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Subject[PATCH v2 25/28] thunderbolt: Make tb_switch_alloc() return ERR_PTR()
Date
In order to detect possible connections to other domains we need to be
able to find out why tb_switch_alloc() fails so make it return ERR_PTR()
instead. This allows the caller to differentiate between errors such as
-ENOMEM which comes from the kernel and for instance -EIO which comes
from the hardware when trying to access the possible switch.

Convert all the current call sites to handle this properly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/thunderbolt/icm.c | 6 +++---
drivers/thunderbolt/switch.c | 36 ++++++++++++++++++++----------------
drivers/thunderbolt/tb.c | 6 +++---
3 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
index 041e7ab0efd3..e28a4255d56a 100644
--- a/drivers/thunderbolt/icm.c
+++ b/drivers/thunderbolt/icm.c
@@ -468,7 +468,7 @@ static void add_switch(struct tb_switch *parent_sw, u64 route,
pm_runtime_get_sync(&parent_sw->dev);

sw = tb_switch_alloc(parent_sw->tb, &parent_sw->dev, route);
- if (!sw)
+ if (IS_ERR(sw))
goto out;

sw->uuid = kmemdup(uuid, sizeof(*uuid), GFP_KERNEL);
@@ -1852,8 +1852,8 @@ static int icm_start(struct tb *tb)
tb->root_switch = tb_switch_alloc_safe_mode(tb, &tb->dev, 0);
else
tb->root_switch = tb_switch_alloc(tb, &tb->dev, 0);
- if (!tb->root_switch)
- return -ENODEV;
+ if (IS_ERR(tb->root_switch))
+ return PTR_ERR(tb->root_switch);

/*
* NVM upgrade has not been tested on Apple systems and they
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 13eed95fc667..ba7dfce0b96f 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -1481,30 +1481,32 @@ static int tb_switch_get_generation(struct tb_switch *sw)
* separately. The returned switch should be released by calling
* tb_switch_put().
*
- * Return: Pointer to the allocated switch or %NULL in case of failure
+ * Return: Pointer to the allocated switch or ERR_PTR() in case of
+ * failure.
*/
struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
u64 route)
{
struct tb_switch *sw;
int upstream_port;
- int i, cap, depth;
+ int i, ret, depth;

/* Make sure we do not exceed maximum topology limit */
depth = tb_route_length(route);
if (depth > TB_SWITCH_MAX_DEPTH)
- return NULL;
+ return ERR_PTR(-EADDRNOTAVAIL);

upstream_port = tb_cfg_get_upstream_port(tb->ctl, route);
if (upstream_port < 0)
- return NULL;
+ return ERR_PTR(upstream_port);

sw = kzalloc(sizeof(*sw), GFP_KERNEL);
if (!sw)
- return NULL;
+ return ERR_PTR(-ENOMEM);

sw->tb = tb;
- if (tb_cfg_read(tb->ctl, &sw->config, route, 0, TB_CFG_SWITCH, 0, 5))
+ ret = tb_cfg_read(tb->ctl, &sw->config, route, 0, TB_CFG_SWITCH, 0, 5);
+ if (ret)
goto err_free_sw_ports;

tb_dbg(tb, "current switch config:\n");
@@ -1520,8 +1522,10 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
/* initialize ports */
sw->ports = kcalloc(sw->config.max_port_number + 1, sizeof(*sw->ports),
GFP_KERNEL);
- if (!sw->ports)
+ if (!sw->ports) {
+ ret = -ENOMEM;
goto err_free_sw_ports;
+ }

for (i = 0; i <= sw->config.max_port_number; i++) {
/* minimum setup for tb_find_cap and tb_drom_read to work */
@@ -1531,16 +1535,16 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,

sw->generation = tb_switch_get_generation(sw);

- cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_PLUG_EVENTS);
- if (cap < 0) {
+ ret = tb_switch_find_vse_cap(sw, TB_VSE_CAP_PLUG_EVENTS);
+ if (ret < 0) {
tb_sw_warn(sw, "cannot find TB_VSE_CAP_PLUG_EVENTS aborting\n");
goto err_free_sw_ports;
}
- sw->cap_plug_events = cap;
+ sw->cap_plug_events = ret;

- cap = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
- if (cap > 0)
- sw->cap_lc = cap;
+ ret = tb_switch_find_vse_cap(sw, TB_VSE_CAP_LINK_CONTROLLER);
+ if (ret > 0)
+ sw->cap_lc = ret;

/* Root switch is always authorized */
if (!route)
@@ -1559,7 +1563,7 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
kfree(sw->ports);
kfree(sw);

- return NULL;
+ return ERR_PTR(ret);
}

/**
@@ -1574,7 +1578,7 @@ struct tb_switch *tb_switch_alloc(struct tb *tb, struct device *parent,
*
* The returned switch must be released by calling tb_switch_put().
*
- * Return: Pointer to the allocated switch or %NULL in case of failure
+ * Return: Pointer to the allocated switch or ERR_PTR() in case of failure
*/
struct tb_switch *
tb_switch_alloc_safe_mode(struct tb *tb, struct device *parent, u64 route)
@@ -1583,7 +1587,7 @@ tb_switch_alloc_safe_mode(struct tb *tb, struct device *parent, u64 route)

sw = kzalloc(sizeof(*sw), GFP_KERNEL);
if (!sw)
- return NULL;
+ return ERR_PTR(-ENOMEM);

sw->tb = tb;
sw->config.depth = tb_route_length(route);
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 2565e30cdb96..65a206f01941 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -155,7 +155,7 @@ static void tb_scan_port(struct tb_port *port)
}
sw = tb_switch_alloc(port->sw->tb, &port->sw->dev,
tb_downstream_route(port));
- if (!sw)
+ if (IS_ERR(sw))
return;

if (tb_switch_configure(sw)) {
@@ -516,8 +516,8 @@ static int tb_start(struct tb *tb)
int ret;

tb->root_switch = tb_switch_alloc(tb, &tb->dev, 0);
- if (!tb->root_switch)
- return -ENOMEM;
+ if (IS_ERR(tb->root_switch))
+ return PTR_ERR(tb->root_switch);

/*
* ICM firmware upgrade needs running firmware and in native
--
2.20.1
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