----- Original Message ----- From: oleg.drokin@xxxxxxxxx To: lidza.louina@xxxxxxxxxx Cc: gregkh@xxxxxxxxxxxxxxxxxxx, lustre-devel@xxxxxxxxxxxxxxxx, devel@xxxxxxxxxxxxxxxxxxxx, andreas.dilger@xxxxxxxxx Sent: Thursday, June 23, 2016 10:52:24 AM GMT -08:00 US/Canada Pacific Subject: Re: [lustre-devel] [PATCH] staging/lustre/lnet: correctly casts value for arithmetic NAK. On Jun 23, 2016, at 1:24 PM, Lidza Louina wrote: > The code attempted to add an unsigned int to a an unsigned 64-bit > integer. This patch casts the unsigned regular int to suppress > smatch warnings. > > Signed-off-by: Lidza Louina <Lidza.Louina@xxxxxxxxxx> > --- > drivers/staging/lustre/lnet/lnet/api-ni.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/lustre/lnet/lnet/api-ni.c b/drivers/staging/lustre/lnet/lnet/api-ni.c > index 346db89..5ecb2c7 100644 > --- a/drivers/staging/lustre/lnet/lnet/api-ni.c > +++ b/drivers/staging/lustre/lnet/lnet/api-ni.c > @@ -513,7 +513,7 @@ lnet_res_lh_initialize(struct lnet_res_container *rec, lnet_libhandle_t *lh) > unsigned int hash; > > lh->lh_cookie = rec->rec_lh_cookie; > - rec->rec_lh_cookie += 1 << ibits; > + rec->rec_lh_cookie += (__u64)(1 << ibits); This does not do what you think it does? You want to convert 1 into 1ULL so that the value you are shifting if already wide enough bit-wise? But in fact ibits is: LNET_COOKIE_TYPE_BITS + LNET_CPT_BITS LNET_COOKIE_TYPE_BITS is 2 and LNET_CPT_BITS is at max 8, so 10 in total, this should fit into a regular 32 bit integer with zero problems. So we should be fine I imagine either way. And adding 32bit int to 64bit int should always be ok anyway, right? Is it that the addition of signed to unsigned is problematic? Or what was the smatch warning? The smatch warning had to do with the type of value rec->rec_1h_cookie was expecting. It's expecting it to be an unsigned 64 bit integer (I realize I didn't make that clear in my log). The math is correct, it's just the assignment that should be cast. The smatch warning was "drivers/staging/lustre/lnet/lnet/api-ni.c:516 lnet_res_lh_initialize() warn: should '1 << ibits' be a 64 bit type?" > > hash = (lh->lh_cookie >> ibits) & LNET_LH_HASH_MASK; > > -- > 1.9.1 > > > > _______________________________________________ > lustre-devel mailing list > lustre-devel@xxxxxxxxxxxxxxxx > http://lists.lustre.org/listinfo.cgi/lustre-devel-lustre.org _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
