Re: [PATCH v4 1/2] virtio_blk: Add control virtqueue support
From: kernel test robot
Date: Fri Oct 09 2026 - 21:14:29 EST
Hi Linlin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on axboe/for-next]
[also build test WARNING on mst-vhost/linux-next linus/master v7.3-rc6 next-20261008]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Linlin-Zhang/virtio_blk-Add-control-virtqueue-support/20261008-211713
base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link: https://lore.kernel.org/r/20261009041727.3170811-2-linlin.zhang%40oss.qualcomm.com
patch subject: [PATCH v4 1/2] virtio_blk: Add control virtqueue support
config: x86_64-defconfig (https://download.01.org/0day-ci/archive/20261010/202610100905.au1oY0vX-lkp@xxxxxxxxx/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20261010/202610100905.au1oY0vX-lkp@xxxxxxxxx/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202610100905.au1oY0vX-lkp@xxxxxxxxx/
All warnings (new ones prefixed by >>):
>> drivers/block/virtio_blk.c:1000:12: warning: 'virtblk_ctrl_vq_request' defined but not used [-Wunused-function]
1000 | static int virtblk_ctrl_vq_request(struct virtio_blk *vblk,
| ^~~~~~~~~~~~~~~~~~~~~~~
vim +/virtblk_ctrl_vq_request +1000 drivers/block/virtio_blk.c
998
999 /* Submit a control-queue request and wait for completion. */
> 1000 static int virtblk_ctrl_vq_request(struct virtio_blk *vblk,
1001 struct virtblk_ctrl_request *creq,
1002 struct scatterlist *sgs[],
1003 unsigned int out_sgs, unsigned int in_sgs)
1004 {
1005 struct virtblk_ctrl_completion *comp;
1006 unsigned long flags;
1007 int err;
1008
1009 /*
1010 * GFP_NOIO: this may be reached on the bio-submission path
1011 * (memory reclaim writing back dirty pages to this same device),
1012 * so GFP_KERNEL could self-deadlock.
1013 */
1014 comp = kmalloc_obj(*comp, GFP_NOIO);
1015 if (!comp)
1016 return -ENOMEM;
1017 init_completion(&comp->done);
1018 comp->abandoned = false;
1019
1020 mutex_lock(&vblk->ctrl_vq.mutex);
1021 creq->compl = comp;
1022
1023 spin_lock_irqsave(&vblk->ctrl_vq.lock, flags);
1024 if (vblk->ctrl_vq.dead) {
1025 spin_unlock_irqrestore(&vblk->ctrl_vq.lock, flags);
1026 mutex_unlock(&vblk->ctrl_vq.mutex);
1027 kfree(comp);
1028 creq->compl = NULL;
1029 return -ENODEV;
1030 }
1031 err = virtqueue_add_sgs(vblk->ctrl_vq.vq, sgs, out_sgs, in_sgs, creq, GFP_ATOMIC);
1032 if (!err) {
1033 vblk->ctrl_vq.inflight++;
1034 virtqueue_kick(vblk->ctrl_vq.vq);
1035 }
1036 spin_unlock_irqrestore(&vblk->ctrl_vq.lock, flags);
1037 if (err) {
1038 mutex_unlock(&vblk->ctrl_vq.mutex);
1039 kfree(comp);
1040 creq->compl = NULL;
1041 return err;
1042 }
1043
1044 if (wait_for_completion_timeout(&comp->done, VIRTBLK_CTRL_VQ_TIMEOUT)) {
1045 mutex_unlock(&vblk->ctrl_vq.mutex);
1046 kfree(comp);
1047 creq->compl = NULL;
1048 return 0;
1049 }
1050
1051 /*
1052 * The host hasn't responded within the timeout. @creq is still
1053 * owned by the device, so don't touch its DMA-target fields or
1054 * free it here. Mark it abandoned and hand ownership of both @creq
1055 * and @comp to whichever of virtblk_ctrlq_callback() or
1056 * virtblk_ctrl_vq_drain() retrieves the buffer later; unlock the
1057 * mutex so subsequent requests aren't serialized behind an
1058 * unresponsive host.
1059 */
1060 spin_lock_irqsave(&vblk->ctrl_vq.lock, flags);
1061 comp->abandoned = true;
1062 spin_unlock_irqrestore(&vblk->ctrl_vq.lock, flags);
1063 mutex_unlock(&vblk->ctrl_vq.mutex);
1064
1065 dev_warn(&vblk->vdev->dev,
1066 "control queue request timed out, abandoning\n");
1067 return -ETIMEDOUT;
1068 }
1069
--
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