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The commit c5dec1c3

 introduced
__bio_copy_iov() to add bounce support to blk_rq_map_user_iov.

__bio_copy_iov() uses bio->bv_len to copy data for READ commands after
the completion but it doesn't work with a request that partially
completed. SCSI always completes a PC request as a whole but seems
some don't.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

The commit 68154e90

 introduced
bio_copy_kern() to add bounce support to blk_rq_map_kern.

bio_copy_kern() uses bio->bv_len to copy data for READ commands after
the completion but it doesn't work with a request that partially
completed. SCSI always completes a PC request as a whole but seems
some don't.

This patch fixes bio_copy_kern to handle the above case. As
bio_copy_user does, bio_copy_kern uses struct bio_map_data to store
struct bio_vec.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Reported-by: Nix <nix@esperi.org.uk>
Tested-by: Nix <nix@esperi.org.uk>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Since introduced in 7ba1ba12

, it should be made use of.
Signed-off-by: Denis ChengRq <crquan@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Use get_user_pages_fast in the common/generic block and fs direct IO paths.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When devices are stacked, one device's merge_bvec_fn may need to perform
the mapping and then call one or more functions for its underlying devices.

The following bio fields are used:
  bio->bi_sector
  bio->bi_bdev
  bio->bi_size
  bio->bi_rw  using bio_data_dir()

This patch creates a new struct bvec_merge_data holding a copy of those
fields to avoid having to change them directly in the struct bio when
going down the stack only to have to change them back again on the way
back up.  (And then when the bio gets mapped for real, the whole
exercise gets repeated, but that's a problem for another day...)
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Milan Broz <mbroz@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.

This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.

See Documentation/block/data-integrity.txt for more information.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Move struct bio_set and biovec_slab definitions to bio.h so they can
be used outside of bio.c.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Fix fs/bio.c kernel-doc parameter warning:
Warning(linux-2.6.25-git14//fs/bio.c:972): No description found for parameter 'reading'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Better than setting idx to some random value and it silences the
same bogus gcc warning.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This patch adds bio_copy_kern similar to
bio_copy_user. blk_rq_map_kern uses bio_copy_kern instead of
bio_map_kern if necessary.

bio_copy_kern uses temporary pages and the bi_end_io callback frees
these pages. bio_copy_kern saves the original kernel buffer at
bio->bi_private it doesn't use something like struct bio_map_data to
store the information about the caller.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This patch enables bio_copy_user to take struct sg_iovec (renamed
bio_copy_user_iov). bio_copy_user uses bio_copy_user_iov internally as
bio_map_user uses bio_map_user_iov.

The major changes are:

- adds sg_iovec array to struct bio_map_data

- adds __bio_copy_iov that copy data between bio and
sg_iovec. bio_copy_user_iov and bio_uncopy_user use it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Outside users like asmlib uses the mapping functions. API wise, the
export is definitely sane. It's a better idea to keep this export
than to require external users to open-code this piece of code instead.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Commit b2e895db

 #if 0'ed this code stating:

<--  snip  -->

    [PATCH] revert blockdev direct io back to 2.6.19 version

    Andrew Vasquez is reporting as-iosched oopses and a 65% throughput
    slowdown due to the recent special-casing of direct-io against
    blockdevs.  We don't know why either of these things are occurring.

    The patch minimally reverts us back to the 2.6.19 code for a 2.6.20
    release.

<--  snip  -->

It has since been dead code, and unless someone wants to revive it now
it's time to remove it.

This patch also makes bio_release_pages() static again and removes the
ki_bio_count member from struct kiocb, reverting changes that had been
done for this dead code.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>

If the users sets a new ->bi_bdev on the bio after __bio_clone() has
returned it, the "segment counts valid" flag still remains even though
it may be different with the new target. So don't calculate segment
counts in __bio_clone().
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

The empty barrier patches do not carry data, so they have no
iovec attached.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Use memset() to clear the bio, instead of doing each field manually.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

The only caller of bio_endio that does not pass the full bi_size
is end_that_request_first.  Also, no ->bi_end_io method is really
interested in bi_size being decremented.

So move the decrement and related code into ll_rw_blk and merge it
with order_bio_endio to form req_bio_endio which does endio functionality
specific to request completion.

As some ->bi_end_io methods do check bi_size of 0, we set it thus for
now, but that will go in the next patch.
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./block/ll_rw_blk.c |   42 +++++++++++++++++++++++++++---------------
 ./fs/bio.c          |   23 +++++++++++------------
 2 files changed, 38 insertions(+), 27 deletions(-)

diff .prev/block/ll_rw_blk.c ./block/ll_rw_blk.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Currently bi_end_io can be called multiple times as sub-requests
complete.  However no ->bi_end_io function wants to know about that.
So only call when the bio is complete.
Signed-off-by: Neil Brown <neilb@suse.de>

### Diffstat output
 ./fs/bio.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff .prev/fs/bio.c ./fs/bio.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Slab destructors were no longer supported after Christoph's
c59def9f

 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

bio_{,un}map_user no longer have any modular users.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

This patch provides a new macro

KMEM_CACHE(<struct>, <flags>)

to simplify slab creation. KMEM_CACHE creates a slab with the name of the
struct, with the size of the struct and with the alignment of the struct.
Additional slab flags may be specified if necessary.

Example

struct test_slab {
	int a,b,c;
	struct list_head;
} __cacheline_aligned_in_smp;

test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC)

will create a new slab named "test_slab" of the size sizeof(struct
test_slab) and aligned to the alignment of test slab.  If it fails then we
panic.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently we scale the mempool sizes depending on memory installed
in the machine, except for the bio pool itself which sits at a fixed
256 entry pre-allocation.

