We already do this in the caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

The intel-iommu driver currently has a partial reimplementation
of the direct mapping code for devices that use pass through
mode.  Replace that code with calls to the relevant dma_direct
routines at the highest level.  This means we have exactly the
same behvior as the dma direct code itself, and can prepare for
eventually only attaching the intel_iommu ops to devices that
actually need dynamic iommu mappings.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Invert the return value to avoid double negatives, use a bool
instead of int as the return value, and reduce some indentation
after early returns.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

This adds support to return the default pasid associated with
an auxiliary domain. The PCI device which is bound with this
domain should use this value as the pasid for all DMA requests
of the subset of device which is isolated and protected with
this domain.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

When multiple domains per device has been enabled by the
device driver, the device will tag the default PASID for
the domain to all DMA traffics out of the subset of this
device; and the IOMMU should translate the DMA requests
in PASID granularity.

This adds the intel_iommu_aux_attach/detach_device() ops
to support managing PASID granular translation structures
when the device driver has enabled multiple domains per
device.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

This part of code could be used by both normal and aux
domain specific attach entries. Hence move them into a
common function to avoid duplication.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

This adds the iommu ops entries for aux-domain per-device
feature query and enable/disable.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Sanjay Kumar <sanjay.k.kumar@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

This moves intel_iommu_enable_pasid() out of the scope of
CONFIG_INTEL_IOMMU_SVM with more and more features requiring
pasid function.

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Add bind() and unbind() operations to the IOMMU API.
iommu_sva_bind_device() binds a device to an mm, and returns a handle to
the bond, which is released by calling iommu_sva_unbind_device().

Each mm bound to devices gets a PASID (by convention, a 20-bit system-wide
ID representing the address space), which can be retrieved with
iommu_sva_get_pasid(). When programming DMA addresses, device drivers
include this PASID in a device-specific manner, to let the device access
the given address space. Since the process memory may be paged out, device
and IOMMU must support I/O page faults (e.g. PCI PRI).

Using iommu_sva_set_ops(), device drivers provide an mm_exit() callback
that is called by the IOMMU driver if the process exits before the device
driver called unbind(). In mm_exit(), device driver should disable DMA
from the given context, so that the core IOMMU can reallocate the PASID.
Whether the process exited or nor, the device driver should always release
the handle with unbind().

To use these functions, device driver must first enable the
IOMMU_DEV_FEAT_SVA device feature with iommu_dev_enable_feature().
Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Sharing a physical PCI device in a finer-granularity way
is becoming a consensus in the industry. IOMMU vendors
are also engaging efforts to support such sharing as well
as possible. Among the efforts, the capability of support
finer-granularity DMA isolation is a common requirement
due to the security consideration. With finer-granularity
DMA isolation, subsets of a PCI function can be isolated
from each others by the IOMMU. As a result, there is a
request in software to attach multiple domains to a physical
PCI device. One example of such use model is the Intel
Scalable IOV [1] [2]. The Intel vt-d 3.0 spec [3] introduces
the scalable mode which enables PASID granularity DMA
isolation.

This adds the APIs to support multiple domains per device.
In order to ease the discussions, we call it 'a domain in
auxiliary mode' or simply 'auxiliary domain' when multiple
domains are attached to a physical device.

The APIs include:

* iommu_dev_has_feature(dev, IOMMU_DEV_FEAT_AUX)
  - Detect both IOMMU and PCI endpoint devices supporting
    the feature (aux-domain here) without the host driver
    dependency.

* iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX)
  - Check the enabling status of the feature (aux-domain
    here). The aux-domain interfaces are available only
    if this returns true.

* iommu_dev_enable/disable_feature(dev, IOMMU_DEV_FEAT_AUX)
  - Enable/disable device specific aux-domain feature.

* iommu_aux_attach_device(domain, dev)
  - Attaches @domain to @dev in the auxiliary mode. Multiple
    domains could be attached to a single device in the
    auxiliary mode with each domain representing an isolated
    address space for an assignable subset of the device.

* iommu_aux_detach_device(domain, dev)
  - Detach @domain which has been attached to @dev in the
    auxiliary mode.

* iommu_aux_get_pasid(domain, dev)
  - Return ID used for finer-granularity DMA translation.
    For the Intel Scalable IOV usage model, this will be
    a PASID. The device which supports Scalable IOV needs
    to write this ID to the device register so that DMA
    requests could be tagged with a right PASID prefix.

