| Message ID | 20200916191544.5104-1-oneukum@suse.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PATCHv2] base: force NOIO allocations during unplug | expand |
On Wed, Sep 16, 2020 at 09:15:44PM +0200, Oliver Neukum wrote: > There is one overlooked situation under which a driver > must not do IO to allocate memory. You cannot do that > while disconnecting a device. A device being disconnected > is no longer functional in most cases, yet IO may fail > only when the handler runs. > > v2: extended section for NOIO until after second notifier chain > > Signed-off-by: Oliver Neukum <oneukum@suse.com> > --- > drivers/base/core.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index bb5806a2bd4c..b79783454293 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -26,6 +26,7 @@ > #include <linux/pm_runtime.h> > #include <linux/netdevice.h> > #include <linux/sched/signal.h> > +#include <linux/sched/mm.h> > #include <linux/sysfs.h> > > #include "base.h" > @@ -3062,6 +3063,7 @@ void device_del(struct device *dev) > struct device *parent = dev->parent; > struct kobject *glue_dir = NULL; > struct class_interface *class_intf; > + unsigned int noio_flag; > > device_lock(dev); > kill_device(dev); > @@ -3073,6 +3075,7 @@ void device_del(struct device *dev) > /* Notify clients of device removal. This call must come > * before dpm_sysfs_remove(). > */ > + noio_flag = memalloc_noio_save(); > if (dev->bus) > blocking_notifier_call_chain(&dev->bus->p->bus_notifier, > BUS_NOTIFY_DEL_DEVICE, dev); > @@ -3114,6 +3117,7 @@ void device_del(struct device *dev) > glue_dir = get_glue_dir(dev); > kobject_del(&dev->kobj); > cleanup_glue_dir(dev, glue_dir); > + memalloc_noio_restore(noio_flag); > put_device(parent); > } > EXPORT_SYMBOL_GPL(device_del); > -- > 2.16.4 > Thanks, now queued up. greg k-h
diff --git a/drivers/base/core.c b/drivers/base/core.c index bb5806a2bd4c..b79783454293 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -26,6 +26,7 @@ #include <linux/pm_runtime.h> #include <linux/netdevice.h> #include <linux/sched/signal.h> +#include <linux/sched/mm.h> #include <linux/sysfs.h> #include "base.h" @@ -3062,6 +3063,7 @@ void device_del(struct device *dev) struct device *parent = dev->parent; struct kobject *glue_dir = NULL; struct class_interface *class_intf; + unsigned int noio_flag; device_lock(dev); kill_device(dev); @@ -3073,6 +3075,7 @@ void device_del(struct device *dev) /* Notify clients of device removal. This call must come * before dpm_sysfs_remove(). */ + noio_flag = memalloc_noio_save(); if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_DEL_DEVICE, dev); @@ -3114,6 +3117,7 @@ void device_del(struct device *dev) glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj); cleanup_glue_dir(dev, glue_dir); + memalloc_noio_restore(noio_flag); put_device(parent); } EXPORT_SYMBOL_GPL(device_del);
There is one overlooked situation under which a driver must not do IO to allocate memory. You cannot do that while disconnecting a device. A device being disconnected is no longer functional in most cases, yet IO may fail only when the handler runs. v2: extended section for NOIO until after second notifier chain Signed-off-by: Oliver Neukum <oneukum@suse.com> --- drivers/base/core.c | 4 ++++ 1 file changed, 4 insertions(+)