Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753978Ab0AELZo (ORCPT ); Tue, 5 Jan 2010 06:25:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753535Ab0AELZn (ORCPT ); Tue, 5 Jan 2010 06:25:43 -0500 Received: from www84.your-server.de ([213.133.104.84]:48708 "EHLO www84.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753095Ab0AELZm (ORCPT ); Tue, 5 Jan 2010 06:25:42 -0500 Subject: Re: USB: serial: kfifo_len locking From: Stefani Seibold To: Johan Hovold Cc: Pete Zaitcev , Greg KH , Andrew Morton , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org In-Reply-To: <20100105111401.GB10442@localhost> References: <20100104174352.GA26606@localhost> <1262632804.4814.17.camel@wall-e> <20100105004344.082bb69f@redhat.com> <20100105110418.GA10442@localhost> <1262689759.21020.2.camel@wall-e> <20100105111401.GB10442@localhost> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 05 Jan 2010 12:25:34 +0100 Message-ID: <1262690734.22009.3.camel@wall-e> Mime-Version: 1.0 X-Mailer: Evolution 2.28.2 Content-Transfer-Encoding: 7bit X-Authenticated-Sender: stefani@seibold.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6091 Lines: 149 Am Dienstag, den 05.01.2010, 12:14 +0100 schrieb Johan Hovold: > > > > > > http://git.kernel.org/?p=linux/kernel/git/gregkh/patches.git;a=blob;f=usb/usb-serial-mct_usb232-add-drain-on-close.patch;h=c464f1a82e93df0dd41762a8cb33b0b22e90cdd7;hb=1ea72e7c40b239c6b6f88a4993196be66fc3d892 > > > > > > 38 --- a/drivers/usb/serial/generic.c > > > 39 +++ b/drivers/usb/serial/generic.c > > > 40 @@ -369,8 +369,11 @@ int usb_serial_generic_write_room(struct > > > 41 room = port->bulk_out_size * > > > 42 (serial->type->max_in_flight_urbs - > > > 43 port->urbs_in_flight); > > > 44 - } else if (serial->num_bulk_out) > > > 45 + } else if (serial->num_bulk_out) { > > > 46 + /* This overcounts badly, but is good enough for drain wait. */ > > > 47 room = kfifo_avail(&port->write_fifo); > > > 48 + room += port->write_urb_busy * port->bulk_out_size; > > > 49 + } > > > 50 spin_unlock_irqrestore(&port->lock, flags); > > > 51 > > > 52 dbg("%s - returns %d", __func__, room); > > > > > > > > > Which does not make any sense at all. Bad merge? What do you say Greg? > > > > > > > I don't know where is your problem? This are two different functions > > usb_serial_generic_write_room() and usb_serial_generic_chars_in_buffer() > > Exactly my point. > > The drain patch needed to modify chars_in_buffer, but the patch in Greg's > tree modifies write_room instead (which does not make sense and was > neither part of the submitted patch). > Sorry, but i am not sure if i the right address about your complains. The only thing i have done in the usb serial driver is the port to the new kfifo API. This is the original patch i had posted: diff -u -N -r -p old/drivers/usb/serial/generic.c new/drivers/usb/serial/generic.c --- old/drivers/usb/serial/generic.c 2009-12-23 08:54:06.966476248 +0100 +++ new/drivers/usb/serial/generic.c 2009-12-23 09:06:25.778474708 +0100 @@ -276,7 +276,7 @@ static int usb_serial_generic_write_star if (port->write_urb_busy) start_io = false; else { - start_io = (kfifo_len(port->write_fifo) != 0); + start_io = (kfifo_len(&port->write_fifo) != 0); port->write_urb_busy = start_io; } spin_unlock_irqrestore(&port->lock, flags); @@ -285,7 +285,7 @@ static int usb_serial_generic_write_star return 0; data = port->write_urb->transfer_buffer; - count = kfifo_out_locked(port->write_fifo, data, port->bulk_out_size, &port->lock); + count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock); usb_serial_debug_data(debug, &port->dev, __func__, count, data); /* set up our urb */ @@ -345,7 +345,7 @@ int usb_serial_generic_write(struct tty_ return usb_serial_multi_urb_write(tty, port, buf, count); - count = kfifo_in_locked(port->write_fifo, buf, count, &port->lock); + count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock); result = usb_serial_generic_write_start(port); if (result >= 0) @@ -370,7 +370,7 @@ int usb_serial_generic_write_room(struct (serial->type->max_in_flight_urbs - port->urbs_in_flight); } else if (serial->num_bulk_out) - room = port->write_fifo->size - kfifo_len(port->write_fifo); + room = kfifo_avail(&port->write_fifo); spin_unlock_irqrestore(&port->lock, flags); dbg("%s - returns %d", __func__, room); @@ -391,7 +391,7 @@ int usb_serial_generic_chars_in_buffer(s chars = port->tx_bytes_flight; spin_unlock_irqrestore(&port->lock, flags); } else if (serial->num_bulk_out) - chars = kfifo_len(port->write_fifo); + chars = kfifo_len(&port->write_fifo); dbg("%s - returns %d", __func__, chars); return chars; @@ -507,7 +507,7 @@ void usb_serial_generic_write_bulk_callb if (status) { dbg("%s - nonzero multi-urb write bulk status " "received: %d", __func__, status); - kfifo_reset(port->write_fifo); + kfifo_reset_out(&port->write_fifo); } else usb_serial_generic_write_start(port); } diff -u -N -r -p old/drivers/usb/serial/usb-serial.c new/drivers/usb/serial/usb-serial.c --- old/drivers/usb/serial/usb-serial.c 2009-12-23 08:54:23.204476351 +0100 +++ new/drivers/usb/serial/usb-serial.c 2009-12-23 09:06:39.664475312 +0100 @@ -595,8 +595,7 @@ static void port_release(struct device * usb_free_urb(port->write_urb); usb_free_urb(port->interrupt_in_urb); usb_free_urb(port->interrupt_out_urb); - if (!IS_ERR(port->write_fifo) && port->write_fifo) - kfifo_free(port->write_fifo); + kfifo_free(&port->write_fifo); kfree(port->bulk_in_buffer); kfree(port->bulk_out_buffer); kfree(port->interrupt_in_buffer); @@ -939,7 +938,7 @@ int usb_serial_probe(struct usb_interfac dev_err(&interface->dev, "No free urbs available\n"); goto probe_error; } - if (kfifo_alloc(port->write_fifo, PAGE_SIZE, GFP_KERNEL)) + if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL)) goto probe_error; buffer_size = le16_to_cpu(endpoint->wMaxPacketSize); port->bulk_out_size = buffer_size; diff -u -N -r -p old/include/linux/usb/serial.h new/include/linux/usb/serial.h --- old/include/linux/usb/serial.h 2009-12-23 08:54:34.368476110 +0100 +++ new/include/linux/usb/serial.h 2009-12-23 09:06:32.870725683 +0100 @@ -16,6 +16,7 @@ #include #include #include +#include #define SERIAL_TTY_MAJOR 188 /* Nice legal number now */ #define SERIAL_TTY_MINORS 254 /* loads of devices :) */ @@ -94,7 +95,7 @@ struct usb_serial_port { unsigned char *bulk_out_buffer; int bulk_out_size; struct urb *write_urb; - struct kfifo *write_fifo; + struct kfifo write_fifo; int write_urb_busy; __u8 bulk_out_endpointAddress; As you can see i didn't changed noting about this drain thing. Stefani -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/