This has been updated with the latest proposal from Joerg
posted here [5].

Many people involved in discussions of this design.

Kevin Tian <kevin.tian@intel.com>
Liu Yi L <yi.l.liu@intel.com>
Ashok Raj <ashok.raj@intel.com>
Sanjay Kumar <sanjay.k.kumar@intel.com>
Jacob Pan <jacob.jun.pan@linux.intel.com>
Alex Williamson <alex.williamson@redhat.com>
Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Joerg Roedel <joro@8bytes.org>

and some discussions can be found here [4] [5].

[1] https://software.intel.com/en-us/download/intel-scalable-io-virtualization-technical-specification
[2] https://schd.ws/hosted_files/lc32018/00/LC3-SIOV-final.pdf
[3] https://software.intel.com/en-us/download/intel-virtualization-technology-for-directed-io-architecture-specification
[4] https://lkml.org/lkml/2018/7/26/4
[5] https://www.spinics.net/lists/iommu/msg31874.html

Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Liu Yi L <yi.l.liu@intel.com>
Suggested-by: Kevin Tian <kevin.tian@intel.com>
Suggested-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Suggested-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Pull ARM SoC fixes from Olof Johansson:
 "A collection of fixes from the last few weeks. Most of them are
  smaller tweaks and fixes to DT and hardware descriptions for boards.
  Some of the more significant ones are:

   - eMMC and RGMII stability tweaks for rk3288

   - DDC fixes for Rock PI 4

   - Audio fixes for two TI am335x eval boards

   - D_CAN clock fix for am335x

   - Compilation fixes for clang

   - !HOTPLUG_CPU compilation fix for one of the new platforms this
     release (milbeaut)

   - A revert of a gpio fix for nomadik that instead was fixed in the
     gpio subsystem

   - Whitespace fix for the DT JSON schema (no tabs allowed)"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (25 commits)
  ARM: milbeaut: fix build with !CONFIG_HOTPLUG_CPU
  ARM: iop: don't use using 64-bit DMA masks
  ARM: orion: don't use using 64-bit DMA masks
  Revert "ARM: dts: nomadik: Fix polarity of SPI CS"
  dt-bindings: cpu: Fix JSON schema
  arm/mach-at91/pm : fix possible object reference leak
  ARM: dts: at91: Fix typo in ISC_D0 on PC9
  ARM: dts: Fix dcan clkctrl clock for am3
  reset: meson-audio-arb: Fix missing .owner setting of reset_controller_dev
  dt-bindings: reset: meson-g12a: Add missing USB2 PHY resets
  ARM: dts: rockchip: Remove #address/#size-cells from rk3288-veyron gpio-keys
  ARM: dts: rockchip: Remove #address/#size-cells from rk3288 mipi_dsi
  ARM: dts: rockchip: Fix gpu opp node names for rk3288
  ARM: dts: am335x-evmsk: Correct the regulators for the audio codec
  ARM: dts: am335x-evm: Correct the regulators for the audio codec
  ARM: OMAP2+: add missing of_node_put after of_device_is_available
  ARM: OMAP1: ams-delta: Fix broken GPIO ID allocation
  arm64: dts: stratix10: add the sysmgr-syscon property from the gmac's
  arm64: dts: rockchip: fix rk3328 sdmmc0 write errors
  arm64: dts: rockchip: fix rk3328 rgmii high tx error rate
  ...

Pull block fixes from Jens Axboe:

 - Fixups for the pf/pcd queue handling (YueHaibing)

 - Revert of the three direct issue changes as they have been proven to
   cause an issue with dm-mpath (Bart)

 - Plug rq_count reset fix (Dongli)

 - io_uring double free in fileset registration error handling (me)

 - Make null_blk handle bad numa node passed in (John)

 - BFQ ifdef fix (Konstantin)

 - Flush queue leak fix (Shenghui)

 - Plug trace fix (Yufen)

* tag 'for-linus-20190407' of git://git.kernel.dk/linux-block:
  xsysace: Fix error handling in ace_setup
  null_blk: prevent crash from bad home_node value
  block: Revert v5.0 blk_mq_request_issue_directly() changes
  paride/pcd: Fix potential NULL pointer dereference and mem leak
  blk-mq: do not reset plug->rq_count before the list is sorted
  paride/pf: Fix potential NULL pointer dereference
  io_uring: fix double free in case of fileset regitration failure
  blk-mq: add trace block plug and unplug for multiple queues
  block: use blk_free_flush_queue() to free hctx->fq in blk_mq_init_hctx
  block/bfq: fix ifdef for CONFIG_BFQ_GROUP_IOSCHED=y

