Now when shmem VMAs can be filled with zero page via userfaultfd we can
report that UFFDIO_ZEROPAGE is available for those VMAs
Link: http://lkml.kernel.org/r/1497939652-16528-7-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All users of pagevec_lookup() and pagevec_lookup_range() now pass
PAGEVEC_SIZE as a desired number of pages.
Just drop the argument.
Link: http://lkml.kernel.org/r/20170726114704.7626-11-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want only pages from given range in page_cache_seek_hole_data(). Use
pagevec_lookup_range() instead of pagevec_lookup() and remove
unnecessary code.
Note that the check for getting less pages than desired can be removed
because index gets updated by pagevec_lookup_range().
Link: http://lkml.kernel.org/r/20170726114704.7626-9-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We want only pages from given range in remove_inode_hugepages(). Use
pagevec_lookup_range() instead of pagevec_lookup().
Link: http://lkml.kernel.org/r/20170726114704.7626-8-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadia Yvette Chambers <nyc@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Both occurences of pagevec_lookup() actually want only pages from a
given range. Use pagevec_lookup_range() for the lookup.
Link: http://lkml.kernel.org/r/20170726114704.7626-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use pagevec_lookup_range() in ext4_find_unwritten_pgoff() since we are
interested only in pages in the given range. Simplify the logic as a
result of not getting pages out of range and index getting automatically
advanced.
Link: http://lkml.kernel.org/r/20170726114704.7626-6-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit e64855c6cf ("fs: Add helper to clean bdev aliases under a bh
and use it") added a wrapper for clean_bdev_aliases() that invalidates
bdev aliases underlying a single buffer head.
However this has caused a performance regression for bonnie++ benchmark
on ext4 filesystem when delayed allocation is turned off (ext3 mode) -
average of 3 runs:
Hmean SeqOut Char 164787.55 ( 0.00%) 107189.06 (-34.95%)
Hmean SeqOut Block 219883.89 ( 0.00%) 168870.32 (-23.20%)
The reason for this regression is that clean_bdev_aliases() is slower
when called for a single block because pagevec_lookup() it uses will end
up iterating through the radix tree until it finds a page (which may
take a while) but we are only interested whether there's a page at a
particular index.
Fix the problem by using pagevec_lookup_range() instead which avoids the
needless iteration.
Fixes: e64855c6cf ("fs: Add helper to clean bdev aliases under a bh and use it")
Link: http://lkml.kernel.org/r/20170726114704.7626-5-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make pagevec_lookup() (and underlying find_get_pages()) update index to
the next page where iteration should continue. Most callers want this
and also pagevec_lookup_tag() already does this.
Link: http://lkml.kernel.org/r/20170726114704.7626-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Ranged pagevec lookup", v2.
In this series I make pagevec_lookup() update the index (to be
consistent with pagevec_lookup_tag() and also as a preparation for
ranged lookups), provide ranged variant of pagevec_lookup() and use it
in places where it makes sense. This not only removes some common code
but is also a measurable performance win for some use cases (see patch
4/10) where radix tree is sparse and searching & grabing of a page after
the end of the range has measurable overhead.
This patch (of 10):
The callback doesn't ever get called. Remove it.
Link: http://lkml.kernel.org/r/20170726114704.7626-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
clean up some unused functions and parameters.
Link: http://lkml.kernel.org/r/598A5E21.2080807@huawei.com
Signed-off-by: Jun Piao <piaojun@huawei.com>
Reviewed-by: Alex Chen <alex.chen@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The function is never called outside of fs/ocfs2/acl.c.
Link: http://lkml.kernel.org/r/20170801141252.19675-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dax_pmd_insert_mapping() contains the following code:
pfn_t pfn;
if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0)
goto fallback;
/* ... */
fallback:
trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret);
When the condition in the if statement fails, the function calls
trace_dax_pmd_insert_mapping_fallback() with an uninitialized pfn value.
This issue has been found while building the kernel with clang. The
compiler reported:
fs/dax.c:1280:6: error: variable 'pfn' is used uninitialized
whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/dax.c:1310:60: note: uninitialized use occurs here
trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret);
^~~
Link: http://lkml.kernel.org/r/20170903083000.587-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use ~PG_PMD_COLOUR in dax_entry_waitqueue() instead of open coding an
equivalent page offset mask.
