| Message ID | 20230525193132.3727-5-mpearson-lenovo@squebb.ca (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [1/5] platform/x86: think-lmi: Enable opcode support on BIOS settings | expand |
Hi Mark, On 5/25/23 21:31, Mark Pearson wrote: > Add mutex protection around cases where an operation needs multiple > WMI calls - e.g. setting password. > > Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca> > --- > Changes in V2: New commit added after review of other patches in series. > > drivers/platform/x86/think-lmi.c | 46 ++++++++++++++++++++++++-------- > 1 file changed, 35 insertions(+), 11 deletions(-) > > diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c > index 64cd453d6e7d..f3e1e4dacba2 100644 > --- a/drivers/platform/x86/think-lmi.c > +++ b/drivers/platform/x86/think-lmi.c > @@ -14,6 +14,7 @@ > #include <linux/acpi.h> > #include <linux/errno.h> > #include <linux/fs.h> > +#include <linux/mutex.h> > #include <linux/string.h> > #include <linux/types.h> > #include <linux/dmi.h> > @@ -195,6 +196,7 @@ static const char * const level_options[] = { > }; > static struct think_lmi tlmi_priv; > static struct class *fw_attr_class; > +static DEFINE_MUTEX(tlmi_mutex); > > /* ------ Utility functions ------------*/ > /* Strip out CR if one is present */ > @@ -463,23 +465,32 @@ static ssize_t new_password_store(struct kobject *kobj, > sprintf(pwd_type, "%s", setting->pwd_type); > } > > + mutex_lock(&tlmi_mutex); > ret = tlmi_opcode_setting("WmiOpcodePasswordType", pwd_type); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > - > + } > if (tlmi_priv.pwd_admin->valid) { > ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", > tlmi_priv.pwd_admin->password); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > } > ret = tlmi_opcode_setting("WmiOpcodePasswordCurrent01", setting->password); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > ret = tlmi_opcode_setting("WmiOpcodePasswordNew01", new_pwd); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > ret = tlmi_simple_call(LENOVO_OPCODE_IF_GUID, "WmiOpcodePasswordSetUpdate;"); > + mutex_unlock(&tlmi_mutex); > } else { > /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */ > auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;", I haven't take a really close / good look yet. But at a first glance I think it would be cleaner to just take the mutex at the top and unlock it after the out label to which all the existing goto-s already go ? > @@ -1000,11 +1011,16 @@ static ssize_t current_value_store(struct kobject *kobj, > goto out; > } > > + mutex_lock(&tlmi_mutex); > ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTING_CERT_GUID, set_str); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > ret = tlmi_simple_call(LENOVO_SAVE_BIOS_SETTING_CERT_GUID, > tlmi_priv.pwd_admin->save_signature); > + > + mutex_unlock(&tlmi_mutex); > if (ret) > goto out; > } else if (tlmi_priv.opcode_support) { > @@ -1021,18 +1037,23 @@ static ssize_t current_value_store(struct kobject *kobj, > goto out; > } > > + mutex_lock(&tlmi_mutex); > ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > > if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) { > ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", > tlmi_priv.pwd_admin->password); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > + } > } > - > ret = tlmi_save_bios_settings(""); > + mutex_unlock(&tlmi_mutex); > } else { /* old non opcode based authentication method (deprecated)*/ > if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) { > auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;", > @@ -1056,14 +1077,17 @@ static ssize_t current_value_store(struct kobject *kobj, > goto out; > } > > + mutex_lock(&tlmi_mutex); > ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str); > - if (ret) > + if (ret) { > + mutex_unlock(&tlmi_mutex); > goto out; > - > + } > if (auth_str) > ret = tlmi_save_bios_settings(auth_str); > else > ret = tlmi_save_bios_settings(""); > + mutex_unlock(&tlmi_mutex); > } > if (!ret && !tlmi_priv.pending_changes) { > tlmi_priv.pending_changes = true; And the same here. Regards, Hans
