From patchwork Mon Oct 19 10:06:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 11844001 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 E63BE16BC for ; Mon, 19 Oct 2020 10:19:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B159322263 for ; Mon, 19 Oct 2020 10:19:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="WK/KUF9n"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="x8rtyLqc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729776AbgJSKTN (ORCPT ); Mon, 19 Oct 2020 06:19:13 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:58742 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727355AbgJSKSI (ORCPT ); Mon, 19 Oct 2020 06:18:08 -0400 Message-Id: <20201019101109.903651690@linutronix.de> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1603102685; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=GspGZAgtTq6gMYfmmkZzHxj2wK5gwCFO/dMv4c+qGNg=; b=WK/KUF9nx+OzfrXpW6AZP63Mk3FL/cEjZl3mU1F9QJ+O6FJ7qFDBgNIs/DFAFqo32p+kRL wd5kaaQ3IHlGruoBf+Rn4HWEy/upe3XziU6BeSZv4kqnKeCytgoMKdNx04mw/kuVTUsi7/ PYSOi/w361WypClc90JwGEnpGTOftBHhyjUjPjTSY2BTbxsTTpxQ5+n0W7qFt+i/X6h3Vb cXkJdxA60UzvFfPnepVkhrjd0HmQQD2yVv8bBmMjy8rEm00gd3dGvgMv8DKmKFb7xE8ttZ W8fcjFZdNQinRYMJy79YUEA9tvaulgCmIKr+DDzUp3pjRz/N51+z8dGvgR3vng== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1603102685; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: references:references; bh=GspGZAgtTq6gMYfmmkZzHxj2wK5gwCFO/dMv4c+qGNg=; b=x8rtyLqc8Pja+okYr4ByLhKQBeW2Ox67gJGffT2WLFy/CoG/rB/9qGuafa5FJRoM3ny9Di GdMrkcGxm7OgQlDg== Date: Mon, 19 Oct 2020 12:06:32 +0200 From: Thomas Gleixner To: LKML Cc: Peter Zijlstra , Sebastian Andrzej Siewior , Johan Hovold , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Thomas Winischhofer , "Ahmed S. Darwish" , Mathias Nyman , Valentina Manea , Shuah Khan , Alan Stern , linux-omap@vger.kernel.org, Kukjin Kim , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Felipe Balbi , Duncan Sands Subject: [patch V2 03/13] USB: serial: keyspan_pda: Consolidate room query References: <20201019100629.419020859@linutronix.de> MIME-Version: 1.0 Content-transfer-encoding: 8-bit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org From: Sebastian Andrzej Siewior Having two copies of the same code doesn't make the code more readable and allocating a buffer of 1 byte for a synchronous operation is a pointless exercise. Allocate a byte buffer at init which can be used instead. The buffer is only used in open() and tty->write(). Console writes are not calling into the query. open() obviously happens before write() and the writes are serialized by bit 0 of port->write_urbs_free which protects also the transaction itself. Move the actual query into a helper function and cleanup the usage sites in keyspan_pda_write() and keyspan_pda_open(). Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Johan Hovold Cc: Greg Kroah-Hartman Cc: linux-usb@vger.kernel.org --- V2; Allocate a real buffer (Alan) --- drivers/usb/serial/keyspan_pda.c | 108 +++++++++++++++++---------------------- 1 file changed, 49 insertions(+), 59 deletions(-) --- a/drivers/usb/serial/keyspan_pda.c +++ b/drivers/usb/serial/keyspan_pda.c @@ -47,6 +47,7 @@ struct keyspan_pda_private { struct work_struct unthrottle_work; struct usb_serial *serial; struct usb_serial_port *port; + u8 *query_buf; }; @@ -436,6 +437,31 @@ static int keyspan_pda_tiocmset(struct t return rc; } +/* + * Using priv->query_buf is safe here because this is only called for TTY + * operations open() and write(). write() comes post open() obviously and + * write() itself is serialized via bit 0 of port->write_urbs_free. Console + * writes