debugobjects: Remove unused return value from fill_pool()

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
debugobjects: printk with irqs enabled

No point in keeping interrupts disabled here.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
debugobjects: Fill_pool() returns void now

There was a return missed in 1fda107d44 "debugobjects: Remove unused
return value from fill_pool()".  It makes gcc complain:

	lib/debugobjects.c: In function ‘fill_pool’:
	lib/debugobjects.c:98:4: warning: ‘return’ with a value, in
		function returning void [enabled by default]

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20120418112810.GA2669@elgon.mountain
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
GFS2: Drop "pull" argument from log_write_header()

The "pull" argument to log_write_header() is only used
for debug purposes and it is not really needed any more. There
are other tests for this particular problem, so I think we can
dispose of it in order to simplify the code.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Make gfs2_log_fake_buf() write the buffer too

Since we always write the buffer directly after this function
returns, we might as well merge it into here. This is a clean
up in preparation for some further updates to the log code
which are coming soon.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Rename function gfs2_close to gfs2_release

This patch renames function gfs2_close to gfs2_release.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: make function gfs2_page_add_databufs static

This patch makes function gfs2_page_add_databufs static.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Use slab for block reservation memory

This patch changes block reservations so it uses slab storage.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Eliminate offset parameter to gfs2_setbit

This patch eliminates a redundant parameter.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Fix function parameter comments in rgrp.c

This patch just fixes a bunch of function parameter comments.
Slowly, over the years, the comments have gotten out of date
(mostly my fault, as I haven't been good at keeping them up to date).
This patch rectifies some of that.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Change variable blk to biblk

In the resource group code, we have no less than three different
kinds of block references: block relative to the file system (u64),
block relative to the rgrp (u32), and block relative to the bitmap.
This is a small step to making the code more readable; it renames
variable blk to biblk to solidify in my mind that it's relative to
the bitmap and nothing else.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Use variable rather than qa to determine if unstuff necessary

In the future, the qadata structure will be eliminated and merged
back in with the block reservation structure, after we extend the
lifespan of that. This patch is a step forward in eliminating the
qadata structure. It adds a variable to the do_grow function to
determine when unstuffing is necessary, and has been done.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Clean up log write code path

Prior to this patch, we have two ways of sending i/o to the log.
One of those is used when we need to allocate both the data
to be written itself and also a buffer head to submit it. This
is done via sb_getblk and friends. This is used mostly for writing
log headers.

The other method is used when writing blocks which have some
in-place counterpart. This is the case for all the metadata
blocks which are journalled, and when journaled data is in use,
for unescaped journalled data blocks.

This patch replaces both of those two methods, and about half
a dozen separate i/o submission points with a single i/o
submission function. We also go direct to bio rather than
using buffer heads, since this allows us to build i/o
requests of the maximum size for the block device in
question. It also reduces the memory required for flushing
the log, which can be very useful in low memory situations.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Remove duplicate log code

The main part of this patch merges the two functions used to
write metadata and data buffers to the log. Most of the code
is common between the two functions, so this provides a nice
clean up, and makes the code more readable.

The gfs2_get_log_desc() function is also extended to take two more
arguments, and thus avoid having to set the length and data1
fields of this strucuture as a separate operation.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Remove bd_list_tr

This is another clean up in the logging code. This per-transaction
list was largely unused. Its main function was to ensure that the
number of buffers in a transaction was correct, however that counter
was only used to check the number of buffers in the bd_list_tr, plus
an assert at the end of each transaction. With the assert now changed
to use the calculated buffer counts, we can remove both bd_list_tr and
its associated counter.

This should make the code easier to understand as well as shrinking
a couple of structures.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Remove unused argument from gfs2_internal_read

gfs2_internal_read accepts an unused ra_state argument, left over from
when we did readahead on the rindex. Since there are currently no plans
to add back this readahead, this patch removes the ra_state parameter
and updates the functions which call gfs2_internal_read accordingly.

Signed-off-by: Andrew Price <anprice@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
GFS2: Log code fixes

This patch removes a log lock from around atomic operation where
it is not needed, removes an unused variable, and also changes
a void pointer used incorrectly to a struct page pointer.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
rcu: List-debug variants of rcu list routines.

* Make __list_add_rcu check the next->prev and prev->next pointers
  just like __list_add does.
* Make list_del_rcu use __list_del_entry, which does the same checking
  at deletion time.

Has been running for a week here without anything being tripped up,
but it seems worth adding for completeness just in case something
ever does corrupt those lists.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu: Replace list_first_entry_rcu() with list_first_or_null_rcu()

The list_first_entry_rcu() macro is inherently unsafe because it cannot
be applied to an empty list.  But because RCU readers do not exclude
updaters, a list might become empty between the time that list_empty()
claimed it was non-empty and the time that list_first_entry_rcu() is
invoked.  Therefore, the list_empty() test cannot be separated from the
list_first_entry_rcu() call.  This commit therefore combines these to
macros to create a new list_first_or_null_rcu() macro that replaces
the old (and unsafe) list_first_entry_rcu() macro.

This patch incorporates Paul's review comments on the previous version of
this patch available here:

https://lkml.org/lkml/2012/4/2/536

This patch cannot break any upstream code because list_first_entry_rcu()
is not being used anywhere in the kernel (tested with grep(1)), and any
external code using it is probably broken as a result of using it.

Signed-off-by: Michel Machado <michel@digirati.com.br>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Dipankar Sarma <dipankar@in.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
rcu: Clarify help text for RCU_BOOST_PRIO

The old text confused real-time applications with real-time threads, so
that you pretty much needed to understand how this kernel configuration
parameter worked to understand the help text.  This commit therefore
attempts to make the help text human-readable.

Reported-by: Jörn Engel <joern@purestorage.com>
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>