When HOTPLUG_CPU is disabled, some fields in the smp operations
are not available or needed:

arch/arm/mach-milbeaut/platsmp.c:90:3: error: field designator 'cpu_die' does not refer to any field in type
      'struct smp_operations'
        .cpu_die                = m10v_cpu_die,
         ^
arch/arm/mach-milbeaut/platsmp.c:91:3: error: field designator 'cpu_kill' does not refer to any field in type
      'struct smp_operations'
        .cpu_kill               = m10v_cpu_kill,
         ^

Hide them in an #ifdef like the other platforms do.

Fixes: 9fb29c73 ("ARM: milbeaut: Add basic support for Milbeaut m10v SoC")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

clang warns about statically defined DMA masks from the DMA_BIT_MASK
macro with length 64:

 arch/arm/mach-iop13xx/setup.c:303:35: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
 static u64 iop13xx_adma_dmamask = DMA_BIT_MASK(64);
                                  ^~~~~~~~~~~~~~~~
 include/linux/dma-mapping.h:141:54: note: expanded from macro 'DMA_BIT_MASK'
 #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))
                                                      ^ ~~~

The ones in iop shouldn't really be 64 bit masks, so changing them
to what the driver can support avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

clang warns about statically defined DMA masks from the DMA_BIT_MASK
macro with length 64:

arch/arm/plat-orion/common.c:625:29: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
                .coherent_dma_mask      = DMA_BIT_MASK(64),
                                          ^~~~~~~~~~~~~~~~
include/linux/dma-mapping.h:141:54: note: expanded from macro 'DMA_BIT_MASK'
 #define DMA_BIT_MASK(n) (((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))

The ones in orion shouldn't really be 64 bit masks, so changing them
to what the driver can support avoids the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Olof Johansson <olof@lixom.net>

This reverts commit fa946356.

Per Linus Walleij:

Dear ARM SoC maintainers,

can you please revert this patch. It was the wrong solution to the
wrong problem, and I must have acted in stress. Andrey fixed the
real bug in a proper way in these commits:

commit e5545c94
"gpio: of: Check propname before applying "cs-gpios" quirks"
commit 7ce40277
"gpio: of: Check for "spi-cs-high" in child instead of parent node"
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'omap-for-v5.1/fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap into arm/fixes

Fixes for omaps for v5.1-rc cycle

Few small fixes for omap variants:

- Fix ams-delta gpio IDs
- Add missing of_node_put for omapdss platform init code
- Fix unconfigured audio regulators for two am335x boards
- Fix use of wrong offset for am335x d_can clocks

* tag 'omap-for-v5.1/fixes-signed' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
  ARM: dts: Fix dcan clkctrl clock for am3
  ARM: dts: am335x-evmsk: Correct the regulators for the audio codec
  ARM: dts: am335x-evm: Correct the regulators for the audio codec
  ARM: OMAP2+: add missing of_node_put after of_device_is_available
  ARM: OMAP1: ams-delta: Fix broken GPIO ID allocation
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'at91-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux into arm/fixes

AT91 fixes for 5.1

- fix a typo in sama5d2 pinmuxing which concerns the ISC data 0 signal
- fix a kobject reference leak

* tag 'at91-5.1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/at91/linux:
  arm/mach-at91/pm : fix possible object reference leak
  ARM: dts: at91: Fix typo in ISC_D0 on PC9
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'v5.1-rockchip-dtfixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip into arm/fixes

Fixes for dtc warnings, fixes for ethernet transfers on rk3328,
sd-card related fixes on both rk3328 ans rk3288-tinker and a
regulator fix on rock64 and making ddc actually work on the
Rock PI 4 due to missing the ddc bus.

