Patch series "userfaultfd: add minor fault handling", v9.
Overview
========
This series adds a new userfaultfd feature, UFFD_FEATURE_MINOR_HUGETLBFS.
When enabled (via the UFFDIO_API ioctl), this feature means that any
hugetlbfs VMAs registered with UFFDIO_REGISTER_MODE_MISSING will *also*
get events for "minor" faults. By "minor" fault, I mean the following
situation:
Let there exist two mappings (i.e., VMAs) to the same page(s) (shared
memory). One of the mappings is registered with userfaultfd (in minor
mode), and the other is not. Via the non-UFFD mapping, the underlying
pages have already been allocated & filled with some contents. The UFFD
mapping has not yet been faulted in; when it is touched for the first
time, this results in what I'm calling a "minor" fault. As a concrete
example, when working with hugetlbfs, we have huge_pte_none(), but
find_lock_page() finds an existing page.
We also add a new ioctl to resolve such faults: UFFDIO_CONTINUE. The idea
is, userspace resolves the fault by either a) doing nothing if the
contents are already correct, or b) updating the underlying contents using
the second, non-UFFD mapping (via memcpy/memset or similar, or something
fancier like RDMA, or etc...). In either case, userspace issues
UFFDIO_CONTINUE to tell the kernel "I have ensured the page contents are
correct, carry on setting up the mapping".
Use Case
========
Consider the use case of VM live migration (e.g. under QEMU/KVM):
1. While a VM is still running, we copy the contents of its memory to a
target machine. The pages are populated on the target by writing to the
non-UFFD mapping, using the setup described above. The VM is still running
(and therefore its memory is likely changing), so this may be repeated
several times, until we decide the target is "up to date enough".
2. We pause the VM on the source, and start executing on the target machine.
During this gap, the VM's user(s) will *see* a pause, so it is desirable to
minimize this window.
3. Between the last time any page was copied from the source to the target, and
when the VM was paused, the contents of that page may have changed - and
therefore the copy we have on the target machine is out of date. Although we
can keep track of which pages are out of date, for VMs with large amounts of
memory, it is "slow" to transfer this information to the target machine. We
want to resume execution before such a transfer would complete.
4. So, the guest begins executing on the target machine. The first time it
touches its memory (via the UFFD-registered mapping), userspace wants to
intercept this fault. Userspace checks whether or not the page is up to date,
and if not, copies the updated page from the source machine, via the non-UFFD
mapping. Finally, whether a copy was performed or not, userspace issues a
UFFDIO_CONTINUE ioctl to tell the kernel "I have ensured the page contents
are correct, carry on setting up the mapping".
We don't have to do all of the final updates on-demand. The userfaultfd manager
can, in the background, also copy over updated pages once it receives the map of
which pages are up-to-date or not.
Interaction with Existing APIs
==============================
Because this is a feature, a registered VMA could potentially receive both
missing and minor faults. I spent some time thinking through how the
existing API interacts with the new feature:
UFFDIO_CONTINUE cannot be used to resolve non-minor faults, as it does not
allocate a new page. If UFFDIO_CONTINUE is used on a non-minor fault:
- For non-shared memory or shmem, -EINVAL is returned.
- For hugetlb, -EFAULT is returned.
UFFDIO_COPY and UFFDIO_ZEROPAGE cannot be used to resolve minor faults.
Without modifications, the existing codepath assumes a new page needs to
be allocated. This is okay, since userspace must have a second
non-UFFD-registered mapping anyway, thus there isn't much reason to want
to use these in any case (just memcpy or memset or similar).
- If UFFDIO_COPY is used on a minor fault, -EEXIST is returned.
- If UFFDIO_ZEROPAGE is used on a minor fault, -EEXIST is returned (or -EINVAL
in the case of hugetlb, as UFFDIO_ZEROPAGE is unsupported in any case).
- UFFDIO_WRITEPROTECT simply doesn't work with shared memory, and returns
-ENOENT in that case (regardless of the kind of fault).
