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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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220721130916.1869719-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2022-07-21 15:09:15 +02:00 committed by Jens Axboe
parent cfee7e4de2
commit c50061f0f1
1 changed files with 24 additions and 31 deletions
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55
drivers/block/ublk_drv.c
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@ -1245,26 +1245,15 @@ out_unlock:
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)
@ -1276,30 +1265,34 @@ 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;
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);
}
ret = -EFAULT;
retlen = min_t(unsigned short, header->len, cpumask_size());
if (copy_to_user(argp, hctx->cpumask, retlen)) {
ret = -EFAULT;
goto out;
}
if (retlen != header->len) {
if (clear_user(argp + retlen, header->len - retlen)) {
ret = -EFAULT;
goto out;
}
}
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)
ublk_put_device(ub);
out_free_cpumask:
free_cpumask_var(cpumask);
out_put_device:
ublk_put_device(ub);
return ret;
}