linux.git/drivers/usb/serial/generic.c, branch v2.6.24

usbserial: fix inconsistent lock state

2007-11-28T21:58:34+00:00

In commit acd2a847e7fee7df11817f67dba75a2802793e5d usb_serial_generic_write()
disables interrupts when taking &port->lock which is also taken in
usb_serial_generic_read_bulk_callback() resulting in an inconsistent lock state
due to the latter not disabling interrupts on the local cpu. Fix that by
disabling interrupts in the latter call site also.

Signed-off-by: Borislav Petkov 
Acked-by: Jiri Kosina 
Signed-off-by: Greg Kroah-Hartman

USB: usbserial - fix potential deadlock between write() and IRQ

2007-10-25T19:18:45+00:00

USB: usbserial - fix potential deadlock between write() and IRQ

usb_serial_generic_write() doesn't disable interrupts when taking port->lock,
and could therefore deadlock with usb_serial_generic_read_bulk_callback()
being called from interrupt, taking the same lock. Fix it.

Signed-off-by: Jiri Kosina 
Acked-by: Larry Finger 
Signed-off-by: Greg Kroah-Hartman

USB: serial: generic: clean up urb->status usage

2007-07-12T23:34:33+00:00

This done in anticipation of removal of urb->status, which will make
that patch easier to review and apply in the future.


Cc: 
Signed-off-by: Greg Kroah-Hartman

USB: generic usb serial to new buffering scheme

2007-07-12T23:29:51+00:00

the generic driver also had its own buffering.

Signed-off-by: Oliver Neukum

USB: suspend support for usb serial

2007-07-12T23:29:44+00:00

this implements generic support for suspend/resume for usb serial.

Signed-off-by: Oliver Neukum 
Signed-off-by: Greg Kroah-Hartman

USB: fix usb-serial/generic build warning

2007-03-26T21:17:48+00:00

Fix annoying build warning when CONFIG_USB_SERIAL_GENERIC is undefined.

  drivers/usb/serial/generic.c:24: warning: `generic_probe' declared `static' but never defined

Signed-off-by: David Brownell 
Signed-off-by: Greg Kroah-Hartman

USB: add flow control to usb-serial generic driver.

2007-02-16T23:32:18+00:00

I added two fields to struct usb_serial_port to keep track of the
throttle state. Other usb-serial drivers typically use private data for
such things, but the generic driver can not really do that because some
of its code is also used by other drivers (which may have their own
private data needs).

As it is, I am not sure that this patch is useful in all scenarios.
It is certainly helpful for low-bandwidth devices that can hold their
data in response to throttling. But for devices that pump data in
real-time as fast as possible (webcam, A/D converter, etc), throttling
may actually cause more data loss.

From: Joris van Rantwijk 
Signed-off-by: Greg Kroah-Hartman

USB serial: add driver pointer to all usb-serial drivers

2007-02-07T23:44:34+00:00

Every usb serial driver should have a pointer to the corresponding usb driver.
So the usb serial core can add a new id not only to the usb serial driver, but
also to the usb driver.

Also the usb drivers of ark3116, mos7720 and mos7840 missed the flag
no_dynamic_id=1. This is added now.

Signed-off-by: Johannes Hölzl 
Signed-off-by: Greg Kroah-Hartman

IRQ: Maintain regs pointer globally rather than passing to IRQ handlers

2006-10-05T14:10:12+00:00

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells 
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

usb-serial: possible irq lock inversion (PPP vs. usb/serial)

2006-09-28T22:36:43+00:00

=========================================================
[ INFO: possible irq lock inversion dependency detected ]