From: "Kweh, Hock Leong" <hock.leong.kweh@xxxxxxxxx>
Besides aborting through user helper interface, a new API
request_firmware_abort() allows kernel driver module to abort the
request_firmware() / request_firmware_nowait() when they are no
longer needed. It is useful for cancelling an outstanding firmware
load if initiated from inside a module where that module is in the
process of being unloaded, since the unload function may not have
a handle to the struct firmware_buf.
Note for people who use request_firmware_nowait():
You are required to do your own synchronization after you call
request_firmware_abort() in order to continue unloading the
module. The example synchronization code shows below:
while (THIS_MODULE && module_refcount(THIS_MODULE))
msleep(20);
Cc: Matt Fleming <matt.fleming@xxxxxxxxx>
Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@xxxxxxxxx>
---
drivers/base/firmware_class.c | 52 +++++++++++++++++++++++++++++++----------
include/linux/firmware.h | 4 ++++
2 files changed, 44 insertions(+), 12 deletions(-)
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index d276e33..a238a46 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1291,6 +1291,46 @@ request_firmware_nowait(
}
EXPORT_SYMBOL(request_firmware_nowait);
+static struct firmware_buf *fw_lookup_buf(const char *fw_name)
+{
+ struct firmware_buf *tmp;
+ struct firmware_cache *fwc = &fw_cache;
+
+ spin_lock(&fwc->lock);
+ tmp = __fw_lookup_buf(fw_name);
+ spin_unlock(&fwc->lock);
+
+ return tmp;
+}
+
+/**
+ * request_firmware_abort - abort the waiting of firmware request
+ * @fw_name: name of firmware file
+ *
+ * @fw_name is the same name string while calling to request_firmware()
+ * or request_firmware_nowait().
+ **/
+int request_firmware_abort(const char *fw_name)
+{
+ struct firmware_buf *buf;
+ struct firmware_buf *entry;
+
+ buf = fw_lookup_buf(fw_name);
+ if (!buf)
+ return -ENOENT;
+
+ mutex_lock(&fw_lock);
+ list_for_each_entry(entry, &pending_fw_head, pending_list) {
+ if (entry == buf) {
+ __fw_load_abort(buf);
+ break;
+ }
+ }
+ mutex_unlock(&fw_lock);
+ return 0;
+}
+EXPORT_SYMBOL(request_firmware_abort);
+
#ifdef CONFIG_PM_SLEEP
static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
@@ -1324,18 +1364,6 @@ static int cache_firmware(const char *fw_name)
return ret;
}
-static struct firmware_buf *fw_lookup_buf(const char *fw_name)
-{
- struct firmware_buf *tmp;
- struct firmware_cache *fwc = &fw_cache;
-
- spin_lock(&fwc->lock);
- tmp = __fw_lookup_buf(fw_name);
- spin_unlock(&fwc->lock);
-
- return tmp;
-}
-
/**
* uncache_firmware - remove one cached firmware image
* @fw_name: the firmware image name
diff --git a/include/linux/firmware.h b/include/linux/firmware.h
index 5952933..ed90c8b 100644
--- a/include/linux/firmware.h
+++ b/include/linux/firmware.h
@@ -47,6 +47,7 @@ int request_firmware_nowait(
void (*cont)(const struct firmware *fw, void *context));
void release_firmware(const struct firmware *fw);
+int request_firmware_abort(const char *fw_name);
#else
static inline int request_firmware(const struct firmware **fw,
const char *name,
@@ -66,6 +67,9 @@ static inline void release_firmware(const struct firmware *fw)
{
}
+static inline int request_firmware_abort(const char *fw_name)
+{
+}
#endif
#ifdef CONFIG_FW_LOADER_USER_HELPER
--
1.7.9.5
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