Commit graph

327 commits

Author SHA1 Message Date
Randy Dunlap
06bbb761c1 fuse: fix all W=1 kernel-doc warnings
Use correct function name in kernel-doc notation. (1)
Don't use "/**" to begin non-kernel-doc comments. (3)

Fixes these warnings:

fs/fuse/cuse.c:272: warning: expecting prototype for cuse_parse_dev_info(). Prototype was for cuse_parse_devinfo() instead
fs/fuse/dev.c:212: warning: expecting prototype for A new request is available, wake fiq(). Prototype was for fuse_dev_wake_and_unlock() instead
fs/fuse/dir.c:149: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
fs/fuse/file.c:656: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
 * In case of short read, the caller sets 'pos' to the position of

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-01-26 17:10:58 +01:00
Miklos Szeredi
15d937d7ca fuse: add request extension
Will need to add supplementary groups to create messages, so add the
general concept of a request extension.  A request extension is appended to
the end of the main request.  It has a header indicating the size and type
of the extension.

The create security context (fuse_secctx_*) is similar to the generic
request extension, so include that as well in a backward compatible manner.

Add the total extension length to the request header.  The offset of the
extension block within the request can be calculated by:

  inh->len - inh->total_extlen * 8

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2023-01-26 17:10:37 +01:00
Linus Torvalds
e2ca6ba6ba MM patches for 6.2-rc1.
- More userfaultfs work from Peter Xu.
 
 - Several convert-to-folios series from Sidhartha Kumar and Huang Ying.
 
 - Some filemap cleanups from Vishal Moola.
 
 - David Hildenbrand added the ability to selftest anon memory COW handling.
 
 - Some cpuset simplifications from Liu Shixin.
 
 - Addition of vmalloc tracing support by Uladzislau Rezki.
 
 - Some pagecache folioifications and simplifications from Matthew Wilcox.
 
 - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use it.
 
 - Miguel Ojeda contributed some cleanups for our use of the
   __no_sanitize_thread__ gcc keyword.  This series shold have been in the
   non-MM tree, my bad.
 
 - Naoya Horiguchi improved the interaction between memory poisoning and
   memory section removal for huge pages.
 
 - DAMON cleanups and tuneups from SeongJae Park
 
 - Tony Luck fixed the handling of COW faults against poisoned pages.
 
 - Peter Xu utilized the PTE marker code for handling swapin errors.
 
 - Hugh Dickins reworked compound page mapcount handling, simplifying it
   and making it more efficient.
 
 - Removal of the autonuma savedwrite infrastructure from Nadav Amit and
   David Hildenbrand.
 
 - zram support for multiple compression streams from Sergey Senozhatsky.
 
 - David Hildenbrand reworked the GUP code's R/O long-term pinning so
   that drivers no longer need to use the FOLL_FORCE workaround which
   didn't work very well anyway.
 
 - Mel Gorman altered the page allocator so that local IRQs can remnain
   enabled during per-cpu page allocations.
 
 - Vishal Moola removed the try_to_release_page() wrapper.
 
 - Stefan Roesch added some per-BDI sysfs tunables which are used to
   prevent network block devices from dirtying excessive amounts of
   pagecache.
 
 - David Hildenbrand did some cleanup and repair work on KSM COW
   breaking.
 
 - Nhat Pham and Johannes Weiner have implemented writeback in zswap's
   zsmalloc backend.
 
 - Brian Foster has fixed a longstanding corner-case oddity in
   file[map]_write_and_wait_range().
 
 - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
   Chen.
 
 - Shiyang Ruan has done some work on fsdax, to make its reflink mode
   work better under xfstests.  Better, but still not perfect.
 
 - Christoph Hellwig has removed the .writepage() method from several
   filesystems.  They only need .writepages().
 
 - Yosry Ahmed wrote a series which fixes the memcg reclaim target
   beancounting.
 
 - David Hildenbrand has fixed some of our MM selftests for 32-bit
   machines.
 
 - Many singleton patches, as usual.
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Merge tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - More userfaultfs work from Peter Xu

 - Several convert-to-folios series from Sidhartha Kumar and Huang Ying

 - Some filemap cleanups from Vishal Moola

 - David Hildenbrand added the ability to selftest anon memory COW
   handling

 - Some cpuset simplifications from Liu Shixin

 - Addition of vmalloc tracing support by Uladzislau Rezki

 - Some pagecache folioifications and simplifications from Matthew
   Wilcox

 - A pagemap cleanup from Kefeng Wang: we have VM_ACCESS_FLAGS, so use
   it

 - Miguel Ojeda contributed some cleanups for our use of the
   __no_sanitize_thread__ gcc keyword.

