From: Marek Vasut marex@denx.de Sent: Sunday, November 24, 2024 11:11 PM
On 11/24/24 10:10 PM, Marek Vasut wrote:
On 11/21/24 6:21 PM, Christoph Niedermaier wrote:
The env variable "SN" is used to store the serial number on DH electronics SoMs. New SoMs will use the variable "dh_som_serial_number". To ensure compatibility, these env variables are synchronized. This is achieved using callback functions. To avoid recursive calls, these are locked against each other.
What kind of recursive calls?
It would be good to expand the commit message and elaborate on the recursive calls problem .
diff --git a/board/dhelectronics/common/dh_common.c b/board/ dhelectronics/common/dh_common.c index a7b0472a09..2e3e5c483b 100644 --- a/board/dhelectronics/common/dh_common.c +++ b/board/dhelectronics/common/dh_common.c @@ -45,6 +45,32 @@ struct eeprom_id_page { #define DH_EEPROM_ID_PAGE_V1_0_DATA_LEN (sizeof(struct eeprom_id_page) - \ offsetof(struct eeprom_id_page, mac0)) +static bool in_dh_som_serial_number; +static bool in_SN;
+static int on_dh_som_serial_number(const char *name, const char *value, enum env_op op,
int flags)+{
- in_dh_som_serial_number = true;
- if (!in_SN)
env_set("SN", value);- in_dh_som_serial_number = false;
- return 0;
+}
Maybe a more generic solution is:
diff --git a/lib/hashtable.c b/lib/hashtable.c index e8a59e2dcac..75c263b5053 100644 --- a/lib/hashtable.c +++ b/lib/hashtable.c @@ -221,11 +221,32 @@ static int do_callback(const struct env_entry *e, const char *name, const char *value, enum env_op op, int flags) {
int ret = 0;- #ifndef CONFIG_XPL_BUILD
if (e->callback)return e->callback(name, value, op, flags);
static bool in_callback;if (!e->callback || in_callback)return 0;/** In case there are two variables which each implement env callback* that performs env_set() on the other variable, the callbacks will* call each other recursively until the stack runs out. Prevent such* a recursion from happening.** Example which triggers this behavior:* static int on_foo(...) { env_set("bar", 0); ... }* static int on_bar(...) { env_set("foo", 0); ... }* U_BOOT_ENV_CALLBACK(foo, on_foo);* U_BOOT_ENV_CALLBACK(bar, on_bar);*/in_callback = true;ret = e->callback(name, value, op, flags);in_callback = false;
return 0;
return ret;}
/*
Looks good, I will integrate it in V4.
Regards Christoph