Quoting Cedric Le Goater ([EMAIL PROTECTED]): > From: Cedric Le Goater <[EMAIL PROTECTED]> > > We have at least 2 patchsets requiring each a new clone flag and there it > is, we've reached the limit, none are left. > This patch uses the CLONE_DETACHED flag (unused) as a marker to extend the
Are we pretty sure that there is no legacy software out there which has continued to specify CLONE_DETACHED since the kernel ignores it? > clone flags through the parent_tidptr argument. > > Initially, we thought on using the last bit but it has recently been taken > by CLONE_IO. > > Obviously, this hack doesn't work for unshare() for which I don't see any > other solution than to add a new syscall : > long sys_unshare64(unsigned long clone_flags_high, > unsigned long > clone_flags_low); > > > > Is this the right path to extend the clone flags ? should we add a > clone64() rather than hack the extending clone() ? > Thanks for any comments ! > > C. > > Signed-off-by: Cedric Le Goater <[EMAIL PROTECTED]> > --- > include/linux/sched.h | 1 + > kernel/fork.c | 14 +++++++++++++- > 2 files changed, 14 insertions(+), 1 deletion(-) > > Index: 2.6.24-mm1/include/linux/sched.h > =================================================================== > --- 2.6.24-mm1.orig/include/linux/sched.h > +++ 2.6.24-mm1/include/linux/sched.h > @@ -28,6 +28,7 @@ > #define CLONE_NEWPID 0x20000000 /* New pid namespace */ > #define CLONE_NEWNET 0x40000000 /* New network namespace */ > #define CLONE_IO 0x80000000 /* Clone io context */ > +#define CLONE_EXTFLAGS CLONE_DETACHED /* use parent_tidptr as > an extended > set of flags */ > > /* > * Scheduling policies > Index: 2.6.24-mm1/kernel/fork.c > =================================================================== > --- 2.6.24-mm1.orig/kernel/fork.c > +++ 2.6.24-mm1/kernel/fork.c > @@ -1012,6 +1012,14 @@ static struct task_struct *copy_process( > struct task_struct *p; > int cgroup_callbacks_done = 0; > > + /* > + * It is not permitted to specify both CLONE_EXTFLAGS and > + * CLONE_PARENT_SETTID > + */ > + if ((clone_flags & (CLONE_EXTFLAGS|CLONE_PARENT_SETTID)) == > + (CLONE_EXTFLAGS|CLONE_PARENT_SETTID)) > + return ERR_PTR(-EINVAL); > + > if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS)) > return ERR_PTR(-EINVAL); > > @@ -1455,6 +1463,7 @@ long do_fork(unsigned long clone_flags, > struct task_struct *p; > int trace = 0; > long nr; > + u64 clone_flags64 = clone_flags; > > /* > * We hope to recycle these flags after 2.6.26 > @@ -1479,7 +1488,10 @@ long do_fork(unsigned long clone_flags, > clone_flags |= CLONE_PTRACE; > } > > - p = copy_process(clone_flags, stack_start, regs, stack_size, > + if (clone_flags & CLONE_EXTFLAGS) > + clone_flags64 = ((u64) (uintptr_t) parent_tidptr << 32) | > clone_flags; > + > + p = copy_process(clone_flags64, stack_start, regs, stack_size, > child_tidptr, NULL); > /* > * Do this prior waking up the new thread - the thread pointer > _______________________________________________ > Containers mailing list > [EMAIL PROTECTED] > https://lists.linux-foundation.org/mailman/listinfo/containers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