Future Work
===========
This series only supports hugetlbfs. I have a second series in flight to
support shmem as well, extending the functionality. This series is more
mature than the shmem support at this point, and the functionality works
fully on hugetlbfs, so this series can be merged first and then shmem
support will follow.
This patch (of 6):
This feature allows userspace to intercept "minor" faults. By "minor"
faults, I mean the following situation:
Let there exist two mappings (i.e., VMAs) to the same page(s). One of the
mappings is registered with userfaultfd (in minor mode), and the other is
not. Via the non-UFFD mapping, the underlying pages have already been
allocated & filled with some contents. The UFFD mapping has not yet been
faulted in; when it is touched for the first time, this results in what
I'm calling a "minor" fault. As a concrete example, when working with
hugetlbfs, we have huge_pte_none(), but find_lock_page() finds an existing
page.
This commit adds the new registration mode, and sets the relevant flag on
the VMAs being registered. In the hugetlb fault path, if we find that we
have huge_pte_none(), but find_lock_page() does indeed find an existing
page, then we have a "minor" fault, and if the VMA has the userfaultfd
registration flag, we call into userfaultfd to handle it.
This is implemented as a new registration mode, instead of an API feature.
This is because the alternative implementation has significant drawbacks
[1].
However, doing it this was requires we allocate a VM_* flag for the new
registration mode. On 32-bit systems, there are no unused bits, so this
feature is only supported on architectures with
CONFIG_ARCH_USES_HIGH_VMA_FLAGS. When attempting to register a VMA in
MINOR mode on 32-bit architectures, we return -EINVAL.
[1] https://lore.kernel.org/patchwork/patch/1380226/
[peterx@redhat.com: fix minor fault page leak]
Link: https://lkml.kernel.org/r/20210322175132.36659-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20210301222728.176417-1-axelrasmussen@google.com
Link: https://lkml.kernel.org/r/20210301222728.176417-2-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Michal Koutn" <mkoutny@suse.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Cc: Shawn Anastasio <shawn@anastas.io>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Adam Ruprecht <ruprecht@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Cannon Matthews <cannonmatthews@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Upton <oupton@google.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alloc_contig_range will fail if it ever sees a HugeTLB page within the
range we are trying to allocate, even when that page is free and can be
easily reallocated.
This has proved to be problematic for some users of alloc_contic_range,
e.g: CMA and virtio-mem, where those would fail the call even when those
pages lay in ZONE_MOVABLE and are free.
We can do better by trying to replace such page.
Free hugepages are tricky to handle so as to no userspace application
notices disruption, we need to replace the current free hugepage with a
new one.
In order to do that, a new function called alloc_and_dissolve_huge_page is
introduced. This function will first try to get a new fresh hugepage, and
if it succeeds, it will replace the old one in the free hugepage pool.
The free page replacement is done under hugetlb_lock, so no external users
of hugetlb will notice the change. To allocate the new huge page, we use
alloc_buddy_huge_page(), so we do not have to deal with any counters, and
prep_new_huge_page() is not called. This is valulable because in case we
need to free the new page, we only need to call __free_pages().
Once we know that the page to be replaced is a genuine 0-refcounted huge
page, we remove the old page from the freelist by remove_hugetlb_page().
Then, we can call __prep_new_huge_page() and
__prep_account_new_huge_page() for the new huge page to properly
initialize it and increment the hstate->nr_huge_pages counter (previously
decremented by remove_hugetlb_page()). Once done, the page is enqueued by
enqueue_huge_page() and it is ready to be used.
There is one tricky case when page's refcount is 0 because it is in the
process of being released. A missing PageHugeFreed bit will tell us that
freeing is in flight so we retry after dropping the hugetlb_lock. The
race window should be small and the next retry should make a forward
progress.
