On Fri, Oct 24, 2014 at 2:18 PM, Kweh Hock Leong
<hock.leong.kweh@xxxxxxxxx> wrote:
> 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 | 30 ++++++++++++++++++++++++++++++
> include/linux/firmware.h | 4 ++++
> 2 files changed, 34 insertions(+)
>
> diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> index d276e33..b2fe40b 100644
> --- a/drivers/base/firmware_class.c
> +++ b/drivers/base/firmware_class.c
> @@ -1291,6 +1291,36 @@ request_firmware_nowait(
> }
> EXPORT_SYMBOL(request_firmware_nowait);
>
> +/**
> + * 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;
> +
> + spin_lock(&fw_cache.lock);
> + buf = __fw_lookup_buf(fw_name);
> + spin_unlock(&fw_cache.lock);
You can call fw_lookup_buf() directly, otherwise feel free to add:
Acked-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
> + 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);
>
> 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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