Commit Graph

376 Commits

Author SHA1 Message Date
Paul Mackerras
5975a2e095 KVM: PPC: Book3S: Add API for in-kernel XICS emulation
This adds the API for userspace to instantiate an XICS device in a VM
and connect VCPUs to it.  The API consists of a new device type for
the KVM_CREATE_DEVICE ioctl, a new capability KVM_CAP_IRQ_XICS, which
functions similarly to KVM_CAP_IRQ_MPIC, and the KVM_IRQ_LINE ioctl,
which is used to assert and deassert interrupt inputs of the XICS.

The XICS device has one attribute group, KVM_DEV_XICS_GRP_SOURCES.
Each attribute within this group corresponds to the state of one
interrupt source.  The attribute number is the same as the interrupt
source number.

This does not support irq routing or irqfd yet.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-05-02 15:28:36 +02:00
Alex Williamson
2a5bab1004 kvm: Allow build-time configuration of KVM device assignment
We hope to at some point deprecate KVM legacy device assignment in
favor of VFIO-based assignment.  Towards that end, allow legacy
device assignment to be deconfigured.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
2013-04-28 12:58:56 +03:00
Michael Ellerman
8e591cb720 KVM: PPC: Book3S: Add infrastructure to implement kernel-side RTAS calls
For pseries machine emulation, in order to move the interrupt
controller code to the kernel, we need to intercept some RTAS
calls in the kernel itself.  This adds an infrastructure to allow
in-kernel handlers to be registered for RTAS services by name.
A new ioctl, KVM_PPC_RTAS_DEFINE_TOKEN, then allows userspace to
associate token values with those service names.  Then, when the
guest requests an RTAS service with one of those token values, it
will be handled by the relevant in-kernel handler rather than being
passed up to userspace as at present.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix warning]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:29 +02:00
Scott Wood
eb1e4f43e0 kvm/ppc/mpic: add KVM_CAP_IRQ_MPIC
Enabling this capability connects the vcpu to the designated in-kernel
MPIC.  Using explicit connections between vcpus and irqchips allows
for flexibility, but the main benefit at the moment is that it
simplifies the code -- KVM doesn't need vm-global state to remember
which MPIC object is associated with this vm, and it doesn't need to
care about ordering between irqchip creation and vcpu creation.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: add stub functions for kvmppc_mpic_{dis,}connect_vcpu]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:24 +02:00
Scott Wood
5df554ad5b kvm/ppc/mpic: in-kernel MPIC emulation
Hook the MPIC code up to the KVM interfaces, add locking, etc.

Signed-off-by: Scott Wood <scottwood@freescale.com>
[agraf: add stub function for kvmppc_mpic_set_epr, non-booke, 64bit]
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:23 +02:00
Scott Wood
852b6d57dc kvm: add device control API
Currently, devices that are emulated inside KVM are configured in a
hardcoded manner based on an assumption that any given architecture
only has one way to do it.  If there's any need to access device state,
it is done through inflexible one-purpose-only IOCTLs (e.g.
KVM_GET/SET_LAPIC).  Defining new IOCTLs for every little thing is
cumbersome and depletes a limited numberspace.

This API provides a mechanism to instantiate a device of a certain
type, returning an ID that can be used to set/get attributes of the
device.  Attributes may include configuration parameters (e.g.
register base address), device state, operational commands, etc.  It
is similar to the ONE_REG API, except that it acts on devices rather
than vcpus.

Both device types and individual attributes can be tested without having
to create the device or get/set the attribute, without the need for
separately managing enumerated capabilities.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
2013-04-26 20:27:20 +02:00
Alexander Graf
948a902c84 KVM: Drop __KVM_HAVE_IOAPIC condition on irq routing
We have a capability enquire system that allows user space to ask kvm
whether a feature is available.

The point behind this system is that we can have different kernel
configurations with different capabilities and user space can adjust
accordingly.

Because features can always be non existent, we can drop any #ifdefs
on CAP defines that could be used generically, like the irq routing
bits. These can be easily reused for non-IOAPIC systems as well.

Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
2013-04-26 20:27:15 +02:00
Marcelo Tosatti
2ae33b3896 Merge remote-tracking branch 'upstream/master' into queue
Merge reason:

From: Alexander Graf <agraf@suse.de>

"Just recently this really important patch got pulled into Linus' tree for 3.9:

commit 1674400aae
Author: Anton Blanchard <anton <at> samba.org>
Date:   Tue Mar 12 01:51:51 2013 +0000

Without that commit, I can not boot my G5, thus I can't run automated tests on it against my queue.

Could you please merge kvm/next against linus/master, so that I can base my trees against that?"

* upstream/master: (653 commits)
  PCI: Use ROM images from firmware only if no other ROM source available
  sparc: remove unused "config BITS"
  sparc: delete "if !ULTRA_HAS_POPULATION_COUNT"
  KVM: Fix bounds checking in ioapic indirect register reads (CVE-2013-1798)
  KVM: x86: Convert MSR_KVM_SYSTEM_TIME to use gfn_to_hva_cache functions (CVE-2013-1797)
  KVM: x86: fix for buffer overflow in handling of MSR_KVM_SYSTEM_TIME (CVE-2013-1796)
  arm64: Kconfig.debug: Remove unused CONFIG_DEBUG_ERRORS
  arm64: Do not select GENERIC_HARDIRQS_NO_DEPRECATED
  inet: limit length of fragment queue hash table bucket lists
  qeth: Fix scatter-gather regression
  qeth: Fix invalid router settings handling
  qeth: delay feature trace
  sgy-cts1000: Remove __dev* attributes
  KVM: x86: fix deadlock in clock-in-progress request handling
  KVM: allow host header to be included even for !CONFIG_KVM
  hwmon: (lm75) Fix tcn75 prefix
  hwmon: (lm75.h) Update header inclusion
  MAINTAINERS: Remove Mark M. Hoffman
  xfs: ensure we capture IO errors correctly
  xfs: fix xfs_iomap_eof_prealloc_initial_size type
  ...

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-03-21 11:11:52 -03:00
Linus Torvalds
842d223f28 Merge branch 'akpm' (fixes from Andrew)
Merge misc fixes from Andrew Morton:

 - A bunch of fixes

 - Finish off the idr API conversions before someone starts to use the
   old interfaces again.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  idr: idr_alloc() shouldn't trigger lowmem warning when preloaded
  UAPI: fix endianness conditionals in M32R's asm/stat.h
  UAPI: fix endianness conditionals in linux/raid/md_p.h
  UAPI: fix endianness conditionals in linux/acct.h
  UAPI: fix endianness conditionals in linux/aio_abi.h
  decompressors: fix typo "POWERPC"
  mm/fremap.c: fix oops on error path
  idr: deprecate idr_pre_get() and idr_get_new[_above]()
  tidspbridge: convert to idr_alloc()
  zcache: convert to idr_alloc()
  mlx4: remove leftover idr_pre_get() call
  workqueue: convert to idr_alloc()
  nfsd: convert to idr_alloc()
  nfsd: remove unused get_new_stid()
  kernel/signal.c: use __ARCH_HAS_SA_RESTORER instead of SA_RESTORER
  signal: always clear sa_restorer on execve
  mm: remove_memory(): fix end_pfn setting
  include/linux/res_counter.h needs errno.h
2013-03-13 15:21:57 -07:00
David Howells
ca044f9a9e UAPI: fix endianness conditionals in linux/raid/md_p.h
In the UAPI header files, __BIG_ENDIAN and __LITTLE_ENDIAN must be
compared against __BYTE_ORDER in preprocessor conditionals where these are
exposed to userspace (that is they're not inside __KERNEL__ conditionals).

However, in the main kernel the norm is to check for
"defined(__XXX_ENDIAN)" rather than comparing against __BYTE_ORDER and
this has incorrectly leaked into the userspace headers.

