On Mon, 12 Jun 2023 at 19:57, Eddie James <eajames@xxxxxxxxxxxxx> wrote:
>
> Master indexing is problematic if a hub is rescanned while the
> root master is being rescanned. Move the IDA free below the device
> unregistration, lock the scan mutex in the probe function, and
> request a specific idx in the hub driver.
I've applied this series, but taking a closer look at this patch I
think it can be improved. If you resend, just send this patch.
>
> Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxx>
> ---
> drivers/fsi/fsi-core.c | 41 ++++++++++++++++++++++--------------
> drivers/fsi/fsi-master-hub.c | 2 ++
> 2 files changed, 27 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> index ec4d02264391..503061a6740b 100644
> --- a/drivers/fsi/fsi-core.c
> +++ b/drivers/fsi/fsi-core.c
> @@ -1327,46 +1327,55 @@ static struct class fsi_master_class = {
> int fsi_master_register(struct fsi_master *master)
> {
> int rc;
> - struct device_node *np;
>
> mutex_init(&master->scan_lock);
> - master->idx = ida_alloc(&master_ida, GFP_KERNEL);
> +
> + if (master->idx) {
Why do we allocate a new idx if there's already one?
> + master->idx = ida_alloc_range(&master_ida, master->idx,
> + master->idx, GFP_KERNEL);
If we can't get one in the range we want, we ask for any? Should this
print a warning?
> + if (master->idx < 0)
> + master->idx = ida_alloc(&master_ida, GFP_KERNEL);
> + } else {
If ixd was zero, we create one. This is the "normal" case?
> + master->idx = ida_alloc(&master_ida, GFP_KERNEL);
> + }
> +
We check the same error condition again.
> if (master->idx < 0)
> return master->idx;
>
> - dev_set_name(&master->dev, "fsi%d", master->idx);
> + if (!dev_name(&master->dev))
> + dev_set_name(&master->dev, "fsi%d", master->idx);
> +
> master->dev.class = &fsi_master_class;
>
> + mutex_lock(&master->scan_lock);
> rc = device_register(&master->dev);
> if (rc) {
> ida_free(&master_ida, master->idx);
> - return rc;
> - }
> + } else {
> + struct device_node *np = dev_of_node(&master->dev);
This change looks a bit different to the idx changes. What's happening here?
>
> - np = dev_of_node(&master->dev);
> - if (!of_property_read_bool(np, "no-scan-on-init")) {
> - mutex_lock(&master->scan_lock);
> - fsi_master_scan(master);
> - mutex_unlock(&master->scan_lock);
> + if (!of_property_read_bool(np, "no-scan-on-init"))
> + fsi_master_scan(master);
> }
>
> - return 0;
> + mutex_unlock(&master->scan_lock);
> + return rc;
> }
> EXPORT_SYMBOL_GPL(fsi_master_register);
>
> void fsi_master_unregister(struct fsi_master *master)
> {
> - trace_fsi_master_unregister(master);
> + int idx = master->idx;
>
> - if (master->idx >= 0) {
> - ida_free(&master_ida, master->idx);
> - master->idx = -1;
> - }
> + trace_fsi_master_unregister(master);
>
> mutex_lock(&master->scan_lock);
> fsi_master_unscan(master);
> + master->n_links = 0;
> mutex_unlock(&master->scan_lock);
> +
> device_unregister(&master->dev);
> + ida_free(&master_ida, idx);
> }
> EXPORT_SYMBOL_GPL(fsi_master_unregister);
>
> diff --git a/drivers/fsi/fsi-master-hub.c b/drivers/fsi/fsi-master-hub.c
> index 6d8b6e8854e5..36da643b3201 100644
> --- a/drivers/fsi/fsi-master-hub.c
> +++ b/drivers/fsi/fsi-master-hub.c
> @@ -12,6 +12,7 @@
> #include <linux/slab.h>
>
> #include "fsi-master.h"
> +#include "fsi-slave.h"
>
> #define FSI_ENGID_HUB_MASTER 0x1c
>
> @@ -229,6 +230,7 @@ static int hub_master_probe(struct device *dev)
> hub->master.dev.release = hub_master_release;
> hub->master.dev.of_node = of_node_get(dev_of_node(dev));
>
> + hub->master.idx = fsi_dev->slave->link + 1;
> hub->master.n_links = links;
> hub->master.read = hub_master_read;
> hub->master.write = hub_master_write;
> --
> 2.31.1
>