There's really no point in "optimizing" this OOM path, we just need
enough preallocated to make progress. A single unit is enough, lets
scale it down to 2 just to be on the safe side.

This patch saves ~150kb of pinned kernel memory on a 32-bit box.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Implement block device specific .direct_IO method instead of going through
generic direct_io_worker for block device.

direct_io_worker() is fairly complex because it needs to handle O_DIRECT on
file system, where it needs to perform block allocation, hole detection,
extents file on write, and tons of other corner cases.  The end result is
that it takes tons of CPU time to submit an I/O.

For block device, the block allocation is much simpler and a tight triple
loop can be written to iterate each iovec and each page within the iovec in
order to construct/prepare bio structure and then subsequently submit it to
the block layer.  This significantly speeds up O_D on block device.

[akpm@osdl.org: small speedup]
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Replace all uses of kmem_cache_t with struct kmem_cache.

The patch was generated using the following script:

	#!/bin/sh
	#
	# Replace one string by another in all the kernel sources.
	#

	set -e

	for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
		quilt add $file
		sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
		mv /tmp/$$ $file
		quilt refresh
	done

The script was run like this

	sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

This patch modifies blk_rq_map/unmap_user() and the cdrom and scsi_ioctl.c
users so that it supports requests larger than bio by chaining them together.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

The target mode support is mapping in bios using bio_map_user. The
current targets do not need their len to be aligned with a queue limit
so this check is causing some problems. Note: pointers passed into the
kernel are properly aligned by usersapace tgt code so the uaddr check
in bio_map_user is ok.

The major user, blk_bio_map_user checks for the len before mapping
so it is not affected by this patch.

And the semi-newly added user blk_rq_map_user_iov has been failing
out when the len is not aligned properly so maybe people have been
good and not sending misaligned lens or that path is not used very
often and this change will not be very dangerous. st and sg do not
check the length and we have not seen any problem reports from those
wider used paths so this patch should be fairly safe - for mm
and wider testing at least.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

Pass the work_struct pointer to the work function rather than context data.
The work function can use container_of() to work out the data.

For the cases where the container of the work_struct may go away the moment the
pending bit is cleared, it is made possible to defer the release of the
structure by deferring the clearing of the pending bit.

To make this work, an extra flag is introduced into the management side of the
work_struct.  This governs auto-release of the structure upon execution.

Ordinarily, the work queue executor would release the work_struct for further
scheduling or deallocation by clearing the pending bit prior to jumping to the
work function.  This means that, unless the driver makes some guarantee itself
that the work_struct won't go away, the work function may not access anything
else in the work_struct or its container lest they be deallocated..  This is a
problem if the auxiliary data is taken away (as done by the last patch).

However, if the pending bit is *not* cleared before jumping to the work
function, then the work function *may* access the work_struct and its container
with no problems.  But then the work function must itself release the
work_struct by calling work_release().

In most cases, automatic release is fine, so this is the default.  Special
initiators exist for the non-auto-release case (ending in _NAR).
Signed-Off-By: David Howells <dhowells@redhat.com>

- Calculate a variable in bvec_alloc_bs() only once needed, not earlier
  (bio.o down from 18408 to 18376 Bytes, 32 Bytes saved, probably due to
  data locality improvements).

- Init variable idx to silence a gcc warning which already existed in the
  unmodified original base file (bvec_alloc_bs() handles idx correctly, so
  there's no need for the warning):

	fs/bio.c: In function `bio_alloc_bioset':
	fs/bio.c:169: warning: `idx' may be used uninitialized in this function
Signed-off-by: Andreas Mohr <andi@lisas.de>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

As people often look for the copyright in files to see who to mail,
update the link to a neutral one.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

In the very low memory systems is in the init_bio call
scale parameter set to zero and it leads to creating
zero sized mempool.

This patch prevents pool_entries parameter become zero,
so the created pool have at least 1 entry.

Mempool with 0 entries lead to incorrect behaviour
of mempool_free. (Alloc requests are not waken up
and system stalls in mempool_alloc->ioschedule).
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If get_user_pages() returns less pages than what we asked for, we jump
to out_unmap which will return ERR_PTR(ret).  But ret can contain a
positive number just smaller than local_nr_pages, so be sure to set it
to -EFAULT always.

Problem found and diagnosed by Damien Le Moal <damien@sdl.hitachi.co.jp>
Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Else a subsequent bio_clone might make a mess.
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: "Don Dupuis" <dondster@gmail.com>
Acked-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Modify well over a dozen mempool users to call mempool_create_slab_pool()
rather than calling mempool_create() with extra arguments, saving about 30
lines of code and increasing readability.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

This patch changes several mempool users, all of which are basically just
wrappers around kmalloc(), to use the common mempool_kmalloc/kfree, rather
than their own wrapper function, removing a bunch of duplicated code.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

I discovered on oprofile hunting on a SMP platform that dentry lookups were
slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in
a cache line that contained inodes_stat.  So each time inodes_stats is
changed by a cpu, other cpus have to refill their cache line.

This patch moves some variables to the __read_mostly section, in order to
avoid false sharing.  RCU dentry lookups can go full speed.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Signed-off-by: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Signed-off-by: Jens Axboe <axboe@suse.de>

The biovec default mempool limit of 256 entries results in over 3MB of RAM
being permanently pinned, even on systems with only 128MB of RAM.  Since
mempool tries to allocate from the system pool first, it makes sense to
reduce the size of the mempool fallbacks to a more reasonable limit of 1-5
entries -- enough for the system to be able to make progress even under
load.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Acked-by: Jens Axboe <axboe@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>