On Sat, Sep 20, 2014 at 10:18:39PM +0900, Roman Peniaev wrote: > On Sat, Sep 20, 2014 at 6:42 AM, Greg Kroah-Hartman > <gre...@linuxfoundation.org> wrote: > > On Fri, Sep 19, 2014 at 09:44:24PM +0900, Roman Pen wrote: > >> The thing is that built-in modules are being inited before > >> rootfs mount. Some of the modules can request firmware loading > >> from another thread using async 'request_firmware_nowait' call > >> on inition, so we can catch this kind of race: > >> rootfs does not exist yet, but we are going to open and load > >> firmware file requesting it from the kernel thread. > >> > >> Solution is simple: before any rootfs access firmware loader > >> must wait for rootfs mount. > > > > Even simpler solution, don't do that :) > > > > If your hardware needs firmware this early, and you don't put the > > firmare into the initrd/initramfs, then it will just be loaded later on, > > when the root filesystem is needed and the driver asks for it again > > (your driver is failing "nicely" and allows the firmware to be loaded > > later, right? If not, that should be fixed...) > > > > Or, build the firmware into the kernel, I think we still have that > > option for some drivers that really wanted/needed this. > > > > What has changed recently that requires this type of patch? What is > > wrong with the above solutions? > > > I definitely agree with that "do not do that", I do agree.
Great, no need for a patch, we can move on now. :) > But, I did not find any other solution, because in my case this "to be loaded > later" really matters. The source of the problem is the rtlwifi, which > randomly > delays the startup, it randomly warns me about "firmware loading failed" and > repeats loading later. This later costs around one second. For my tiny arm > setup it is important. And it happens because of this race. What "costs one second"? I don't understand, if the firmware isn't there, are you timing out? Fix the driver to do async firmware loading and that timeout shouldn't be an issue. > So, all I want to say with this patch is: > > 1. 'mount / firmware loading' race exists, and it can cost time. Switch the driver to do async firmware loading and you should be able to fix this. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
