linux-kernel - Re: [PATCH v5 2/5] firmware: encapsulate firmware loading status

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Date:   Wed, 5 Oct 2016 22:27:50 +0200
From:   "Luis R. Rodriguez" <mcgrof@...nel.org>
To:     Daniel Wagner <daniel.wagner@...-carit.de>
Cc:     "Luis R . Rodriguez" <mcgrof@...nel.org>,
        Daniel Wagner <wagi@...om.org>, linux-kernel@...r.kernel.org,
        Ming Lei <ming.lei@...onical.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Srivatsa S . Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>,
        "Rafael J . Wysocki" <rjw@...k.pl>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Takashi Iwai <tiwai@...e.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Arend van Spriel <arend.vanspriel@...adcom.com>
Subject: Re: [PATCH v5 2/5] firmware: encapsulate firmware loading status

On Tue, Sep 13, 2016 at 11:47:08AM +0200, Daniel Wagner wrote:
> Hi Luis,
> 
> 
> On 09/09/2016 02:12 PM, Daniel Wagner wrote:
> >The firmware user helper code tracks the current state of the loading
> >process via unsigned long status and a complection in struct
> >firmware_buf. We only need this for the usermode helper as such we can
> >encapsulate all this data into its own data structure.
> 
> I don't think we are able to move the completion code into a
> CONFIG_FW_LOADER_HELPER section. The direct loading path uses
> completion as well.

Where?

> >+#ifdef CONFIG_FW_LOADER_USER_HELPER
> >+
> >+enum {
> >+	FW_UMH_UNKNOWN,
> >+	FW_UMH_LOADING,
> >+	FW_UMH_DONE,
> >+	FW_UMH_ABORTED,
> >+};
> 
> The direct loading path just uses two states, LOADING and DONE.
> ABORTED is not used.
> 
> >+struct fw_umh {
> >+	struct completion completion;
> >+	unsigned long status;
> >+};
> >+
> >+static void fw_umh_init(struct fw_umh *fw_umh)
> >+{
> >+	init_completion(&fw_umh->completion);
> >+	fw_umh->status = FW_UMH_UNKNOWN;
> >+}
> >+
> >+static int __fw_umh_check(struct fw_umh *fw_umh, unsigned long status)
> >+{
> >+	return test_bit(status, &fw_umh->status);
> >+}
> >+
> >+static int fw_umh_wait_timeout(struct fw_umh *fw_umh, long timeout)
> >+{
> >+	int ret;
> >+
> >+	ret = wait_for_completion_interruptible_timeout(&fw_umh->completion,
> >+							timeout);
> >+	if (ret != 0 && test_bit(FW_UMH_ABORTED, &fw_umh->status))
> >+		return -ENOENT;
> >+
> >+	return ret;
> >+}
> >+
> >+static void __fw_umh_set(struct fw_umh *fw_umh,
> >+			  unsigned long status)
> >+{
> >+	set_bit(status, &fw_umh->status);
> >+
> >+	if (status == FW_UMH_DONE || status == FW_UMH_ABORTED) {
> >+		clear_bit(FW_UMH_LOADING, &fw_umh->status);
> >+		complete_all(&fw_umh->completion);
> >+	}
> >+}
> >+
> >+#define fw_umh_start(fw_umh)					\
> >+	__fw_umh_set(fw_umh, FW_UMH_LOADING)
> >+#define fw_umh_done(fw_umh)					\
> >+	__fw_umh_set(fw_umh, FW_UMH_DONE)
> >+#define fw_umh_aborted(fw_umh)					\
> >+	__fw_umh_set(fw_umh, FW_UMH_ABORTED)
> >+#define fw_umh_is_loading(fw_umh)				\
> >+	__fw_umh_check(fw_umh, FW_UMH_LOADING)
> >+#define fw_umh_is_done(fw_umh)					\
> >+	__fw_umh_check(fw_umh, FW_UMH_DONE)
> >+#define fw_umh_is_aborted(fw_umh)				\
> >+	__fw_umh_check(fw_umh, FW_UMH_ABORTED)
> >+
> >+#else /* CONFIG_FW_LOADER_USER_HELPER */
> >+
> >+#define fw_umh_wait_timeout(fw_st, long)	0
> >+
> >+#define fw_umh_done(fw_st)
> >+#define fw_umh_is_done(fw_st)			true
> >+#define fw_umh_is_aborted(fw_st)		false
> 
> We still need the implementation for fw_umh_wait_timeout() and
> fw_umh_start(), fw_umh_done() etc.

Why?

> fw_umh_is_aborted() is not
> needed.
> 
> 
> >@@ -309,8 +373,7 @@ static void fw_finish_direct_load(struct device *device,
> > 				  struct firmware_buf *buf)
> > {
> > 	mutex_lock(&fw_lock);
> >-	set_bit(FW_STATUS_DONE, &buf->status);
> >-	complete_all(&buf->completion);
> >+	fw_umh_done(&buf->fw_umh);
> > 	mutex_unlock(&fw_lock);
> > }
> 
> Here we signal that we have loaded the firmware

The struct firmware_buf is only used for the sysfs stuff no?

> > /* wait until the shared firmware_buf becomes ready (or error) */
> > static int sync_cached_firmware_buf(struct firmware_buf *buf)
> > {
> > 	int ret = 0;
> >
> > 	mutex_lock(&fw_lock);
> >-	while (!test_bit(FW_STATUS_DONE, &buf->status)) {
> >-		if (is_fw_load_aborted(buf)) {
> >+	while (!fw_umh_is_done(&buf->fw_umh)) {
> >+		if (fw_umh_is_aborted(&buf->fw_umh)) {
> > 			ret = -ENOENT;
> > 			break;
> > 		}
> > 		mutex_unlock(&fw_lock);
> >-		ret = wait_for_completion_interruptible(&buf->completion);
> >+		ret = fw_umh_wait_timeout(&buf->fw_umh, 0);
> > 		mutex_lock(&fw_lock);
> > 	}
> 
> and here we here we wait for it.

Likewise.

  Luis