E.g:
CPU0 CPU1
free_huge_page() isolate_or_dissolve_huge_page
PageHuge() == T
alloc_and_dissolve_huge_page
alloc_buddy_huge_page()
spin_lock_irq(hugetlb_lock)
// PageHuge() && !PageHugeFreed &&
// !PageCount()
spin_unlock_irq(hugetlb_lock)
spin_lock_irq(hugetlb_lock)
1) update_and_free_page
PageHuge() == F
__free_pages()
2) enqueue_huge_page
SetPageHugeFreed()
spin_unlock_irq(&hugetlb_lock)
spin_lock_irq(hugetlb_lock)
1) PageHuge() == F (freed by case#1 from CPU0)
2) PageHuge() == T
PageHugeFreed() == T
- proceed with replacing the page
In the case above we retry as the window race is quite small and we have
high chances to succeed next time.
With regard to the allocation, we restrict it to the node the page belongs
to with __GFP_THISNODE, meaning we do not fallback on other node's zones.
Note that gigantic hugetlb pages are fenced off since there is a cyclic
dependency between them and alloc_contig_range.
Link: https://lkml.kernel.org/r/20210419075413.1064-6-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The helper routine hstate_next_node_to_alloc accesses and modifies the
hstate variable next_nid_to_alloc. The helper is used by the routines
alloc_pool_huge_page and adjust_pool_surplus. adjust_pool_surplus is
called with hugetlb_lock held. However, alloc_pool_huge_page can not be
called with the hugetlb lock held as it will call the page allocator.
Two instances of alloc_pool_huge_page could be run in parallel or
alloc_pool_huge_page could run in parallel with adjust_pool_surplus
which may result in the variable next_nid_to_alloc becoming invalid for
the caller and pages being allocated on the wrong node.
Both alloc_pool_huge_page and adjust_pool_surplus are only called from
the routine set_max_huge_pages after boot. set_max_huge_pages is only
called as the reusult of a user writing to the proc/sysfs nr_hugepages,
or nr_hugepages_mempolicy file to adjust the number of hugetlb pages.
It makes little sense to allow multiple adjustment to the number of
hugetlb pages in parallel. Add a mutex to the hstate and use it to only
allow one hugetlb page adjustment at a time. This will synchronize
modifications to the next_nid_to_alloc variable.
Link: https://lkml.kernel.org/r/20210409205254.242291-4-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Remove nrexceptional tracking", v2.
We actually use nrexceptional for very little these days. It's a minor
pain to keep in sync with nrpages, but the pain becomes much bigger with
the THP patches because we don't know how many indices a shadow entry
occupies. It's easier to just remove it than keep it accurate.
Also, we save 8 bytes per inode which is nothing to sneeze at; on my
laptop, it would improve shmem_inode_cache from 22 to 23 objects per
16kB, and inode_cache from 26 to 27 objects. Combined, that saves
a megabyte of memory from a combined usage of 25MB for both caches.
Unfortunately, ext4 doesn't cross a magic boundary, so it doesn't save
any memory for ext4.
This patch (of 4):
Instead of checking the two counters (nrpages and nrexceptional), we can
just check whether i_pages is empty.
Link: https://lkml.kernel.org/r/20201026151849.24232-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20201026151849.24232-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Revert the uAPI changes from the below commit with notice that these
regions and capabilities are no longer provided.
Fixes: b392a19891 ("vfio/pci: remove vfio_pci_nvlink2")
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <162014341432.3807030.11054087109120670135.stgit@omen>
Pull f2fs updates from Jaegeuk Kim:
"In this round, we added a new mount option, "checkpoint_merge", which
introduces a kernel thread dealing with the f2fs checkpoints. Once we
start to manage the IO priority along with blk-cgroup, the checkpoint
operation can be processed in a lower priority under the process
context. Since the checkpoint holds all the filesystem operations, we
give a higher priority to the checkpoint thread all the time.
