On Wed, Sep 23, 2020 at 12:59:00PM +0200, Oliver Neukum wrote: > Hi, > > you probably do not want to hear this. I was out of comission > for the last week weeks and I should have looked at this more closely. > > You may notice that usb_control_msg() for times immemorial has been > using GFP_NOIO internally. This is because control messages are needed > in a lot of contexts such as SCSI error handling and runtime PM > that require GFP_NOIO. IIRC at that time we found ourselves unable to > go through all those call chains, so we pulled the nuclear option > and slapped a blanket GFP_NOIO on the function. > > Today I got a patch that outright deleted a memory allocation with > GFP_NOIO, so I looked into this. We are making the same mistake > we couldn't fix in the past. > I am afraid the API has to be changed to include memory flags. > And we should do this now while the damage is still within limits. > I am preparing patches. How about we always use GPF_NOIO for the calls? That should be fine and make it easier, right? thanks, greg k-h
