On Wed, 18 Jun 2008, Linus Torvalds wrote:
>
> And yes, the "lock andl" should be noticeably faster than the xchgl.

I dunno. Here's a untested (!!) patch that turns constant-bit
set/clear_bit ops into byte mask ops (lock orb/andb).

It's not exactly pretty. The reason for using the byte versions is that a
locked op is serialized in the memory pipeline anyway, so there are no
forwarding issues (that could slow down things when we access things with
different sizes), and the byte ops are a lot smaller than 32-bit and
particularly 64-bit ops (big constants, and the 64-bit ops need the REX
prefix byte too).

[ Side note: I wonder if we should turn the "test_bit()" C version into a
  "char *" version too.. It could actually help with alias analysis, since
  char pointers can alias anything. So it might be the RightThing(tm) to
  do for multiple reasons. I dunno. It's a separate issue. ]

It does actually shrink the kernel image a bit (a couple of hundred bytes
on the text segment for my everything-compiled-in image), and while it's
totally untested the (admittedly few) code generation points I looked at
seemed sane. And "lock orb" should be noticeably faster than "lock bts".

If somebody wants to play with it, go wild. I didn't do "change_bit()",
because nobody sane uses that thing anyway. I guarantee nothing. And if it
breaks, nobody saw me do anything.  You can't prove this email wasn't sent
by somebody who is good at forging smtp.

This does require a gcc that is recent enough for "__builtin_constant_p()"
to work in an inline function, but I suspect our kernel requirements are
already higher than that. And if you do have an old gcc that is supported,
the worst that would happen is that the optimization doesn't trigger.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

All (or most) other architectures do this.  So should x86.  Fix.

Cc: Andrea Arcangeli <andrea@qumranet.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  [CIFS] Fix reversed memset arguments
  Adds username in the upcall key for unattended mounts with keytab
  [CIFS] Remove redundant NULL check

Signed-off-by: NDave Jones <davej@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NIgor Mammedov <niallain@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  net: The world is not perfect patch.
  tcp: Make prior_ssthresh a u32
  xfrm_user: Remove zero length key checks.
  net/ipv4/arp.c: Use common hex_asc helpers
  cassini: Only use chip checksum for ipv4 packets.
  tcp: TCP connection times out if ICMP frag needed is delayed
  netfilter: Move linux/types.h inclusions outside of #ifdef __KERNEL__
  af_key: Fix selector family initialization.
  libertas: Fix ethtool statistics
  mac80211: fix NULL pointer dereference in ieee80211_compatible_rates
  mac80211: don't claim iwspy support
  orinoco_cs: add ID for SpeedStream wireless adapters
  hostap_cs: add ID for Conceptronic CON11CPro
  rtl8187: resource leak in error case
  ath5k: Fix loop variable initializations

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
  sparc64: Prevent stack backtrace false positives on trap frames.
  sparc64: Fix stack tracing through trap frames.
  sparc64: Fix kernel thread stack termination.
  sunhv: Fix locking in non-paged I/O case.

When we fully commit to returning back to kernel mode from
a trap, zero out the regs->magic value to prevent false
positives during stack backtraces.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Noticed by Coverity checker.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The offset to the pt_regs area was wrong, so we weren't
looking at the right location for the magic cookie.

A trap frame is composed of a "struct sparc_stackf" then
a "struct pt_regs", the code was using "struct reg_window"
instead of "struct sparc_stackf".
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because of the silly way I set up the initial stack for
new kernel threads, there is a loop at the top of the
stack.

To fix this, properly add another stack frame that is copied
from the parent and terminate it in the child by setting
the frame pointer in that frame to zero.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

  Unless there will be any objection here, I suggest consider the
following patch which simply removes the code for the
-DI_WISH_WORLD_WERE_PERFECT in the three methods which use it.

The compilation errors we get when using -DI_WISH_WORLD_WERE_PERFECT
show that this code was not built and not used for really a long time.
Signed-off-by: NRami Rosen <ramirose@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If previous window was above representable values of u16,
strange things will happen if undo with the truncated value
is called for. Alternatively, this could be fixed by some
max trickery but that would limit undoing high-speed undos.

Adds 16-bit hole but there isn't anything to fill it with.
Signed-off-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The crypto layer will determine whether that is valid
or not.

