[PATCH v8 3/9] mailbox: Fix up error handling in mbox_request_channel()

Andrew Bresticker
2015-05-04T17:45:09Z

From: Benson Leung <bleung@chromium.org>

mbox_request_channel() currently returns EBUSY in the event the controller
is not present or if of_xlate() fails, but in neither case is EBUSY really
appropriate. Return EPROBE_DEFER if the controller is not yet present
and change of_xlate() to return an ERR_PTR instead of NULL so that the
error can be propagated back to the caller of mbox_request_channel().

Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Acked-by: Suman Anna <s-anna@ti.com>
Cc: Jassi Brar <jassisinghbrar@gmail.com>
---
No changes from v7.
Changes from v6:
- Update omap-mailbox's xlate() to return error codes.
No changes from v5.
New for v5.
---
drivers/mailbox/mailbox.c | 11 ++++++++---
drivers/mailbox/omap-mailbox.c | 6 +++---
2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 19b491d..c3c42d4 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -318,7 +318,7 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
return ERR_PTR(-ENODEV);
}

- chan = NULL;
+ chan = ERR_PTR(-EPROBE_DEFER);
list_for_each_entry(mbox, &mbox_cons, node)
if (mbox->dev->of_node == spec.np) {
chan = mbox->of_xlate(mbox, &spec);
@@ -327,7 +327,12 @@ struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)

of_node_put(spec.np);

- if (!chan || chan->cl || !try_module_get(mbox->dev->driver->owner)) {
+ if (IS_ERR(chan)) {
+ mutex_unlock(&con_mutex);
+ return chan;
+ }
+
+ if (chan->cl || !try_module_get(mbox->dev->driver->owner)) {
dev_dbg(dev, "%s: mailbox not free\n", __func__);
mutex_unlock(&con_mutex);
return ERR_PTR(-EBUSY);
@@ -390,7 +395,7 @@ of_mbox_index_xlate(struct mbox_controller *mbox,
int ind = sp->args[0];

if (ind >= mbox->num_chans)
- return NULL;
+ return ERR_PTR(-EINVAL);

return &mbox->chans[ind];
}
diff --git a/drivers/mailbox/omap-mailbox.c b/drivers/mailbox/omap-mailbox.c
index 03f8545..a3dbfd9 100644
--- a/drivers/mailbox/omap-mailbox.c
+++ b/drivers/mailbox/omap-mailbox.c
@@ -639,18 +639,18 @@ static struct mbox_chan *omap_mbox_of_xlate(struct mbox_controller *controller,

mdev = container_of(controller, struct omap_mbox_device, controller);
if (WARN_ON(!mdev))
- return NULL;
+ return ERR_PTR(-EINVAL);

node = of_find_node_by_phandle(phandle);
if (!node) {
pr_err("%s: could not find node phandle 0x%x\n",
__func__, phandle);
- return NULL;
+ return ERR_PTR(-ENODEV);
}

mbox = omap_mbox_device_find(mdev, node->name);
of_node_put(node);
- return mbox ? mbox->chan : NULL;
+ return mbox ? mbox->chan : ERR_PTR(-ENOENT);
}

static int omap_mbox_probe(struct platform_device *pdev)
--
2.2.0.rc0.207.ga3a616c