* tag 'v5.1-rockchip-dtfixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip:
  ARM: dts: rockchip: Remove #address/#size-cells from rk3288-veyron gpio-keys
  ARM: dts: rockchip: Remove #address/#size-cells from rk3288 mipi_dsi
  ARM: dts: rockchip: Fix gpu opp node names for rk3288
  arm64: dts: rockchip: fix rk3328 sdmmc0 write errors
  arm64: dts: rockchip: fix rk3328 rgmii high tx error rate
  ARM: dts: rockchip: Fix SD card detection on rk3288-tinker
  arm64: dts: rockchip: Fix vcc_host1_5v GPIO polarity on rk3328-rock64
  ARM: dts: rockchip: fix rk3288 cpu opp node reference
  arm64: dts: rockchip: add DDC bus on Rock Pi 4
  arm64: dts: rockchip: fix rk3328-roc-cc gmac2io tx/rx_delay
Signed-off-by: Olof Johansson <olof@lixom.net>

Merge tag 'stratix10_fix_for_v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux into arm/fixes

arm64: dts: stratix10: fix emac loading warning
- Add missing "altr,sysmgr-syscon" property to all gmac nodes

* tag 'stratix10_fix_for_v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux:
  arm64: dts: stratix10: add the sysmgr-syscon property from the gmac's
Signed-off-by: Olof Johansson <olof@lixom.net>

Reset controller fixes for v5.1

This tag adds missing USB PHY reset lines to the Meson G12A reset
controller header and fixes the Meson Audio ARB driver to prevent
module unloading while it is in use.

* tag 'reset-fixes-for-v5.1' of git://git.pengutronix.de/pza/linux:
  reset: meson-audio-arb: Fix missing .owner setting of reset_controller_dev
  dt-bindings: reset: meson-g12a: Add missing USB2 PHY resets
Signed-off-by: Olof Johansson <olof@lixom.net>

Commit fd73403a ("dt-bindings: arm: Add SMP enable-method for
Milbeaut") added support for a new cpu enable-method, but did so using
tabulations to ident. This is however invalid in the syntax, and resulted
in a failure when trying to use that schemas for validation.

Use spaces instead of tabs to indent to fix this.

Fixes: fd73403a ("dt-bindings: arm: Add SMP enable-method for Milbeaut")
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Sugaya Taichi <sugaya.taichi@socionext.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

Pull xen fixes from Juergen Gross:
 "One minor fix and a small cleanup for the xen privcmd driver"

* tag 'for-linus-5.1b-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: Prevent buffer overflow in privcmd ioctl
  xen: use struct_size() helper in kzalloc()

Pull MTD fix from Richard Weinberger:
 "A single fix for a possible infinite loop in the cfi_cmdset_0002
  driver"

* tag 'mtd/fixes-for-5.1-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
  mtd: cfi: fix deadloop in cfi_cmdset_0002.c do_write_buffer

Pull SCSI fixes from James Bottomley:
 "Five small fixes. Four in three drivers: qedi, lpfc and storvsc. The
  final one is labelled core, but merely adds a dh rdac entry for Lenovo
  systems"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: lpfc: Fix missing wakeups on abort threads
  scsi: storvsc: Reduce default ring buffer size to 128 Kbytes
  scsi: storvsc: Fix calculation of sub-channel count
  scsi: core: add new RDAC LENOVO/DE_Series device
  scsi: qedi: remove declaration of nvm_image from stack

Pull i2c fix from Wolfram Sang:
 "A simple but wanted driver bugfix"

* 'i2c/for-current-fixed' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: imx: don't leak the i2c adapter on error

Pull parisc fixes from Helge Deller:
 "A 32-bit boot regression fix introduced in the merge window, a QEMU
  detection fix and two fixes by Sven regarding ptrace & kprobes"

* 'parisc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Detect QEMU earlier in boot process
  parisc: also set iaoq_b in instruction_pointer_set()
  parisc: regs_return_value() should return gpr28
  Revert: parisc: Use F_EXTEND() macro in iosapic code

While adding LASI support to QEMU, I noticed that the QEMU detection in
the kernel happens much too late. For example, when a LASI chip is found
by the kernel, it registers the LASI LED driver as well.  But when we
run on QEMU it makes sense to avoid spending unnecessary CPU cycles, so
we need to access the running_on_QEMU flag earlier than before.

This patch now makes the QEMU detection the fist task of the Linux
kernel by moving it to where the kernel enters the C-coding.

