scsi: zfcp: Use prandom_u32_max() for backoff

We don't need crypto-grade random numbers for randomized backoffs.  Instead
use prandom_u32_max(ep_ro) which generates a pseudo-random number uniformly
distributed in the interval [0, ep_ro).

Link: https://lore.kernel.org/r/8fc7c4c4069ff1783f4a9ccd84a923f581a09ec5.1593780621.git.bblock@linux.ibm.com
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: George Spelvin <lkml@sdf.org>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/s390/scsi/zfcp_fc.c b/drivers/s390/scsi/zfcp_fc.c
index b018b61bd168edc580d24326f6c5d214dea4fa37..d24cafe02708fa941346510c6fd8aac21f1110e3 100644 (file)
--- a/drivers/s390/scsi/zfcp_fc.c
+++ b/drivers/s390/scsi/zfcp_fc.c
@@ -48,7 +48,7 @@ unsigned int zfcp_fc_port_scan_backoff(void)
 {
        if (!port_scan_backoff)
                return 0;
-       return get_random_int() % port_scan_backoff;
+       return prandom_u32_max(port_scan_backoff);
 }
 
 static void zfcp_fc_port_scan_time(struct zfcp_adapter *adapter)