linux.git/net/dccp, branch v2.6.33

dccp: fix auto-loading of dccp(_probe)

2010-02-04T03:00:31+00:00

This fixes commit (38ff3e6bb987ec583268da8eb22628293095d43b) ("dccp_probe:
Fix module load dependencies between dccp and dccp_probe", from 15 Jan).

It fixes the construction of the first argument of try_then_request_module(),
where only valid return codes from the first argument should be returned.

What we do now is assign the result of register_jprobe() to ret, without
the side effect of the comparison.

Acked-by: Gerrit Renker 
Signed-off-by: Neil Horman 
Signed-off-by: David S. Miller

dccp: fix bug in cache allocation

2010-02-04T03:00:30+00:00

This fixes a bug introduced in commit de4ef86cfce60d2250111f34f8a084e769f23b16
("dccp: fix dccp rmmod when kernel configured to use slub", 17 Jan): the
vsnprintf used sizeof(slab_name_fmt), which became truncated to 4 bytes, since
slab_name_fmt is now a 4-byte pointer and no longer a 32-character array.

This lead to error messages such as
 FATAL: Error inserting dccp: No buffer space available

 >> kernel: [ 1456.341501] kmem_cache_create: duplicate cache cci
generated due to the truncation after the 3rd character.

Fixed for the moment by introducing a symbolic constant. Tested to fix the bug.

Signed-off-by: Gerrit Renker 
Acked-by: Neil Horman 
Signed-off-by: David S. Miller

Merge branch 'master' of /home/davem/src/GIT/linux-2.6/

2010-01-23T06:45:46+00:00

dccp: fix dccp rmmod when kernel configured to use slub

2010-01-19T09:59:01+00:00

Hey all-
	I was tinkering with dccp recently and noticed that I BUG halted the
kernel when I rmmod-ed the dccp module.  The bug halt occured because the page
that I passed to kfree failed the PageCompound and PageSlab test in the slub
implementation of kfree.  I tracked the problem down to the following set of
events:

1) dccp, unlike all other uses of kmem_cache_create, allocates a string
dynamically when registering a slab cache.  This allocated string is freed when
the cache is destroyed.

2) Normally, (1) is not an issue, but when Slub is in use, it is possible that
caches are 'merged'.  This process causes multiple caches of simmilar
configuration to use the same cache data structure.  When this happens, the new
name of the cache is effectively dropped.

3) (2) results in kmem_cache_name returning an ambigous value (i.e.
ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer
for freeing), is no longer guaranteed that the string it assigned is what is
returned.

4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer,
which trips over the BUG in the slub implementation of kfree (since its likely
not a slab allocation, but rather a pointer into the static string table
section.

So, what to do about this.  At first blush this is pretty clearly a leak in the
information that slub owns, and as such a slub bug.  Unfortunately, theres no
really good way to fix it, without exposing slub specific implementation details
to the generic slab interface.  Also, even if we could fix this in slub cleanly,
I think the RCU free option would force us to do lots of string duplication, not
only in slub, but in every slab allocator.  As such, I'd like to propose this
solution.  Basically, I just move the storage for the kmem cache name to the
ccid_operations structure.  In so doing, we don't have to do the kstrdup or
kfree when we allocate/free the various caches for dccp, and so we avoid the
problem, by storing names with static memory, rather than heap, the way all
other calls to kmem_cache_create do.

I've tested this out myself here, and it solves the problem quite well.

Signed-off-by: Neil Horman 
Acked-by: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller

dccp_probe: Fix module load dependencies between dccp and dccp_probe

2010-01-15T09:40:55+00:00

This was just recently reported to me.  When built as modules, the
dccp_probe module has a silent dependency on the dccp module.  This
stems from the fact that the module_init routine of dccp_probe
registers a jprobe on the dccp_sendmsg symbol.  Since the symbol is
only referenced as a text string (the .symbol_name field in the jprobe
struct) rather than the address of the symbol itself, depmod never
picks this dependency up, and so if you load the dccp_probe module
without the dccp module loaded, the register_jprobe call fails with an
-EINVAL, and the whole module load fails.