Fixes: 310d8278 ("parisc: qemu idle sleep support")
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # v4.14+

When setting the instruction pointer on PA-RISC we also need
to set the back of the instruction queue to the new offset, otherwise
we will execute on instruction from the new location, and jumping
back to the old location stored in iaoq_b.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: 75ebedf1 ("parisc: Add HAVE_REGS_AND_STACK_ACCESS_API feature")
Cc: stable@vger.kernel.org # 4.19+

While working on kretprobes for PA-RISC I was wondering while the
kprobes sanity test always fails on kretprobes. This is caused by
returning gpr20 instead of gpr28.
Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.14+

Revert parts of commit 97d7e2e3 ("parisc: Use F_EXTEND() macro in
iosapic code"). It breaks booting the 32-bit kernel on some machines.
Reported-by: Sven Schnelle <svens@stackframe.org>
Tested-by: Sven Schnelle <svens@stackframe.org>
Fixes: 97d7e2e3 ("parisc: Use F_EXTEND() macro in iosapic code")
Signed-off-by: Helge Deller <deller@gmx.de>

fs: stream_open - opener for stream-like files so that read and write can run simultaneously without deadlock

Commit 9c225f26 ("vfs: atomic f_pos accesses as per POSIX") added
locking for file.f_pos access and in particular made concurrent read and
write not possible - now both those functions take f_pos lock for the
whole run, and so if e.g. a read is blocked waiting for data, write will
deadlock waiting for that read to complete.

This caused regression for stream-like files where previously read and
write could run simultaneously, but after that patch could not do so
anymore. See e.g. commit 581d21a2 ("xenbus: fix deadlock on writes
to /proc/xen/xenbus") which fixes such regression for particular case of
/proc/xen/xenbus.

The patch that added f_pos lock in 2014 did so to guarantee POSIX thread
safety for read/write/lseek and added the locking to file descriptors of
all regular files. In 2014 that thread-safety problem was not new as it
was already discussed earlier in 2006.

However even though 2006'th version of Linus's patch was adding f_pos
locking "only for files that are marked seekable with FMODE_LSEEK (thus
avoiding the stream-like objects like pipes and sockets)", the 2014
version - the one that actually made it into the tree as 9c225f26 -
is doing so irregardless of whether a file is seekable or not.

See

    https://lore.kernel.org/lkml/53022DB1.4070805@gmail.com/
    https://lwn.net/Articles/180387
    https://lwn.net/Articles/180396

for historic context.

The reason that it did so is, probably, that there are many files that
are marked non-seekable, but e.g. their read implementation actually
depends on knowing current position to correctly handle the read. Some
examples:

	kernel/power/user.c		snapshot_read
	fs/debugfs/file.c		u32_array_read
	fs/fuse/control.c		fuse_conn_waiting_read + ...
	drivers/hwmon/asus_atk0110.c	atk_debugfs_ggrp_read
	arch/s390/hypfs/inode.c		hypfs_read_iter
	...

Despite that, many nonseekable_open users implement read and write with
pure stream semantics - they don't depend on passed ppos at all. And for
those cases where read could wait for something inside, it creates a
situation similar to xenbus - the write could be never made to go until
read is done, and read is waiting for some, potentially external, event,
for potentially unbounded time -> deadlock.

Besides xenbus, there are 14 such places in the kernel that I've found
with semantic patch (see below):

	drivers/xen/evtchn.c:667:8-24: ERROR: evtchn_fops: .read() can deadlock .write()
	drivers/isdn/capi/capi.c:963:8-24: ERROR: capi_fops: .read() can deadlock .write()
	drivers/input/evdev.c:527:1-17: ERROR: evdev_fops: .read() can deadlock .write()
	drivers/char/pcmcia/cm4000_cs.c:1685:7-23: ERROR: cm4000_fops: .read() can deadlock .write()
	net/rfkill/core.c:1146:8-24: ERROR: rfkill_fops: .read() can deadlock .write()
	drivers/s390/char/fs3270.c:488:1-17: ERROR: fs3270_fops: .read() can deadlock .write()
	drivers/usb/misc/ldusb.c:310:1-17: ERROR: ld_usb_fops: .read() can deadlock .write()
	drivers/hid/uhid.c:635:1-17: ERROR: uhid_fops: .read() can deadlock .write()
	net/batman-adv/icmp_socket.c:80:1-17: ERROR: batadv_fops: .read() can deadlock .write()
	drivers/media/rc/lirc_dev.c:198:1-17: ERROR: lirc_fops: .read() can deadlock .write()
	drivers/leds/uleds.c:77:1-17: ERROR: uleds_fops: .read() can deadlock .write()
	drivers/input/misc/uinput.c:400:1-17: ERROR: uinput_fops: .read() can deadlock .write()
	drivers/infiniband/core/user_mad.c:985:7-23: ERROR: umad_fops: .read() can deadlock .write()
	drivers/gnss/core.c:45:1-17: ERROR: gnss_fops: .read() can deadlock .write()

In addition to the cases above another regression caused by f_pos
locking is that now FUSE filesystems that implement open with
FOPEN_NONSEEKABLE flag, can no longer implement bidirectional
stream-like files - for the same reason as above e.g. read can deadlock
write locking on file.f_pos in the kernel.