Link: http://lkml.kernel.org/r/20170822222436.18926-2-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Slusarz, Marcin" <marcin.slusarz@intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a comment explaining how the user addresses provided to read(2) and
write(2) are validated in the DAX I/O path.
We call dax_copy_from_iter() or copy_to_iter() on these without calling
access_ok() first in the DAX code, and there was a concern that the user
might be able to read/write to arbitrary kernel addresses with this
path.
Link: http://lkml.kernel.org/r/20170816173615.10098-1-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we no longer insert struct page pointers in DAX radix trees the
page cache code no longer needs to know anything about DAX exceptional
entries. Move all the DAX exceptional entry definitions from dax.h to
fs/dax.c.
Link: http://lkml.kernel.org/r/20170724170616.25810-6-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that we no longer insert struct page pointers in DAX radix trees we
can remove the special casing for DAX in page_cache_tree_insert().
This also allows us to make dax_wake_mapping_entry_waiter() local to
fs/dax.c, removing it from dax.h.
Link: http://lkml.kernel.org/r/20170724170616.25810-5-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When servicing mmap() reads from file holes the current DAX code
allocates a page cache page of all zeroes and places the struct page
pointer in the mapping->page_tree radix tree.
This has three major drawbacks:
1) It consumes memory unnecessarily. For every 4k page that is read via
a DAX mmap() over a hole, we allocate a new page cache page. This
means that if you read 1GiB worth of pages, you end up using 1GiB of
zeroed memory. This is easily visible by looking at the overall
memory consumption of the system or by looking at /proc/[pid]/smaps:
7f62e72b3000-7f63272b3000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 1048576 kB
Pss: 1048576 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 1048576 kB
Private_Dirty: 0 kB
Referenced: 1048576 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
2) It is slower than using a common zero page because each page fault
has more work to do. Instead of just inserting a common zero page we
have to allocate a page cache page, zero it, and then insert it. Here
are the average latencies of dax_load_hole() as measured by ftrace on
a random test box:
Old method, using zeroed page cache pages: 3.4 us
New method, using the common 4k zero page: 0.8 us
This was the average latency over 1 GiB of sequential reads done by
this simple fio script:
[global]
size=1G
filename=/root/dax/data
fallocate=none
[io]
rw=read
ioengine=mmap
3) The fact that we had to check for both DAX exceptional entries and
for page cache pages in the radix tree made the DAX code more
complex.
Solve these issues by following the lead of the DAX PMD code and using a
common 4k zero page instead. As with the PMD code we will now insert a
DAX exceptional entry into the radix tree instead of a struct page
pointer which allows us to remove all the special casing in the DAX
code.
Note that we do still pretty aggressively check for regular pages in the
DAX radix tree, especially where we take action based on the bits set in
the page. If we ever find a regular page in our radix tree now that
most likely means that someone besides DAX is inserting pages (which has
happened lots of times in the past), and we want to find that out early
and fail loudly.
This solution also removes the extra memory consumption. Here is that
same /proc/[pid]/smaps after 1GiB of reading from a hole with the new
code:
7f2054a74000-7f2094a74000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
Overall system memory consumption is similarly improved.
Another major change is that we remove dax_pfn_mkwrite() from our fault
flow, and instead rely on the page fault itself to make the PTE dirty
and writeable. The following description from the patch adding the
vm_insert_mixed_mkwrite() call explains this a little more:
"To be able to use the common 4k zero page in DAX we need to have our
PTE fault path look more like our PMD fault path where a PTE entry
can be marked as dirty and writeable as it is first inserted rather
than waiting for a follow-up dax_pfn_mkwrite() =>
finish_mkwrite_fault() call.
Right now we can rely on having a dax_pfn_mkwrite() call because we
can distinguish between these two cases in do_wp_page():
case 1: 4k zero page => writable DAX storage
case 2: read-only DAX storage => writeable DAX storage
This distinction is made by via vm_normal_page(). vm_normal_page()
returns false for the common 4k zero page, though, just as it does
for DAX ptes. Instead of special casing the DAX + 4k zero page case
we will simplify our DAX PTE page fault sequence so that it matches
our DAX PMD sequence, and get rid of the dax_pfn_mkwrite() helper.
We will instead use dax_iomap_fault() to handle write-protection
faults.
