Re: [PATCHv7 4/6] ublk: zc register/unregister bvec

[kernel test robot <lkp@intel.com>]

Hi Keith,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20250226]
[cannot apply to axboe-block/for-next linux-nvme/for-next linus/master v6.14-rc4 v6.14-rc3 v6.14-rc2 v6.14-rc4]
[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/Keith-Busch/io_uring-rw-move-fixed-buffer-import-to-issue-path/20250227-022853
base:   next-20250226
patch link:    https://lore.kernel.org/r/20250226182102.2631321-5-kbusch%40meta.com
patch subject: [PATCHv7 4/6] ublk: zc register/unregister bvec
config: i386-randconfig-014-20250227 (https://download.01.org/0day-ci/archive/20250227/202502272337.CubkA5JN-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250227/202502272337.CubkA5JN-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202502272337.CubkA5JN-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/block/ublk_drv.c: In function 'ublk_ctrl_add_dev':
>> drivers/block/ublk_drv.c:2510:32: warning: suggest parentheses around arithmetic in operand of '|' [-Wparentheses]
    2510 |                 if (info.flags & UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY)

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for FB_IOMEM_HELPERS
   Depends on [n]: HAS_IOMEM [=y] && FB_CORE [=n]
   Selected by [m]:
   - DRM_XE_DISPLAY [=y] && HAS_IOMEM [=y] && DRM [=y] && DRM_XE [=m] && DRM_XE [=m]=m [=m] && HAS_IOPORT [=y]