Enhancements:
- introduce gc_merge mount option to introduce a checkpoint thread
- improve to run discard thread efficiently
- allow modular compression algorithms
- expose # of overprivision segments to sysfs
- expose runtime compression stat to sysfs
Bug fixes:
- fix OOB memory access by the node id lookup
- avoid touching checkpointed data in the checkpoint-disabled mode
- fix the resizing flow to avoid kernel panic and race conditions
- fix block allocation issues on pinned files
- address some swapfile issues
- fix hugtask problem and kernel panic during atomic write operations
- don't start checkpoint thread in RO
And, we've cleaned up some kernel coding style and build warnings. In
addition, we fixed some minor race conditions and error handling
routines"
* tag 'f2fs-for-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (48 commits)
f2fs: drop inplace IO if fs status is abnormal
f2fs: compress: remove unneed check condition
f2fs: clean up left deprecated IO trace codes
f2fs: avoid using native allocate_segment_by_default()
f2fs: remove unnecessary struct declaration
f2fs: fix to avoid NULL pointer dereference
f2fs: avoid duplicated codes for cleanup
f2fs: document: add description about compressed space handling
f2fs: clean up build warnings
f2fs: fix the periodic wakeups of discard thread
f2fs: fix to avoid accessing invalid fio in f2fs_allocate_data_block()
f2fs: fix to avoid GC/mmap race with f2fs_truncate()
f2fs: set checkpoint_merge by default
f2fs: Fix a hungtask problem in atomic write
f2fs: fix to restrict mount condition on readonly block device
f2fs: introduce gc_merge mount option
f2fs: fix to cover __allocate_new_section() with curseg_lock
f2fs: fix wrong alloc_type in f2fs_do_replace_block
f2fs: delete empty compress.h
f2fs: fix a typo in inode.c
...
Pull dmaengine updates from Vinod Koul:
"New drivers/devices:
- Support for QCOM SM8150 GPI DMA
Updates:
- Big pile of idxd updates including support for performance
monitoring
- Support in dw-edma for interleaved dma
- Support for synchronize() in Xilinx driver"
* tag 'dmaengine-5.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (42 commits)
dmaengine: idxd: Enable IDXD performance monitor support
dmaengine: idxd: Add IDXD performance monitor support
dmaengine: idxd: remove MSIX masking for interrupt handlers
dmaengine: idxd: device cmd should use dedicated lock
dmaengine: idxd: support reporting of halt interrupt
dmaengine: idxd: enable SVA feature for IOMMU
dmaengine: idxd: convert sprintf() to sysfs_emit() for all usages
dmaengine: idxd: add interrupt handle request and release support
dmaengine: idxd: add support for readonly config mode
dmaengine: idxd: add percpu_ref to descriptor submission path
dmaengine: idxd: remove detection of device type
dmaengine: idxd: iax bus removal
dmaengine: idxd: fix cdev setup and free device lifetime issues
dmaengine: idxd: fix group conf_dev lifetime
dmaengine: idxd: fix engine conf_dev lifetime
dmaengine: idxd: fix wq conf_dev 'struct device' lifetime
dmaengine: idxd: fix idxd conf_dev 'struct device' lifetime
dmaengine: idxd: use ida for device instance enumeration
dmaengine: idxd: removal of pcim managed mmio mapping
dmaengine: idxd: cleanup pci interrupt vector allocation management
...
Pull remoteproc updates from Bjorn Andersson:
"This adds support to the remoteproc core for detaching Linux from a
running remoteproc, e.g. to reboot Linux while leaving the remoteproc
running, and it enable this support in the stm32 remoteproc driver.
It also introduces a property for memory carveouts to track if they
are iomem or system ram, to enable proper handling of the differences.
The imx_rproc received a number of fixes and improvements, in
particular support for attaching to already running remote processors
and i.MX8MQ and i.MX8MM support.
The Qualcomm wcss driver gained support for starting and stopping the
wireless subsystem on QCS404, when not using the TrustZone-based
validator/loader.