The fix is pretty easy, we can just wrap the register_jprobe call in a
try_then_request_module call, which forces the dependency to get
satisfied prior to the probe registration.

Signed-off-by: Neil Horman 
Acked-by: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller

kfifo: rename kfifo_put... into kfifo_in... and kfifo_get... into kfifo_out...

2009-12-22T22:17:56+00:00

rename kfifo_put...  into kfifo_in...  to prevent miss use of old non in
kernel-tree drivers

ditto for kfifo_get...  -> kfifo_out...

Improve the prototypes of kfifo_in and kfifo_out to make the kerneldoc
annotations more readable.

Add mini "howto porting to the new API" in kfifo.h

Signed-off-by: Stefani Seibold 
Acked-by: Greg Kroah-Hartman 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Andi Kleen 
Acked-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: cleanup namespace

2009-12-22T22:17:56+00:00

change name of __kfifo_* functions to kfifo_*, because the prefix __kfifo
should be reserved for internal functions only.

Signed-off-by: Stefani Seibold 
Acked-by: Greg Kroah-Hartman 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Andi Kleen 
Acked-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: move out spinlock

2009-12-22T22:17:56+00:00

Move the pointer to the spinlock out of struct kfifo.  Most users in
tree do not actually use a spinlock, so the few exceptions now have to
call kfifo_{get,put}_locked, which takes an extra argument to a
spinlock.

Signed-off-by: Stefani Seibold 
Acked-by: Greg Kroah-Hartman 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Andi Kleen 
Acked-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kfifo: move struct kfifo in place

2009-12-22T22:17:55+00:00

This is a new generic kernel FIFO implementation.

The current kernel fifo API is not very widely used, because it has to
many constrains.  Only 17 files in the current 2.6.31-rc5 used it.
FIFO's are like list's a very basic thing and a kfifo API which handles
the most use case would save a lot of development time and memory
resources.

I think this are the reasons why kfifo is not in use:

 - The API is to simple, important functions are missing
 - A fifo can be only allocated dynamically
 - There is a requirement of a spinlock whether you need it or not
 - There is no support for data records inside a fifo

So I decided to extend the kfifo in a more generic way without blowing up
the API to much.  The new API has the following benefits:

 - Generic usage: For kernel internal use and/or device driver.
 - Provide an API for the most use case.
 - Slim API: The whole API provides 25 functions.
 - Linux style habit.
 - DECLARE_KFIFO, DEFINE_KFIFO and INIT_KFIFO Macros
 - Direct copy_to_user from the fifo and copy_from_user into the fifo.
 - The kfifo itself is an in place member of the using data structure, this save an
   indirection access and does not waste the kernel allocator.
 - Lockless access: if only one reader and one writer is active on the fifo,
   which is the common use case, no additional locking is necessary.
 - Remove spinlock - give the user the freedom of choice what kind of locking to use if
   one is required.
 - Ability to handle records. Three type of records are supported:
   - Variable length records between 0-255 bytes, with a record size
     field of 1 bytes.
   - Variable length records between 0-65535 bytes, with a record size
     field of 2 bytes.
   - Fixed size records, which no record size field.
 - Preserve memory resource.
 - Performance!
 - Easy to use!

This patch:

Since most users want to have the kfifo as part of another object,
reorganize the code to allow including struct kfifo in another data
structure.  This requires changing the kfifo_alloc and kfifo_init
prototypes so that we pass an existing kfifo pointer into them.  This
patch changes the implementation and all existing users.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: Stefani Seibold 
Acked-by: Greg Kroah-Hartman 
Acked-by: Mauro Carvalho Chehab 
Acked-by: Andi Kleen 
Acked-by: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

tcp: Fix a connect() race with timewait sockets

2009-12-09T04:17:51+00:00

First patch changes __inet_hash_nolisten() and __inet6_hash()
to get a timewait parameter to be able to unhash it from ehash
at same time the new socket is inserted in hash.

This makes sure timewait socket wont be found by a concurrent
writer in __inet_check_established()

Reported-by: kapil dakhane 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller