We seperate the bio allocation (bio_alloc) from the bio submission so
that the error paths are much easier, and also so that the bio
submission can be done in one tight loop. It also makes the
plug/unplug calls much much easier.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

commit 7eaceacc ("block: remove per-queue plugging")
added two new interfaces to plug and unplug: blk_start_plug
and blk_finish_plug. Lets use those.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

+               sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;

WARNING: line over 80 characters
+               BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);

as breaking them up really does not help that much.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

checkpatch.pl suggested that we don't use the typdef in common.h
and this triggered this avalanche of patches.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The WRITE_BARRIER was missing the REQ_WRITE option. This
was causing the blktap to die.
Signed-off-by: NTom Goetz <tom.goetz@virtualcomputer.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The patch titled:"xen/blkback: Use 'vzalloc' for page arrays and pre-allocate pages."
allocates the structures and its member variables using the 'vzalloc'.

Daniel Stodden pointed out that vzalloc is good when we use
big number of pages - while these are at the max two pages.

We can do this using kzalloc. Also the GFP_HIGHMEM does not
work properly with Xen, so take that out.

We will have to revisit this when a "get_empty_pages_and_pagevec"
type API shows up to leverage that.

BugLink: http://mid.gmane.org/1299898639.11681.227.camel@agari.van.xensource.com

CC: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Instead of doing copy grants lets do mapping grants using
the M2P(and P2M) override mechanism.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Conflicts:

	drivers/xen/blkback/blkback.c

Previously we would allocate the array for page using 'kmalloc' which
we can as easily do with 'vzalloc'. The pre-allocation of pages
was done a bit differently in the past - it used to be that
the balloon driver would export "alloc_empty_pages_and_pagevec"
which would have in one function created an array, allocated
the pages, balloned the pages out (so the memory behind those
pages would be non-present), and provide us those pages.

This was OK as those pages were shared between other guest and
the only thing we needed was to "swizzel" the MFN of those pages
to point to the other guest MFN. We can still "swizzel" the MFNs
using the M2P (and P2M) override API calls, but for the sake of
simplicity we are dropping the balloon API calls. We can return
to those later on.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Following in the steps of patch:
"xen: Union the blkif_request request specific fields" this patch
changes the blkback. Per the original patch:

"Prepare for extending the block device ring to allow request
specific fields, by moving the request specific fields for
reads, writes and barrier requests to a union member."

Cc: Owen Smith <owen.smith@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Bundle the lot of discrete variables into a single structure.
This is based on what was done in the xen-netback driver:
xen: netback: Move global/static variables into struct xen_netbk.
(094944631cc5a9d6e623302c987f78117c0bf7ac)
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Cherry-pick and modified from 69d64727c42eecd47fdf82c15a54474d21a4012a
("blkback/blktap2: simplify address translations"):

"There are quite a number of places where e.g. page->va->page
translations happen.

Besides yielding smaller code (source and binary), a second goal is to
make it easier to determine where virtual addresses of pages allocated
through alloc_empty_pages_and_pagevec() are really used (in turn in
order to determine whether using highmem pages would be possible
there)."

The second goal is not the purpose of this patch - it is just to
make it easier to read the code.

linux-2.6-pvops:
 * Stripped drivers/xen/gntdev/*
 * Stripped drivers/xen/netback/*

[v2: Stripped blktap off]
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NDaniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The API for opening a block device has changed since 2.6.32. The
correct function to open a device is blkdev_get_by_dev.

TODO: Double check xen-blkfront.c

A guest can cause the backend driver to leak a kernel thread. Such
leaked threads hold references to the device, whichmakes the device
impossible to tear down. If shut down, the guest remains a zombie
domain, the xenwatch process hangs, and most xm commands will stop
working.

This patch tries to do the following for blkback:
    - identify/extract idempotent teardown operations,
    - add/move the invocation of said teardown operation
      right before we're about to allocate new resources in the
      Connected states.

[ linux-2.6.18-xen.hg 59f097ef181b ]
Signed-off-by: NLaszlo Ersek <lersek@redhat.com>
Signed-off-by: NKeir Fraser <keir@xen.org>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NK. Y. Srinivasan <ksrinivasan@novell.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

First cut at flushing blkback data when first connecting
blkback.  This should avoid the pygrub issues we are experiencing
in (RedHat bugzilla) 466681.

[ 2.6.18-xen.hg commit 63b4d7f56688 ]
Signed-off-by: NChris Lalancette <clalance@redhat.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Since backend_info is hidden away now.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Support dynamic resizing of virtual block devices. This patch supports
both file backed block devices as well as physical devices that can be
dynamically resized on the host side.
Signed-off-by: NK. Y. Srinivasan <ksrinivasan@novell.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Direct driver_data access is obsolete and will disappear.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

blkbk is rather generic for a modular distro style kernel.
Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

We neglect to check the return value of xenbus_register_backend
and take actions when that fails. This patch fixes that and adds
code to deal with those type of failures.
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Remove unused local prototype; group headers.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

It's a user-mode header for users of /dev/evtchn
Signed-off-by: NJeremy Fitzhardinge <jeremy@goop.org>

Signed-off-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Conflicts:

	drivers/xen/Makefile

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

These functions take irq_data as an argument and avoid a redundant
lookup in the sparse irq case.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Converted with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

These functions take irq_data as an argument and avoid a redundant
lookup in the sparse irq case.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Converted with coccinelle.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

We should unlock here and also decrement the number of &map->users.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

copy_to_user() returns the amount of data remaining to be copied.  We
want to return a negative error code here.  The upper layers just
call WARN_ON() if we return non-zero so this doesn't change the
behavior.  But returning -EFAULT is still cleaner.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Use PM_FREEZE, PM_THAW and PM_RESTORE power events for
suspend/resume/checkpoint functionality, instead of PM_SUSPEND
and PM_RESUME. Use of these pm events fixes the Xen Guest hangup
when taking checkpoints. When a suspend event is cancelled
(while taking checkpoints once/continuously), we use PM_THAW
instead of PM_RESUME. PM_RESTORE is used when suspend is not
cancelled. See Documentation/power/devices.txt and linux/pm.h
for more info about freeze, thaw and restore. The sequence of
pm events in a suspend-resume scenario is shown below.

        dpm_suspend_start(PMSG_FREEZE);

                dpm_suspend_noirq(PMSG_FREEZE);

                       sysdev_suspend(PMSG_FREEZE);
                       cancelled = suspend_hypercall()
                       sysdev_resume();

               dpm_resume_noirq(cancelled ? PMSG_THAW : PMSG_RESTORE);

       dpm_resume_end(cancelled ? PMSG_THAW : PMSG_RESTORE);
Acked-by: NIan Campbell <ian.campbell@citrix.com>
Signed-off-by: NShriram Rajagopalan <rshriram@cs.ubc.ca>
Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>