On Thu, 2017-01-26 at 11:17 +0000, Augusto Mecking Caringi wrote: > In a 64bit system (where long is 64bit wide), even dividing LONG_MAX by > HZ will always be bigger than the max value that an int variable can > hold. > > This has been detected by building the driver with W=1: > > drivers/scsi/scsi_transport_srp.c: In function ‘srp_tmo_valid’: > drivers/scsi/scsi_transport_srp.c:92:19: warning: comparison is always > false due to limited range of data type [-Wtype-limits] > if (dev_loss_tmo >= LONG_MAX / HZ) > ^ > > Signed-off-by: Augusto Mecking Caringi <augustocari...@gmail.com> > --- > drivers/scsi/scsi_transport_srp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi_transport_srp.c > b/drivers/scsi/scsi_transport_srp.c > index b87a786..d8c83f4 100644 > --- a/drivers/scsi/scsi_transport_srp.c > +++ b/drivers/scsi/scsi_transport_srp.c > @@ -89,7 +89,7 @@ int srp_tmo_valid(int reconnect_delay, int > fast_io_fail_tmo, int dev_loss_tmo) > if (fast_io_fail_tmo < 0 && > dev_loss_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT) > return -EINVAL; > - if (dev_loss_tmo >= LONG_MAX / HZ) > + if (dev_loss_tmo >= INT_MAX / HZ) > return -EINVAL; > if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 && > fast_io_fail_tmo >= dev_loss_tmo)
This patch is wrong. The purpose of the dev_loss_tmo >= LONG_MAX / HZ check is to avoid that the expression 1UL * dev_loss_tmo * HZ further down overflows. Can you check whether changing the if-statement into if (1UL * dev_loss_tmo >= LONG_MAX / HZ) also suppresses the compiler warning? Bart.
