| Message ID | 20200324153643.15527-10-will@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Improve list integrity checking | expand |
On Tue, Mar 24, 2020 at 03:36:31PM +0000, Will Deacon wrote: > There is no need to use WRITE_ONCE() when inserting into a non-RCU > protected list. > > Cc: Paul E. McKenney <paulmck@kernel.org> > Cc: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Will Deacon <will@kernel.org> OK, I will bite... Why "unsigned long" instead of "uintptr_t"? Not that it matters in the context of the Linux kernel, so: Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Thanx, Paul > --- > include/linux/list_bl.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h > index 1804fdb84dda..c93e7e3aa8fc 100644 > --- a/include/linux/list_bl.h > +++ b/include/linux/list_bl.h > @@ -91,15 +91,15 @@ static inline void hlist_bl_add_before(struct hlist_bl_node *n, > struct hlist_bl_node *next) > { > struct hlist_bl_node **pprev = next->pprev; > + unsigned long val; > > n->pprev = pprev; > n->next = next; > next->pprev = &n->next; > > /* pprev may be `first`, so be careful not to lose the lock bit */ > - WRITE_ONCE(*pprev, > - (struct hlist_bl_node *) > - ((uintptr_t)n | ((uintptr_t)*pprev & LIST_BL_LOCKMASK))); > + val = (unsigned long)n | ((unsigned long)*pprev & LIST_BL_LOCKMASK); > + *pprev = (struct hlist_bl_node *)val; > } > > static inline void hlist_bl_add_behind(struct hlist_bl_node *n, > -- > 2.20.1 >
On Mon, Mar 30, 2020 at 04:30:20PM -0700, Paul E. McKenney wrote: > On Tue, Mar 24, 2020 at 03:36:31PM +0000, Will Deacon wrote: > > There is no need to use WRITE_ONCE() when inserting into a non-RCU > > protected list. > > > > Cc: Paul E. McKenney <paulmck@kernel.org> > > Cc: Peter Zijlstra <peterz@infradead.org> > > Signed-off-by: Will Deacon <will@kernel.org> > > OK, I will bite... Why "unsigned long" instead of "uintptr_t"? I just did that for consistency with the rest of the file, e.g. hlist_bl_first(), hlist_bl_set_first(), hlist_bl_empty() and __hlist_bl_del() all cast to 'unsigned long', yet only hlist_bl_add_before() was using 'uintptr_t' > Not that it matters in the context of the Linux kernel, so: > > Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Thanks, Paul! Will
diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h index 1804fdb84dda..c93e7e3aa8fc 100644 --- a/include/linux/list_bl.h +++ b/include/linux/list_bl.h @@ -91,15 +91,15 @@ static inline void hlist_bl_add_before(struct hlist_bl_node *n, struct hlist_bl_node *next) { struct hlist_bl_node **pprev = next->pprev; + unsigned long val; n->pprev = pprev; n->next = next; next->pprev = &n->next; /* pprev may be `first`, so be careful not to lose the lock bit */ - WRITE_ONCE(*pprev, - (struct hlist_bl_node *) - ((uintptr_t)n | ((uintptr_t)*pprev & LIST_BL_LOCKMASK))); + val = (unsigned long)n | ((unsigned long)*pprev & LIST_BL_LOCKMASK); + *pprev = (struct hlist_bl_node *)val; } static inline void hlist_bl_add_behind(struct hlist_bl_node *n,
There is no need to use WRITE_ONCE() when inserting into a non-RCU protected list. Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Will Deacon <will@kernel.org> --- include/linux/list_bl.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)