The definition of struct mdp_superblock_s in linux/raid/md_p.h is wrong in
this way.  Note that userspace will likely interpret the ordering of the
fields incorrectly as the big-endian variant on a little-endian machines -
depending on header inclusion order.

[!!!] NOTE [!!!]  This patch may adversely change the userspace API.  It might
be better to fix the ordering of events_hi, events_lo, cp_events_hi and
cp_events_lo in struct mdp_superblock_s / typedef mdp_super_t.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:49 -07:00
David Howells
29ba06b9ed UAPI: fix endianness conditionals in linux/acct.h
In the UAPI header files, __BIG_ENDIAN and __LITTLE_ENDIAN must be
compared against __BYTE_ORDER in preprocessor conditionals where these are
exposed to userspace (that is they're not inside __KERNEL__ conditionals).

However, in the main kernel the norm is to check for
"defined(__XXX_ENDIAN)" rather than comparing against __BYTE_ORDER and
this has incorrectly leaked into the userspace headers.

The definition of ACCT_BYTEORDER in linux/acct.h is wrong in this way.
Note that userspace will likely interpret this incorrectly as the
big-endian variant on little-endian machines - depending on header
inclusion order.

[!!!] NOTE [!!!]  This patch may adversely change the userspace API.  It might
be better to fix the value of ACCT_BYTEORDER.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:48 -07:00
David Howells
51b154ed52 UAPI: fix endianness conditionals in linux/aio_abi.h
In the UAPI header files, __BIG_ENDIAN and __LITTLE_ENDIAN must be
compared against __BYTE_ORDER in preprocessor conditionals where these are
exposed to userspace (that is they're not inside __KERNEL__ conditionals).

However, in the main kernel the norm is to check for
"defined(__XXX_ENDIAN)" rather than comparing against __BYTE_ORDER and
this has incorrectly leaked into the userspace headers.

The definition of PADDED() in linux/aio_abi.h is wrong in this way.  Note
that userspace will likely interpret this and thus the order of fields in
struct iocb incorrectly as the little-endian variant on big-endian
machines - depending on header inclusion order.

[!!!] NOTE [!!!]  This patch may adversely change the userspace API.  It might
be better to fix the ordering of aio_key and aio_reserved1 in struct iocb.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Benjamin LaHaise <bcrl@kvack.org>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-13 15:21:48 -07:00
Ley Foon Tan
e06c93cacb tty/serial: Add support for Altera serial port
Add support for Altera 8250/16550 compatible serial port.

Signed-off-by: Ley Foon Tan <lftan@altera.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-12 08:53:23 -07:00
Cornelia Huck
2b83451b45 KVM: ioeventfd for virtio-ccw devices.
Enhance KVM_IOEVENTFD with a new flag that allows to attach to virtio-ccw
devices on s390 via the KVM_VIRTIO_CCW_NOTIFY_BUS.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2013-03-05 19:12:17 -03:00
Linus Torvalds
ea882c2ece Merge tag 'disintegrate-fbdev-20121220' of git://git.infradead.org/users/dhowells/linux-headers
Pull fbdev UAPI disintegration from David Howells:
 "You'll be glad to here that the end is nigh for the UAPI patches.
  Only the fbdev/framebuffer piece remains now that the SCSI stuff has
  gone in.

  Here are the UAPI disintegration bits for the fbdev drivers.  It
  appears that Florian hasn't had time to deal with my patch, but back
  in December he did say he didn't mind if I pushed it forward."

Yay.  No more uapi movement.  And hopefully no more big header file
cleanups coming up either, it just tends to be very painful.

