From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Johan Hovold <johan@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org,
Thomas Winischhofer <thomas@winischhofer.net>,
"Ahmed S. Darwish" <a.darwish@linutronix.de>,
Mathias Nyman <mathias.nyman@intel.com>,
Valentina Manea <valentina.manea.m@gmail.com>,
Shuah Khan <shuah@kernel.org>,
Alan Stern <stern@rowland.harvard.edu>,
linux-omap@vger.kernel.org, Kukjin Kim <kgene@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org,
Felipe Balbi <balbi@kernel.org>,
Duncan Sands <duncan.sands@free.fr>
Subject: [patch 03/12] USB: serial: keyspan_pda: Consolidate room query
Date: Wed, 14 Oct 2020 16:52:18 +0200 [thread overview]
Message-ID: <20201014145727.338773481@linutronix.de> (raw)
In-Reply-To: 20201014145215.518912759@linutronix.de
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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 <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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)
next prev parent reply other threads:[~2020-10-14 15:19 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-14 14:52 [patch 00/12] UBS: Cleanup in_interupt/in_irq/in_atomic() usage Thomas Gleixner
2020-10-14 14:52 ` [patch 01/12] USB: sisusbvga: Make console support depend on BROKEN Thomas Gleixner
2020-10-14 14:52 ` [patch 02/12] USB: serial: keyspan_pda: Replace in_interrupt() usage Thomas Gleixner
2020-10-14 14:52 ` Thomas Gleixner [this message]
2020-10-14 16:14 ` [patch 03/12] USB: serial: keyspan_pda: Consolidate room query Alan Stern
2020-10-14 16:17 ` Thomas Gleixner
2020-10-14 16:27 ` Sebastian Andrzej Siewior
2020-10-14 16:34 ` Alan Stern
2020-10-14 16:44 ` Sebastian Andrzej Siewior
2020-10-14 14:52 ` [patch 04/12] USB: serial: digi_acceleport: Remove in_interrupt() usage Thomas Gleixner
2020-10-14 14:52 ` [patch 05/12] usb: xhci: Remove in_interrupt() checks Thomas Gleixner
2020-10-23 13:38 ` Mathias Nyman
2020-10-14 14:52 ` [patch 06/12] usb: host: isp1362: Replace in_interrupt() usage Thomas Gleixner
2020-10-14 18:49 ` kernel test robot
2020-10-14 14:52 ` [patch 07/12] usbip: Remove in_interrupt() check Thomas Gleixner
2020-10-14 15:45 ` Shuah Khan
2020-10-14 14:52 ` [patch 08/12] usb: hosts: Remove in_interrupt() from comments Thomas Gleixner
2020-10-14 15:24 ` Krzysztof Kozlowski
2020-10-14 16:20 ` Alan Stern
2020-10-14 14:52 ` [patch 09/12] usb: gadget: pxa27x_udc: Replace in_interrupt() usage in comments Thomas Gleixner
2020-10-14 14:52 ` [patch 10/12] usb: gadget: udc: Remove in_interrupt()/in_irq() from comments Thomas Gleixner
2020-10-14 16:22 ` Alan Stern
2020-10-14 14:52 ` [patch 11/12] usb: core: Replace in_interrupt() in comments Thomas Gleixner
2020-10-14 16:27 ` Alan Stern
2020-10-14 16:41 ` Sebastian Andrzej Siewior
2020-10-14 18:13 ` Alan Stern
2020-10-14 14:52 ` [patch 12/12] usb: atm: Replace in_interrupt() usage in comment Thomas Gleixner
2020-10-23 8:01 ` [patch 00/12] UBS: Cleanup in_interupt/in_irq/in_atomic() usage Pavel Machek
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