On Thu, May 25, 2023, at 3:41 PM, Hans de Goede wrote: > Hi Mark, > > On 5/25/23 21:31, Mark Pearson wrote: >> Add mutex protection around cases where an operation needs multiple >> WMI calls - e.g. setting password. >> >> Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca> >> --- >> Changes in V2: New commit added after review of other patches in series. >> >> drivers/platform/x86/think-lmi.c | 46 ++++++++++++++++++++++++-------- >> 1 file changed, 35 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c >> index 64cd453d6e7d..f3e1e4dacba2 100644 >> --- a/drivers/platform/x86/think-lmi.c >> +++ b/drivers/platform/x86/think-lmi.c >> @@ -14,6 +14,7 @@ >> #include <linux/acpi.h> >> #include <linux/errno.h> >> #include <linux/fs.h> >> +#include <linux/mutex.h> >> #include <linux/string.h> >> #include <linux/types.h> >> #include <linux/dmi.h> >> @@ -195,6 +196,7 @@ static const char * const level_options[] = { >> }; >> static struct think_lmi tlmi_priv; >> static struct class *fw_attr_class; >> +static DEFINE_MUTEX(tlmi_mutex); >> >> /* ------ Utility functions ------------*/ >> /* Strip out CR if one is present */ >> @@ -463,23 +465,32 @@ static ssize_t new_password_store(struct kobject *kobj, >> sprintf(pwd_type, "%s", setting->pwd_type); >> } >> >> + mutex_lock(&tlmi_mutex); >> ret = tlmi_opcode_setting("WmiOpcodePasswordType", pwd_type); >> - if (ret) >> + if (ret) { >> + mutex_unlock(&tlmi_mutex); >> goto out; >> - >> + } >> if (tlmi_priv.pwd_admin->valid) { >> ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", >> tlmi_priv.pwd_admin->password); >> - if (ret) >> + if (ret) { >> + mutex_unlock(&tlmi_mutex); >> goto out; >> + } >> } >> ret = tlmi_opcode_setting("WmiOpcodePasswordCurrent01", setting->password); >> - if (ret) >> + if (ret) { >> + mutex_unlock(&tlmi_mutex); >> goto out; >> + } >> ret = tlmi_opcode_setting("WmiOpcodePasswordNew01", new_pwd); >> - if (ret) >> + if (ret) { >> + mutex_unlock(&tlmi_mutex); >> goto out; >> + } >> ret = tlmi_simple_call(LENOVO_OPCODE_IF_GUID, "WmiOpcodePasswordSetUpdate;"); >> + mutex_unlock(&tlmi_mutex); >> } else { >> /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */ >> auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;", > > > I haven't take a really close / good look yet. But at a first glance > I think it would be cleaner to just take the mutex at the top > and unlock it after the out label to which all the existing goto-s > already go ? > I did consider that - and it was in my first implementation; but then I got concerned about if the mutex_unlock could potentially get called without mutex_lock having been called beforehand. I couldn't find any good reference as to whether that was safe or not. I ended up deciding that a few extra brackets and unlock calls wasn't that ugly and was 'safer'...and so went that route. Happy to change it - but do you happen to know if it's safe to call unlock without a lock? If it is then that implementation is cleaner. Mark