* tag 'disintegrate-fbdev-20121220' of git://git.infradead.org/users/dhowells/linux-headers:
  UAPI: (Scripted) Disintegrate include/video
2013-03-03 14:24:59 -08:00
Linus Torvalds
8fd5e7a2d9 Merge tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag
Pull new ImgTec Meta architecture from James Hogan:
 "This adds core architecture support for Imagination's Meta processor
  cores, followed by some later miscellaneous arch/metag cleanups and
  fixes which I kept separate to ease review:

   - Support for basic Meta 1 (ATP) and Meta 2 (HTP) core architecture
   - A few fixes all over, particularly for symbol prefixes
   - A few privilege protection fixes
   - Several cleanups (setup.c includes, split out a lot of
     metag_ksyms.c)
   - Fix some missing exports
   - Convert hugetlb to use vm_unmapped_area()
   - Copy device tree to non-init memory
   - Provide dma_get_sgtable()"

* tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag: (61 commits)
  metag: Provide dma_get_sgtable()
  metag: prom.h: remove declaration of metag_dt_memblock_reserve()
  metag: copy devicetree to non-init memory
  metag: cleanup metag_ksyms.c includes
  metag: move mm/init.c exports out of metag_ksyms.c
  metag: move usercopy.c exports out of metag_ksyms.c
  metag: move setup.c exports out of metag_ksyms.c
  metag: move kick.c exports out of metag_ksyms.c
  metag: move traps.c exports out of metag_ksyms.c
  metag: move irq enable out of irqflags.h on SMP
  genksyms: fix metag symbol prefix on crc symbols
  metag: hugetlb: convert to vm_unmapped_area()
  metag: export clear_page and copy_page
  metag: export metag_code_cache_flush_all
  metag: protect more non-MMU memory regions
  metag: make TXPRIVEXT bits explicit
  metag: kernel/setup.c: sort includes
  perf: Enable building perf tools for Meta
  metag: add boot time LNKGET/LNKSET check
  metag: add __init to metag_cache_probe()
  ...
2013-03-03 12:06:09 -08:00
Linus Torvalds
b695188dd3 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs
Pull btrfs update from Chris Mason:
 "The biggest feature in the pull is the new (and still experimental)
  raid56 code that David Woodhouse started long ago.  I'm still working
  on the parity logging setup that will avoid inconsistent parity after
  a crash, so this is only for testing right now.  But, I'd really like
  to get it out to a broader audience to hammer out any performance
  issues or other problems.

  scrub does not yet correct errors on raid5/6 either.

  Josef has another pass at fsync performance.  The big change here is
  to combine waiting for metadata with waiting for data, which is a big
  latency win.  It is also step one toward using atomics from the
  hardware during a commit.

  Mark Fasheh has a new way to use btrfs send/receive to send only the
  metadata changes.  SUSE is using this to make snapper more efficient
  at finding changes between snapshosts.

  Snapshot-aware defrag is also included.

  Otherwise we have a large number of fixes and cleanups.  Eric Sandeen
  wins the award for removing the most lines, and I'm hoping we steal
  this idea from XFS over and over again."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (118 commits)
  btrfs: fixup/remove module.h usage as required
  Btrfs: delete inline extents when we find them during logging
  btrfs: try harder to allocate raid56 stripe cache
  Btrfs: cleanup to make the function btrfs_delalloc_reserve_metadata more logic
  Btrfs: don't call btrfs_qgroup_free if just btrfs_qgroup_reserve fails
  Btrfs: remove reduplicate check about root in the function btrfs_clean_quota_tree
  Btrfs: return ENOMEM rather than use BUG_ON when btrfs_alloc_path fails
  Btrfs: fix missing deleted items in btrfs_clean_quota_tree
  btrfs: use only inline_pages from extent buffer
  Btrfs: fix wrong reserved space when deleting a snapshot/subvolume
  Btrfs: fix wrong reserved space in qgroup during snap/subv creation
  Btrfs: remove unnecessary dget_parent/dput when creating the pending snapshot
  btrfs: remove a printk from scan_one_device
  Btrfs: fix NULL pointer after aborting a transaction
  Btrfs: fix memory leak of log roots
  Btrfs: copy everything if we've created an inline extent
  btrfs: cleanup for open-coded alignment
  Btrfs: do not change inode flags in rename
  Btrfs: use reserved space for creating a snapshot
  clear chunk_alloc flag on retryable failure
  ...
2013-03-02 16:41:54 -08:00
James Hogan
bc3966bf15 metag: ptrace
The ptrace interface for metag provides access to some core register
sets using the PTRACE_GETREGSET and PTRACE_SETREGSET operations. The
details of the internal context structures is abstracted into user API
structures to both ease use and allow flexibility to change the internal
context layouts. Copyin and copyout functions for these register sets
are exposed to allow signal handling code to use them to copy to and
from the signal context.

