The existing code had the following race:
Thread-1 Thread-2
inc/read in_use
inc/read in_use
inc tx_free_list[qos].len
inc tx_free_list[qos].len
The actual in_use value was incremented twice, but thread-1 is going
to free memory based on its stale value, and will free one too many
times. The result is that memory is freed back to the kernel while
its packet is still in the transmit buffer. If the memory is
overwritten before it is transmitted, the hardware will put a valid
checksum on it and send it out (just like it does with good packets).
If by chance the TCP flags are clobbered but not the addresses or
ports, the result can be a broken TCP stream.
The fix is to track the number of freed packets in a single location
(a Fetch-and-Add Unit register). That way it can never get out of sync
with itself.
We try to free up to MAX_SKB_TO_FREE (currently 10) buffers at a time.
If fewer are available we adjust the free count with the difference.
The action of claiming buffers to free is atomic so two threads cannot
claim the same buffers.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Convert the driver to use net_device_ops as it is now mandatory.
Also compensate for the removal of struct sk_buff's dst field.
The changes are mostly mechanical, the content of ethernet-common.c
was moved to ethernet.c and ethernet-common.{c,h} are removed.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Remove the replicated urban legends from the comments and fix a couple of
other silly calls
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some of the comedi drivers need timer.h to build properly, so put it
in the comedidev.h file to fix these errors.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There are others remaining due to the __iomem namespace of the
framebuffer data pointer.
Cc: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This cleans up a bunch of checkpatch.pl warnings in the udlfb.c file.
Cc: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This cleans up a bunch of checkpatch.pl warnings in the udlfb.h file.
Cc: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This adds the udlfb driver, a framebuffer driver for DisplayLink devices.
From: Roberto De Ioris <roberto@unbit.it>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
These comments contribute nothing to the code, and most were just cut
and pasted from another driver.
Cc: Kevin Huang <Kevin.Huang@rdc.com.tw>
Cc: Tomy Wang <Tomy.Wang@rdc.com.tw>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
They are not needed, and the version one was pointless now that the code
is merged into the tree.
Cc: Kevin Huang <Kevin.Huang@rdc.com.tw>
Cc: Tomy Wang <Tomy.Wang@rdc.com.tw>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Now that Bill rewrote the driver "properly", this old thing can be removed.
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is the serqt_usb driver rewritten to use usb-serial.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
David Daney
Alan Cox
Greg Kroah-Hartman
Roberto De Ioris
Kevin Huang
Bill Pemberton