Currently really_probe() returns 1 on success and 0 if the probe() call
fails. This return code arrangement is designed to be useful for
__device_attach_driver() which is walking the device list and trying every
driver. 0 means to keep trying.
However, it is not useful for the other places that call through to
really_probe() that do actually want to see the probe() return code.
For instance bind_store() would be better to return the actual error code
from the driver's probe method, not discarding it and returning -ENODEV.
Reorganize things so that really_probe() always returns an error code on
failure and 0 on success. Move the special code for device list walking
into the walker callback __device_attach_driver() and trigger it based on
an output flag from really_probe(). Update the rest of the API surface to
return a normal -ERR or 0 on success.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/base/bus.c | 6 +----
drivers/base/dd.c | 61 ++++++++++++++++++++++++++++++----------------
2 files changed, 41 insertions(+), 26 deletions(-)
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 36d0c654ea6124..03591f82251302 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -212,13 +212,9 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf,
dev = bus_find_device_by_name(bus, NULL, buf);
if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
err = device_driver_attach(drv, dev);
-
- if (err > 0) {
+ if (!err) {
/* success */
err = count;
- } else if (err == 0) {
- /* driver didn't accept device */
- err = -ENODEV;
}
}
put_device(dev);
diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index c1a92cff159873..7fb58e6219b255 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -513,7 +513,13 @@ static ssize_t state_synced_show(struct device *dev,
}
static DEVICE_ATTR_RO(state_synced);
-static int really_probe(struct device *dev, struct device_driver *drv)
+enum {
+ /* Set on output if the -ERR has come from a probe() function */
+ PROBEF_DRV_FAILED = 1 << 0,
+};
+
+static int really_probe(struct device *dev, struct device_driver *drv,
+ unsigned int *flags)
{
int ret = -EPROBE_DEFER;
int local_trigger_count = atomic_read(&deferred_trigger_count);
@@ -574,12 +580,16 @@ static int really_probe(struct device *dev, struct device_driver *drv)
if (dev->bus->probe) {
ret = dev->bus->probe(dev);
- if (ret)
+ if (ret) {
+ *flags |= PROBEF_DRV_FAILED;
goto probe_failed;
+ }
} else if (drv->probe) {
ret = drv->probe(dev);
- if (ret)
+ if (ret) {
+ *flags |= PROBEF_DRV_FAILED;
goto probe_failed;
+ }
}
if (device_add_groups(dev, drv->dev_groups)) {
@@ -621,7 +631,6 @@ static int really_probe(struct device *dev, struct device_driver *drv)
dev->pm_domain->sync(dev);
driver_bound(dev);
- ret = 1;
pr_debug("bus: '%s': %s: bound device %s to driver %s\n",
drv->bus->name, __func__, dev_name(dev), drv->name);
goto done;
@@ -656,7 +665,7 @@ static int really_probe(struct device *dev, struct device_driver *drv)
/* Driver requested deferred probing */
dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
driver_deferred_probe_add_trigger(dev, local_trigger_count);
- goto done;
+ break;
case -ENODEV:
case -ENXIO:
pr_debug("%s: probe of %s rejects match %d\n",
@@ -667,11 +676,6 @@ static int really_probe(struct device *dev, struct device_driver *drv)
pr_warn("%s: probe of %s failed with error %d\n",
drv->name, dev_name(dev), ret);
}
- /*
- * Ignore errors returned by ->probe so that the next driver can try
- * its luck.
- */
- ret = 0;
done:
atomic_dec(&probe_count);
wake_up_all(&probe_waitqueue);
@@ -681,13 +685,14 @@ static int really_probe(struct device *dev, struct device_driver *drv)
/*
* For initcall_debug, show the driver probe time.
*/
-static int really_probe_debug(struct device *dev, struct device_driver *drv)
+static int really_probe_debug(struct device *dev, struct device_driver *drv,
+ unsigned int *flags)
{
ktime_t calltime, rettime;
int ret;
calltime = ktime_get();
- ret = really_probe(dev, drv);
+ ret = really_probe(dev, drv, flags);
rettime = ktime_get();
pr_debug("probe of %s returned %d after %lld usecs\n",
dev_name(dev), ret, ktime_us_delta(rettime, calltime));
@@ -732,17 +737,18 @@ EXPORT_SYMBOL_GPL(wait_for_device_probe);
* driver_probe_device - attempt to bind device & driver together
* @drv: driver to bind a device to
* @dev: device to try to bind to the driver
+ * @flags: PROBEF flags input/output
*
* This function returns -ENODEV if the device is not registered, -EBUSY if it
- * already has a driver, and 1 if the device is bound successfully and 0
- * otherwise.
+ * already has a driver, and 0 if the device is bound successfully.
*
* This function must be called with @dev lock held. When called for a
* USB interface, @dev->parent lock must be held as well.
*
* If the device has a parent, runtime-resume the parent before driver probing.
*/
-static int driver_probe_device(struct device_driver *drv, struct device *dev)
+static int driver_probe_device(struct device_driver *drv, struct device *dev,
+ unsigned int *flags)
{
int ret = 0;
@@ -761,9 +767,9 @@ static int driver_probe_device(struct device_driver *drv, struct device *dev)
pm_runtime_barrier(dev);
if (initcall_debug)
- ret = really_probe_debug(dev, drv);
+ ret = really_probe_debug(dev, drv, flags);
else
- ret = really_probe(dev, drv);
+ ret = really_probe(dev, drv, flags);
pm_request_idle(dev);
if (dev->parent)
@@ -847,6 +853,7 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
struct device_attach_data *data = _data;
struct device *dev = data->dev;
bool async_allowed;
+ int flags = 0;
int ret;
ret = driver_match_device(drv, dev);
@@ -870,7 +877,17 @@ static int __device_attach_driver(struct device_driver *drv, void *_data)
if (data->check_async && async_allowed != data->want_async)
return 0;
- return driver_probe_device(drv, dev);
+ ret = driver_probe_device(drv, dev, &flags);
+ if (ret) {
+ /*
+ * Ignore errors returned by ->probe so that the next driver can
+ * try its luck.
+ */
+ if (flags & PROBEF_DRV_FAILED)
+ return 0;
+ return ret;
+ }
+ return 1;
}
static void __device_attach_async_helper(void *_dev, async_cookie_t cookie)
@@ -1026,10 +1043,11 @@ static void __device_driver_unlock(struct device *dev, struct device *parent)
* @dev: Device to attach it to
*
* Manually attach driver to a device. Will acquire both @dev lock and
- * @dev->parent lock if needed.
+ * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
*/
int device_driver_attach(struct device_driver *drv, struct device *dev)
{
+ unsigned int flags = 0;
int ret = 0;
__device_driver_lock(dev, dev->parent);
@@ -1039,7 +1057,7 @@ int device_driver_attach(struct device_driver *drv, struct device *dev)
* just skip the driver probe call.
*/
if (!dev->driver)
- ret = driver_probe_device(drv, dev);
+ ret = driver_probe_device(drv, dev, &flags);
__device_driver_unlock(dev, dev->parent);
@@ -1050,11 +1068,12 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
{
struct device *dev = _dev;
struct device_driver *drv;
+ unsigned int flags = 0;
int ret;
__device_driver_lock(dev, dev->parent);
drv = dev->p->async_driver;
- ret = driver_probe_device(drv, dev);
+ ret = driver_probe_device(drv, dev, &flags);
__device_driver_unlock(dev, dev->parent);
dev_dbg(dev, "driver %s async attach completed: %d\n", drv->name, ret);
--
2.31.1