Finally it brings a few fixes to the TI PRU and to the firmware loader
for the Qualcomm modem subsystem drivers"
* tag 'rproc-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc: (53 commits)
remoteproc: stm32: add capability to detach
dt-bindings: remoteproc: stm32-rproc: add new mailbox channel for detach
remoteproc: imx_rproc: support remote cores booted before Linux Kernel
remoteproc: imx_rproc: move memory parsing to rproc_ops
remoteproc: imx_rproc: enlarge IMX7D_RPROC_MEM_MAX
remoteproc: imx_rproc: add missing of_node_put
remoteproc: imx_rproc: fix build error without CONFIG_MAILBOX
remoteproc: qcom: wcss: Remove unnecessary PTR_ERR()
remoteproc: qcom: wcss: Fix wrong pointer passed to PTR_ERR()
remoteproc: qcom: pas: Add modem support for SDX55
dt-bindings: remoteproc: qcom: pas: Add binding for SDX55
remoteproc: qcom: wcss: Fix return value check in q6v5_wcss_init_mmio()
remoteproc: pru: Fix and cleanup firmware interrupt mapping logic
remoteproc: pru: Fix wrong success return value for fw events
remoteproc: pru: Fixup interrupt-parent logic for fw events
remoteproc: qcom: wcnss: Allow specifying firmware-name
remoteproc: qcom: wcss: explicitly request exclusive reset control
remoteproc: qcom: wcss: Add non pas wcss Q6 support for QCS404
dt-bindings: remoteproc: qcom: Add Q6V5 Modem PIL binding for QCS404
remoteproc: qcom: wcss: populate hardcoded param using driver data
...
Pull rpmsg updates from Bjorn Andersson:
"In addition to some bug fixes and cleanups this adds support for
exposing the virtio based transport to user space using the rpmsg_char
driver"
* tag 'rpmsg-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/andersson/remoteproc:
rpmsg: qcom_glink_native: fix error return code of qcom_glink_rx_data()
rpmsg: char: Return an error if device already open
rpmsg: virtio: Register the rpmsg_char device
rpmsg: char: Use rpmsg_sendto to specify the message destination address
rpmsg: Add short description of the IOCTL defined in UAPI.
rpmsg: Move RPMSG_ADDR_ANY in user API
rpmsg: char: Rename rpmsg_char_init to rpmsg_chrdev_init
Pull swiotlb updates from Konrad Rzeszutek Wilk:
"Christoph Hellwig has taken a cleaver and trimmed off the not-needed
code and nicely folded duplicate code in the generic framework.
This lays the groundwork for more work to add extra DMA-backend-ish in
the future. Along with that some bug-fixes to make this a nice working
package"
* 'stable/for-linus-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: don't override user specified size in swiotlb_adjust_size
swiotlb: Fix the type of index
swiotlb: Make SWIOTLB_NO_FORCE perform no allocation
ARM: Qualify enabling of swiotlb_init()
swiotlb: remove swiotlb_nr_tbl
swiotlb: dynamically allocate io_tlb_default_mem
swiotlb: move global variables into a new io_tlb_mem structure
xen-swiotlb: remove the unused size argument from xen_swiotlb_fixup
xen-swiotlb: split xen_swiotlb_init
swiotlb: lift the double initialization protection from xen-swiotlb
xen-swiotlb: remove xen_io_tlb_start and xen_io_tlb_nslabs
xen-swiotlb: remove xen_set_nslabs
xen-swiotlb: use io_tlb_end in xen_swiotlb_dma_supported
xen-swiotlb: use is_swiotlb_buffer in is_xen_swiotlb_buffer
swiotlb: split swiotlb_tbl_sync_single
swiotlb: move orig addr and size validation into swiotlb_bounce
swiotlb: remove the alloc_size parameter to swiotlb_tbl_unmap_single
powerpc/svm: stop using io_tlb_start
Pull dma-mapping updates from Christoph Hellwig:
- add a new dma_alloc_noncontiguous API (me, Ricardo Ribalda)
- fix a copyright notice (Hao Fang)
