[PATCH] uml: revert block driver use of host AIO

The patch to use host AIO support that I submitted early after 2.6.13 exposed
some problems in the block driver. I have fixes for these, but am not

[PATCH] uml: revert block driver use of host AIO

The patch to use host AIO support that I submitted early after 2.6.13 exposed
some problems in the block driver. I have fixes for these, but am not
comfortable putting them into 2.6.14 at this late date. So, this patch reverts
the use of host AIO.

I will resubmit the original patch, plus fixes to the driver after 2.6.14
in order to get a reasonable amount of testing before they're exposed to
the general public.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: add host AIO support to block driver

This adds AIO support to the ubd driver.

The driver breaks a struct request into IO requests to the host, based on the
hardware segments in the req

[PATCH] uml: add host AIO support to block driver

This adds AIO support to the ubd driver.

The driver breaks a struct request into IO requests to the host, based on the
hardware segments in the request and on any COW blocks covered by the request.

The ubd IO thread is gone, since there is now an equivalent thread in the AIO
module.

There is provision for multiple outstanding requests now. Requests aren't
retired until all pieces of it have been completed. The AIO requests have a
shared count, which is decremented as IO operations come in until it reaches
0. This can be possibly moved to the request struct - haven't looked at this
yet.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: error path cleanup

This cleans up the error path in ubd_open, causing it now to call ubd_close
appropriately when something fails.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paol

[PATCH] uml: error path cleanup

This cleans up the error path in ubd_open, causing it now to call ubd_close
appropriately when something fails.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: hot-unplug code cleanup

Clean up the hot-unplugging code. There is now an id procedure which is
called to figure out what device we're talking to. The error messages from
that are now

[PATCH] uml: hot-unplug code cleanup

Clean up the hot-unplugging code. There is now an id procedure which is
called to figure out what device we're talking to. The error messages from
that are now done from mconsole_remove instead of the driver. remove is now
called with the device number, after it has been checked, so doesn't need to
do sanity checking on it.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: single-space a help message

One of the ubd driver help strings was bust.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus

[PATCH] uml: single-space a help message

One of the ubd driver help strings was bust.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: remove 2_5compat.h

Remove old useless header that was used in Ye Olde Times during 2.4->2.5
porting to abstract differences. It's definitions are no more used anyway, so
let's finally

[PATCH] uml: remove 2_5compat.h

Remove old useless header that was used in Ye Olde Times during 2.4->2.5
porting to abstract differences. It's definitions are no more used anyway, so
let's finally kill it.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml: Remove ubd-mmap support

Finally rip out the ubd-mmap code, which turned out to be broken by design.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: <viro@parcelfarce.linux.theplanet.c

[PATCH] uml: Remove ubd-mmap support

Finally rip out the ubd-mmap code, which turned out to be broken by design.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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[PATCH] uml ubd: handle readonly status

Use the set_disk_ro() API when the backing file is read-only, to mark the disk
read-only, during the ->open(). The current hack does not work when doing a
mo

[PATCH] uml ubd: handle readonly status

Use the set_disk_ro() API when the backing file is read-only, to mark the disk
read-only, during the ->open(). The current hack does not work when doing a
mount -o remount.

Also, mark explicitly the code paths which should no more be triggerable (I've
removed the WARN_ON(1) things). They should actually become BUG()s probably
but I'll avoid that since I'm not so sure the change works so well. I gave it
only some limited testing.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Jens Axboe <axboe@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

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Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

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um: ubd: Submit all data segments atomically

[ Upstream commit fc6b6a872dcd48c6f39c7975836d75113db67d37 ]

Internally, UBD treats each physical IO segment as a separate command to

um: ubd: Submit all data segments atomically

[ Upstream commit fc6b6a872dcd48c6f39c7975836d75113db67d37 ]

Internally, UBD treats each physical IO segment as a separate command to
be submitted in the execution pipe. If the pipe returns a transient
error after a few segments have already been written, UBD will tell the
block layer to requeue the request, but there is no way to reclaim the
segments already submitted. When a new attempt to dispatch the request
is done, those segments already submitted will get duplicated, causing
the WARN_ON below in the best case, and potentially data corruption.