This means that insert_pfn() needs to follow the lead of
insert_pfn_pmd() and allow us to pass in a 'mkwrite' flag. If
'mkwrite' is set insert_pfn() will do the work that was previously
done by wp_page_reuse() as part of the dax_pfn_mkwrite() call path"
Link: http://lkml.kernel.org/r/20170724170616.25810-4-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dax_load_hole() will soon need to call dax_insert_mapping_entry(), so it
needs to be moved lower in dax.c so the definition exists.
dax_wake_mapping_entry_waiter() will soon be removed from dax.h and be
made static to dax.c, so we need to move its definition above all its
callers.
Link: http://lkml.kernel.org/r/20170724170616.25810-3-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here is the big char/misc driver update for 4.14-rc1.
Lots of different stuff in here, it's been an active development cycle
for some reason. Highlights are:
- updated binder driver, this brings binder up to date with what
shipped in the Android O release, plus some more changes that
happened since then that are in the Android development trees.
- coresight updates and fixes
- mux driver file renames to be a bit "nicer"
- intel_th driver updates
- normal set of hyper-v updates and changes
- small fpga subsystem and driver updates
- lots of const code changes all over the driver trees
- extcon driver updates
- fmc driver subsystem upadates
- w1 subsystem minor reworks and new features and drivers added
- spmi driver updates
Plus a smattering of other minor driver updates and fixes.
All of these have been in linux-next with no reported issues for a
while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver updates from Greg KH:
"Here is the big char/misc driver update for 4.14-rc1.
Lots of different stuff in here, it's been an active development cycle
for some reason. Highlights are:
- updated binder driver, this brings binder up to date with what
shipped in the Android O release, plus some more changes that
happened since then that are in the Android development trees.
- coresight updates and fixes
- mux driver file renames to be a bit "nicer"
- intel_th driver updates
- normal set of hyper-v updates and changes
- small fpga subsystem and driver updates
- lots of const code changes all over the driver trees
- extcon driver updates
- fmc driver subsystem upadates
- w1 subsystem minor reworks and new features and drivers added
- spmi driver updates
Plus a smattering of other minor driver updates and fixes.
All of these have been in linux-next with no reported issues for a
while"
* tag 'char-misc-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (244 commits)
ANDROID: binder: don't queue async transactions to thread.
ANDROID: binder: don't enqueue death notifications to thread todo.
ANDROID: binder: Don't BUG_ON(!spin_is_locked()).
ANDROID: binder: Add BINDER_GET_NODE_DEBUG_INFO ioctl
ANDROID: binder: push new transactions to waiting threads.
ANDROID: binder: remove proc waitqueue
android: binder: Add page usage in binder stats
android: binder: fixup crash introduced by moving buffer hdr
drivers: w1: add hwmon temp support for w1_therm
drivers: w1: refactor w1_slave_show to make the temp reading functionality separate
drivers: w1: add hwmon support structures
eeprom: idt_89hpesx: Support both ACPI and OF probing
mcb: Fix an error handling path in 'chameleon_parse_cells()'
MCB: add support for SC31 to mcb-lpc
mux: make device_type const
char: virtio: constify attribute_group structures.
Documentation/ABI: document the nvmem sysfs files
lkdtm: fix spelling mistake: "incremeted" -> "incremented"
perf: cs-etm: Fix ETMv4 CONFIGR entry in perf.data file
nvmem: include linux/err.h from header
...
Here is the "big" driver core update for 4.14-rc1.
It's really not all that big, the largest thing here being some firmware
tests to help ensure that that crazy api is working properly.
There's also a new uevent for when a driver is bound or unbound from a
device, fixing a hole in the driver model that's been there since the
very beginning. Many thanks to Dmitry for being persistent and pointing
out how wrong I was about this all along :)
Patches for the new uevents are already in the systemd tree, if people
want to play around with them.
Otherwise just a number of other small api changes and updates here,
nothing major. All of these patches have been in linux-next for a
while with no reported issues.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'driver-core-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core update from Greg KH:
"Here is the "big" driver core update for 4.14-rc1.
It's really not all that big, the largest thing here being some
firmware tests to help ensure that that crazy api is working properly.
There's also a new uevent for when a driver is bound or unbound from a
device, fixing a hole in the driver model that's been there since the
very beginning. Many thanks to Dmitry for being persistent and
pointing out how wrong I was about this all along :)
Patches for the new uevents are already in the systemd tree, if people
want to play around with them.
