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From: Daniel Wagner <wagi@monom.org>
To: Daniel Wagner <daniel.wagner@bmw-carit.de>,
	"Luis R. Rodriguez" <mcgrof@kernel.org>,
	Takashi Iwai <tiwai@suse.de>
Cc: linux-kernel@vger.kernel.org, Ming Lei <ming.lei@canonical.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v4 2/4] firmware: encapsulate firmware loading status
Date: Thu, 8 Sep 2016 11:45:56 +0200	[thread overview]
Message-ID: <8dfb5256-8ac8-98f0-ad16-6a891065d204@monom.org> (raw)
In-Reply-To: <1aae9991-0fc2-3da7-b60b-001548f36daa@bmw-carit.de>

On 09/08/2016 10:05 AM, Daniel Wagner wrote:
> This while loop was originally a goto loop:
>
> 1f2b79599ee8 ("firmware loader: always let firmware_buf own the pages
> buffer")
>
> I don't think the code doesn't do what it was indented to do. The reason
> is that calling complete_all() the wait_for_completion() will not block
> again until it has 'eaten up' the done counter. That is around UMAX/2
> loops. So there is an reinit_completion() missing in this case.

Ah, I think I got it. It looks like kind of optimization. Instead doing

	wait_for_completion()
	if (done)
		do_this()
	if (abort)
		do_that()

we have

check_again:
	if (done) {
		do_this()
		goto out
	}
	if (abort) {
		do_that()
		goto out
	}
	wait_for_completion()
	goto check_again
out:

> Before the above commit, the completion was used to wait inside
> _request_firmware_load() till the UML had done its job. The answer for
> your question is probably in 1f2b79599ee8 ("firmware loader: always let
> firmware_buf own the pages buffer").

So it still does the same job after this change. Check if we have the 
firmware loaded already in buf if not kick off the umh loader and wait 
for the result.

  reply	other threads:[~2016-09-08  9:46 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-07  8:45 [PATCH v4 0/4] firmware: encapsulate firmware loading status Daniel Wagner
2016-09-07  8:45 ` [PATCH v4 1/4] firmware: Move umh locking code into fw_load_from_user_helper() Daniel Wagner
2016-09-07 23:33   ` Luis R. Rodriguez
2016-09-08 12:41     ` Daniel Wagner
2016-09-08 14:55       ` Luis R. Rodriguez
2016-09-08 15:37   ` Ming Lei
2016-09-08 20:11     ` Luis R. Rodriguez
2016-09-09  1:22       ` Ming Lei
     [not found]         ` <CAB=NE6XK9g9muQ8p5+VaVGt2t0E_4K0wiavacQGqt_S4PyN28A@mail.gmail.com>
2016-09-09  4:19           ` Ming Lei
2016-09-09 22:10             ` Luis R. Rodriguez
     [not found]               ` <efba9730-d3bc-1fd4-2511-e509a4c60971@bmw-carit.de>
2016-09-15 15:43                 ` Luis R. Rodriguez
2016-09-07  8:45 ` [PATCH v4 2/4] firmware: encapsulate firmware loading status Daniel Wagner
2016-09-08  1:39   ` Luis R. Rodriguez
2016-09-08  8:05     ` Daniel Wagner
2016-09-08  9:45       ` Daniel Wagner [this message]
2016-09-08 11:26   ` Ming Lei
2016-09-08 12:26     ` Daniel Wagner
2016-09-08 15:49       ` Ming Lei
2016-09-09 11:43         ` Daniel Wagner
2016-09-08 12:32   ` Daniel Wagner
2016-09-07  8:45 ` [PATCH v4 3/4] firmware: Drop bit ops in favor of simple state machine Daniel Wagner
2016-09-08  1:45   ` Luis R. Rodriguez
2016-09-08 12:44     ` Daniel Wagner
2016-09-07  8:45 ` [PATCH v4 4/4] firmware: Do not use fw_lock for fw_status protection Daniel Wagner

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