   This series should have been in the non-MM tree, my bad

 - Naoya Horiguchi improved the interaction between memory poisoning and
   memory section removal for huge pages

 - DAMON cleanups and tuneups from SeongJae Park

 - Tony Luck fixed the handling of COW faults against poisoned pages

 - Peter Xu utilized the PTE marker code for handling swapin errors

 - Hugh Dickins reworked compound page mapcount handling, simplifying it
   and making it more efficient

 - Removal of the autonuma savedwrite infrastructure from Nadav Amit and
   David Hildenbrand

 - zram support for multiple compression streams from Sergey Senozhatsky

 - David Hildenbrand reworked the GUP code's R/O long-term pinning so
   that drivers no longer need to use the FOLL_FORCE workaround which
   didn't work very well anyway

 - Mel Gorman altered the page allocator so that local IRQs can remnain
   enabled during per-cpu page allocations

 - Vishal Moola removed the try_to_release_page() wrapper

 - Stefan Roesch added some per-BDI sysfs tunables which are used to
   prevent network block devices from dirtying excessive amounts of
   pagecache

 - David Hildenbrand did some cleanup and repair work on KSM COW
   breaking

 - Nhat Pham and Johannes Weiner have implemented writeback in zswap's
   zsmalloc backend

 - Brian Foster has fixed a longstanding corner-case oddity in
   file[map]_write_and_wait_range()

 - sparse-vmemmap changes for MIPS, LoongArch and NIOS2 from Feiyang
   Chen

 - Shiyang Ruan has done some work on fsdax, to make its reflink mode
   work better under xfstests. Better, but still not perfect

 - Christoph Hellwig has removed the .writepage() method from several
   filesystems. They only need .writepages()

 - Yosry Ahmed wrote a series which fixes the memcg reclaim target
   beancounting

 - David Hildenbrand has fixed some of our MM selftests for 32-bit
   machines

 - Many singleton patches, as usual

* tag 'mm-stable-2022-12-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (313 commits)
  mm/hugetlb: set head flag before setting compound_order in __prep_compound_gigantic_folio
  mm: mmu_gather: allow more than one batch of delayed rmaps
  mm: fix typo in struct pglist_data code comment
  kmsan: fix memcpy tests
  mm: add cond_resched() in swapin_walk_pmd_entry()
  mm: do not show fs mm pc for VM_LOCKONFAULT pages
  selftests/vm: ksm_functional_tests: fixes for 32bit
  selftests/vm: cow: fix compile warning on 32bit
  selftests/vm: madv_populate: fix missing MADV_POPULATE_(READ|WRITE) definitions
  mm/gup_test: fix PIN_LONGTERM_TEST_READ with highmem
  mm,thp,rmap: fix races between updates of subpages_mapcount
  mm: memcg: fix swapcached stat accounting
  mm: add nodes= arg to memory.reclaim
  mm: disable top-tier fallback to reclaim on proactive reclaim
  selftests: cgroup: make sure reclaim target memcg is unprotected
  selftests: cgroup: refactor proactive reclaim code to reclaim_until()
  mm: memcg: fix stale protection of reclaim target memcg
  mm/mmap: properly unaccount memory on mas_preallocate() failure
  omfs: remove ->writepage
  jfs: remove ->writepage
  ...
2022-12-13 19:29:45 -08:00
Vishal Moola (Oracle)
063aaad792 fuse: convert fuse_try_move_page() to use folios
Converts the function to try to move folios instead of pages. Also
converts fuse_check_page() to fuse_get_folio() since this is its only
caller. This change removes 15 calls to compound_head().

Link: https://lkml.kernel.org/r/20221101175326.13265-3-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:12 -08:00
Vishal Moola (Oracle)
3720dd6dca filemap: convert replace_page_cache_page() to replace_page_cache_folio()
Patch series "Removing the lru_cache_add() wrapper".

This patchset replaces all calls of lru_cache_add() with the folio
equivalent: folio_add_lru().  This is allows us to get rid of the wrapper
The series passes xfstests and the userfaultfd selftests.


This patch (of 5):

Eliminates 7 calls to compound_head().

Link: https://lkml.kernel.org/r/20221101175326.13265-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20221101175326.13265-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-12-11 18:12:12 -08:00
Jann Horn
0618021e34 fuse: Remove user_ns check for FUSE_DEV_IOC_CLONE
Commit 8ed1f0e22f ("fs/fuse: fix ioctl type confusion") fixed a type
confusion bug by adding an ->f_op comparison.

Based on some off-list discussion back then, another check was added to
compare the f_cred->user_ns.  This is not for security reasons, but was
based on the idea that a FUSE device FD should be using the UID/GID
mappings of its f_cred->user_ns, and those translations are done using
fc->user_ns, which matches the f_cred->user_ns of the initial FUSE device
FD thanks to the check in fuse_fill_super().  See also commit 8cb08329b0
("fuse: Support fuse filesystems outside of init_user_ns").

But FUSE_DEV_IOC_CLONE is, at a higher level, a *cloning* operation that
copies an existing context (with a weird API that involves first opening
/dev/fuse, then tying the resulting new FUSE device FD to an existing FUSE
instance).  So if an application is already passing FUSE FDs across userns
boundaries and dealing with the resulting ID mapping complications somehow,
it doesn't make much sense to block this cloning operation.

I've heard that this check is an obstacle for some folks, and I don't see a
good reason to keep it, so remove it.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2022-11-23 09:10:49 +01:00
Miklos Szeredi
4f8d37020e fuse: add "expire only" mode to FUSE_NOTIFY_INVAL_ENTRY
Add a flag to entry expiration that lets the filesystem expire a dentry
without kicking it out from the cache immediately.

This makes a difference for overmounted dentries, where plain invalidation
would detach all submounts before dropping the dentry from the cache.  If
only expiry is set on the dentry, then any overmounts are left alone and
until ->d_revalidate() is called.

Note: ->d_revalidate() is not called for the case of following a submount,
so invalidation will only be triggered for the non-overmounted case.  The
dentry could also be mounted in a different mount instance, in which case
any submounts will still be detached.