- add an unlikely annotation to dma_mapping_error (Heiner Kallweit)
- remove a pointless empty line (Wang Qing)
- add support for multi-pages map/unmap bencharking (Xiang Chen)
* tag 'dma-mapping-5.13' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: add unlikely hint to error path in dma_mapping_error
dma-mapping: benchmark: Add support for multi-pages map/unmap
dma-mapping: benchmark: use the correct HiSilicon copyright
dma-mapping: remove a pointless empty line in dma_alloc_coherent
media: uvcvideo: Use dma_alloc_noncontiguous API
dma-iommu: implement ->alloc_noncontiguous
dma-iommu: refactor iommu_dma_alloc_remap
dma-mapping: add a dma_alloc_noncontiguous API
dma-mapping: refactor dma_{alloc,free}_pages
dma-mapping: add a dma_mmap_pages helper
The only remaining user of ->io_private is the generic ioend merging
infrastructure. The only user of that is XFS, which no longer sets
->io_private or passes an associated merge callback. Remove the
unused parameter and the ->io_private field.
CC: linux-fsdevel@vger.kernel.org
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
- Add reset_control_rearm() stub for !CONFIG_RESET_CONTROLLER (Jim Quinlan)
- Fix use of BCM7216 reset controller (Jim Quinlan)
- Use reset/rearm for Broadcom STB pulse reset instead of deassert/assert
(Jim Quinlan)
* pci/brcmstb:
PCI: brcmstb: Use reset/rearm instead of deassert/assert
ata: ahci_brcm: Fix use of BCM7216 reset controller
reset: add missing empty function reset_control_rearm()
- Convert tegra to MSI domains (Marc Zyngier)
- Use rcar controller address as MSI doorbell instead of allocating a page
(Marc Zyngier)
- Convert rcar to MSI domains (Marc Zyngier)
- Use xilinx port structure as MSI doorbell instead of allocating a page
(Marc Zyngier)
- Convert xilinx to MSI domains (Marc Zyngier)
- Remove unused Hyper-V msi_controller structure (Marc Zyngier)
- Remove unused PCI core msi_controller support (Marc Zyngier)
- Remove struct msi_controller (Marc Zyngier)
- Remove unused default_teardown_msi_irqs() (Marc Zyngier)
- Let host bridges declare their reliance on MSI domains (Marc Zyngier)
- Make pci_host_common_probe() declare its reliance on MSI domains (Marc
Zyngier)
- Advertise mediatek lack of built-in MSI handling (Thomas Gleixner)
- Document ways of ending up with NO_MSI (Marc Zyngier)
- Refactor HT advertising of NO_MSI flag (Marc Zyngier)
* remotes/lorenzo/pci/msi:
PCI: Refactor HT advertising of NO_MSI flag
PCI/MSI: Document the various ways of ending up with NO_MSI
PCI: mediatek: Advertise lack of built-in MSI handling
PCI/MSI: Make pci_host_common_probe() declare its reliance on MSI domains
PCI/MSI: Let PCI host bridges declare their reliance on MSI domains
PCI/MSI: Kill default_teardown_msi_irqs()
PCI/MSI: Kill msi_controller structure
PCI/MSI: Drop use of msi_controller from core code
PCI: hv: Drop msi_controller structure
PCI: xilinx: Convert to MSI domains
PCI: xilinx: Don't allocate extra memory for the MSI capture address
PCI: rcar: Convert to MSI domains
PCI: rcar: Don't allocate extra memory for the MSI capture address
PCI: tegra: Convert to MSI domains
When switching virtio_pci_modern to use a helper for mappings we lost an
__iomem tag. Restore it.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 9e3bb9b79a ("virtio_pci_modern: introduce helper to map vq notify area")
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Daniel Borkmann says:
====================
pull-request: bpf 2021-05-04
The following pull-request contains BPF updates for your *net* tree.
