On 8/9/23 02:08, Joel Stanley wrote:
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?
At this point, the master driver (aspeed, hub, i2cr, whatever) might
just be requesting a certain index. It's not allocated yet, so it needs
to be allocated so that we don't get overlap.
+ 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?
Perhaps, we could also return error here if we decide that the requested
index is needed and not just wanted.
+ 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?
Yes, the assumption is: zero is the default due to zero-alloc'd master
structures.
+ master->idx = ida_alloc(&master_ida, GFP_KERNEL);
+ }
+
We check the same error condition again.
Yes I might be able to make this cleaner...
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?
This is just restructuring to get the lock before the scan. It could be
a separate commit, yea.
Thanks for the review!
Eddie
- 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