Suggested by Herbert Xu, based upon a report and patch
by Martin Willi.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>

Here the local hexbuf is a duplicate of global const char hex_asc from
lib/hexdump.c, except the hex letters' cases:

	const char hexbuf[] = "0123456789ABCDEF";

	const char hex_asc[] = "0123456789abcdef";

and here to print HW addresses, the hex cases are not significant.

Thanks to Harvey Harrison to introduce the hex_asc_hi/hex_asc_lo helpers.
Signed-off-by: NDenis Cheng <crquan@gmail.com>
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

According to David Monro, at least with Natsemi Saturn chips the
cassini driver has some trouble with ipv6 checksums.

Until we have more information about what's going on here, only
use the chip checksums for ipv4.

This workaround was suggested and tested by David.

Update version and release date.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

driver uses symbols defined only on ARM
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Whether we sidestep it in init/main.c or not, such situations
will arise again; compiler does generate calls of strcat()
on optimizations, so we really ought to have an out-of-line
version...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

... and we have few enough places using the latter to make it
simpler to do search and replace...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memcpy() from userland pointer is a Bad Thing(tm)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fallout from commit 46d7b522 ("uml: move
hppfs_kern.c to hppfs.c")
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We want sys/ptrace.h before any includes of linux/ptrace.h and
asm/user.h pulls the latter.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We are seeing an issue with TCP in handling an ICMP frag needed
message that is received after net.ipv4.tcp_retries1 retransmits.
The default value of retries1 is 3. So if the path mtu changes
and ICMP frag needed is lost for the first 3 retransmits or if
it gets delayed until 3 retransmits are done, TCP doesn't update
MSS correctly and continues to retransmit the orginal message
until it timesout after tcp_retries2 retransmits.

I am seeing this issue even with the latest 2.6.25.4 kernel.

In tcp_retransmit_timer(), when retransmits counter exceeds 
tcp_retries1 value, the dst cache entry of the socket is reset.
At this time, if we receive an ICMP frag needed message, the 
dst entry gets updated with the new MTU, but the TCP sockets
dst_cache entry remains NULL.

So the next time when we try to retransmit after the ICMP frag
needed is received, tcp_retransmit_skb() gets called. Here the
cur_mss value is calculated at the start of the routine with
a NULL sk_dst_cache. Instead we should call tcp_current_mss after
the rebuild_header that caches the dst entry with the updated mtu.
Also the rebuild_header should be called before tcp_fragment
so that skb is fragmented if the mss goes down.
Signed-off-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Greg Steuck <greg@nest.cx> points out that some of the netfilter
headers can't be used in userspace without including linux/types.h
first. The headers include their own linux/types.h include statements,
these are stripped by make headers-install because they are inside
#ifdef __KERNEL__ however. Move them out to fix this.

Reported and Tested by Greg Steuck.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This propagates the xfrm_user fix made in commit
bcf0dda8 ("[XFRM]: xfrm_user: fix
selector family initialization")

Based upon a bug report from, and tested by, Alan Swanson.
Signed-off-by: NKazunori MIYAZAWA <kazunori@miyazawa.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This causes the lock to be taken twice, thus resulting in
a deadlock.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6: (21 commits)
  [CIFS] Remove debug statement
  Fix possible access to undefined memory region.
  [CIFS] Enable DFS support for Windows query path info
  [CIFS] Enable DFS support for Unix query path info
  [CIFS] add missing seq_printf to cifs_show_options for hard mount option
  [CIFS] add more complete mount options to cifs_show_options
  [CIFS] Add missing defines for DFS
  CIFSGetDFSRefer cleanup + dfs_referral_level_3 fixed to conform REFERRAL_V3 the MS-DFSC spec.
  Fixed DFS code to work with new 'build_path_from_dentry', that returns full path if share in the dfs, now.
  [CIFS] enable parsing for transport encryption mount parm
  [CIFS] Finishup DFS code
  [CIFS] BKL-removal: convert CIFS over to unlocked_ioctl
  [CIFS] suppress duplicate warning
  [CIFS] Fix paths when share is in DFS to include proper prefix
  add function to convert access flags to legacy open mode
  clarify return value of cifs_convert_flags()
  [CIFS] don't explicitly do a FindClose on rewind when directory search has ended
  [CIFS] cleanup old checkpatch warnings
  [CIFS] CIFSSMBPosixLock should return -EINVAL on error
  fix memory leak in CIFSFindNext
  ...

Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NIgor Mammedov <niallain@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>