Hi, On 5/25/23 21:50, Mark Pearson wrote: > > > On Thu, May 25, 2023, at 3:41 PM, Hans de Goede wrote: >> Hi Mark, >> >> On 5/25/23 21:31, Mark Pearson wrote: >>> Add mutex protection around cases where an operation needs multiple >>> WMI calls - e.g. setting password. >>> >>> Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca> >>> --- >>> Changes in V2: New commit added after review of other patches in series. >>> >>> drivers/platform/x86/think-lmi.c | 46 ++++++++++++++++++++++++-------- >>> 1 file changed, 35 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c >>> index 64cd453d6e7d..f3e1e4dacba2 100644 >>> --- a/drivers/platform/x86/think-lmi.c >>> +++ b/drivers/platform/x86/think-lmi.c >>> @@ -14,6 +14,7 @@ >>> #include <linux/acpi.h> >>> #include <linux/errno.h> >>> #include <linux/fs.h> >>> +#include <linux/mutex.h> >>> #include <linux/string.h> >>> #include <linux/types.h> >>> #include <linux/dmi.h> >>> @@ -195,6 +196,7 @@ static const char * const level_options[] = { >>> }; >>> static struct think_lmi tlmi_priv; >>> static struct class *fw_attr_class; >>> +static DEFINE_MUTEX(tlmi_mutex); >>> >>> /* ------ Utility functions ------------*/ >>> /* Strip out CR if one is present */ >>> @@ -463,23 +465,32 @@ static ssize_t new_password_store(struct kobject *kobj, >>> sprintf(pwd_type, "%s", setting->pwd_type); >>> } >>> >>> + mutex_lock(&tlmi_mutex); >>> ret = tlmi_opcode_setting("WmiOpcodePasswordType", pwd_type); >>> - if (ret) >>> + if (ret) { >>> + mutex_unlock(&tlmi_mutex); >>> goto out; >>> - >>> + } >>> if (tlmi_priv.pwd_admin->valid) { >>> ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", >>> tlmi_priv.pwd_admin->password); >>> - if (ret) >>> + if (ret) { >>> + mutex_unlock(&tlmi_mutex); >>> goto out; >>> + } >>> } >>> ret = tlmi_opcode_setting("WmiOpcodePasswordCurrent01", setting->password); >>> - if (ret) >>> + if (ret) { >>> + mutex_unlock(&tlmi_mutex); >>> goto out; >>> + } >>> ret = tlmi_opcode_setting("WmiOpcodePasswordNew01", new_pwd); >>> - if (ret) >>> + if (ret) { >>> + mutex_unlock(&tlmi_mutex); >>> goto out; >>> + } >>> ret = tlmi_simple_call(LENOVO_OPCODE_IF_GUID, "WmiOpcodePasswordSetUpdate;"); >>> + mutex_unlock(&tlmi_mutex); >>> } else { >>> /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */ >>> auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;", >> >> >> I haven't take a really close / good look yet. But at a first glance >> I think it would be cleaner to just take the mutex at the top >> and unlock it after the out label to which all the existing goto-s >> already go ? >> > I did consider that - and it was in my first implementation; but then I got concerned > about if the mutex_unlock could potentially get called without mutex_lock having been > called beforehand. I couldn't find any good reference as to whether that was safe or not. > > I ended up deciding that a few extra brackets and unlock calls wasn't that ugly and was 'safer'...and > so went that route. > > Happy to change it - but do you happen to know if it's safe to call unlock without a lock? If it is then > that implementation is cleaner. It is not allowed to unlock without a lock. But if you put the lock directly after the malloc for which the out: does the free then there should be no goto out paths which don't have the lock. E.g. for new_password_store() put it here: new_pwd = kstrdup(buf, GFP_KERNEL); if (!new_pwd) return -ENOMEM; mutex_lock(&tlmi_mutex); /* Strip out CR if one is present, setting password won't work if it is present */ ... This does mean also taking the lock in the case where the new password store is done with a single WMI call, but that is not an issue. It makes things a tiny bit slower but WMI calls already are not fast and it is not like we are going to change the password / settings 100-times per second. And the same thing can be done in current_value_store(): new_setting = kstrdup(buf, GFP_KERNEL); if (!new_setting) return -ENOMEM; mutex_lock(&tlmi_mutex); /* Strip out CR if one is present */ ... Regards, Hans
