From patchwork Mon Sep 21 11:37:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Neukum X-Patchwork-Id: 11789487 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7291859D for ; Mon, 21 Sep 2020 11:37:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54F1020BED for ; Mon, 21 Sep 2020 11:37:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="k0rulDly" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726862AbgIULh5 (ORCPT ); Mon, 21 Sep 2020 07:37:57 -0400 Received: from mx2.suse.de ([195.135.220.15]:45696 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726860AbgIULh4 (ORCPT ); Mon, 21 Sep 2020 07:37:56 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1600688274; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=Yu2UIPZdnC3rC5zUhHQZTIJxVQ7KVQ/n4uYuoJNyZhk=; b=k0rulDlyohydW1hhaN/zJNsqZeVbE/FLjWpi7LdOp9oXaJ07hD8WBhIxCYf9RzRicKC8+5 mdd80l+kkhR+5Bck/D3O6bn2F54124uPMYzzsQuZRcLh+i7ae4aJbOmAbtuM7XK2A+mGRm UDJZ4SRjBMc23MZeAnZvYks2cjIPgpk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id EB5B3B54A; Mon, 21 Sep 2020 11:38:30 +0000 (UTC) From: Oliver Neukum To: keithp@keithp.com, linux-usb@vger.kernel.org Cc: Oliver Neukum Subject: [RFT 2/4] chaoskey: introduce asynchronous reads Date: Mon, 21 Sep 2020 13:37:30 +0200 Message-Id: <20200921113732.11524-3-oneukum@suse.com> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200921113732.11524-1-oneukum@suse.com> References: <20200921113732.11524-1-oneukum@suse.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org This divides requesting IO and waiting for IO from each other. Signed-off-by: Oliver Neukum Reported-by: kernel test robot --- drivers/usb/misc/chaoskey.c | 39 +++++++++++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/usb/misc/chaoskey.c b/drivers/usb/misc/chaoskey.c index ad4c0b6d02cf..d47c2cc65269 100644 --- a/drivers/usb/misc/chaoskey.c +++ b/drivers/usb/misc/chaoskey.c @@ -336,15 +336,13 @@ static void chaos_read_callback(struct urb *urb) wake_up(&dev->wait_q); } -/* Fill the buffer. Called with dev->lock held - */ -static int _chaoskey_fill(struct chaoskey *dev) +static int chaoskey_request_fill(struct chaoskey *dev) { DEFINE_WAIT(wait); int result; bool started; - usb_dbg(dev->interface, "fill"); + usb_dbg(dev->interface, "request fill"); /* Return immediately if someone called before the buffer was * empty */ @@ -382,10 +380,26 @@ static int _chaoskey_fill(struct chaoskey *dev) */ started = dev->reads_started; dev->reads_started = true; + /* + * powering down while a read is under way + * is blocked in suspend() + */ + usb_autopm_put_interface(dev->interface); + return 0; +out: + usb_autopm_put_interface(dev->interface); + return result; +} + +static int chaoskey_wait_fill(struct chaoskey *dev) +{ + DEFINE_WAIT(wait); + int result; + result = wait_event_interruptible_timeout( dev->wait_q, !dev->reading, - (started ? NAK_TIMEOUT : ALEA_FIRST_TIMEOUT) ); + (dev->reads_started ? NAK_TIMEOUT : ALEA_FIRST_TIMEOUT) ); if (result < 0) { usb_kill_urb(dev->urb); @@ -400,7 +414,6 @@ static int _chaoskey_fill(struct chaoskey *dev) } out: /* Let the device go back to sleep eventually */ - usb_autopm_put_interface(dev->interface); usb_dbg(dev->interface, "read %d bytes", dev->valid); @@ -449,7 +462,12 @@ static ssize_t chaoskey_read(struct file *file, goto bail; } if (dev->valid == dev->used) { - result = _chaoskey_fill(dev); + result = chaoskey_request_fill(dev); + if (result < 0) { + mutex_unlock(&dev->lock); + goto bail; + } + result = chaoskey_wait_fill(dev); if (result < 0) { mutex_unlock(&dev->lock); goto bail; @@ -517,7 +535,7 @@ static int chaoskey_rng_read(struct hwrng *rng, void *data, * the buffer will still be empty */ if (dev->valid == dev->used) - (void) _chaoskey_fill(dev); + (void) chaoskey_request_fill(dev); this_time = dev->valid - dev->used; if (this_time > max) @@ -537,6 +555,11 @@ static int chaoskey_rng_read(struct hwrng *rng, void *data, static int chaoskey_suspend(struct usb_interface *interface, pm_message_t message) { + struct chaoskey *dev = usb_get_intfdata(interface); + + if (dev->reading && PMSG_IS_AUTO(message)) + return -EBUSY; + usb_dbg(interface, "suspend"); return 0; }