struct user_gp_regs (NT_PRSTATUS) provides access to the core general
purpose register context.

struct user_cb_regs (NT_METAG_CBUF) provides access to the TXCATCH*
registers which contains information abuot a memory fault, unaligned
access error or watchpoint. This can be modified to alter the way the
fault is replayed on resume ("catch replay"), or to prevent the replay
taking place.

struct user_rp_state (NT_METAG_RPIPE) provides access to the state of
the Meta read pipeline which can be used to hide memory latencies in
hand optimised data loops.

Extended DSP register state, DSP RAM, and hardware breakpoint registers
aren't yet exposed through ptrace.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
2013-03-02 20:09:22 +00:00
Linus Torvalds
37cae6ad4c Merge tag 'dm-3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm
Pull device-mapper update from Alasdair G Kergon:
 "The main addition here is a long-desired target framework to allow an
  SSD to be used as a cache in front of a slower device.  Cache tuning
  is delegated to interchangeable policy modules so these can be
  developed independently of the mechanics needed to shuffle the data
  around.

  Other than that, kcopyd users acquire a throttling parameter, ioctl
  buffer usage gets streamlined, more mempool reliance is reduced and
  there are a few other bug fixes and tidy-ups."

* tag 'dm-3.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-dm: (30 commits)
  dm cache: add cleaner policy
  dm cache: add mq policy
  dm: add cache target
  dm persistent data: add bitset
  dm persistent data: add transactional array
  dm thin: remove cells from stack
  dm bio prison: pass cell memory in
  dm persistent data: add btree_walk
  dm: add target num_write_bios fn
  dm kcopyd: introduce configurable throttling
  dm ioctl: allow message to return data
  dm ioctl: optimize functions without variable params
  dm ioctl: introduce ioctl_flags
  dm: merge io_pool and tio_pool
  dm: remove unused _rq_bio_info_cache
  dm: fix limits initialization when there are no data devices
  dm snapshot: add missing module aliases
  dm persistent data: set some btree fn parms const
  dm: refactor bio cloning
  dm: rename bio cloning functions
  ...
2013-03-02 11:44:27 -08:00
Linus Torvalds
426d266c12 Merge tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI updates from James Bottomley:
 "This is an assorted set of stragglers into the merge window with
  driver updates for qla2xxx, megaraid_sas, storvsc and ufs.

  It also includes pulls of the uapi tree (all the remaining SCSI
  pieces) and the fcoe tree (updates to fcoe and libfc)"

* tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (81 commits)
  [SCSI] ufs: Separate PCI code into glue driver
  [SCSI] ufs: Segregate PCI Specific Code
  [SCSI] scsi: fix lpfc build when wmb() is defined as mb()
  [SCSI] storvsc: Handle dynamic resizing of the device
  [SCSI] storvsc: Restructure error handling code on command completion
  [SCSI] storvsc: avoid usage of WRITE_SAME
  [SCSI] aacraid: suppress two GCC warnings
  [SCSI] hpsa: check for dma_mapping_error in hpsa_passthru ioctls
  [SCSI] hpsa: reorganize error handling in hpsa_passthru_ioctl
  [SCSI] hpsa: check for dma_mapping_error in hpsa_map_sg_chain_block
  [SCSI] hpsa: Check for dma_mapping_error for all code paths using fill_cmd
  [SCSI] hpsa: Check for dma_mapping_error in hpsa_map_one
  [SCSI] dc395x: uninitialized variable in device_alloc()
  [SCSI] Fix range check in scsi_host_dif_capable()
  [SCSI] storvsc: Initialize the sglist
  [SCSI] mpt2sas: Add support for OEM specific controller
  [SCSI] ipr: Fix oops while resetting an ipr adapter
  [SCSI] fnic: Fnic Trace Utility
  [SCSI] fnic: New debug flags and debug log messages
  [SCSI] fnic: fnic driver may hit BUG_ON on device reset
  ...
2013-03-02 11:42:16 -08:00
Mikulas Patocka
a26062416e dm ioctl: allow message to return data
This patch introduces enhanced message support that allows the
device-mapper core to recognise messages that are common to all devices,
and for messages to return data to userspace.