Otherwise just a number of other small api changes and updates here,
nothing major. All of these patches have been in linux-next for a
while with no reported issues"
* tag 'driver-core-4.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (28 commits)
driver core: bus: Fix a potential double free
Do not disable driver and bus shutdown hook when class shutdown hook is set.
base: topology: constify attribute_group structures.
base: Convert to using %pOF instead of full_name
kernfs: Clarify lockdep name for kn->count
fbdev: uvesafb: remove DRIVER_ATTR() usage
xen: xen-pciback: remove DRIVER_ATTR() usage
driver core: Document struct device:dma_ops
mod_devicetable: Remove excess description from structured comment
test_firmware: add batched firmware tests
firmware: enable a debug print for batched requests
firmware: define pr_fmt
firmware: send -EINTR on signal abort on fallback mechanism
test_firmware: add test case for SIGCHLD on sync fallback
initcall_debug: add deferred probe times
Input: axp20x-pek - switch to using devm_device_add_group()
Input: synaptics_rmi4 - use devm_device_add_group() for attributes in F01
Input: gpio_keys - use devm_device_add_group() for attributes
driver core: add devm_device_add_group() and friends
driver core: add device_{add|remove}_group() helpers
...
Pull locking updates from Ingo Molnar:
- Add 'cross-release' support to lockdep, which allows APIs like
completions, where it's not the 'owner' who releases the lock, to be
tracked. It's all activated automatically under
CONFIG_PROVE_LOCKING=y.
- Clean up (restructure) the x86 atomics op implementation to be more
readable, in preparation of KASAN annotations. (Dmitry Vyukov)
- Fix static keys (Paolo Bonzini)
- Add killable versions of down_read() et al (Kirill Tkhai)
- Rework and fix jump_label locking (Marc Zyngier, Paolo Bonzini)
- Rework (and fix) tlb_flush_pending() barriers (Peter Zijlstra)
- Remove smp_mb__before_spinlock() and convert its usages, introduce
smp_mb__after_spinlock() (Peter Zijlstra)
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (56 commits)
locking/lockdep/selftests: Fix mixed read-write ABBA tests
sched/completion: Avoid unnecessary stack allocation for COMPLETION_INITIALIZER_ONSTACK()
acpi/nfit: Fix COMPLETION_INITIALIZER_ONSTACK() abuse
locking/pvqspinlock: Relax cmpxchg's to improve performance on some architectures
smp: Avoid using two cache lines for struct call_single_data
locking/lockdep: Untangle xhlock history save/restore from task independence
locking/refcounts, x86/asm: Disable CONFIG_ARCH_HAS_REFCOUNT for the time being
futex: Remove duplicated code and fix undefined behaviour
Documentation/locking/atomic: Finish the document...
locking/lockdep: Fix workqueue crossrelease annotation
workqueue/lockdep: 'Fix' flush_work() annotation
locking/lockdep/selftests: Add mixed read-write ABBA tests
mm, locking/barriers: Clarify tlb_flush_pending() barriers
locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE and CONFIG_LOCKDEP_COMPLETIONS truly non-interactive
locking/lockdep: Explicitly initialize wq_barrier::done::map
locking/lockdep: Rename CONFIG_LOCKDEP_COMPLETE to CONFIG_LOCKDEP_COMPLETIONS
locking/lockdep: Reword title of LOCKDEP_CROSSRELEASE config
locking/lockdep: Make CONFIG_LOCKDEP_CROSSRELEASE part of CONFIG_PROVE_LOCKING
locking/refcounts, x86/asm: Implement fast refcount overflow protection
locking/lockdep: Fix the rollback and overwrite detection logic in crossrelease
...