Suggested-by: Jakob Blomer <jblomer@cern.ch>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2022-11-23 09:10:49 +01:00
Yu Zhao
ec1c86b25f mm: multi-gen LRU: groundwork
Evictable pages are divided into multiple generations for each lruvec.
The youngest generation number is stored in lrugen->max_seq for both
anon and file types as they are aged on an equal footing. The oldest
generation numbers are stored in lrugen->min_seq[] separately for anon
and file types as clean file pages can be evicted regardless of swap
constraints. These three variables are monotonically increasing.

Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits
in order to fit into the gen counter in folio->flags. Each truncated
generation number is an index to lrugen->lists[]. The sliding window
technique is used to track at least MIN_NR_GENS and at most
MAX_NR_GENS generations. The gen counter stores a value within [1,
MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it
stores 0.

There are two conceptually independent procedures: "the aging", which
produces young generations, and "the eviction", which consumes old
generations.  They form a closed-loop system, i.e., "the page reclaim". 
Both procedures can be invoked from userspace for the purposes of working
set estimation and proactive reclaim.  These techniques are commonly used
to optimize job scheduling (bin packing) in data centers [1][2].

To avoid confusion, the terms "hot" and "cold" will be applied to the
multi-gen LRU, as a new convention; the terms "active" and "inactive" will
be applied to the active/inactive LRU, as usual.

The protection of hot pages and the selection of cold pages are based
on page access channels and patterns. There are two access channels:
one through page tables and the other through file descriptors. The
protection of the former channel is by design stronger because:
1. The uncertainty in determining the access patterns of the former
   channel is higher due to the approximation of the accessed bit.
2. The cost of evicting the former channel is higher due to the TLB
   flushes required and the likelihood of encountering the dirty bit.
3. The penalty of underprotecting the former channel is higher because
   applications usually do not prepare themselves for major page
   faults like they do for blocked I/O. E.g., GUI applications
   commonly use dedicated I/O threads to avoid blocking rendering
   threads.

There are also two access patterns: one with temporal locality and the
other without.  For the reasons listed above, the former channel is
assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is
present; the latter channel is assumed to follow the latter pattern unless
outlying refaults have been observed [3][4].

The next patch will address the "outlying refaults".  Three macros, i.e.,
LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in
this patch to make the entire patchset less diffy.

A page is added to the youngest generation on faulting.  The aging needs
to check the accessed bit at least twice before handing this page over to
the eviction.  The first check takes care of the accessed bit set on the
initial fault; the second check makes sure this page has not been used
since then.  This protocol, AKA second chance, requires a minimum of two
generations, hence MIN_NR_GENS.

[1] https://dl.acm.org/doi/10.1145/3297858.3304053
[2] https://dl.acm.org/doi/10.1145/3503222.3507731
[3] https://lwn.net/Articles/495543/
[4] https://lwn.net/Articles/815342/

Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org>
Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Acked-by: Steven Barrett <steven@liquorix.net>
Acked-by: Suleiman Souhlal <suleiman@google.com>
Tested-by: Daniel Byrne <djbyrne@mtu.edu>
Tested-by: Donald Carr <d@chaos-reins.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru>
Tested-by: Shuang Zhai <szhai2@cs.rochester.edu>
Tested-by: Sofia Trinh <sofia.trinh@edi.works>
Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-26 19:46:09 -07:00
Al Viro
1ef255e257 iov_iter: advancing variants of iov_iter_get_pages{,_alloc}()
Most of the users immediately follow successful iov_iter_get_pages()
with advancing by the amount it had returned.

Provide inline wrappers doing that, convert trivial open-coded
uses of those.

BTW, iov_iter_get_pages() never returns more than it had been asked
to; such checks in cifs ought to be removed someday...

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-08-08 22:37:22 -04:00
Al Viro
fcb14cb1bd new iov_iter flavour - ITER_UBUF
Equivalent of single-segment iovec.  Initialized by iov_iter_ubuf(),
checked for by iter_is_ubuf(), otherwise behaves like ITER_IOVEC
ones.

We are going to expose the things like ->write_iter() et.al. to those
in subsequent commits.

New predicate (user_backed_iter()) that is true for ITER_IOVEC and
ITER_UBUF; places like direct-IO handling should use that for
checking that pages we modify after getting them from iov_iter_get_pages()
would need to be dirtied.

DO NOT assume that replacing iter_is_iovec() with user_backed_iter()
will solve all problems - there's code that uses iter_is_iovec() to
decide how to poke around in iov_iter guts and for that the predicate
replacement obviously won't suffice.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-08-08 22:37:15 -04:00
NeilBrown
670d21c6e1 fuse: remove reliance on bdi congestion
The bdi congestion tracking in not widely used and will be removed.

Fuse is one of a small number of filesystems that uses it, setting both
the sync (read) and async (write) congestion flags at what it determines
are appropriate times.

The only remaining effect of the sync flag is to cause read-ahead to be
skipped.  The only remaining effect of the async flag is to cause (some)
WB_SYNC_NONE writes to be skipped.

So instead of setting the flags, change:

 - .readahead to stop when it has submitted all non-async pages for
   read.

 - .writepages to do nothing if WB_SYNC_NONE and the flag would be set

 - .writepage to return AOP_WRITEPAGE_ACTIVATE if WB_SYNC_NONE and the
   flag would be set.