On Fri, May 26, 2023, at 4:12 AM, Hans de Goede wrote: > Hi, > > On 5/25/23 21:50, Mark Pearson wrote: >> >> >> On Thu, May 25, 2023, at 3:41 PM, Hans de Goede wrote: >>> Hi Mark, >>> >>> On 5/25/23 21:31, Mark Pearson wrote: >>>> Add mutex protection around cases where an operation needs multiple >>>> WMI calls - e.g. setting password. >>>> >>>> Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca> >>>> --- >>>> Changes in V2: New commit added after review of other patches in series. >>>> >>>> drivers/platform/x86/think-lmi.c | 46 ++++++++++++++++++++++++-------- >>>> 1 file changed, 35 insertions(+), 11 deletions(-) >>>> >>>> diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c >>>> index 64cd453d6e7d..f3e1e4dacba2 100644 >>>> --- a/drivers/platform/x86/think-lmi.c >>>> +++ b/drivers/platform/x86/think-lmi.c >>>> @@ -14,6 +14,7 @@ >>>> #include <linux/acpi.h> >>>> #include <linux/errno.h> >>>> #include <linux/fs.h> >>>> +#include <linux/mutex.h> >>>> #include <linux/string.h> >>>> #include <linux/types.h> >>>> #include <linux/dmi.h> >>>> @@ -195,6 +196,7 @@ static const char * const level_options[] = { >>>> }; >>>> static struct think_lmi tlmi_priv; >>>> static struct class *fw_attr_class; >>>> +static DEFINE_MUTEX(tlmi_mutex); >>>> >>>> /* ------ Utility functions ------------*/ >>>> /* Strip out CR if one is present */ >>>> @@ -463,23 +465,32 @@ static ssize_t new_password_store(struct kobject *kobj, >>>> sprintf(pwd_type, "%s", setting->pwd_type); >>>> } >>>> >>>> + mutex_lock(&tlmi_mutex); >>>> ret = tlmi_opcode_setting("WmiOpcodePasswordType", pwd_type); >>>> - if (ret) >>>> + if (ret) { >>>> + mutex_unlock(&tlmi_mutex); >>>> goto out; >>>> - >>>> + } >>>> if (tlmi_priv.pwd_admin->valid) { >>>> ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", >>>> tlmi_priv.pwd_admin->password); >>>> - if (ret) >>>> + if (ret) { >>>> + mutex_unlock(&tlmi_mutex); >>>> goto out; >>>> + } >>>> } >>>> ret = tlmi_opcode_setting("WmiOpcodePasswordCurrent01", setting->password); >>>> - if (ret) >>>> + if (ret) { >>>> + mutex_unlock(&tlmi_mutex); >>>> goto out; >>>> + } >>>> ret = tlmi_opcode_setting("WmiOpcodePasswordNew01", new_pwd); >>>> - if (ret) >>>> + if (ret) { >>>> + mutex_unlock(&tlmi_mutex); >>>> goto out; >>>> + } >>>> ret = tlmi_simple_call(LENOVO_OPCODE_IF_GUID, "WmiOpcodePasswordSetUpdate;"); >>>> + mutex_unlock(&tlmi_mutex); >>>> } else { >>>> /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */ >>>> auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;", >>> >>> >>> I haven't take a really close / good look yet. But at a first glance >>> I think it would be cleaner to just take the mutex at the top >>> and unlock it after the out label to which all the existing goto-s >>> already go ? >>> >> I did consider that - and it was in my first implementation; but then I got concerned >> about if the mutex_unlock could potentially get called without mutex_lock having been >> called beforehand. I couldn't find any good reference as to whether that was safe or not. >> >> I ended up deciding that a few extra brackets and unlock calls wasn't that ugly and was 'safer'...and >> so went that route. >> >> Happy to change it - but do you happen to know if it's safe to call unlock without a lock? If it is then >> that implementation is cleaner. > > It is not allowed to unlock without a lock. But if you put the lock > directly after the malloc for which the out: does the free then there > should be no goto out paths which don't have the lock. > > E.g. for new_password_store() put it here: > > new_pwd = kstrdup(buf, GFP_KERNEL); > if (!new_pwd) > return -ENOMEM; > > mutex_lock(&tlmi_mutex); > > /* Strip out CR if one is present, setting password won't work if it > is present */ > ... > > This does mean also taking the lock in the case where the new password > store is done with a single WMI call, but that is not an issue. It > makes things a tiny bit slower but WMI calls already are not fast and > it is not like we are going to change the password / settings 100-times > per second. > > And the same thing can be done in current_value_store(): > > new_setting = kstrdup(buf, GFP_KERNEL); > if (!new_setting) > return -ENOMEM; > > mutex_lock(&tlmi_mutex); > > /* Strip out CR if one is present */ > ... > Yeah - you're right. For some reason I was trying to do the lock only in the block of code that needed locking...but it makes more sense to do it earlier. I'll update. Thanks! Mark
