From 83e32a5910772e1475d3640a429b7686695f04d1 Mon Sep 17 00:00:00 2001 From: Xuewei Zhang Date: Thu, 6 Sep 2018 13:37:19 -0700 Subject: scsi: sd: Contribute to randomness when running rotational device MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently a scsi device won't contribute to kernel randomness when it uses blk-mq. Since we commonly use scsi on rotational device with blk-mq, it make sense to keep contributing to kernel randomness in these cases. This is especially important for virtual machines. commit b5b6e8c8d3b4 ("scsi: virtio_scsi: fix IO hang caused by automatic irq vector affinity") made all virtio-scsi device to use blk-mq, which does not contribute to randomness today. So for a virtual machine only having virtio-scsi disk (which is common), it will simple stop getting randomness from its disks in today's implementation. With this patch, if the above VM has rotational virtio-scsi device, then it can still benefit from the entropy generated from the disk. Reported-by: Xuewei Zhang Signed-off-by: Xuewei Zhang Reviewed-by: Ming Lei Reviewed-by: Maciej Żenczykowski Reviewed-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/scsi/sd.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'drivers/scsi/sd.c') diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index b79b366a94f7..5e4f10d28065 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2959,6 +2959,9 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp) if (rot == 1) { blk_queue_flag_set(QUEUE_FLAG_NONROT, q); blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, q); + } else { + blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); + blk_queue_flag_set(QUEUE_FLAG_ADD_RANDOM, q); } if (sdkp->device->type == TYPE_ZBC) { -- cgit v1.2.3-59-g8ed1b