The writepages change causes a behavioural change in that pageout() can
now return PAGE_ACTIVATE instead of PAGE_KEEP, so SetPageActive() will be
called on the page which (I think) will further delay the next attempt at
writeout.  This might be a good thing.

Link: https://lkml.kernel.org/r/164549983737.9187.2627117501000365074.stgit@noble.brown
Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <lars.ellenberg@linbit.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Paolo Valente <paolo.valente@linaro.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-22 15:57:00 -07:00
Miklos Szeredi
0c4bcfdecb fuse: fix pipe buffer lifetime for direct_io
In FOPEN_DIRECT_IO mode, fuse_file_write_iter() calls
fuse_direct_write_iter(), which normally calls fuse_direct_io(), which then
imports the write buffer with fuse_get_user_pages(), which uses
iov_iter_get_pages() to grab references to userspace pages instead of
actually copying memory.

On the filesystem device side, these pages can then either be read to
userspace (via fuse_dev_read()), or splice()d over into a pipe using
fuse_dev_splice_read() as pipe buffers with &nosteal_pipe_buf_ops.

This is wrong because after fuse_dev_do_read() unlocks the FUSE request,
the userspace filesystem can mark the request as completed, causing write()
to return. At that point, the userspace filesystem should no longer have
access to the pipe buffer.

Fix by copying pages coming from the user address space to new pipe
buffers.

Reported-by: Jann Horn <jannh@google.com>
Fixes: c3021629a0 ("fuse: support splice() reading from fuse device")
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2022-03-07 16:30:44 +01:00
Miklos Szeredi
473441720c fuse: release pipe buf after last use
Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.

This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.

Reported-by: Justin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-11-25 14:05:18 +01:00
Miklos Szeredi
712a951025 fuse: fix page stealing
It is possible to trigger a crash by splicing anon pipe bufs to the fuse
device.

The reason for this is that anon_pipe_buf_release() will reuse buf->page if
the refcount is 1, but that page might have already been stolen and its
flags modified (e.g. PG_lru added).

This happens in the unlikely case of fuse_dev_splice_write() getting around
to calling pipe_buf_release() after a page has been stolen, added to the
page cache and removed from the page cache.

Fix by calling pipe_buf_release() right after the page was inserted into
the page cache.  In this case the page has an elevated refcount so any
release function will know that the page isn't reusable.

Reported-by: Frank Dinoff <fdinoff@google.com>
Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/
Fixes: dd3bb14f44 ("fuse: support splice() writing to fuse device")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-11-02 11:10:37 +01:00
Miklos Szeredi
d347739a0e fuse: always invalidate attributes after writes
Extend the fuse_write_update_attr() helper to invalidate cached attributes
after a write.

This has already been done in all cases except in fuse_notify_store(), so
this is mostly a cleanup.

fuse_direct_write_iter() calls fuse_direct_IO() which already calls
fuse_write_update_attr(), so don't repeat that again in the former.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-28 09:45:32 +02:00
Miklos Szeredi
27ae449ba2 fuse: rename fuse_write_update_size()
This function already updates the attr_version in fuse_inode, regardless of
whether the size was changed or not.

Rename the helper to fuse_write_update_attr() to reflect the more generic
nature.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-28 09:45:32 +02:00
Peng Hao
5fe0fc9f1d fuse: use kmap_local_page()
Due to the introduction of kmap_local_*, the storage of slots used for
short-term mapping has changed from per-CPU to per-thread.  kmap_atomic()
disable preemption, while kmap_local_*() only disable migration.

There is no need to disable preemption in several kamp_atomic places used
in fuse.

Link: https://lwn.net/Articles/836144/
Signed-off-by: Peng Hao <flyingpeng@tencent.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-10-22 17:03:01 +02:00
Miklos Szeredi
e1e71c1688 fuse: fix use after free in fuse_read_interrupt()
There is a potential race between fuse_read_interrupt() and
fuse_request_end().

TASK1
  in fuse_read_interrupt(): delete req->intr_entry (while holding
  fiq->lock)

TASK2
  in fuse_request_end(): req->intr_entry is empty -> skip fiq->lock
  wake up TASK3

TASK3
  request is freed

TASK1
  in fuse_read_interrupt(): dereference req->in.h.unique ***BAM***


Fix by always grabbing fiq->lock if the request was ever interrupted
(FR_INTERRUPTED set) thereby serializing with concurrent
fuse_read_interrupt() calls.

FR_INTERRUPTED is set before the request is queued on fiq->interrupts.
Dequeing the request is done with list_del_init() but FR_INTERRUPTED is not
cleared in this case.

Reported-by: lijiazi <lijiazi@xiaomi.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-08-04 13:22:58 +02:00
Zheng Yongjun
c4e0cd4e0c virtiofs: Fix spelling mistakes
Fix some spelling mistakes in comments:
refernce  ==> reference
happnes  ==> happens
threhold  ==> threshold
splitted  ==> split
mached  ==> matched

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22 09:15:36 +02:00
Miklos Szeredi
49221cf86d fuse: reject internal errno
Don't allow userspace to report errors that could be kernel-internal.

Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Fixes: 334f485df8 ("[PATCH] FUSE - device functions")
Cc: <stable@vger.kernel.org> # v2.6.14
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22 09:15:35 +02:00
Miklos Szeredi
80ef08670d fuse: check connected before queueing on fpq->io
A request could end up on the fpq->io list after fuse_abort_conn() has
reset fpq->connected and aborted requests on that list:

Thread-1			  Thread-2
========			  ========
->fuse_simple_request()           ->shutdown
  ->__fuse_request_send()
    ->queue_request()		->fuse_abort_conn()
->fuse_dev_do_read()                ->acquire(fpq->lock)
  ->wait_for(fpq->lock) 	  ->set err to all req's in fpq->io
				  ->release(fpq->lock)
  ->acquire(fpq->lock)
  ->add req to fpq->io

After the userspace copy is done the request will be ended, but
req->out.h.error will remain uninitialized.  Also the copy might block
despite being already aborted.

Fix both issues by not allowing the request to be queued on the fpq->io
list after fuse_abort_conn() has processed this list.

Reported-by: Pradeep P V K <pragalla@codeaurora.org>
Fixes: fd22d62ed0 ("fuse: no fc->lock for iqueue parts")
Cc: <stable@vger.kernel.org> # v4.2
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-22 09:15:35 +02:00
Miklos Szeredi
b89ecd60d3 fuse: ignore PG_workingset after stealing
Fix the "fuse: trying to steal weird page" warning.

Description from Johannes Weiner:

  "Think of it as similar to PG_active. It's just another usage/heat
   indicator of file and anon pages on the reclaim LRU that, unlike
   PG_active, persists across deactivation and even reclaim (we store it in
   the page cache / swapper cache tree until the page refaults).

   So if fuse accepts pages that can legally have PG_active set,
   PG_workingset is fine too."

Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com>
Fixes: 1899ad18c6 ("mm: workingset: tell cache transitions from workingset thrashing")
Cc: <stable@vger.kernel.org> # v4.20
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-06-18 21:16:42 +02:00
Alessio Balsini
6076f5f341 fuse: fix matching of FUSE_DEV_IOC_CLONE command
With commit f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse
device") the matching constraints for the FUSE_DEV_IOC_CLONE ioctl command
are relaxed, limited to the testing of command type and number.  As Arnd
noticed, this is wrong as it wouldn't ensure the correctness of the data
size or direction for the received FUSE device ioctl.

Fix by bringing back the comparison of the ioctl received by the FUSE
device to the originally generated FUSE_DEV_IOC_CLONE.

Fixes: f8425c9396 ("fuse: 32-bit user space ioctl compat for fuse device")
Reported-by: Arnd Bergmann <arnd@kernel.org>
Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-04-14 10:40:57 +02:00
Alessio Balsini
f8425c9396 fuse: 32-bit user space ioctl compat for fuse device
With a 64-bit kernel build the FUSE device cannot handle ioctl requests
coming from 32-bit user space.  This is due to the ioctl command
translation that generates different command identifiers that thus cannot
be used for direct comparisons without proper manipulation.

Explicitly extract type and number from the ioctl command to enable 32-bit
user space compatibility on 64-bit kernel builds.

Signed-off-by: Alessio Balsini <balsini@android.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-03-16 15:20:16 +01:00
Baolin Wang
1f7ef65774 mm/filemap: remove unused parameter and change to void type for replace_page_cache_page()
Since commit 74d609585d ("page cache: Add and replace pages using the
XArray") was merged, the replace_page_cache_page() can not fail and always
return 0, we can remove the redundant return value and void it.  Moreover
remove the unused gfp_mask.

Link: https://lkml.kernel.org/r/609c30e5274ba15d8b90c872fd0d8ac437a9b2bb.1610071401.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-24 13:38:27 -08:00
Max Reitz
fcee216beb fuse: split fuse_mount off of fuse_conn
We want to allow submounts for the same fuse_conn, but with different
superblocks so that each of the submounts has its own device ID.  To do
so, we need to split all mount-specific information off of fuse_conn
into a new fuse_mount structure, so that multiple mounts can share a
single fuse_conn.

We need to take care only to perform connection-level actions once (i.e.
when the fuse_conn and thus the first fuse_mount are established, or
when the last fuse_mount and thus the fuse_conn are destroyed).  For
example, fuse_sb_destroy() must invoke fuse_send_destroy() until the
last superblock is released.

To do so, we keep track of which fuse_mount is the root mount and
perform all fuse_conn-level actions only when this fuse_mount is
involved.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18 15:17:41 +02:00
Max Reitz
8f622e9497 fuse: drop fuse_conn parameter where possible
With the last commit, all functions that handle some existing fuse_req
no longer need to be given the associated fuse_conn, because they can
get it from the fuse_req object.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18 15:17:41 +02:00
Max Reitz
24754db272 fuse: store fuse_conn in fuse_req
Every fuse_req belongs to a fuse_conn.  Right now, we always know which
fuse_conn that is based on the respective device, but we want to allow
multiple (sub)mounts per single connection, and then the corresponding
filesystem is not going to be so trivial to obtain.

Storing a pointer to the associated fuse_conn in every fuse_req will
allow us to trivially find any request's superblock (and thus
filesystem) even then.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18 15:17:40 +02:00
Miklos Szeredi
d78092e493 fuse: fix page dereference after free
After unlock_request() pages from the ap->pages[] array may be put (e.g. by
aborting the connection) and the pages can be freed.

Prevent use after free by grabbing a reference to the page before calling
unlock_request().