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:
- fix affine wakeups (Peter Zijlstra)
- improve CPU onlining (and general bootup) scalability on systems
with ridiculous number (thousands) of CPUs (Peter Zijlstra)
- sched/numa updates (Rik van Riel)
- sched/deadline updates (Byungchul Park)
- sched/cpufreq enhancements and related cleanups (Viresh Kumar)
- sched/debug enhancements (Xie XiuQi)
- various fixes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
sched/debug: Optimize sched_domain sysctl generation
sched/topology: Avoid pointless rebuild
sched/topology, cpuset: Avoid spurious/wrong domain rebuilds
sched/topology: Improve comments
sched/topology: Fix memory leak in __sdt_alloc()
sched/completion: Document that reinit_completion() must be called after complete_all()
sched/autogroup: Fix error reporting printk text in autogroup_create()
sched/fair: Fix wake_affine() for !NUMA_BALANCING
sched/debug: Intruduce task_state_to_char() helper function
sched/debug: Show task state in /proc/sched_debug
sched/debug: Use task_pid_nr_ns in /proc/$pid/sched
sched/core: Remove unnecessary initialization init_idle_bootup_task()
sched/deadline: Change return value of cpudl_find()
sched/deadline: Make find_later_rq() choose a closer CPU in topology
sched/numa: Scale scan period with tasks in group and shared/private
sched/numa: Slow down scan rate if shared faults dominate
sched/pelt: Fix false running accounting
sched: Mark pick_next_task_dl() and build_sched_domain() as static
sched/cpupri: Don't re-initialize 'struct cpupri'
sched/deadline: Don't re-initialize 'struct cpudl'
...
Pull misc fixes from Al Viro:
"Loose ends and regressions from the last merge window.
Strictly speaking, only binfmt_flat thing is a build regression per
se - the rest is 'only sparse cares about that' stuff"
[ This came in before the 4.13 release and could have gone there, but it
was late in the release and nothing seemed critical enough to care, so
I'm pulling it in the 4.14 merge window instead - Linus ]
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
binfmt_flat: fix arch/m32r and arch/microblaze flat_put_addr_at_rp()
compat_hdio_ioctl: Fix a declaration
<linux/uaccess.h>: Fix copy_in_user() declaration
annotate RWF_... flags
teach SYSCALL_DEFINE/COMPAT_SYSCALL_DEFINE to handle __bitwise arguments
Pull cifs version warning fix from Steve French:
"As requested, additional kernel warning messages to clarify the
default dialect changes"
[ There is still some discussion about exactly which version should be
the new default. Longer-term we have auto-negotiation coming, but
that's not there yet.. - Linus ]
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
Fix warning messages when mounting to older servers
The race was introduced by me in commit 971316f050 ("epoll:
ep_unregister_pollwait() can use the freed pwq->whead"). I did not
realize that nothing can protect eventpoll after ep_poll_callback() sets
->whead = NULL, only whead->lock can save us from the race with
ep_free() or ep_remove().
Move ->whead = NULL to the end of ep_poll_callback() and add the
necessary barriers.
TODO: cleanup the ewake/EPOLLEXCLUSIVE logic, it was confusing even
before this patch.
Hopefully this explains use-after-free reported by syzcaller:
BUG: KASAN: use-after-free in debug_spin_lock_before
...
_raw_spin_lock_irqsave+0x4a/0x60 kernel/locking/spinlock.c:159
ep_poll_callback+0x29f/0xff0 fs/eventpoll.c:1148
this is spin_lock(eventpoll->lock),
...
Freed by task 17774:
...
kfree+0xe8/0x2c0 mm/slub.c:3883
ep_free+0x22c/0x2a0 fs/eventpoll.c:865
Fixes: 971316f050 ("epoll: ep_unregister_pollwait() can use the freed pwq->whead")
Reported-by: 范龙飞 <long7573@126.com>
Cc: stable@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When mounting to older servers, such as Windows XP (or even Windows 7),
the limited error messages that can be passed back to user space can
get confusing since the default dialect has changed from SMB1 (CIFS) to
more secure SMB3 dialect. Log additional information when the user chooses
to use the default dialects and when the server does not support the
dialect requested.
Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Merge mmu_notifier fixes from Jérôme Glisse:
"The invalidate_page callback suffered from 2 pitfalls. First it used
to happen after page table lock was release and thus a new page might
have been setup for the virtual address before the call to
invalidate_page().
This is in a weird way fixed by commit c7ab0d2fdc ("mm: convert
try_to_unmap_one() to use page_vma_mapped_walk()") which moved the
callback under the page table lock. Which also broke several existing
user of the mmu_notifier API that assumed they could sleep inside this
callback.
The second pitfall was invalidate_page being the only callback not
taking a range of address in respect to invalidation but was giving an
address and a page. Lot of the callback implementer assumed this could
never be THP and thus failed to invalidate the appropriate range for
THP pages.
By killing this callback we unify the mmu_notifier callback API to
always take a virtual address range as input.
