The callers for of_modalias() generally need the module alias as part of
some larger string. That results in some error prone manipulation of the
buffer prepend/append the module alias string. In fact,
of_device_uevent_modalias() has several issues. First, it's off by one
too few characters in utilization of the full buffer. Second, the error
paths leave OF_MODALIAS with a truncated value when in the end nothing
should be added to the buffer. It is also fragile because it needs
internal details of struct kobj_uevent_env. add_uevent_var() really
wants to write the env variable and value in one shot which would need
either a temporary buffer for value or a format specifier.
Fix these issues by adding a new printf format specifier, "%pOFm". With
the format specifier in place, simplify all the callers of
of_modalias(). of_modalias() can also be simplified with vsprintf()
being the only caller as it avoids the error conditions.
Cc: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
Signed-off-by: Rob Herring (Arm) <robh@xxxxxxxxxx>
---
Documentation/core-api/printk-formats.rst | 1 +
drivers/of/device.c | 25 ++--------------
drivers/of/module.c | 35 +++++------------------
drivers/of/unittest.c | 2 ++
include/linux/of.h | 8 +++---
lib/vsprintf.c | 7 +++--
6 files changed, 22 insertions(+), 56 deletions(-)
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index ecccc0473da9..d72fe3d8c427 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -496,6 +496,7 @@ equivalent to %pOFf.
- F - device node flags
- c - major compatible string
- C - full compatible string
+ - m - module alias string
The separator when using multiple arguments is ':'
diff --git a/drivers/of/device.c b/drivers/of/device.c
index edf3be197265..ae8c47d5db8e 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -199,14 +199,9 @@ ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
if (!dev || !dev->of_node || dev->of_node_reused)
return -ENODEV;
- sl = of_modalias(dev->of_node, str, len - 2);
- if (sl < 0)
- return sl;
- if (sl > len - 2)
+ sl = snprintf(str, len, "%pOFm\n", dev->of_node);
+ if (sl >= len)
return -ENOMEM;
-
- str[sl++] = '\n';
- str[sl] = 0;
return sl;
}
EXPORT_SYMBOL_GPL(of_device_modalias);
@@ -256,24 +251,10 @@ EXPORT_SYMBOL_GPL(of_device_uevent);
int of_device_uevent_modalias(const struct device *dev, struct kobj_uevent_env *env)
{
- int sl;
-
if ((!dev) || (!dev->of_node) || dev->of_node_reused)
return -ENODEV;
- /* Devicetree modalias is tricky, we add it in 2 steps */
- if (add_uevent_var(env, "MODALIAS="))
- return -ENOMEM;
-
- sl = of_modalias(dev->of_node, &env->buf[env->buflen-1],
- sizeof(env->buf) - env->buflen);
- if (sl < 0)
- return sl;
- if (sl >= (sizeof(env->buf) - env->buflen))
- return -ENOMEM;
- env->buflen += sl;
-
- return 0;
+ return add_uevent_var(env, "MODALIAS=%pOFm", dev->of_node);
}
EXPORT_SYMBOL_GPL(of_device_uevent_modalias);
diff --git a/drivers/of/module.c b/drivers/of/module.c
index 1e735fc130ad..80879d2abea8 100644
--- a/drivers/of/module.c
+++ b/drivers/of/module.c
@@ -8,21 +8,14 @@
#include <linux/slab.h>
#include <linux/string.h>
-ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len)
+/* Do not use directly, use %pOFm format specifier instead */
+size_t of_modalias(const struct device_node *np, char *str, size_t len)
{
const char *compat;
char *c;
struct property *p;
- ssize_t csize;
- ssize_t tsize;
-
- /*
- * Prevent a kernel oops in vsnprintf() -- it only allows passing a
- * NULL ptr when the length is also 0. Also filter out the negative
- * lengths...
- */
- if ((len > 0 && !str) || len < 0)
- return -EINVAL;
+ size_t csize;
+ size_t tsize;
/* Name & Type */
/* %p eats all alphanum characters, so %c must be used here */
@@ -53,29 +46,15 @@ ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len)
int of_request_module(const struct device_node *np)
{
- char *str;
- ssize_t size;
- int ret;
+ char *str __free(kfree);
if (!np)
return -ENODEV;
- size = of_modalias(np, NULL, 0);
- if (size < 0)
- return size;
-
- /* Reserve an additional byte for the trailing '\0' */
- size++;
-
- str = kmalloc(size, GFP_KERNEL);
+ str = kasprintf(GFP_KERNEL, "%pOFm", np);
if (!str)
return -ENOMEM;
- of_modalias(np, str, size);
- str[size - 1] = '\0';
- ret = request_module(str);
- kfree(str);
-
- return ret;
+ return request_module(str);
}
EXPORT_SYMBOL_GPL(of_request_module);
diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index daf9a2dddd7e..93921399f02d 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -342,6 +342,8 @@ static void __init of_unittest_printf(void)
of_unittest_printf_one(np, "%pOFc", "test-sub-device");
of_unittest_printf_one(np, "%pOFC",
"\"test-sub-device\",\"test-compat2\",\"test-compat3\"");
+ of_unittest_printf_one(np, "%pOFm",
+ "of:NdevT(null)Ctest-sub-deviceCtest-compat2Ctest-compat3");
}
struct node_hash {
diff --git a/include/linux/of.h b/include/linux/of.h
index f921786cb8ac..9fe7d17ce7e2 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -382,7 +382,7 @@ extern int of_count_phandle_with_args(const struct device_node *np,
const char *list_name, const char *cells_name);
/* module functions */
-extern ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len);
+extern size_t of_modalias(const struct device_node *np, char *str, size_t len);
extern int of_request_module(const struct device_node *np);
/* phandle iterator functions */
@@ -762,10 +762,10 @@ static inline int of_count_phandle_with_args(const struct device_node *np,
return -ENOSYS;
}
-static inline ssize_t of_modalias(const struct device_node *np, char *str,
- ssize_t len)
+static inline size_t of_modalias(const struct device_node *np, char *str,
+ size_t len)
{
- return -ENODEV;
+ return 0;
}
static inline int of_request_module(const struct device_node *np)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 9d3dac38a3f4..6a4f99b39de0 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2169,10 +2169,10 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
/* simple case without anything any more format specifiers */
fmt++;
- if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcC") > 0)
+ if (fmt[0] == '\0' || strcspn(fmt,"fnpPFcCm") > 0)
fmt = "f";
- for (pass = false; strspn(fmt,"fnpPFcC"); fmt++, pass = true) {
+ for (pass = false; strspn(fmt,"fnpPFcCm"); fmt++, pass = true) {
int precision;
if (pass) {
if (buf < end)
@@ -2226,6 +2226,9 @@ char *device_node_string(char *buf, char *end, struct device_node *dn,
has_mult = true;
}
break;
+ case 'm':
+ buf += of_modalias(dn, buf, end - buf);
+ break;
default:
break;
}
--
2.45.2