FUSE's FOPEN_NONSEEKABLE was added in 2008 in a7c1b990 ("fuse:
implement nonseekable open") to support OSSPD. OSSPD implements /dev/dsp
in userspace with FOPEN_NONSEEKABLE flag, with corresponding read and
write routines not depending on current position at all, and with both
read and write being potentially blocking operations:

See

    https://github.com/libfuse/osspd
    https://lwn.net/Articles/308445

    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1406
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1438-L1477
    https://github.com/libfuse/osspd/blob/14a9cff0/osspd.c#L1479-L1510

Corresponding libfuse example/test also describes FOPEN_NONSEEKABLE as
"somewhat pipe-like files ..." with read handler not using offset.
However that test implements only read without write and cannot exercise
the deadlock scenario:

    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L124-L131
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L146-L163
    https://github.com/libfuse/libfuse/blob/fuse-3.4.2-3-ga1bff7d/example/poll.c#L209-L216

I've actually hit the read vs write deadlock for real while implementing
my FUSE filesystem where there is /head/watch file, for which open
creates separate bidirectional socket-like stream in between filesystem
and its user with both read and write being later performed
simultaneously. And there it is semantically not easy to split the
stream into two separate read-only and write-only channels:

    https://lab.nexedi.com/kirr/wendelin.core/blob/f13aa600/wcfs/wcfs.go#L88-169

Let's fix this regression. The plan is:

1. We can't change nonseekable_open to include &~FMODE_ATOMIC_POS -
   doing so would break many in-kernel nonseekable_open users which
   actually use ppos in read/write handlers.

2. Add stream_open() to kernel to open stream-like non-seekable file
   descriptors. Read and write on such file descriptors would never use
   nor change ppos. And with that property on stream-like files read and
   write will be running without taking f_pos lock - i.e. read and write
   could be running simultaneously.

3. With semantic patch search and convert to stream_open all in-kernel
   nonseekable_open users for which read and write actually do not
   depend on ppos and where there is no other methods in file_operations
   which assume @offset access.

4. Add FOPEN_STREAM to fs/fuse/ and open in-kernel file-descriptors via
   steam_open if that bit is present in filesystem open reply.

   It was tempting to change fs/fuse/ open handler to use stream_open
   instead of nonseekable_open on just FOPEN_NONSEEKABLE flags, but
   grepping through Debian codesearch shows users of FOPEN_NONSEEKABLE,
   and in particular GVFS which actually uses offset in its read and
   write handlers

	https://codesearch.debian.net/search?q=-%3Enonseekable+%3D
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1080
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1247-1346
	https://gitlab.gnome.org/GNOME/gvfs/blob/1.40.0-6-gcbc54396/client/gvfsfusedaemon.c#L1399-1481

   so if we would do such a change it will break a real user.

5. Add stream_open and FOPEN_STREAM handling to stable kernels starting
   from v3.14+ (the kernel where 9c225f26 first appeared).

   This will allow to patch OSSPD and other FUSE filesystems that
   provide stream-like files to return FOPEN_STREAM | FOPEN_NONSEEKABLE
   in their open handler and this way avoid the deadlock on all kernel
   versions. This should work because fs/fuse/ ignores unknown open
   flags returned from a filesystem and so passing FOPEN_STREAM to a
   kernel that is not aware of this flag cannot hurt. In turn the kernel
   that is not aware of FOPEN_STREAM will be < v3.14 where just
   FOPEN_NONSEEKABLE is sufficient to implement streams without read vs
   write deadlock.

This patch adds stream_open, converts /proc/xen/xenbus to it and adds
semantic patch to automatically locate in-kernel places that are either
required to be converted due to read vs write deadlock, or that are just
safe to be converted because read and write do not use ppos and there
are no other funky methods in file_operations.

Regarding semantic patch I've verified each generated change manually -
that it is correct to convert - and each other nonseekable_open instance
left - that it is either not correct to convert there, or that it is not
converted due to current stream_open.cocci limitations.

