From patchwork Mon Dec 5 07:51:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "\(Exiting\) Baolin Wang" X-Patchwork-Id: 86510 Delivered-To: patch@linaro.org Received: by 10.140.20.101 with SMTP id 92csp1355820qgi; Mon, 5 Dec 2016 00:01:12 -0800 (PST) X-Received: by 10.98.210.10 with SMTP id c10mr56630731pfg.23.1480924872334; Mon, 05 Dec 2016 00:01:12 -0800 (PST) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id z4si13791910pgb.25.2016.12.05.00.01.12; Mon, 05 Dec 2016 00:01:12 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-usb-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@linaro.org; spf=pass (google.com: best guess record for domain of linux-usb-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-usb-owner@vger.kernel.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751420AbcLEIBK (ORCPT + 4 others); Mon, 5 Dec 2016 03:01:10 -0500 Received: from mail-pg0-f42.google.com ([74.125.83.42]:36692 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100AbcLEIBK (ORCPT ); Mon, 5 Dec 2016 03:01:10 -0500 Received: by mail-pg0-f42.google.com with SMTP id f188so133665783pgc.3 for ; Mon, 05 Dec 2016 00:01:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :in-reply-to:references; bh=foyILpc6b/Ol30OJY2j5RVb5lUf1lxWcTdDpNj56WXU=; b=hk3XCMKHJyTsmMiJozAMKz8JlwnRPj+2cfL2nbDPRJ9kJuFrLziTPQuZM0RCVoBt5Z Yu5yS9MnetduwYrj42/467qLdX/zLa1kK1siFEdtxgJgEngSx+yjYjCrQrWh7YVH3swf rdLZZkyVHBj/dTmCzTtfYqtCWh7IFq9VMBVSA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:in-reply-to:references; bh=foyILpc6b/Ol30OJY2j5RVb5lUf1lxWcTdDpNj56WXU=; b=Nh0KxOqzIvqTpeJvjnGls9JtiwlIaP7RwaPv2qVhmJgbAGyNMYbOrG9UyVKbVArNnY eTaxUeQ7NJxi6eSZxORSKP3X00wEcSnf99z6XJgHxvMQ07OwJUPNl9xfNwnR+OJEdGag +5eJFaP0xuHzjZh0y3vc/2k2cgFlW9WdBuEcsQCxDyFb2uc06FeCGZOLbqD7FWBrewha I7Atw+rjSsFy0Mjzxz3IjC59sPdWkUj3t+DNkkraYf3kQhU4FTkMZiLUje5hhp/PIdPG 9uOmx+ADbj/sOYlG7lj2SRFv3oFnR3vrpIvdIZ03OurNWHGA+gjUY2TQFlIsO41omFre oKng== X-Gm-Message-State: AKaTC00f1cjgm5aabewIHvPn7GZzZxFTQLSEDPXjnfgbWNaPfZtMxz7pSmwQXtwI3iz+QYZu X-Received: by 10.84.164.106 with SMTP id m39mr120992273plg.97.1480924351601; Sun, 04 Dec 2016 23:52:31 -0800 (PST) Received: from baolinwangubtpc.spreadtrum.com ([175.111.195.49]) by smtp.gmail.com with ESMTPSA id t20sm24947924pfk.48.2016.12.04.23.52.28 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sun, 04 Dec 2016 23:52:30 -0800 (PST) From: Baolin Wang To: mathias.nyman@intel.com, gregkh@linuxfoundation.org Cc: baolu.lu@linux.intel.com, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, broonie@kernel.org, baolin.wang@linaro.org Subject: [PATCH 2/2] usb: host: xhci: Handle the right timeout command Date: Mon, 5 Dec 2016 15:51:50 +0800 Message-Id: <0c39bfed1cf6f7b747e702aa841f82c9d2140f27.1480922249.git.baolin.wang@linaro.org> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: References: In-Reply-To: References: Sender: linux-usb-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org If a command event is found on the event ring during an interrupt, we need to stop the command timer with del_timer(). Since del_timer() can fail if the timer is running and waiting on the xHCI lock, then it maybe get the wrong timeout command in xhci_handle_command_timeout() if host fetched a new command and updated the xhci->current_cmd in handle_cmd_completion(). For this situation, we need a way to signal to the command timer that everything is fine and it should exit. We should introduce a counter (xhci->current_cmd_pending) for the number of pending commands. If we need to cancel the command timer and del_timer() succeeds, we decrement the number of pending commands. If del_timer() fails, we leave the number of pending commands alone. For handling timeout command, in xhci_handle_command_timeout() we