We've added 5 non-merge commits during the last 4 day(s) which contain
a total of 6 files changed, 52 insertions(+), 30 deletions(-).
The main changes are:
1) Fix libbpf overflow when processing BPF ring buffer in case of extreme
application behavior, from Brendan Jackman.
2) Fix potential data leakage of uninitialized BPF stack under speculative
execution, from Daniel Borkmann.
3) Fix off-by-one when validating xsk pool chunks, from Xuan Zhuo.
4) Fix snprintf BPF selftest with a pid filter to avoid racing its output
test buffer, from Florent Revest.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Like with iptables and ebtables, hook unregistration has to use the
pernet ops struct, not the template.
This triggered following splat:
hook not found, pf 3 num 0
WARNING: CPU: 0 PID: 224 at net/netfilter/core.c:480 __nf_unregister_net_hook+0x1eb/0x610 net/netfilter/core.c:480
[..]
nf_unregister_net_hook net/netfilter/core.c:502 [inline]
nf_unregister_net_hooks+0x117/0x160 net/netfilter/core.c:576
arpt_unregister_table_pre_exit+0x67/0x80 net/ipv4/netfilter/arp_tables.c:1565
Fixes: f9006acc8d ("netfilter: arp_tables: pass table pointer via nf_hook_ops")
Reported-by: syzbot+dcccba8a1e41a38cb9df@syzkaller.appspotmail.com
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This extension breaks when trying to delete rules, add a new revision to
fix this.
Fixes: 5e6874cdb8 ("[SECMARK]: Add xtables SECMARK target")
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Pull tracing updates from Steven Rostedt:
"New feature:
- A new "func-no-repeats" option in tracefs/options directory.
When set the function tracer will detect if the current function
being traced is the same as the previous one, and instead of
recording it, it will keep track of the number of times that the
function is repeated in a row. And when another function is
recorded, it will write a new event that shows the function that
repeated, the number of times it repeated and the time stamp of
when the last repeated function occurred.
Enhancements:
- In order to implement the above "func-no-repeats" option, the ring
buffer timestamp can now give the accurate timestamp of the event
as it is being recorded, instead of having to record an absolute
timestamp for all events. This helps the histogram code which no
longer needs to waste ring buffer space.
- New validation logic to make sure all trace events that access
dereferenced pointers do so in a safe way, and will warn otherwise.
Fixes:
- No longer limit the PIDs of tasks that are recorded for
"saved_cmdlines" to PID_MAX_DEFAULT (32768), as systemd now allows
for a much larger range. This caused the mapping of PIDs to the
task names to be dropped for all tasks with a PID greater than
32768.
- Change trace_clock_global() to never block. This caused a deadlock.
Clean ups:
- Typos, prototype fixes, and removing of duplicate or unused code.
- Better management of ftrace_page allocations"
* tag 'trace-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (32 commits)
tracing: Restructure trace_clock_global() to never block
tracing: Map all PIDs to command lines
ftrace: Reuse the output of the function tracer for func_repeats
tracing: Add "func_no_repeats" option for function tracing
tracing: Unify the logic for function tracing options
tracing: Add method for recording "func_repeats" events
tracing: Add "last_func_repeats" to struct trace_array
tracing: Define new ftrace event "func_repeats"
tracing: Define static void trace_print_time()
ftrace: Simplify the calculation of page number for ftrace_page->records some more
ftrace: Store the order of pages allocated in ftrace_page
tracing: Remove unused argument from "ring_buffer_time_stamp()
tracing: Remove duplicate struct declaration in trace_events.h
tracing: Update create_system_filter() kernel-doc comment
tracing: A minor cleanup for create_system_filter()
kernel: trace: Mundane typo fixes in the file trace_events_filter.c
tracing: Fix various typos in comments
scripts/recordmcount.pl: Make vim and emacs indent the same
scripts/recordmcount.pl: Make indent spacing consistent
tracing: Add a verifier to check string pointers for trace events
...