vim +2510 drivers/block/ublk_drv.c

  2455	
  2456	static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
  2457	{
  2458		const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
  2459		void __user *argp = (void __user *)(unsigned long)header->addr;
  2460		struct ublksrv_ctrl_dev_info info;
  2461		struct ublk_device *ub;
  2462		int ret = -EINVAL;
  2463	
  2464		if (header->len < sizeof(info) || !header->addr)
  2465			return -EINVAL;
  2466		if (header->queue_id != (u16)-1) {
  2467			pr_warn("%s: queue_id is wrong %x\n",
  2468				__func__, header->queue_id);
  2469			return -EINVAL;
  2470		}
  2471	
  2472		if (copy_from_user(&info, argp, sizeof(info)))
  2473			return -EFAULT;
  2474	
  2475		if (capable(CAP_SYS_ADMIN))
  2476			info.flags &= ~UBLK_F_UNPRIVILEGED_DEV;
  2477		else if (!(info.flags & UBLK_F_UNPRIVILEGED_DEV))
  2478			return -EPERM;
  2479	
  2480		/* forbid nonsense combinations of recovery flags */
  2481		switch (info.flags & UBLK_F_ALL_RECOVERY_FLAGS) {
  2482		case 0:
  2483		case UBLK_F_USER_RECOVERY:
  2484		case (UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_REISSUE):
  2485		case (UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_FAIL_IO):
  2486			break;
  2487		default:
  2488			pr_warn("%s: invalid recovery flags %llx\n", __func__,
  2489				info.flags & UBLK_F_ALL_RECOVERY_FLAGS);
  2490			return -EINVAL;
  2491		}
  2492	
  2493		/*
  2494		 * unprivileged device can't be trusted, but RECOVERY and
  2495		 * RECOVERY_REISSUE still may hang error handling, so can't
  2496		 * support recovery features for unprivileged ublk now
  2497		 *
  2498		 * TODO: provide forward progress for RECOVERY handler, so that
  2499		 * unprivileged device can benefit from it
  2500		 */
  2501		if (info.flags & UBLK_F_UNPRIVILEGED_DEV) {
  2502			info.flags &= ~(UBLK_F_USER_RECOVERY_REISSUE |
  2503					UBLK_F_USER_RECOVERY);
  2504	
  2505			/*
  2506			 * For USER_COPY, we depends on userspace to fill request
  2507			 * buffer by pwrite() to ublk char device, which can't be
  2508			 * used for unprivileged device
  2509			 */
> 2510			if (info.flags & UBLK_F_USER_COPY | UBLK_F_SUPPORT_ZERO_COPY)
  2511				return -EINVAL;
  2512		}
  2513	
  2514		/* the created device is always owned by current user */
  2515		ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid);
  2516	
  2517		if (header->dev_id != info.dev_id) {
  2518			pr_warn("%s: dev id not match %u %u\n",
  2519				__func__, header->dev_id, info.dev_id);
  2520			return -EINVAL;
  2521		}
  2522	
  2523		if (header->dev_id != U32_MAX && header->dev_id >= UBLK_MAX_UBLKS) {
  2524			pr_warn("%s: dev id is too large. Max supported is %d\n",
  2525				__func__, UBLK_MAX_UBLKS - 1);
  2526			return -EINVAL;
  2527		}
  2528	
  2529		ublk_dump_dev_info(&info);
  2530	
  2531		ret = mutex_lock_killable(&ublk_ctl_mutex);
  2532		if (ret)
  2533			return ret;
  2534	
  2535		ret = -EACCES;
  2536		if (ublks_added >= ublks_max)
  2537			goto out_unlock;
  2538	
  2539		ret = -ENOMEM;
  2540		ub = kzalloc(sizeof(*ub), GFP_KERNEL);
  2541		if (!ub)
  2542			goto out_unlock;
  2543		mutex_init(&ub->mutex);
  2544		spin_lock_init(&ub->lock);
  2545		INIT_WORK(&ub->nosrv_work, ublk_nosrv_work);
  2546	
  2547		ret = ublk_alloc_dev_number(ub, header->dev_id);
  2548		if (ret < 0)
  2549			goto out_free_ub;
  2550	
  2551		memcpy(&ub->dev_info, &info, sizeof(info));
  2552	
  2553		/* update device id */
  2554		ub->dev_info.dev_id = ub->ub_number;
  2555	
  2556		/*
  2557		 * 64bit flags will be copied back to userspace as feature
  2558		 * negotiation result, so have to clear flags which driver
  2559		 * doesn't support yet, then userspace can get correct flags
  2560		 * (features) to handle.
  2561		 */
  2562		ub->dev_info.flags &= UBLK_F_ALL;
  2563	
  2564		ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE |
  2565			UBLK_F_URING_CMD_COMP_IN_TASK;
  2566	
  2567		/* GET_DATA isn't needed any more with USER_COPY */
  2568		if (ublk_dev_is_user_copy(ub))
  2569			ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
  2570	
  2571		/* Zoned storage support requires user copy feature */
  2572		if (ublk_dev_is_zoned(ub) &&
  2573		    (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) || !ublk_dev_is_user_copy(ub))) {
  2574			ret = -EINVAL;
  2575			goto out_free_dev_number;
  2576		}
  2577	
  2578		ub->dev_info.nr_hw_queues = min_t(unsigned int,
  2579				ub->dev_info.nr_hw_queues, nr_cpu_ids);
  2580		ublk_align_max_io_size(ub);
  2581	
  2582		ret = ublk_init_queues(ub);
  2583		if (ret)
  2584			goto out_free_dev_number;
  2585	
  2586		ret = ublk_add_tag_set(ub);
  2587		if (ret)
  2588			goto out_deinit_queues;
  2589	
  2590		ret = -EFAULT;
  2591		if (copy_to_user(argp, &ub->dev_info, sizeof(info)))
  2592			goto out_free_tag_set;
  2593	
  2594		/*
  2595		 * Add the char dev so that ublksrv daemon can be setup.
  2596		 * ublk_add_chdev() will cleanup everything if it fails.
  2597		 */
  2598		ret = ublk_add_chdev(ub);
  2599		goto out_unlock;
  2600	
  2601	out_free_tag_set:
  2602		blk_mq_free_tag_set(&ub->tag_set);
  2603	out_deinit_queues:
  2604		ublk_deinit_queues(ub);
  2605	out_free_dev_number:
  2606		ublk_free_dev_number(ub);
  2607	out_free_ub:
  2608		mutex_destroy(&ub->mutex);
  2609		kfree(ub);
  2610	out_unlock:
  2611		mutex_unlock(&ublk_ctl_mutex);
  2612		return ret;
  2613	}
  2614	

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