In my system, running a UML instance with 2GB of RAM and a 50M UBD disk,
I can reproduce the WARN_ON by simply running mkfs.fvat against the
disk on a freshly booted system.

There are a few ways to around this, like reducing the pressure on
the pipe by reducing the queue depth, which almost eliminates the
occurrence of the problem, increasing the pipe buffer size on the host
system, or by limiting the request to one physical segment, which causes
the block layer to submit way more requests to resolve a single
operation.

Instead, this patch modifies the format of a UBD command, such that all
segments are sent through a single element in the communication pipe,
turning the command submission atomic from the point of view of the
block layer. The new format has a variable size, depending on the
number of elements, and looks like this:

+------------+-----------+-----------+------------
| cmd_header | segment 0 | segment 1 | segment ...
+------------+-----------+-----------+------------

With this format, we push a pointer to cmd_header in the submission
pipe.

This has the advantage of reducing the memory footprint of executing a
single request, since it allow us to merge some fields in the header.
It is possible to reduce even further each segment memory footprint, by
merging bitmap_words and cow_offset, for instance, but this is not the
focus of this patch and is left as future work. One issue with the
patch is that for a big number of segments, we now perform one big
memory allocation instead of multiple small ones, but I wasn't able to
trigger any real issues or -ENOMEM because of this change, that wouldn't
be reproduced otherwise.

This was tested using fio with the verify-crc32 option, and by running
an ext4 filesystem over this UBD device.

The original WARN_ON was:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at lib/refcount.c:28 refcount_warn_saturate+0x13f/0x141
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 5.5.0-rc6-00002-g2a5bb2cf75c8 #346
Stack:
6084eed0 6063dc77 00000009 6084ef60
00000000 604b8d9f 6084eee0 6063dcbc
6084ef40 6006ab8d e013d780 1c00000000
Call Trace:
[<600a0c1c>] ? printk+0x0/0x94
[<6004a888>] show_stack+0x13b/0x155
[<6063dc77>] ? dump_stack_print_info+0xdf/0xe8
[<604b8d9f>] ? refcount_warn_saturate+0x13f/0x141
[<6063dcbc>] dump_stack+0x2a/0x2c
[<6006ab8d>] __warn+0x107/0x134
[<6008da6c>] ? wake_up_process+0x17/0x19
[<60487628>] ? blk_queue_max_discard_sectors+0x0/0xd
[<6006b05f>] warn_slowpath_fmt+0xd1/0xdf
[<6006af8e>] ? warn_slowpath_fmt+0x0/0xdf
[<600acc14>] ? raw_read_seqcount_begin.constprop.0+0x0/0x15
[<600619ae>] ? os_nsecs+0x1d/0x2b
[<604b8d9f>] refcount_warn_saturate+0x13f/0x141
[<6048bc8f>] refcount_sub_and_test.constprop.0+0x2f/0x37
[<6048c8de>] blk_mq_free_request+0xf1/0x10d
[<6048ca06>] __blk_mq_end_request+0x10c/0x114
[<6005ac0f>] ubd_intr+0xb5/0x169
[<600a1a37>] __handle_irq_event_percpu+0x6b/0x17e
[<600a1b70>] handle_irq_event_percpu+0x26/0x69
[<600a1bd9>] handle_irq_event+0x26/0x34
[<600a1bb3>] ? handle_irq_event+0x0/0x34
[<600a5186>] ? unmask_irq+0x0/0x37
[<600a57e6>] handle_edge_irq+0xbc/0xd6
[<600a131a>] generic_handle_irq+0x21/0x29
[<60048f6e>] do_IRQ+0x39/0x54
[...]
---[ end trace c6e7444e55386c0f ]---

Cc: Christopher Obbard <chris.obbard@collabora.com>
Reported-by: Martyn Welch <martyn@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Tested-by: Christopher Obbard <chris.obbard@collabora.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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um: ubd: Retry buffer read on any kind of error

Should bulk_req_safe_read return an error, we want to retry the read,
otherwise, even though no IO will be done, os_write_file might still

um: ubd: Retry buffer read on any kind of error

Should bulk_req_safe_read return an error, we want to retry the read,
otherwise, even though no IO will be done, os_write_file might still end
up writing garbage to the pipe.

Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: ubd: Prevent buffer overrun on command completion

On the hypervisor side, when completing commands and the pipe is full,
we retry writing only the entries that failed, by offsetting

um: ubd: Prevent buffer overrun on command completion

On the hypervisor side, when completing commands and the pipe is full,
we retry writing only the entries that failed, by offsetting
io_req_buffer, but we don't reduce the number of bytes written, which
can cause a buffer overrun of io_req_buffer, and write garbage to the
pipe.

Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
"This series is slightly unusual because it includes Arnd's comp

Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
"This series is slightly unusual because it includes Arnd's compat
ioctl tree here:

1c46a2cf2dbd Merge tag 'block-ioctl-cleanup-5.6' into 5.6/scsi-queue

Excluding Arnd's changes, this is mostly an update of the usual
drivers: megaraid_sas, mpt3sas, qla2xxx, ufs, lpfc, hisi_sas.

There are a couple of core and base updates around error propagation
and atomicity in the attribute container base we use for the SCSI
transport classes.

The rest is minor changes and updates"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (149 commits)
scsi: hisi_sas: Rename hisi_sas_cq.pci_irq_mask
scsi: hisi_sas: Add prints for v3 hw interrupt converge and automatic affinity
scsi: hisi_sas: Modify the file permissions of trigger_dump to write only
scsi: hisi_sas: Replace magic number when handle channel interrupt
scsi: hisi_sas: replace spin_lock_irqsave/spin_unlock_restore with spin_lock/spin_unlock
scsi: hisi_sas: use threaded irq to process CQ interrupts
scsi: ufs: Use UFS device indicated maximum LU number
scsi: ufs: Add max_lu_supported in struct ufs_dev_info
scsi: ufs: Delete is_init_prefetch from struct ufs_hba
scsi: ufs: Inline two functions into their callers
scsi: ufs: Move ufshcd_get_max_pwr_mode() to ufshcd_device_params_init()
scsi: ufs: Split ufshcd_probe_hba() based on its called flow
scsi: ufs: Delete struct ufs_dev_desc
scsi: ufs: Fix ufshcd_probe_hba() reture value in case ufshcd_scsi_add_wlus() fails
scsi: ufs-mediatek: enable low-power mode for hibern8 state
scsi: ufs: export some functions for vendor usage
scsi: ufs-mediatek: add dbg_register_dump implementation
scsi: qla2xxx: Fix a NULL pointer dereference in an error path
scsi: qla1280: Make checking for 64bit support consistent
scsi: megaraid_sas: Update driver version to 07.713.01.00-rc1
...

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compat_ioctl: ubd, aoe: use blkdev_compat_ptr_ioctl

These drivers implement the HDIO_GET_IDENTITY and CDROMVOLREAD ioctl
commands, which are compatible between 32-bit and 64-bit user spa

compat_ioctl: ubd, aoe: use blkdev_compat_ptr_ioctl

These drivers implement the HDIO_GET_IDENTITY and CDROMVOLREAD ioctl
commands, which are compatible between 32-bit and 64-bit user space and
traditionally handled by compat_blkdev_driver_ioctl().

As a prerequisite to removing that function, make both drivers use
blkdev_compat_ptr_ioctl() as their .compat_ioctl callback.

Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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um: ubd: use 64-bit time_t where possible

The ubd code suffers from a possible y2038 overflow on 32-bit
architectures, both for the cow header and the os_file_modtime()
function.

um: ubd: use 64-bit time_t where possible

The ubd code suffers from a possible y2038 overflow on 32-bit
architectures, both for the cow header and the os_file_modtime()
function.

Replace time_t with time64_t to extend the ubd_kern side as much
as possible.

Whether this makes a difference for the user side depends on
the host libc implementation that may use either 32-bit or 64-bit
time_t.