The original patch was created by Pradeep P V K.

Reported-by: Pradeep P V K <ppvk@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-09-18 10:36:50 +02:00
Linus Torvalds
5b14671be5 fuse update for 5.8
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Merge tag 'fuse-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse updates from Miklos Szeredi:

 - Fix a rare deadlock in virtiofs

 - Fix st_blocks in writeback cache mode

 - Fix wrong checks in splice move causing spurious warnings

 - Fix a race between a GETATTR request and a FUSE_NOTIFY_INVAL_INODE
   notification

 - Use rb-tree instead of linear search for pages currently under
   writeout by userspace

 - Fix copy_file_range() inconsistencies

* tag 'fuse-update-5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: copy_file_range should truncate cache
  fuse: fix copy_file_range cache issues
  fuse: optimize writepages search
  fuse: update attr_version counter on fuse_notify_inval_inode()
  fuse: don't check refcount after stealing page
  fuse: fix weird page warning
  fuse: use dump_page
  virtiofs: do not use fuse_fill_super_common() for device installation
  fuse: always allow query of st_dev
  fuse: always flush dirty data on close(2)
  fuse: invalidate inode attr in writeback cache mode
  fuse: Update stale comment in queue_interrupt()
  fuse: BUG_ON correction in fuse_dev_splice_write()
  virtiofs: Add mount option and atime behavior to the doc
  virtiofs: schedule blocking async replies in separate worker
2020-06-09 15:48:24 -07:00
Linus Torvalds
ee01c4d72a Merge branch 'akpm' (patches from Andrew)
Merge more updates from Andrew Morton:
 "More mm/ work, plenty more to come

  Subsystems affected by this patch series: slub, memcg, gup, kasan,
  pagealloc, hugetlb, vmscan, tools, mempolicy, memblock, hugetlbfs,
  thp, mmap, kconfig"

* akpm: (131 commits)
  arm64: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  x86: mm: use ARCH_HAS_DEBUG_WX instead of arch defined
  riscv: support DEBUG_WX
  mm: add DEBUG_WX support
  drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup
  mm/thp: rename pmd_mknotpresent() as pmd_mkinvalid()
  powerpc/mm: drop platform defined pmd_mknotpresent()
  mm: thp: don't need to drain lru cache when splitting and mlocking THP
  hugetlbfs: get unmapped area below TASK_UNMAPPED_BASE for hugetlbfs
  sparc32: register memory occupied by kernel as memblock.memory
  include/linux/memblock.h: fix minor typo and unclear comment
  mm, mempolicy: fix up gup usage in lookup_node
  tools/vm/page_owner_sort.c: filter out unneeded line
  mm: swap: memcg: fix memcg stats for huge pages
  mm: swap: fix vmstats for huge pages
  mm: vmscan: limit the range of LRU type balancing
  mm: vmscan: reclaim writepage is IO cost
  mm: vmscan: determine anon/file pressure balance at the reclaim root
  mm: balance LRU lists based on relative thrashing
  mm: only count actual rotations as LRU reclaim cost
  ...
2020-06-03 20:24:15 -07:00
Johannes Weiner
6058eaec81 mm: fold and remove lru_cache_add_anon() and lru_cache_add_file()
They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().

[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-03 20:09:48 -07:00
Linus Torvalds
ae03c53d00 Merge branch 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull splice updates from Al Viro:
 "Christoph's assorted splice cleanups"

* 'work.splice' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: rename pipe_buf ->steal to ->try_steal
  fs: make the pipe_buf_operations ->confirm operation optional
  fs: make the pipe_buf_operations ->steal operation optional
  trace: remove tracing_pipe_buf_ops
  pipe: merge anon_pipe_buf*_ops
  fs: simplify do_splice_from
  fs: simplify do_splice_to
2020-06-03 15:52:19 -07:00
Christoph Hellwig
c928f642c2 fs: rename pipe_buf ->steal to ->try_steal
And replace the arcane return value convention with a simple bool
where true means success and false means failure.

[AV: braino fix folded in]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-05-20 12:14:10 -04:00
Miklos Szeredi
32f98877c5 fuse: don't check refcount after stealing page
page_count() is unstable.  Unless there has been an RCU grace period
between when the page was removed from the page cache and now, a
speculative reference may exist from the page cache.

Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-19 14:50:37 +02:00
Miklos Szeredi
a5005c3cda fuse: fix weird page warning
When PageWaiters was added, updating this check was missed.

Reported-by: Nikolaus Rath <Nikolaus@rath.org>
Reported-by: Hugh Dickins <hughd@google.com>
Fixes: 6290602709 ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-19 14:50:37 +02:00
Miklos Szeredi
0058938617 fuse: use dump_page
Instead of custom page dumping, use the standard helper.

Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-05-19 14:50:37 +02:00
Mauro Carvalho Chehab
72ef5e52b3 docs: fix broken references to text files
Several references got broken due to txt to ReST conversion.