The script also does not convert files that should be valid to convert,
but that currently have .llseek = noop_llseek or generic_file_llseek for
unknown reason despite file being opened with nonseekable_open (e.g.
drivers/input/mousedev.c)

Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Yongzhi Pan <panyongzhi@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Tejun Heo <tj@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Nikolaus Rath <Nikolaus@rath.org>
Cc: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Kirill Smelkov <kirr@nexedi.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If xace hardware reports a bad version number, the error handling code
in ace_setup() calls put_disk(), followed by queue cleanup. However, since
the disk data structure has the queue pointer set, put_disk() also
cleans and releases the queue. This results in blk_cleanup_queue()
accessing an already released data structure, which in turn may result
in a crash such as the following.

[   10.681671] BUG: Kernel NULL pointer dereference at 0x00000040
[   10.681826] Faulting instruction address: 0xc0431480
[   10.682072] Oops: Kernel access of bad area, sig: 11 [#1]
[   10.682251] BE PAGE_SIZE=4K PREEMPT Xilinx Virtex440
[   10.682387] Modules linked in:
[   10.682528] CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.0.0-rc6-next-20190218+ #2
[   10.682733] NIP:  c0431480 LR: c043147c CTR: c0422ad8
[   10.682863] REGS: cf82fbe0 TRAP: 0300   Tainted: G        W          (5.0.0-rc6-next-20190218+)
[   10.683065] MSR:  00029000 <CE,EE,ME>  CR: 22000222  XER: 00000000
[   10.683236] DEAR: 00000040 ESR: 00000000
[   10.683236] GPR00: c043147c cf82fc90 cf82ccc0 00000000 00000000 00000000 00000002 00000000
[   10.683236] GPR08: 00000000 00000000 c04310bc 00000000 22000222 00000000 c0002c54 00000000
[   10.683236] GPR16: 00000000 00000001 c09aa39c c09021b0 c09021dc 00000007 c0a68c08 00000000
[   10.683236] GPR24: 00000001 ced6d400 ced6dcf0 c0815d9c 00000000 00000000 00000000 cedf0800
[   10.684331] NIP [c0431480] blk_mq_run_hw_queue+0x28/0x114
[   10.684473] LR [c043147c] blk_mq_run_hw_queue+0x24/0x114
[   10.684602] Call Trace:
[   10.684671] [cf82fc90] [c043147c] blk_mq_run_hw_queue+0x24/0x114 (unreliable)
[   10.684854] [cf82fcc0] [c04315bc] blk_mq_run_hw_queues+0x50/0x7c
[   10.685002] [cf82fce0] [c0422b24] blk_set_queue_dying+0x30/0x68
[   10.685154] [cf82fcf0] [c0423ec0] blk_cleanup_queue+0x34/0x14c
[   10.685306] [cf82fd10] [c054d73c] ace_probe+0x3dc/0x508
[   10.685445] [cf82fd50] [c052d740] platform_drv_probe+0x4c/0xb8
[   10.685592] [cf82fd70] [c052abb0] really_probe+0x20c/0x32c
[   10.685728] [cf82fda0] [c052ae58] driver_probe_device+0x68/0x464
[   10.685877] [cf82fdc0] [c052b500] device_driver_attach+0xb4/0xe4
[   10.686024] [cf82fde0] [c052b5dc] __driver_attach+0xac/0xfc
[   10.686161] [cf82fe00] [c0528428] bus_for_each_dev+0x80/0xc0
[   10.686314] [cf82fe30] [c0529b3c] bus_add_driver+0x144/0x234
[   10.686457] [cf82fe50] [c052c46c] driver_register+0x88/0x15c
[   10.686610] [cf82fe60] [c09de288] ace_init+0x4c/0xac
[   10.686742] [cf82fe80] [c0002730] do_one_initcall+0xac/0x330
[   10.686888] [cf82fee0] [c09aafd0] kernel_init_freeable+0x34c/0x478
[   10.687043] [cf82ff30] [c0002c6c] kernel_init+0x18/0x114
[   10.687188] [cf82ff40] [c000f2f0] ret_from_kernel_thread+0x14/0x1c
[   10.687349] Instruction dump:
[   10.687435] 3863ffd4 4bfffd70 9421ffd0 7c0802a6 93c10028 7c9e2378 93e1002c 38810008
[   10.687637] 7c7f1b78 90010034 4bfffc25 813f008c <81290040> 75290100 4182002c 80810008
[   10.688056] ---[ end trace 13c9ff51d41b9d40 ]---

Fix the problem by setting the disk queue pointer to NULL before calling
put_disk(). A more comprehensive fix might be to rearrange the code
to check the hardware version before initializing data structures,
but I don't know if this would have undesirable side effects, and
it would increase the complexity of backporting the fix to older kernels.