There is now two clear API (I am not mentioning the youngess API which
is seldomly used):
- invalidate_range_start()/end() callback (which allow you to sleep)
- invalidate_range() where you can not sleep but happen right after
page table update under page table lock
Note that a lot of existing user feels broken in respect to
range_start/ range_end. Many user only have range_start() callback but
there is nothing preventing them to undo what was invalidated in their
range_start() callback after it returns but before any CPU page table
update take place.
The code pattern use in kvm or umem odp is an example on how to
properly avoid such race. In a nutshell use some kind of sequence
number and active range invalidation counter to block anything that
might undo what the range_start() callback did.
If you do not care about keeping fully in sync with CPU page table (ie
you can live with CPU page table pointing to new different page for a
given virtual address) then you can take a reference on the pages
inside the range_start callback and drop it in range_end or when your
driver is done with those pages.
Last alternative is to use invalidate_range() if you can do
invalidation without sleeping as invalidate_range() callback happens
under the CPU page table spinlock right after the page table is
updated.
The first two patches convert existing mmu_notifier_invalidate_page()
calls to mmu_notifier_invalidate_range() and bracket those call with
call to mmu_notifier_invalidate_range_start()/end().
The next ten patches remove existing invalidate_page() callback as it
can no longer happen.
Finally the last page remove the invalidate_page() callback completely
so it can RIP.
Changes since v1:
- remove more dead code in kvm (no testing impact)
- more accurate end address computation (patch 2) in page_mkclean_one
and try_to_unmap_one
- added tested-by/reviewed-by gotten so far"
* emailed patches from Jérôme Glisse <jglisse@redhat.com>:
mm/mmu_notifier: kill invalidate_page
KVM: update to new mmu_notifier semantic v2
xen/gntdev: update to new mmu_notifier semantic
sgi-gru: update to new mmu_notifier semantic
misc/mic/scif: update to new mmu_notifier semantic
iommu/intel: update to new mmu_notifier semantic
iommu/amd: update to new mmu_notifier semantic
IB/hfi1: update to new mmu_notifier semantic
IB/umem: update to new mmu_notifier semantic
drm/amdgpu: update to new mmu_notifier semantic
powerpc/powernv: update to new mmu_notifier semantic
mm/rmap: update to new mmu_notifier semantic v2
dax: update to new mmu_notifier semantic
jfs had previously avoided the use of MAX_LFS_FILESIZE because it hadn't
accounted for the whole 32-bit index range on 32-bit systems. That has
been fixed by commit 0cc3b0ec23 ("Clarify (and fix) MAX_LFS_FILESIZE
macros"), so we can simplify the code now.
Suggested by Andreas Dilger.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Cc: jfs-discussion@lists.sourceforge.net
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace all mmu_notifier_invalidate_page() calls by *_invalidate_range()
and make sure it is bracketed by calls to *_invalidate_range_start()/end().
Note that because we can not presume the pmd value or pte value we have
to assume the worst and unconditionaly report an invalidation as
happening.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Bernhard Held <berny156@gmx.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: axie <axie@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ceph_readpage() unlocks page prematurely prematurely in the case
that page is reading from fscache. Caller of readpage expects that
page is uptodate when it get unlocked. So page shoule get locked
by completion callback of fscache_read_or_alloc_pages()
Cc: stable@vger.kernel.org # 4.1+, needs backporting for < 4.7
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Recent patch had an endian warning ie
cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup()
Signed-off-by: Steve French <smfrench@gmail.com>
CC: Ronnie Sahlberg <lsahlber@redhat.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Currently the maximum size of SMB2/3 header is set incorrectly which
leads to hanging of directory listing operations on encrypted SMB3
connections. Fix this by setting the maximum size to 170 bytes that
is calculated as RFC1002 length field size (4) + transform header
size (52) + SMB2 header size (64) + create response size (56).
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Commit 464d62421c ("select: switch compat_{get,put}_fd_set() to
compat_{get,put}_bitmap()") changed the calculation on how many bytes
need to be zeroed when userspace handed over a NULL pointer for a fdset
array in the select syscall.
The calculation was changed in compat_get_fd_set() wrongly from
memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
to
memset(fdset, 0, ALIGN(nr, BITS_PER_LONG));
The ALIGN(nr, BITS_PER_LONG) calculates the number of _bits_ which need
to be zeroed in the target fdset array (rounded up to the next full bits
for an unsigned long).
