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    Subject[PATCH 11/14] fsi: Improve master indexing
    Date
    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.

    Signed-off-by: Eddie James <eajames@linux.ibm.com>
    ---
    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) {
    + master->idx = ida_alloc_range(&master_ida, master->idx,
    + master->idx, GFP_KERNEL);
    + if (master->idx < 0)
    + master->idx = ida_alloc(&master_ida, GFP_KERNEL);
    + } else {
    + master->idx = ida_alloc(&master_ida, GFP_KERNEL);
    + }
    +
    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);

    - 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
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