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a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1602688730; 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=U5e/I1LEps/afnk/Iuom4s8zC2J5fj9A9vBnraNGwBY=; b=T1li4Nmu5IdgyVFY9Z66pGAIssT6pJwg6cilkd4bGydN/iicCJSC9Dxiy/ZiY/3tfUn+oU K93kEsTNhcHafjCA== Date: Wed, 14 Oct 2020 16:52:18 +0200 From: Thomas Gleixner To: LKML Subject: [patch 03/12] USB: serial: keyspan_pda: Consolidate room query References: <20201014145215.518912759@linutronix.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201014_111851_587314_7A0E9F22 X-CRM114-Status: GOOD ( 21.17 ) X-Spam-Score: -0.9 (/) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-0.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [2a0a:51c0:0:12e:550:0:0:1 listed in] [list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Felipe Balbi , Thomas Winischhofer , Mathias Nyman , Peter Zijlstra , Greg Kroah-Hartman , Sebastian Andrzej Siewior , linux-usb@vger.kernel.org, Johan Hovold , Krzysztof Kozlowski , Valentina Manea , linux-samsung-soc@vger.kernel.org, Kukjin Kim , Alan Stern , Duncan Sands , "Ahmed S. Darwish" , linux-omap@vger.kernel.org, Shuah Khan , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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. Add a byte buffer to struct keyspan_pda_private 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 --- drivers/usb/serial/keyspan_pda.c | 102 ++++++++++++++++----------------------- 1 file changed, 43 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)