But the memset() call expects the number of _bytes_ to be zeroed.
This leads to clearing more memory than wanted (on the stack area or
even at kmalloc()ed memory areas) and to random kernel crashes as we
have seen them on the parisc platform.
The correct change should have been
memset(fdset, 0, (ALIGN(nr, BITS_PER_LONG) / BITS_PER_LONG) * BYTES_PER_LONG);
which is the same as can be archieved with a call to
zero_fd_set(nr, fdset).
Fixes: 464d62421c ("select: switch compat_{get,put}_fd_set() to compat_{get,put}_bitmap()"
Acked-by:: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The reference count in kernfs_node structure is treated like a rwsem by
using lockdep instrumentation code. The lockdep name, however, is still
"s_active" which is carried over from the old sysfs code. As s_active
is no longer the variable name, its use may confuse users on where the
lock is when it is reported by lockdep. So it is changed to "kn->count"
which is how this variable is normally referenced in kernfs code.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge misc fixes from Andrew Morton:
"6 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
mm/memblock.c: reversed logic in memblock_discard()
fork: fix incorrect fput of ->exe_file causing use-after-free
mm/madvise.c: fix freeing of locked page with MADV_FREE
dax: fix deadlock due to misaligned PMD faults
mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled
PM/hibernate: touch NMI watchdog when creating snapshot
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Merge tag 'cifs-fixes-for-4.13-rc6-and-stable' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs fixes from Steve French:
"Some bug fixes for stable for cifs"
* tag 'cifs-fixes-for-4.13-rc6-and-stable' of git://git.samba.org/sfrench/cifs-2.6:
cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup()
cifs: Fix df output for users with quota limits
In DAX there are two separate places where the 2MiB range of a PMD is
defined.
The first is in the page tables, where a PMD mapping inserted for a
given address spans from (vmf->address & PMD_MASK) to ((vmf->address &
PMD_MASK) + PMD_SIZE - 1). That is, from the 2MiB boundary below the
address to the 2MiB boundary above the address.
So, for example, a fault at address 3MiB (0x30 0000) falls within the
PMD that ranges from 2MiB (0x20 0000) to 4MiB (0x40 0000).
The second PMD range is in the mapping->page_tree, where a given file
offset is covered by a radix tree entry that spans from one 2MiB aligned
file offset to another 2MiB aligned file offset.
So, for example, the file offset for 3MiB (pgoff 768) falls within the
PMD range for the order 9 radix tree entry that ranges from 2MiB (pgoff
512) to 4MiB (pgoff 1024).
This system works so long as the addresses and file offsets for a given
mapping both have the same offsets relative to the start of each PMD.
Consider the case where the starting address for a given file isn't 2MiB
aligned - say our faulting address is 3 MiB (0x30 0000), but that
corresponds to the beginning of our file (pgoff 0). Now all the PMDs in
the mapping are misaligned so that the 2MiB range defined in the page
tables never matches up with the 2MiB range defined in the radix tree.
The current code notices this case for DAX faults to storage with the
following test in dax_pmd_insert_mapping():
if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR)
goto unlock_fallback;
This test makes sure that the pfn we get from the driver is 2MiB
aligned, and relies on the assumption that the 2MiB alignment of the pfn
we get back from the driver matches the 2MiB alignment of the faulting
address.
However, faults to holes were not checked and we could hit the problem
described above.
This was reported in response to the NVML nvml/src/test/pmempool_sync
TEST5:
$ cd nvml/src/test/pmempool_sync
$ make TEST5
You can grab NVML here:
https://github.com/pmem/nvml/
The dmesg warning you see when you hit this error is:
WARNING: CPU: 13 PID: 2900 at fs/dax.c:641 dax_insert_mapping_entry+0x2df/0x310
Where we notice in dax_insert_mapping_entry() that the radix tree entry
we are about to replace doesn't match the locked entry that we had
previously inserted into the tree. This happens because the initial
insertion was done in grab_mapping_entry() using a pgoff calculated from
the faulting address (vmf->address), and the replacement in
dax_pmd_load_hole() => dax_insert_mapping_entry() is done using
vmf->pgoff.
In our failure case those two page offsets (one calculated from
vmf->address, one using vmf->pgoff) point to different order 9 radix
tree entries.