Fixes: 74489a91 ("Add support for Xilinx SystemACE CompactFlash interface")
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

At module load, if the selected home_node value is greater than
the available numa nodes, the system will crash in
__alloc_pages_nodemask() due to a bad paging request.  Prevent this
user error crash by detecting the bad value, logging an error, and
setting g_home_node back to the default of NUMA_NO_NODE.
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull RTC fixes from Alexandre Belloni:

 - Various alarm fixes for da9063, cros-ec and sh

 - sd3078 manufacturer name fix as this was introduced this cycle

* tag 'rtc-5.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux:
  rtc: da9063: set uie_unsupported when relevant
  rtc: sd3078: fix manufacturer name
  rtc: sh: Fix invalid alarm warning for non-enabled alarm
  rtc: cros-ec: Fail suspend/resume if wake IRQ can't be configured

Make sure to free the i2c adapter on the error exit path.
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: e1ab9a46 ("i2c: imx: improve the error handling in i2c_imx_dma_request()")
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Merge misc fixes from Andrew Morton:
 "14 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  kernel/sysctl.c: fix out-of-bounds access when setting file-max
  mm/util.c: fix strndup_user() comment
  sh: fix multiple function definition build errors
  MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM
  MAINTAINERS: fix bad pattern in ARM/NUVOTON NPCM
  mm: writeback: use exact memcg dirty counts
  psi: clarify the units used in pressure files
  mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()
  hugetlbfs: fix memory leak for resv_map
  mm: fix vm_fault_t cast in VM_FAULT_GET_HINDEX()
  lib/lzo: fix bugs for very short or empty input
  include/linux/bitrev.h: fix constant bitrev
  kmemleak: powerpc: skip scanning holes in the .bss section
  lib/string.c: implement a basic bcmp

Commit 32a5ad9c ("sysctl: handle overflow for file-max") hooked up
min/max values for the file-max sysctl parameter via the .extra1 and
.extra2 fields in the corresponding struct ctl_table entry.

Unfortunately, the minimum value points at the global 'zero' variable,
which is an int.  This results in a KASAN splat when accessed as a long
by proc_doulongvec_minmax on 64-bit architectures:

  | BUG: KASAN: global-out-of-bounds in __do_proc_doulongvec_minmax+0x5d8/0x6a0
  | Read of size 8 at addr ffff2000133d1c20 by task systemd/1
  |
  | CPU: 0 PID: 1 Comm: systemd Not tainted 5.1.0-rc3-00012-g40b114779944 #2
  | Hardware name: linux,dummy-virt (DT)
  | Call trace:
  |  dump_backtrace+0x0/0x228
  |  show_stack+0x14/0x20
  |  dump_stack+0xe8/0x124
  |  print_address_description+0x60/0x258
  |  kasan_report+0x140/0x1a0
  |  __asan_report_load8_noabort+0x18/0x20
  |  __do_proc_doulongvec_minmax+0x5d8/0x6a0
  |  proc_doulongvec_minmax+0x4c/0x78
  |  proc_sys_call_handler.isra.19+0x144/0x1d8
  |  proc_sys_write+0x34/0x58
  |  __vfs_write+0x54/0xe8
  |  vfs_write+0x124/0x3c0
  |  ksys_write+0xbc/0x168
  |  __arm64_sys_write+0x68/0x98
  |  el0_svc_common+0x100/0x258
  |  el0_svc_handler+0x48/0xc0
  |  el0_svc+0x8/0xc
  |
  | The buggy address belongs to the variable:
  |  zero+0x0/0x40
  |
  | Memory state around the buggy address:
  |  ffff2000133d1b00: 00 00 00 00 00 00 00 00 fa fa fa fa 04 fa fa fa
  |  ffff2000133d1b80: fa fa fa fa 04 fa fa fa fa fa fa fa 04 fa fa fa
  | >ffff2000133d1c00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
  |                                ^
  |  ffff2000133d1c80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
  |  ffff2000133d1d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Fix the splat by introducing a unsigned long 'zero_ul' and using that
instead.

Link: http://lkml.kernel.org/r/20190403153409.17307-1-will.deacon@arm.com
Fixes: 32a5ad9c ("sysctl: handle overflow for file-max")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Christian Brauner <christian@brauner.io>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>