Walter Harms pointed out the locking was rather obtuse in dupfd. This
patch makes it much clearer.  Present code acquires a lock in dupfd()
callee locate_fd(), and releases it in allocate_fd() OR dupfd() itself.

This changes cleans this up to acquire and release the lock entirely
within dupfd(), which moves locking completely out of locate_fd()
and allows the manual inlining of allocate_fd() into its only caller,
dupfd().

This change is functionally equivalent to the current code
[well, dupfd might run a cycle or two faster if the compiler optimizes well...]

into home.transmeta.com:/home/torvalds/v2.5/linux

into kroah.com:/home/linux/linux/BK/gregkh-2.5

1-fix-lowlat:

QA found that running all four ports at 460800 would drop data. I
traced it to data being dropped in the read callback because the flip
buffers were full. Turning on the low latency flag fixed things.

2-fix-taint

A side-effect of turning on low latency; the interrupt context from
the callback is now passed through to the tty layer, passing it on to
calls back into usb-serial.c. Which causes deadlocks when trying to
re-acquire the per-port semaphore. We've already talked about this.
This patch is my work-around for the usb-serial.c brokenness.
Basically, implemement a buffering scheme, and schedule a software
interrupt to handle the data handoff to the tty layer sometime later.
urb_pool_size defaults to 8, but is a module parameter and can be
modified at runtime.
The buffering is needed so that the driver can run while data is
waiting to be processed, but I could have used the tty layer
scheduling instead of doing my own by turning off low latency.
However, I looked at the tty layer and it seems to me that there's
nothing preventing a really fast device from flipping one buffer,
flipping the next, and flipping back to the still full buffer from
before (actually, the flip just gets scheduled for later), so my
driver needs to be able to hold onto buffered data and schedule them
for processing later anyway. So, might as well leave low_latency on.


diff -Naur linux-2.5.49-0-virgin/drivers/usb/serial/whiteheat.c linux-2.5.49-1-fix-
lowlat/drivers/usb/serial/whiteheat.c

Attached is a patch that changes the 2.5.x disconnect to be similar to
2.4.x disconnect. This doesn't fix the race, but does shrink the
window such that I've never seen it trigger, even under testing
designed to do that.

There doesn't seem to be a good way to fix the race. The fix should be
to have _disconnect force any sleeping semaphore holders to run to
completion between the end of the loop in the patch below and the spot
where the underlying memory is freed, but I don't see a way to do
that.


diff -Naur linux-2.5.49-2-fix-taint/drivers/usb/serial/usb-serial.c linux-2.5.49-3-fix-drvdata/drivers/usb/serial/usb-
serial.c

This patch cleans up the vicam_decode_color function by removing
unused/useless variables and combining the two "x" loops inside the
y loop into one. It also reduces the number of times that the "x"
loop occurs from 512 to 320 which should provide a decent speed
increase. It also fixes a bug in the y loop that wrote beyond its bound.

After a little absence, here's a patch to bring the Philips Webcam driver up
to version 8.9 (skipping 8.8 which has been available as a download on my
website for a while).

This patch is against 2.5.49, and includes some of the following:
* New USB IDs for Logitech and Visionite webcams.
* Better URB link/unlink sequence when opening/closing device
  and switching resolutions.
* Adding probe for CCD/CMOS sensor type.
* Removed remnants of YUV420 palette stuff.

Also updated the description in 'Kconfig'.

Add `unlikely' to error-return path in v850 __syscall_return macro

Shrink v850 exception-trap handling code a bit

Change type of v850 function `gbus_int_disable_irqs' to void

Make v850 syscall6 macro support both old and new gcc versions

Add id for v850 `nb85e_uart' to serial_core.h

Give a compile-time error on the v850 if MAX_ORDER is too large

Make the v850 leds driver's seek routine always return a value

Update make variable used by initramfs `binary blob' creation on v850

Change the default baud rate of the `nb85e_uart' driver to 115200

Tweak some v850 name strings
[basically only affects printed output]

Random whitespace tweaks in v850 files

Add my name to CREDITS file

Update includes in v850 files to reflect recent header changes

Update v850 to use kstat_cpu in irqs.c

The v850 doesn't need sys_old_getrlimit

Add TASK_UNMAPPED_BASE for v850

Update v850 usage of do_fork to supply new args

Add v850 support for initramfs

Random minor fixes for v850 `anna' platform

Update `nb85e_uart' driver for recent serial framework changes

Make NB85E_UART_CKSR_MAX_FREQ (in nb85e_uart driver) overridable
[The proper value is CPU-dependent]

Add v850 nanosecond stat fields

Add support for AS85EP1 platform to v850 arch

Add v850 versions of dump_stack and show_stack
Also move v850 show_regs to same source file (bug.c)