For the cow file format, the header contains an unsigned 32-bit
timestamp, which is good until y2106, passing this through a
'long long' gives us a consistent interpretation between 32-bit
and 64-bit um kernels.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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um-ubd: Entrust re-queue to the upper layers

Fixes crashes due to ubd requeue logic conflicting with the block-mq
logic. Crash is reproducible in 5.0 - 5.3.

Fixes: 53766defb8c8

um-ubd: Entrust re-queue to the upper layers

Fixes crashes due to ubd requeue logic conflicting with the block-mq
logic. Crash is reproducible in 5.0 - 5.3.

Fixes: 53766defb8c8 ("um: Clean-up command processing in UML UBD driver")
Cc: stable@vger.kernel.org # v5.0+
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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um: Add SPDX headers for files in arch/um/drivers

Convert files to use SPDX header. All files are licensed under the GPLv2.

Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Sign

um: Add SPDX headers for files in arch/um/drivers

Convert files to use SPDX header. All files are licensed under the GPLv2.

Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Do not unlock mutex that is not hold.

Return error instead of trying to unlock a mutex that is not hold.

Signed-off-by: Daniel Walter <dwalter@google.com>
Reviewed-by: Anton

um: Do not unlock mutex that is not hold.

Return error instead of trying to unlock a mutex that is not hold.

Signed-off-by: Daniel Walter <dwalter@google.com>
Reviewed-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Fix for a possible OOPS in ubd initialization

If the ubd device failed to allocate a queue during
initialization it tried call blk_cleanup_queue resulting
in an oops.

Th

um: Fix for a possible OOPS in ubd initialization

If the ubd device failed to allocate a queue during
initialization it tried call blk_cleanup_queue resulting
in an oops.

This patch simplifies the cleanup logic and ensures that
blk_queue_cleanup is called only if there is a valid queue.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Remove obsolete reenable_XX calls

reenable_fd has been a NOP since the introduction of the EPOLL
based interrupt controller.
reenable_channel() is no longer needed as the flow co

um: Remove obsolete reenable_XX calls

reenable_fd has been a NOP since the introduction of the EPOLL
based interrupt controller.
reenable_channel() is no longer needed as the flow control is
now handled via the write IRQs on the channel.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Add support for DISCARD in the UBD Driver

Support for DISCARD and WRITE_ZEROES in the ubd driver using
fallocate.

DISCARD is enabled by default and can be disabled using a n

um: Add support for DISCARD in the UBD Driver

Support for DISCARD and WRITE_ZEROES in the ubd driver using
fallocate.

DISCARD is enabled by default and can be disabled using a new
UBD command line flag.

If the underlying fs on which the UBD image is stored does not
support DISCARD the support for both DISCARD and WRITE_ZEROES
is turned off.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Remove unsafe printks from the io thread

Printk out of the io thread has been proven to be unsafe. This
is not surprising as the thread is part of the UML hypervisor
code. It is

um: Remove unsafe printks from the io thread

Printk out of the io thread has been proven to be unsafe. This
is not surprising as the thread is part of the UML hypervisor
code. It is not supposed to invoke any kernel code/resources.

It is necesssary to pass the error to the block IO layer and let it

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Clean-up command processing in UML UBD driver

Clean-up command processing and return BLK_STS_NOTSUP for
uknown commands.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgeg

um: Clean-up command processing in UML UBD driver

Clean-up command processing and return BLK_STS_NOTSUP for
uknown commands.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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um: Switch to block-mq constants in the UML UBD driver

Switch to block mq-constants for both commands, error codes and
various computations.

Signed-off-by: Anton Ivanov <anton.i

um: Switch to block-mq constants in the UML UBD driver

Switch to block mq-constants for both commands, error codes and
various computations.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

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ubd: fix missing initialization of io_req

The SYNC path doesn't initialize io_req->error, which can cause
random errors. Before the conversion to blk-mq, we always
completed requests

ubd: fix missing initialization of io_req

The SYNC path doesn't initialize io_req->error, which can cause
random errors. Before the conversion to blk-mq, we always
completed requests with BLK_STS_OK status, but now we actually
look at the error field and this issue becomes apparent.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>

[axboe: fixed up commit message to explain what is actually going on]

Signed-off-by: Jens Axboe <axboe@kernel.dk>

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