diff --git a/drivers/platform/x86/think-lmi.c b/drivers/platform/x86/think-lmi.c index 64cd453d6e7d..f3e1e4dacba2 100644 --- a/drivers/platform/x86/think-lmi.c +++ b/drivers/platform/x86/think-lmi.c @@ -14,6 +14,7 @@ #include <linux/acpi.h> #include <linux/errno.h> #include <linux/fs.h> +#include <linux/mutex.h> #include <linux/string.h> #include <linux/types.h> #include <linux/dmi.h> @@ -195,6 +196,7 @@ static const char * const level_options[] = { }; static struct think_lmi tlmi_priv; static struct class *fw_attr_class; +static DEFINE_MUTEX(tlmi_mutex); /* ------ Utility functions ------------*/ /* Strip out CR if one is present */ @@ -463,23 +465,32 @@ static ssize_t new_password_store(struct kobject *kobj, sprintf(pwd_type, "%s", setting->pwd_type); } + mutex_lock(&tlmi_mutex); ret = tlmi_opcode_setting("WmiOpcodePasswordType", pwd_type); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; - + } if (tlmi_priv.pwd_admin->valid) { ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", tlmi_priv.pwd_admin->password); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } } ret = tlmi_opcode_setting("WmiOpcodePasswordCurrent01", setting->password); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } ret = tlmi_opcode_setting("WmiOpcodePasswordNew01", new_pwd); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } ret = tlmi_simple_call(LENOVO_OPCODE_IF_GUID, "WmiOpcodePasswordSetUpdate;"); + mutex_unlock(&tlmi_mutex); } else { /* Format: 'PasswordType,CurrentPw,NewPw,Encoding,KbdLang;' */ auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s,%s,%s;", @@ -1000,11 +1011,16 @@ static ssize_t current_value_store(struct kobject *kobj, goto out; } + mutex_lock(&tlmi_mutex); ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTING_CERT_GUID, set_str); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } ret = tlmi_simple_call(LENOVO_SAVE_BIOS_SETTING_CERT_GUID, tlmi_priv.pwd_admin->save_signature); + + mutex_unlock(&tlmi_mutex); if (ret) goto out; } else if (tlmi_priv.opcode_support) { @@ -1021,18 +1037,23 @@ static ssize_t current_value_store(struct kobject *kobj, goto out; } + mutex_lock(&tlmi_mutex); ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) { ret = tlmi_opcode_setting("WmiOpcodePasswordAdmin", tlmi_priv.pwd_admin->password); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; + } } - ret = tlmi_save_bios_settings(""); + mutex_unlock(&tlmi_mutex); } else { /* old non opcode based authentication method (deprecated)*/ if (tlmi_priv.pwd_admin->valid && tlmi_priv.pwd_admin->password[0]) { auth_str = kasprintf(GFP_KERNEL, "%s,%s,%s;", @@ -1056,14 +1077,17 @@ static ssize_t current_value_store(struct kobject *kobj, goto out; } + mutex_lock(&tlmi_mutex); ret = tlmi_simple_call(LENOVO_SET_BIOS_SETTINGS_GUID, set_str); - if (ret) + if (ret) { + mutex_unlock(&tlmi_mutex); goto out; - + } if (auth_str) ret = tlmi_save_bios_settings(auth_str); else ret = tlmi_save_bios_settings(""); + mutex_unlock(&tlmi_mutex); } if (!ret && !tlmi_priv.pending_changes) { tlmi_priv.pending_changes = true;
Add mutex protection around cases where an operation needs multiple WMI calls - e.g. setting password. Signed-off-by: Mark Pearson <mpearson-lenovo@squebb.ca> --- Changes in V2: New commit added after review of other patches in series. drivers/platform/x86/think-lmi.c | 46 ++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 11 deletions(-)