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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2018-06-21 18:00:05 +1000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2018-07-27 09:58:12 +1000
commit9840fcd8cc43bfba486a53b4461044f1a1189cdc (patch)
treea2ba69532326e0b578283f277c741b4c7de7a21f /drivers/fsi
parentd1dcd678257603e71cf3f3d84c70e2b6f0f14bb8 (diff)
fsi: Prevent multiple concurrent rescans
The bus scanning process isn't terribly good at parallel attempts at rescanning the same bus. Let's have a per-master mutex protecting the scanning process. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'drivers/fsi')
-rw-r--r--drivers/fsi/fsi-core.c16
-rw-r--r--drivers/fsi/fsi-master.h2
2 files changed, 16 insertions, 2 deletions
diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
index dea5bd48acc5..2c31563fdcae 100644
--- a/drivers/fsi/fsi-core.c
+++ b/drivers/fsi/fsi-core.c
@@ -1203,8 +1203,14 @@ static void fsi_master_unscan(struct fsi_master *master)
int fsi_master_rescan(struct fsi_master *master)
{
+ int rc;
+
+ mutex_lock(&master->scan_lock);
fsi_master_unscan(master);
- return fsi_master_scan(master);
+ rc = fsi_master_scan(master);
+ mutex_unlock(&master->scan_lock);
+
+ return rc;
}
EXPORT_SYMBOL_GPL(fsi_master_rescan);
@@ -1240,6 +1246,7 @@ int fsi_master_register(struct fsi_master *master)
int rc;
struct device_node *np;
+ mutex_init(&master->scan_lock);
master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
dev_set_name(&master->dev, "fsi%d", master->idx);
@@ -1264,8 +1271,11 @@ int fsi_master_register(struct fsi_master *master)
}
np = dev_of_node(&master->dev);
- if (!of_property_read_bool(np, "no-scan-on-init"))
+ if (!of_property_read_bool(np, "no-scan-on-init")) {
+ mutex_lock(&master->scan_lock);
fsi_master_scan(master);
+ mutex_unlock(&master->scan_lock);
+ }
return 0;
}
@@ -1278,7 +1288,9 @@ void fsi_master_unregister(struct fsi_master *master)
master->idx = -1;
}
+ mutex_lock(&master->scan_lock);
fsi_master_unscan(master);
+ mutex_unlock(&master->scan_lock);
device_unregister(&master->dev);
}
EXPORT_SYMBOL_GPL(fsi_master_unregister);
diff --git a/drivers/fsi/fsi-master.h b/drivers/fsi/fsi-master.h
index f653f75da7be..040a7d4cf717 100644
--- a/drivers/fsi/fsi-master.h
+++ b/drivers/fsi/fsi-master.h
@@ -18,6 +18,7 @@
#define DRIVERS_FSI_MASTER_H
#include <linux/device.h>
+#include <linux/mutex.h>
/* Various protocol delays */
#define FSI_ECHO_DELAY_CLOCKS 16 /* Number clocks for echo delay */
@@ -59,6 +60,7 @@ struct fsi_master {
int idx;
int n_links;
int flags;
+ struct mutex scan_lock;
int (*read)(struct fsi_master *, int link, uint8_t id,
uint32_t addr, void *val, size_t size);
int (*write)(struct fsi_master *, int link, uint8_t id,