Re: [PATCH 1/2] scsi: core: Fix sbitmap depth in scsi_realloc_sdev_budget_map()

Bart Van Assche
2022-03-15T14:33:47Z

On 3/15/22 03:39, John Garry wrote:
> In commit edb854a3680b ("scsi: core: Reallocate device's budget map on
> queue depth change"), the sbitmap for the device budget map may be
> reallocated after the slave device depth is configured.
>
> When the sbitmap is reallocated we use the result from
> scsi_device_max_queue_depth() for the sbitmap size, but don't resize to
> match the actual device queue depth.
>
> Fix by resizing the sbitmap after reallocating the budget sbitmap.
>
> Signed-off-by: John Garry <john.garry@huawei.com>
> ---
> drivers/scsi/scsi_scan.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index f4e6c68ac99e..2ef78083f1ef 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -223,6 +223,8 @@ static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
> int ret;
> struct sbitmap sb_backup;
>
> + depth = min_t(unsigned int, depth, scsi_device_max_queue_depth(sdev));
> +
> /*
> * realloc if new shift is calculated, which is caused by setting
> * up one new default queue depth after calling ->slave_configure
> @@ -245,6 +247,9 @@ static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
> scsi_device_max_queue_depth(sdev),
> new_shift, GFP_KERNEL,
> sdev->request_queue->node, false, true);
> + if (!ret)
> + sbitmap_resize(&sdev->budget_map, depth);

Hmm ... why to call both sbitmap_init_node() and sbitmap_resize()
instead of combining both calls into a single call with the proper depth?

Thanks,

Bart.