On Thu, Jun 20, 2019 at 06:31:53PM +0800, John Garry wrote:
> Add a function to unregister a logical PIO range.
>
> The method used to allocate LOGIC_PIO_CPU_MMIO regions during registration
> is slightly modified to ensure that we get no overlap when regions are
> unregistered. This is needed because the allocation scheme assumed that no
> regions are ever unregistered.
>
> Logical PIO space can still be leaked when unregistering certain
> LOGIC_PIO_CPU_MMIO regions, but this acceptable for now since there are no
> callers to unregister LOGIC_PIO_CPU_MMIO regions, and the logical PIO
> region allocation scheme would need significant work to improve this.
>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
> include/linux/logic_pio.h | 1 +
> lib/logic_pio.c | 16 +++++++++++++++-
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/logic_pio.h b/include/linux/logic_pio.h
> index cbd9d8495690..88e1e6304a71 100644
> --- a/include/linux/logic_pio.h
> +++ b/include/linux/logic_pio.h
> @@ -117,6 +117,7 @@ struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode);
> unsigned long logic_pio_trans_hwaddr(struct fwnode_handle *fwnode,
> resource_size_t hw_addr, resource_size_t size);
> int logic_pio_register_range(struct logic_pio_hwaddr *newrange);
> +void logic_pio_unregister_range(struct logic_pio_hwaddr *range);
> resource_size_t logic_pio_to_hwaddr(unsigned long pio);
> unsigned long logic_pio_trans_cpuaddr(resource_size_t hw_addr);
>
> diff --git a/lib/logic_pio.c b/lib/logic_pio.c
> index 761296376fbc..45eb57af2574 100644
> --- a/lib/logic_pio.c
> +++ b/lib/logic_pio.c
> @@ -56,7 +56,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
> /* for MMIO ranges we need to check for overlap */
> if (start >= range->hw_start + range->size ||
> end < range->hw_start) {
> - mmio_sz += range->size;
> + mmio_sz = range->io_start + range->size;
Should this be renamed to something like "mmio_end"? Computing a
"size" as "start + size" looks wrong at first glance. The code overall
probably makes sense, but maybe breaking this out as a separate "avoid
overlaps" patch that renames "mmio_sz" might make it clearer.
> } else {
> ret = -EFAULT;
> goto end_register;
> @@ -98,6 +98,20 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
> return ret;
> }
>
> +/**
> + * logic_pio_unregister_range - unregister logical PIO range for a host
> + * @range: pointer to the IO range which has been already registered.
> + *
> + * Unregister a previously-registered IO range node.
> + */
> +void logic_pio_unregister_range(struct logic_pio_hwaddr *range)
> +{
> + mutex_lock(&io_range_mutex);
> + list_del_rcu(&range->list);
> + mutex_unlock(&io_range_mutex);
> + synchronize_rcu();
> +}
> +
> /**
> * find_io_range_by_fwnode - find logical PIO range for given FW node
> * @fwnode: FW node handle associated with logical PIO range
> --
> 2.17.1
>
