On Mon, Nov 02, 2020 at 05:50:30PM +0100, Alexey Gladkov wrote: > In order to be able to use ucounts for rlimits, the size must be increased. > For example user_struct.mq_bytes (RLIMIT_MSGQUEUE) is unsigned long.
I don't have any issues with this change I just wonder what the exact reason is. It's not immediately obvious to me. > > Signed-off-by: Alexey Gladkov <[email protected]> > --- > include/linux/user_namespace.h | 4 ++-- > kernel/ucount.c | 14 +++++++------- > 2 files changed, 9 insertions(+), 9 deletions(-) > > diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h > index 6ef1c7109fc4..fc75af812d73 100644 > --- a/include/linux/user_namespace.h > +++ b/include/linux/user_namespace.h > @@ -86,7 +86,7 @@ struct user_namespace { > struct ctl_table_header *sysctls; > #endif > struct ucounts *ucounts; > - int ucount_max[UCOUNT_COUNTS]; > + long ucount_max[UCOUNT_COUNTS]; > } __randomize_layout; > > struct ucounts { > @@ -94,7 +94,7 @@ struct ucounts { > struct user_namespace *ns; > kuid_t uid; > int count; > - atomic_t ucount[UCOUNT_COUNTS]; > + atomic_long_t ucount[UCOUNT_COUNTS]; > }; > > extern struct user_namespace init_user_ns; > diff --git a/kernel/ucount.c b/kernel/ucount.c > index 11b1596e2542..7b2bca8582ef 100644 > --- a/kernel/ucount.c > +++ b/kernel/ucount.c > @@ -175,14 +175,14 @@ static void put_ucounts(struct ucounts *ucounts) > kfree(ucounts); > } > > -static inline bool atomic_inc_below(atomic_t *v, int u) > +static inline bool atomic_long_inc_below(atomic_long_t *v, int u) > { > - int c, old; > - c = atomic_read(v); > + long c, old; > + c = atomic_long_read(v); > for (;;) { > if (unlikely(c >= u)) > return false; > - old = atomic_cmpxchg(v, c, c+1); > + old = atomic_long_cmpxchg(v, c, c+1); > if (likely(old == c)) > return true; > c = old; > @@ -199,14 +199,14 @@ struct ucounts *inc_ucount(struct user_namespace *ns, > kuid_t uid, > int max; > tns = iter->ns; > max = READ_ONCE(tns->ucount_max[type]); > - if (!atomic_inc_below(&iter->ucount[type], max)) > + if (!atomic_long_inc_below(&iter->ucount[type], max)) > goto fail; > } > return ucounts; > fail: > bad = iter; > for (iter = ucounts; iter != bad; iter = iter->ns->ucounts) > - atomic_dec(&iter->ucount[type]); > + atomic_long_dec(&iter->ucount[type]); > > put_ucounts(ucounts); > return NULL; > @@ -216,7 +216,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type > type) > { > struct ucounts *iter; > for (iter = ucounts; iter; iter = iter->ns->ucounts) { > - int dec = atomic_dec_if_positive(&iter->ucount[type]); > + int dec = atomic_long_dec_if_positive(&iter->ucount[type]); > WARN_ON_ONCE(dec < 0); > } > put_ucounts(ucounts); > -- > 2.25.4 >