Several of them can be automatically fixed with:

	scripts/documentation-file-ref-check --fix

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> # hwtracing/coresight/Kconfig
Reviewed-by: Paul E. McKenney <paulmck@kernel.org> # memory-barrier.txt
Acked-by: Alex Shi <alex.shi@linux.alibaba.com> # translations/zh_CN
Acked-by: Federico Vaga <federico.vaga@vaga.pv.it> # translations/it_IT
Acked-by: Marc Zyngier <maz@kernel.org> # kvm/arm64
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6f919ddb83a33b5f2a63b6b5f0575737bb2b36aa.1586881715.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-04-20 15:35:59 -06:00
Kirill Tkhai
75d892588e fuse: Update stale comment in queue_interrupt()
Fixes: 04ec5af077 "fuse: export fuse_end_request()"
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-04-20 17:01:34 +02:00
Vasily Averin
0e9fb6f17a fuse: BUG_ON correction in fuse_dev_splice_write()
commit 9635453572 ("fuse: reduce allocation size for splice_write")
changed size of bufs array, so BUG_ON which checks the index of the array
shold also be fixed.

[SzM: turn BUG_ON into WARN_ON]

Fixes: 9635453572 ("fuse: reduce allocation size for splice_write")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-04-20 17:01:34 +02:00
Miklos Szeredi
3e8cb8b2ea fuse: fix stack use after return
Normal, synchronous requests will have their args allocated on the stack.
After the FR_FINISHED bit is set by receiving the reply from the userspace
fuse server, the originating task may return and reuse the stack frame,
resulting in an Oops if the args structure is dereferenced.

Fix by setting a flag in the request itself upon initializing, indicating
whether it has an asynchronous ->end() callback.

Reported-by: Kyle Sanderson <kyle.leet@gmail.com>
Reported-by: Michael Stapelberg <michael+lkml@stapelberg.ch>
Fixes: 2b319d1f6f ("fuse: don't dereference req->args on finished request")
Cc: <stable@vger.kernel.org> # v5.4
Tested-by: Michael Stapelberg <michael+lkml@stapelberg.ch>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-02-13 09:16:07 +01:00
David Howells
76f6777c9c pipe: Fix iteration end check in fuse_dev_splice_write()
Fix the iteration end check in fuse_dev_splice_write().  The iterator
position can only be compared with == or != since wrappage may be involved.

Fixes: 8cefc107ca ("pipe: Use head and tail pointers for the ring, not cursor and length")
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-12-06 13:57:04 -08:00
Linus Torvalds
0da522107e compat_ioctl: remove most of fs/compat_ioctl.c
As part of the cleanup of some remaining y2038 issues, I came to
 fs/compat_ioctl.c, which still has a couple of commands that need support
 for time64_t.
 
 In completely unrelated work, I spent time on cleaning up parts of this
 file in the past, moving things out into drivers instead.
 
 After Al Viro reviewed an earlier version of this series and did a lot
 more of that cleanup, I decided to try to completely eliminate the rest
 of it and move it all into drivers.
 
 This series incorporates some of Al's work and many patches of my own,
 but in the end stops short of actually removing the last part, which is
 the scsi ioctl handlers. I have patches for those as well, but they need
 more testing or possibly a rewrite.
 
 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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Merge tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground

Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann:
 "As part of the cleanup of some remaining y2038 issues, I came to
  fs/compat_ioctl.c, which still has a couple of commands that need
  support for time64_t.

  In completely unrelated work, I spent time on cleaning up parts of
  this file in the past, moving things out into drivers instead.

  After Al Viro reviewed an earlier version of this series and did a lot
  more of that cleanup, I decided to try to completely eliminate the
  rest of it and move it all into drivers.

  This series incorporates some of Al's work and many patches of my own,
  but in the end stops short of actually removing the last part, which
  is the scsi ioctl handlers. I have patches for those as well, but they
  need more testing or possibly a rewrite"

* tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits)
  scsi: sd: enable compat ioctls for sed-opal
  pktcdvd: add compat_ioctl handler
  compat_ioctl: move SG_GET_REQUEST_TABLE handling
  compat_ioctl: ppp: move simple commands into ppp_generic.c
  compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t
  compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic
  compat_ioctl: unify copy-in of ppp filters
  tty: handle compat PPP ioctls
  compat_ioctl: move SIOCOUTQ out of compat_ioctl.c
  compat_ioctl: handle SIOCOUTQNSD
  af_unix: add compat_ioctl support
  compat_ioctl: reimplement SG_IO handling
  compat_ioctl: move WDIOC handling into wdt drivers
  fs: compat_ioctl: move FITRIM emulation into file systems
  gfs2: add compat_ioctl support
  compat_ioctl: remove unused convert_in_user macro
  compat_ioctl: remove last RAID handling code
  compat_ioctl: remove /dev/raw ioctl translation
  compat_ioctl: remove PCI ioctl translation
  compat_ioctl: remove joystick ioctl translation
  ...
2019-12-01 13:46:15 -08:00
Linus Torvalds
6a965666b7 Pipework for general notification queue
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Merge tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull pipe rework from David Howells:
 "This is my set of preparatory patches for building a general
  notification queue on top of pipes. It makes a number of significant
  changes:

   - It removes the nr_exclusive argument from __wake_up_sync_key() as
     this is always 1. This prepares for the next step:

   - Adds wake_up_interruptible_sync_poll_locked() so that poll can be
     woken up from a function that's holding the poll waitqueue
     spinlock.

   - Change the pipe buffer ring to be managed in terms of unbounded
     head and tail indices rather than bounded index and length. This
     means that reading the pipe only needs to modify one index, not
     two.

   - A selection of helper functions are provided to query the state of
     the pipe buffer, plus a couple to apply updates to the pipe
     indices.