Pull receive_fd update from Al Viro:
"Cleanup of receive_fd mess"
* 'work.file' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: split receive_fd_replace from __receive_fd
bio size can grow up to 4GB when muli-page bvec is enabled.
but sometimes it would lead to inefficient behaviors.
in case of large chunk direct I/O, - 32MB chunk read in user space -
all pages for 32MB would be merged to a bio structure if the pages
physical addresses are contiguous. it makes some delay to submit
until merge complete. bio max size should be limited to a proper size.
When 32MB chunk read with direct I/O option is coming from userspace,
kernel behavior is below now in do_direct_IO() loop. it's timeline.
| bio merge for 32MB. total 8,192 pages are merged.
| total elapsed time is over 2ms.
|------------------ ... ----------------------->|
| 8,192 pages merged a bio.
| at this time, first bio submit is done.
| 1 bio is split to 32 read request and issue.
|--------------->
|--------------->
|--------------->
......
|--------------->
|--------------->|
total 19ms elapsed to complete 32MB read done from device. |
If bio max size is limited with 1MB, behavior is changed below.
| bio merge for 1MB. 256 pages are merged for each bio.
| total 32 bio will be made.
| total elapsed time is over 2ms. it's same.
| but, first bio submit timing is fast. about 100us.
|--->|--->|--->|---> ... -->|--->|--->|--->|--->|
| 256 pages merged a bio.
| at this time, first bio submit is done.
| and 1 read request is issued for 1 bio.
|--------------->
|--------------->
|--------------->
......
|--------------->
|--------------->|
total 17ms elapsed to complete 32MB read done from device. |
As a result, read request issue timing is faster if bio max size is limited.
Current kernel behavior with multipage bvec, super large bio can be created.
And it lead to delay first I/O request issue.
Signed-off-by: Changheun Lee <nanich.lee@samsung.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20210503095203.29076-1-nanich.lee@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The current implemented mechanisms to mitigate data disclosure under
speculation mainly address stack and map value oob access from the
speculative domain. However, Piotr discovered that uninitialized BPF
stack is not protected yet, and thus old data from the kernel stack,
potentially including addresses of kernel structures, could still be
extracted from that 512 bytes large window. The BPF stack is special
compared to map values since it's not zero initialized for every
program invocation, whereas map values /are/ zero initialized upon
their initial allocation and thus cannot leak any prior data in either
domain. In the non-speculative domain, the verifier ensures that every
stack slot read must have a prior stack slot write by the BPF program
to avoid such data leaking issue.
However, this is not enough: for example, when the pointer arithmetic
operation moves the stack pointer from the last valid stack offset to
the first valid offset, the sanitation logic allows for any intermediate
offsets during speculative execution, which could then be used to
extract any restricted stack content via side-channel.
Given for unprivileged stack pointer arithmetic the use of unknown
but bounded scalars is generally forbidden, we can simply turn the
register-based arithmetic operation into an immediate-based arithmetic
operation without the need for masking. This also gives the benefit
of reducing the needed instructions for the operation. Given after
the work in 7fedb63a83 ("bpf: Tighten speculative pointer arithmetic
mask"), the aux->alu_limit already holds the final immediate value for
the offset register with the known scalar. Thus, a simple mov of the
immediate to AX register with using AX as the source for the original
instruction is sufficient and possible now in this case.
Reported-by: Piotr Krysiuk <piotras@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Piotr Krysiuk <piotras@gmail.com>
Reviewed-by: Piotr Krysiuk <piotras@gmail.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Usually iotlb accesses are synchronized with a spinlock.
Let's request it as a new parameter in vringh_set_iotlb() and
hold it when we navigate the iotlb in iotlb_translate() to avoid
race conditions with any new additions/deletions of ranges from
the ioltb.
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210315163450.254396-3-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