are never calling into this. + */ +static int keyspan_pda_query_room(struct usb_serial *serial, + struct keyspan_pda_private *priv) +{ + int res; + + res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), + 6, /* write_room */ + USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_IN, + 0, /* value */ + 0, /* index */ + priv->query_buf, + 1, + 2000); + if (res != 1) + return res < 0 ? res : -EIO; + + return (unsigned int)*priv->query_buf; +} + static int keyspan_pda_write(struct tty_struct *tty, struct usb_serial_port *port, const unsigned char *buf, int count) { @@ -483,39 +509,16 @@ static int keyspan_pda_write(struct tty_ * usage because the console write can't sleep. */ if (count > priv->tx_room && tty) { - u8 *room; - - room = kmalloc(1, GFP_KERNEL); - if (!room) { - rc = -ENOMEM; - goto exit; - } - - rc = usb_control_msg(serial->dev, - usb_rcvctrlpipe(serial->dev, 0), - 6, /* write_room */ - USB_TYPE_VENDOR | USB_RECIP_INTERFACE - | USB_DIR_IN, - 0, /* value: 0 means "remaining room" */ - 0, /* index */ - room, - 1, - 2000); - if (rc > 0) { - dev_dbg(&port->dev, "roomquery says %d\n", *room); - priv->tx_room = *room; - } - kfree(room); + rc = keyspan_pda_query_room(serial, priv); if (rc < 0) { - dev_dbg(&port->dev, "roomquery failed\n"); - goto exit; - } - if (rc == 0) { - dev_dbg(&port->dev, "roomquery returned 0 bytes\n"); - rc = -EIO; /* device didn't return any data */ + dev_dbg(&port->dev, "roomquery failed %d\n", rc); goto exit; } + + dev_dbg(&port->dev, "roomquery says %d\n", rc); + priv->tx_room = rc; } + if (count > priv->tx_room) { /* we're about to completely fill the Tx buffer, so we'll be throttled afterwards. */ @@ -615,45 +618,26 @@ static int keyspan_pda_open(struct tty_s struct usb_serial_port *port) { struct usb_serial *serial = port->serial; - u8 *room; - int rc = 0; struct keyspan_pda_private *priv; + int rc; - /* find out how much room is in the Tx ring */ - room = kmalloc(1, GFP_KERNEL); - if (!room) - return -ENOMEM; + priv = usb_get_serial_port_data(port); - rc = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), - 6, /* write_room */ - USB_TYPE_VENDOR | USB_RECIP_INTERFACE - | USB_DIR_IN, - 0, /* value */ - 0, /* index */ - room, - 1, - 2000); + /* find out how much room is in the Tx ring */ + rc = keyspan_pda_query_room(serial, priv); if (rc < 0) { - dev_dbg(&port->dev, "%s - roomquery failed\n", __func__); - goto error; - } - if (rc == 0) { - dev_dbg(&port->dev, "%s - roomquery returned 0 bytes\n", __func__); - rc = -EIO; - goto error; + dev_dbg(&port->dev, "roomquery failed %d\n", rc); + return rc; } - priv = usb_get_serial_port_data(port); - priv->tx_room = *room; - priv->tx_throttled = *room ? 0 : 1; + + priv->tx_room = rc; + priv->tx_throttled = rc ? 0 : 1; /*Start reading from the device*/ rc = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); - if (rc) { + if (rc) dev_dbg(&port->dev, "%s - usb_submit_urb(read int) failed\n", __func__); - goto error; - } -error: - kfree(room); + return rc; } static void keyspan_pda_close(struct usb_serial_port *port) @@ -715,6 +699,11 @@ static int keyspan_pda_port_probe(struct priv = kmalloc(sizeof(struct keyspan_pda_private), GFP_KERNEL); if (!priv) return -ENOMEM; + priv->query_buf = kmalloc(1, GFP_KERNEL); + if (!priv->query_buf) { + kfree(priv); + return -ENOMEM; + } INIT_WORK(&priv->wakeup_work, keyspan_pda_wakeup_write); INIT_WORK(&priv->unthrottle_work, keyspan_pda_request_unthrottle); @@ -731,6 +720,7 @@ static int keyspan_pda_port_remove(struc struct keyspan_pda_private *priv; priv = usb_get_serial_port_data(port); + kfree(priv->query_buf); kfree(priv); return 0;