will check the counter after decrementing it, if the counter (xhci->current_cmd_pending) is 0, which means xhci->current_cmd is the right timeout command. If the counter (xhci->current_cmd_pending) is greater than 0, which means current timeout command has been handled by host and host has fetched new command as xhci->current_cmd, then just return and wait for new current command. Signed-off-by: Baolin Wang --- drivers/usb/host/xhci-ring.c | 29 ++++++++++++++++++++++++++++- drivers/usb/host/xhci.h | 1 + 2 files changed, 29 insertions(+), 1 deletion(-) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9965a4c..edc9ac2 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1253,6 +1253,7 @@ static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci, if ((xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue) && !(xhci->xhc_state & XHCI_STATE_DYING)) { xhci->current_cmd = cur_cmd; + xhci->current_cmd_pending++; mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT); xhci_ring_cmd_db(xhci); } @@ -1269,11 +1270,27 @@ void xhci_handle_command_timeout(unsigned long data) xhci = (struct xhci_hcd *) data; spin_lock_irqsave(&xhci->lock, flags); + xhci->current_cmd_pending--; + if (!xhci->current_cmd) { spin_unlock_irqrestore(&xhci->lock, flags); return; } + /* + * If the current_cmd_pending is 0, which means current command is + * timeout. + * + * If the current_cmd_pending is greater than 0, which means current + * timeout command has been handled by host and host has fetched new + * command as xhci->current_cmd, then just return and wait for new + * current command. + */ + if (xhci->current_cmd_pending > 0) { + spin_unlock_irqrestore(&xhci->lock, flags); + return; + } + if (xhci->current_cmd->status == COMP_CMD_ABORT) second_timeout = true; xhci->current_cmd->status = COMP_CMD_ABORT; @@ -1282,6 +1299,8 @@ void xhci_handle_command_timeout(unsigned long data) hw_ring_state = xhci_read_64(xhci, &xhci->op_regs->cmd_ring); if ((xhci->cmd_ring_state & CMD_RING_STATE_RUNNING) && (hw_ring_state & CMD_RING_RUNNING)) { + /* Will add command timer again to wait for abort event */ + xhci->current_cmd_pending++; spin_unlock_irqrestore(&xhci->lock, flags); xhci_dbg(xhci, "Command timeout\n"); ret = xhci_abort_cmd_ring(xhci); @@ -1336,7 +1355,13 @@ static void handle_cmd_completion(struct xhci_hcd *xhci, cmd = list_entry(xhci->cmd_list.next, struct xhci_command, cmd_list); - del_timer(&xhci->cmd_timer); + /* + * If the command timer is running on another CPU, we don't decrement + * current_cmd_pending, since we didn't successfully stop the command + * timer. + */ + if (del_timer(&xhci->cmd_timer)) + xhci->current_cmd_pending--; trace_xhci_cmd_completion(cmd_trb, (struct xhci_generic_trb *) event); @@ -1427,6 +1452,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci, if (cmd->cmd_list.next != &xhci->cmd_list) { xhci->current_cmd = list_entry(cmd->cmd_list.next, struct xhci_command, cmd_list); + xhci->current_cmd_pending++; mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT); } else if (xhci->current_cmd == cmd) { xhci->current_cmd = NULL; @@ -3927,6 +3953,7 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd, if (xhci->cmd_list.next == &cmd->cmd_list && !timer_pending(&xhci->cmd_timer)) { xhci->current_cmd = cmd; + xhci->current_cmd_pending++; mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT); } diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h index 9dbaacf..5d81257 100644 --- a/drivers/usb/host/xhci.h +++ b/drivers/usb/host/xhci.h @@ -1567,6 +1567,7 @@ struct xhci_hcd { unsigned int cmd_ring_reserved_trbs; struct timer_list cmd_timer; struct xhci_command *current_cmd; + u32 current_cmd_pending; struct xhci_ring *event_ring; struct xhci_erst erst; /* Scratchpad */