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 <[email protected]>
> ---
> 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?
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