   - The pipe ring is allowed to have kernel-reserved slots. This allows
     many notification messages to be spliced in by the kernel without
     allowing userspace to pin too many pages if it writes to the same
     pipe.

   - Advance the head and tail indices inside the pipe waitqueue lock
     and use wake_up_interruptible_sync_poll_locked() to poke poll
     without having to take the lock twice.

   - Rearrange pipe_write() to preallocate the buffer it is going to
     write into and then drop the spinlock. This allows kernel
     notifications to then be added the ring whilst it is filling the
     buffer it allocated. The read side is stalled because the pipe
     mutex is still held.

   - Don't wake up readers on a pipe if there was already data in it
     when we added more.

   - Don't wake up writers on a pipe if the ring wasn't full before we
     removed a buffer"

* tag 'notifications-pipe-prep-20191115' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  pipe: Remove sync on wake_ups
  pipe: Increase the writer-wakeup threshold to reduce context-switch count
  pipe: Check for ring full inside of the spinlock in pipe_write()
  pipe: Remove redundant wakeup from pipe_write()
  pipe: Rearrange sequence in pipe_write() to preallocate slot
  pipe: Conditionalise wakeup in pipe_read()
  pipe: Advance tail pointer inside of wait spinlock in pipe_read()
  pipe: Allow pipes to have kernel-reserved slots
  pipe: Use head and tail pointers for the ring, not cursor and length
  Add wake_up_interruptible_sync_poll_locked()
  Remove the nr_exclusive argument from __wake_up_sync_key()
  pipe: Reduce #inclusion of pipe_fs_i.h
2019-11-30 14:12:13 -08:00
David Howells
6718b6f855 pipe: Allow pipes to have kernel-reserved slots
Split pipe->ring_size into two numbers:

 (1) pipe->ring_size - indicates the hard size of the pipe ring.

 (2) pipe->max_usage - indicates the maximum number of pipe ring slots that
     userspace orchestrated events can fill.

This allows for a pipe that is both writable by the general kernel
notification facility and by userspace, allowing plenty of ring space for
notifications to be added whilst preventing userspace from being able to
pin too much unswappable kernel space.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-11-15 16:22:54 +00:00
David Howells
8cefc107ca pipe: Use head and tail pointers for the ring, not cursor and length
Convert pipes to use head and tail pointers for the buffer ring rather than
pointer and length as the latter requires two atomic ops to update (or a
combined op) whereas the former only requires one.

 (1) The head pointer is the point at which production occurs and points to
     the slot in which the next buffer will be placed.  This is equivalent
     to pipe->curbuf + pipe->nrbufs.

     The head pointer belongs to the write-side.

 (2) The tail pointer is the point at which consumption occurs.  It points
     to the next slot to be consumed.  This is equivalent to pipe->curbuf.

     The tail pointer belongs to the read-side.

 (3) head and tail are allowed to run to UINT_MAX and wrap naturally.  They
     are only masked off when the array is being accessed, e.g.:

	pipe->bufs[head & mask]

     This means that it is not necessary to have a dead slot in the ring as
     head == tail isn't ambiguous.

 (4) The ring is empty if "head == tail".

     A helper, pipe_empty(), is provided for this.

 (5) The occupancy of the ring is "head - tail".

     A helper, pipe_occupancy(), is provided for this.

 (6) The number of free slots in the ring is "pipe->ring_size - occupancy".

     A helper, pipe_space_for_user() is provided to indicate how many slots
     userspace may use.

 (7) The ring is full if "head - tail >= pipe->ring_size".

     A helper, pipe_full(), is provided for this.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-10-31 15:12:34 +00:00
Arnd Bergmann
1832f2d8ff compat_ioctl: move more drivers to compat_ptr_ioctl
The .ioctl and .compat_ioctl file operations have the same prototype so
they can both point to the same function, which works great almost all
the time when all the commands are compatible.

One exception is the s390 architecture, where a compat pointer is only
31 bit wide, and converting it into a 64-bit pointer requires calling
compat_ptr(). Most drivers here will never run in s390, but since we now
have a generic helper for it, it's easy enough to use it consistently.

I double-checked all these drivers to ensure that all ioctl arguments
are used as pointers or are ignored, but are not interpreted as integer
values.

Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-23 17:23:44 +02:00
Miklos Szeredi
2b319d1f6f fuse: don't dereference req->args on finished request
Move the check for async request after check for the request being already
finished and done with.

Reported-by: syzbot+ae0bb7aae3de6b4594e2@syzkaller.appspotmail.com
Fixes: d49937749f ("fuse: stop copying args to fuse_req")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-10-21 09:11:40 +02:00
YueHaibing
5addcd5dbd fuse: Make fuse_args_to_req static
Fix sparse warning:

fs/fuse/dev.c:468:6: warning: symbol 'fuse_args_to_req' was not declared. Should it be static?

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Fixes: 68583165f9 ("fuse: add pages to fuse_args")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-24 15:28:02 +02:00
Arnd Bergmann
0ed4059302 fuse: unexport fuse_put_request
This function has been made static, which now causes a compile-time
warning:

WARNING: "fuse_put_request" [vmlinux] is a static EXPORT_SYMBOL_GPL

Remove the unneeded export.

Fixes: 66abc3599c ("fuse: unexport request ops")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-24 15:28:01 +02:00