Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Tue, 23 Aug 2022 19:28:56 +0200 | Subject | Re: [PATCH v3 2/6] freezer,umh: Clean up freezer/initrd interaction |
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On Mon, Aug 22, 2022 at 1:48 PM Peter Zijlstra <peterz@infradead.org> wrote: > > handle_initrd() marks itself as PF_FREEZER_SKIP in order to ensure > that the UMH, which is going to freeze the system, doesn't > indefinitely wait for it's caller. > > Rework things by adding UMH_FREEZABLE to indicate the completion is > freezable. > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> --- > include/linux/umh.h | 9 +++++---- > init/do_mounts_initrd.c | 10 +--------- > kernel/umh.c | 8 ++++++++ > 3 files changed, 14 insertions(+), 13 deletions(-) > > --- a/include/linux/umh.h > +++ b/include/linux/umh.h > @@ -11,10 +11,11 @@ > struct cred; > struct file; > > -#define UMH_NO_WAIT 0 /* don't wait at all */ > -#define UMH_WAIT_EXEC 1 /* wait for the exec, but not the process */ > -#define UMH_WAIT_PROC 2 /* wait for the process to complete */ > -#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */ > +#define UMH_NO_WAIT 0x00 /* don't wait at all */ > +#define UMH_WAIT_EXEC 0x01 /* wait for the exec, but not the process */ > +#define UMH_WAIT_PROC 0x02 /* wait for the process to complete */ > +#define UMH_KILLABLE 0x04 /* wait for EXEC/PROC killable */ > +#define UMH_FREEZABLE 0x08 /* wait for EXEC/PROC freezable */ > > struct subprocess_info { > struct work_struct work; > --- a/init/do_mounts_initrd.c > +++ b/init/do_mounts_initrd.c > @@ -79,19 +79,11 @@ static void __init handle_initrd(void) > init_mkdir("/old", 0700); > init_chdir("/old"); > > - /* > - * In case that a resume from disk is carried out by linuxrc or one of > - * its children, we need to tell the freezer not to wait for us. > - */ > - current->flags |= PF_FREEZER_SKIP; > - > info = call_usermodehelper_setup("/linuxrc", argv, envp_init, > GFP_KERNEL, init_linuxrc, NULL, NULL); > if (!info) > return; > - call_usermodehelper_exec(info, UMH_WAIT_PROC); > - > - current->flags &= ~PF_FREEZER_SKIP; > + call_usermodehelper_exec(info, UMH_WAIT_PROC|UMH_FREEZABLE); > > /* move initrd to rootfs' /old */ > init_mount("..", ".", NULL, MS_MOVE, NULL); > --- a/kernel/umh.c > +++ b/kernel/umh.c > @@ -28,6 +28,7 @@ > #include <linux/async.h> > #include <linux/uaccess.h> > #include <linux/initrd.h> > +#include <linux/freezer.h> > > #include <trace/events/module.h> > > @@ -436,6 +437,9 @@ int call_usermodehelper_exec(struct subp > if (wait == UMH_NO_WAIT) /* task has freed sub_info */ > goto unlock; > > + if (wait & UMH_FREEZABLE) > + freezer_do_not_count(); > + > if (wait & UMH_KILLABLE) { > retval = wait_for_completion_killable(&done); > if (!retval) > @@ -448,6 +452,10 @@ int call_usermodehelper_exec(struct subp > } > > wait_for_completion(&done); > + > + if (wait & UMH_FREEZABLE) > + freezer_count(); > + > wait_done: > retval = sub_info->retval; > out: > >
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