Commit c50061f0 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

ublk: rewrite ublk_ctrl_get_queue_affinity to not rely on hctx->cpumask 



Looking at the hctxs and cpumap is not safe without at very last a RCU
reference.  It also requires the queue to be set up before starting the
device, which leads to rather awkward life time rules.

Instead rewrite ublk_ctrl_get_queue_affinity to just build the cpumask
directly from the mq_map in the tag set, similar to hctx->cpumask is
built.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220721130916.1869719-8-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent cfee7e4d

drivers/block/ublk_drv.c

+24 −31
Original line number Diff line number Diff line
@@ -1245,26 +1245,15 @@ static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd) 
	return ret;

}



static struct blk_mq_hw_ctx *ublk_get_hw_queue(struct ublk_device *ub,

		unsigned int index)

{

	struct blk_mq_hw_ctx *hctx;

	unsigned long i;



	queue_for_each_hw_ctx(ub->ub_queue, hctx, i)

		if (hctx->queue_num == index)

			return hctx;

	return NULL;

}



static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd)

{

	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;

	void __user *argp = (void __user *)(unsigned long)header->addr;

	struct blk_mq_hw_ctx *hctx;

	struct ublk_device *ub;

	cpumask_var_t cpumask;

	unsigned long queue;

	unsigned int retlen;

	unsigned int i;

	int ret = -EINVAL;

	

	if (header->len * BITS_PER_BYTE < nr_cpu_ids)
@@ -1276,29 +1265,33 @@ static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd) 


	ub = ublk_get_device_from_id(header->dev_id);

	if (!ub)

		goto out;

		return -EINVAL;



	queue = header->data[0];

	if (queue >= ub->dev_info.nr_hw_queues)

		goto out;

	hctx = ublk_get_hw_queue(ub, queue);

	if (!hctx)

		goto out;

		goto out_put_device;



	retlen = min_t(unsigned short, header->len, cpumask_size());

	if (copy_to_user(argp, hctx->cpumask, retlen)) {

		ret = -EFAULT;

		goto out;

	ret = -ENOMEM;

	if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))

		goto out_put_device;



	for_each_possible_cpu(i) {

		if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue)

			cpumask_set_cpu(i, cpumask);

	}

	if (retlen != header->len) {

		if (clear_user(argp + retlen, header->len - retlen)) {



	ret = -EFAULT;

			goto out;

		}

	}

	retlen = min_t(unsigned short, header->len, cpumask_size());

	if (copy_to_user(argp, cpumask, retlen))

		goto out_free_cpumask;

	if (retlen != header->len &&

	    clear_user(argp + retlen, header->len - retlen))

		goto out_free_cpumask;



	ret = 0;

 out:

	if (ub)

out_free_cpumask:

	free_cpumask_var(cpumask);

out_put_device:

	ublk_put_device(ub);

	return ret;

}