Core messages are processed by the function "message_for_md".  If the
device mapper doesn't support the message, it is passed to the target
driver.

If the message returns data, the kernel sets the flag
DM_MESSAGE_OUT_FLAG.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:49 +00:00
Mikulas Patocka
02cde50b7e dm ioctl: optimize functions without variable params
Device-mapper ioctls receive and send data in a buffer supplied
by userspace.  The buffer has two parts.  The first part contains
a 'struct dm_ioctl' and has a fixed size.  The second part depends
on the ioctl and has a variable size.

This patch recognises the specific ioctls that do not use the variable
part of the buffer and skips allocating memory for it.

In particular, when a device is suspended and a resume ioctl is sent,
this now avoid memory allocation completely.

The variable "struct dm_ioctl tmp" is moved from the function
copy_params to its caller ctl_ioctl and renamed to param_kernel.
It is used directly when the ioctl function doesn't need any arguments.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2013-03-01 22:45:49 +00:00
James Bottomley
3e34c1fc2b [SCSI] Merge tag 'fcoe-02-19-13' into for-linus
FCoE Updates for 3.9

Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-03-01 09:10:08 +00:00
James Bottomley
c157750a90 Merge tag 'uapi-20121219' into for-linus
UAPI Disintegration 2012-12-19

This is the remaining SCSI part of the UAPI

Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-03-01 09:08:44 +00:00
Alex Bligh
75f187aba5 nbd: support FLUSH requests
Currently, the NBD device does not accept flush requests from the Linux
block layer.  If the NBD server opened the target with neither O_SYNC nor
O_DSYNC, however, the device will be effectively backed by a writeback
cache.  Without issuing flushes properly, operation of the NBD device will
not be safe against power losses.

The NBD protocol has support for both a cache flush command and a FUA
command flag; the server will also pass a flag to note its support for
these features.  This patch adds support for the cache flush command and
flag.  In the kernel, we receive the flags via the NBD_SET_FLAGS ioctl,
and map NBD_FLAG_SEND_FLUSH to the argument of blk_queue_flush.  When the
flag is active the block layer will send REQ_FLUSH requests, which we
translate to NBD_CMD_FLUSH commands.

FUA support is not included in this patch because all free software
servers implement it with a full fdatasync; thus it has no advantage over
supporting flush only.  Because I [Paolo] cannot really benchmark it in a
realistic scenario, I cannot tell if it is a good idea or not.  It is also
not clear if it is valid for an NBD server to support FUA but not flush.
The Linux block layer gives a warning for this combination, the NBD
protocol documentation says nothing about it.

The patch also fixes a small problem in the handling of flags: nbd->flags
must be cleared at the end of NBD_DO_IT, but the driver was not doing
that.  The bug manifests itself as follows.  Suppose you two different
client/server pairs to start the NBD device.  Suppose also that the first
client supports NBD_SET_FLAGS, and the first server sends
NBD_FLAG_SEND_FLUSH; the second pair instead does neither of these two
things.  Before this patch, the second invocation of NBD_DO_IT will use a
stale value of nbd->flags, and the second server will issue an error every
time it receives an NBD_CMD_FLUSH command.

This bug is pre-existing, but it becomes much more important after this
patch; flush failures make the device pretty much unusable, unlike

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bligh <alex@alex.org.uk>
Acked-by: Paul Clements <Paul.Clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:22 -08:00