On Sunday 16 May 2010, Nigel Cunningham wrote: > Hi. > > On 16/05/10 06:30, Rafael J. Wysocki wrote: > > On Saturday 15 May 2010, Alan Stern wrote: > >> On Thu, 13 May 2010, Matt Reimer wrote: > >> > >>>> I don't see anything wrong with the patch itself, but I dislike the > >>>> description. Devices can come and go from any hotpluggable bus, not > >>>> just MMC/SD. That just happens to be the first place the problem was > >>>> observed. > >>> > >>> Good point. How about this? > >>> > >>> Matt > >>> > >>> From 813bd223e5a2fa577b9e64ddf12654a93d0aab8b Mon Sep 17 00:00:00 2001 > >>> From: Matt Reimer<mreimer@xxxxxxxxxxxxxx> > >>> Date: Thu, 13 May 2010 14:36:54 -0700 > >>> Subject: [PATCH] fs: prevent hang on suspend/resume when MMC/SD card present > >>> > >>> Devices can come and go bus during suspend or resume, when the > >>> writeback thread is frozen, resulting in a hang. Prevent the hang > >>> by thawing the writeback thread in del_gendisk(). > >> > >> I would have said "the block layer's writeback thread", but this is > >> okay. > > > > OK, so now I have a question who's going to take the patch. > > I object to the patch. > > Tell the patch it ought to exit once thawed, by all means. I'm not sure what you mean. Care to explain? > Make the patch unfreezeable to begin with, by all means. That wouldn't work. > But don't go down the path of having $random_code_path unfreeze a > thread. That will lead to unpredictability, confusion and bugs. As a general rule, I agree, but this particular case is somewhat special. > If you know a disk is going to be unregistered during resume, How do we check that, exactly? > use the hooks early in the suspend / hibernate process to block new I/O and > flush what's already there so that there's no need to block on the > writeback thread, and/or no need to have the writeback thread frozen. I'm not sure if that's realistic. Do you have a specific implementation in mind? Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
