Messages in this thread | | | Subject | Re: [PATCH] ipmi: Don't allow device module unload when in use | From | Tony Camuso <> | Date | Tue, 22 Oct 2019 10:29:12 -0400 |
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Corey,
Testing shows that this patch works as expected.
Regards, Tony
On 10/14/19 11:46 AM, minyard@acm.org wrote: > From: Corey Minyard <cminyard@mvista.com> > > If something has the IPMI driver open, don't allow the device > module to be unloaded. Before it would unload and the user would > get errors on use. > > This change is made on user request, and it makes it consistent > with the I2C driver, which has the same behavior. > > It does change things a little bit with respect to kernel users. > If the ACPI or IPMI watchdog (or any other kernel user) has > created a user, then the device module cannot be unloaded. Before > it could be unloaded, > > This does not affect hot-plug. If the device goes away (it's on > something removable that is removed or is hot-removed via sysfs) > then it still behaves as it did before. > > Reported-by: tony camuso <tcamuso@redhat.com> > Signed-off-by: Corey Minyard <cminyard@mvista.com> > --- > Tony, here is a suggested change for this. Can you look it over and > see if it looks ok? > > Thanks, > > -corey > > drivers/char/ipmi/ipmi_msghandler.c | 23 ++++++++++++++++------- > include/linux/ipmi_smi.h | 12 ++++++++---- > 2 files changed, 24 insertions(+), 11 deletions(-) > > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c > index 2aab80e19ae0..15680de18625 100644 > --- a/drivers/char/ipmi/ipmi_msghandler.c > +++ b/drivers/char/ipmi/ipmi_msghandler.c > @@ -448,6 +448,8 @@ enum ipmi_stat_indexes { > > #define IPMI_IPMB_NUM_SEQ 64 > struct ipmi_smi { > + struct module *owner; > + > /* What interface number are we? */ > int intf_num; > > @@ -1220,6 +1222,11 @@ int ipmi_create_user(unsigned int if_num, > if (rv) > goto out_kfree; > > + if (!try_module_get(intf->owner)) { > + rv = -ENODEV; > + goto out_kfree; > + } > + > /* Note that each existing user holds a refcount to the interface. */ > kref_get(&intf->refcount); > > @@ -1349,6 +1356,7 @@ static void _ipmi_destroy_user(struct ipmi_user *user) > } > > kref_put(&intf->refcount, intf_free); > + module_put(intf->owner); > } > > int ipmi_destroy_user(struct ipmi_user *user) > @@ -2459,7 +2467,7 @@ static int __get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc) > * been recently fetched, this will just use the cached data. Otherwise > * it will run a new fetch. > * > - * Except for the first time this is called (in ipmi_register_smi()), > + * Except for the first time this is called (in ipmi_add_smi()), > * this will always return good data; > */ > static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc, > @@ -3377,10 +3385,11 @@ static void redo_bmc_reg(struct work_struct *work) > kref_put(&intf->refcount, intf_free); > } > > -int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > - void *send_info, > - struct device *si_dev, > - unsigned char slave_addr) > +int ipmi_add_smi(struct module *owner, > + const struct ipmi_smi_handlers *handlers, > + void *send_info, > + struct device *si_dev, > + unsigned char slave_addr) > { > int i, j; > int rv; > @@ -3406,7 +3415,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > return rv; > } > > - > + intf->owner = owner; > intf->bmc = &intf->tmp_bmc; > INIT_LIST_HEAD(&intf->bmc->intfs); > mutex_init(&intf->bmc->dyn_mutex); > @@ -3514,7 +3523,7 @@ int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > > return rv; > } > -EXPORT_SYMBOL(ipmi_register_smi); > +EXPORT_SYMBOL(ipmi_add_smi); > > static void deliver_smi_err_response(struct ipmi_smi *intf, > struct ipmi_smi_msg *msg, > diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h > index 4dc66157d872..deec18b8944a 100644 > --- a/include/linux/ipmi_smi.h > +++ b/include/linux/ipmi_smi.h > @@ -224,10 +224,14 @@ static inline int ipmi_demangle_device_id(uint8_t netfn, uint8_t cmd, > * is called, and the lower layer must get the interface from that > * call. > */ > -int ipmi_register_smi(const struct ipmi_smi_handlers *handlers, > - void *send_info, > - struct device *dev, > - unsigned char slave_addr); > +int ipmi_add_smi(struct module *owner, > + const struct ipmi_smi_handlers *handlers, > + void *send_info, > + struct device *dev, > + unsigned char slave_addr); > + > +#define ipmi_register_smi(handlers, send_info, dev, slave_addr) \ > + ipmi_add_smi(THIS_MODULE, handlers, send_info, dev, slave_addr) > > /* > * Remove a low-level interface from the IPMI driver. This will >
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