ping ?
On 12/16/2022 12:23 PM, Hou Tao wrote:
> From: Hou Tao <houtao1@xxxxxxxxxx>
>
> __hash_remove() removes hash_cell with _hash_lock locked, so acquiring
> _hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must
> have not been removed and hc->md must still be md.
>
> __hash_remove() also acquires dm_hash_cells_mutex before setting mdptr
> as NULL, so in dm_copy_name_and_uuid() after acquiring
> dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned
> hc must still be alive and hc->md must still be md.
>
> So removing these unnecessary hc->md != md checks when using
> dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired.
>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
> drivers/md/dm-ioctl.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index 3bfc1583c20a..2a86524661d1 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *src
>
> down_read(&_hash_lock);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> DMERR("device has been removed from the dev hash table.");
> goto out;
> }
> @@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
> /* stage inactive table */
> down_write(&_hash_lock);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> DMERR("device has been removed from the dev hash table.");
> up_write(&_hash_lock);
> r = -ENXIO;
> @@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
>
> mutex_lock(&dm_hash_cells_mutex);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> r = -ENXIO;
> goto out;
> }
--
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