| Message ID | 20161017221037.1781185-2-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 18, 2016 at 12:10 AM, Arnd Bergmann <arnd@arndb.de> wrote: > When building with gcc-4.9 -Wmaybe-uninitialized, we get a bogus > warning in rbd_watch_cb, as the variable is not used at all > in the one case in which it is not initialized first: > > drivers/block/rbd.c: In function ‘rbd_watch_cb’: > drivers/block/rbd.c:3690:5: error: ‘struct_v’ may be used uninitialized in this function [-Werror=maybe-uninitialized] > drivers/block/rbd.c:3759:5: note: ‘struct_v’ was declared here > > Later compiler versions fix this, but adding another initialization > here is harmless and lets us build cleanly with 4.9 as well. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/block/rbd.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c > index abb7162..4ab990b 100644 > --- a/drivers/block/rbd.c > +++ b/drivers/block/rbd.c > @@ -3776,6 +3776,7 @@ static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie, > } else { > /* legacy notification for header updates */ > notify_op = RBD_NOTIFY_OP_HEADER_UPDATE; > + struct_v = 0; > len = 0; > } It already got silenced by initializing at declaration in one of the downstream trees, so I'd rather we do @@ -3756,7 +3819,7 @@ static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie, struct rbd_device *rbd_dev = arg; void *p = data; void *const end = p + data_len; - u8 struct_v; + u8 struct_v = 0; u32 len; u32 notify_op; int ret; to reduce the churn. The "block" prefix is redundant and "rdb" should be "rbd" in the subject. Thanks, Ilya -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, October 18, 2016 11:57:33 AM CEST Ilya Dryomov wrote: > It already got silenced by initializing at declaration in one of the > downstream trees, so I'd rather we do > > @@ -3756,7 +3819,7 @@ static void rbd_watch_cb(void *arg, u64 > notify_id, u64 cookie, > struct rbd_device *rbd_dev = arg; > void *p = data; > void *const end = p + data_len; > - u8 struct_v; > + u8 struct_v = 0; > u32 len; > u32 notify_op; > int ret; > > to reduce the churn. Fair enough. I try to avoid adding extraneous initializations like this, but my suggested change is not all that different here, except if ceph_start_decoding() got changed in a way that could lead to another uninitialized use. > The "block" prefix is redundant and "rdb" should be "rbd" in the subject. Oops. Arnd -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index abb7162..4ab990b 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -3776,6 +3776,7 @@ static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie, } else { /* legacy notification for header updates */ notify_op = RBD_NOTIFY_OP_HEADER_UPDATE; + struct_v = 0; len = 0; }
When building with gcc-4.9 -Wmaybe-uninitialized, we get a bogus warning in rbd_watch_cb, as the variable is not used at all in the one case in which it is not initialized first: drivers/block/rbd.c: In function ‘rbd_watch_cb’: drivers/block/rbd.c:3690:5: error: ‘struct_v’ may be used uninitialized in this function [-Werror=maybe-uninitialized] drivers/block/rbd.c:3759:5: note: ‘struct_v’ was declared here Later compiler versions fix this, but adding another initialization here is harmless and lets us build cleanly with 4.9 as well. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/block/rbd.c | 1 + 1 file changed, 1 insertion(+)