define ipmi_register_smi(handlers, send_info, dev, slave_addr) \
+#define ipmi_register_smi_owner(handlers, send_info, dev, slave_addr) \
 	ipmi_add_smi(THIS_MODULE, handlers, send_info, dev, slave_addr)
 
+int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
+		      void                     *send_info,
+		      struct device            *dev,
+		      unsigned char            slave_addr);
+
 /*
  * Remove a low-level interface from the IPMI driver.  This will
  * return an error if the interface is still in use by a user.