This failure case can result in a deadlock because the radix tree unlock
also happens on the pgoff calculated from vmf->address. This means that
the locked radix tree entry that we swapped in to the tree in
dax_insert_mapping_entry() using vmf->pgoff is never unlocked, so all
future faults to that 2MiB range will block forever.
Fix this by validating that the faulting address's PMD offset matches
the PMD offset from the start of the file. This check is done at the
very beginning of the fault and covers faults that would have mapped to
storage as well as faults to holes. I left the COLOUR check in
dax_pmd_insert_mapping() in place in case we ever hit the insanity
condition where the alignment of the pfn we get from the driver doesn't
match the alignment of the userspace address.
Link: http://lkml.kernel.org/r/20170822222436.18926-1-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: "Slusarz, Marcin" <marcin.slusarz@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When processing an NFSv4 WRITE operation, argp->end should never
point past the end of the data in the final page of the page list.
Otherwise, nfsd4_decode_compound can walk into uninitialized memory.
More critical, nfsd4_decode_write is failing to increment argp->pagelen
when it increments argp->pagelist. This can cause later xdr decoders
to assume more data is available than really is, which can cause server
crashes on malformed requests.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Pull btrfs fix from David Sterba:
"We have one more fixup that stems from the blk_status_t conversion
that did not quite cover everything.
The normal cases were not affected because the code is 0, but any
error and retries could mix up new and old values"
* 'for-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: fix blk_status_t/errno confusion
The implementation of TIOCGPTPEER has two issues.
When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong
vfsmount is passed to dentry_open. Which results in the kernel displaying
the wrong pathname for the peer.
The second is simply by caching the vfsmount and dentry of the peer it leaves
them open, in a way they were not previously Which because of the inreased
reference counts can cause unnecessary behaviour differences resulting in
regressions.
To fix these move the ioctl into tty_io.c at a generic level allowing
the ioctl to have access to the struct file on which the ioctl is
being called. This allows the path of the slave to be derived when
opening the slave through TIOCGPTPEER instead of requiring the path to
the slave be cached. Thus removing the need for caching the path.
A new function devpts_ptmx_path is factored out of devpts_acquire and
used to implement a function devpts_mntget. The new function devpts_mntget
takes a filp to perform the lookup on and fsi so that it can confirm
that the superblock that is found by devpts_ptmx_path is the proper superblock.
v2: Lots of fixes to make the code actually work
v3: Suggestions by Linus
- Removed the unnecessary initialization of filp in ptm_open_peer
- Simplified devpts_ptmx_path as gotos are no longer required
[ This is the fix for the issue that was reverted in commit
143c97cc65, but this time without breaking 'pbuilder' due to
increased reference counts - Linus ]
Fixes: 54ebbfb160 ("tty: add TIOCGPTPEER ioctl")
Reported-by: Christian Brauner <christian.brauner@canonical.com>
Reported-and-tested-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes several instances of blk_status_t and bare errno ints being
mixed up, some of which are real bugs.
In the normal case, 0 matches BLK_STS_OK, so we don't observe any
effects of the missing conversion, but in case of errors or passes
through the repair/retry paths, the errors get mixed up.
The changes were identified using 'sparse', we don't have reports of the
buggy behaviour.
Fixes: 4e4cbee93d ("block: switch bios to blk_status_t")
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit c8c03f1858.
It turns out that while fixing the ptmx file descriptor to have the
correct 'struct path' to the associated slave pty is a really good
thing, it breaks some user space tools for a very annoying reason.
The problem is that /dev/ptmx and its associated slave pty (/dev/pts/X)
are on different mounts. That was what caused us to have the wrong path
in the first place (we would mix up the vfsmount of the 'ptmx' node,
with the dentry of the pty slave node), but it also means that now while
we use the right vfsmount, having the pty master open also keeps the pts
mount busy.
And it turn sout that that makes 'pbuilder' very unhappy, as noted by
Stefan Lippers-Hollmann:
"This patch introduces a regression for me when using pbuilder
0.228.7[2] (a helper to build Debian packages in a chroot and to
create and update its chroots) when trying to umount /dev/ptmx (inside
the chroot) on Debian/ unstable (full log and pbuilder configuration
file[3] attached).
[...]
Setting up build-essential (12.3) ...
Processing triggers for libc-bin (2.24-15) ...
I: unmounting dev/ptmx filesystem
W: Could not unmount dev/ptmx: umount: /var/cache/pbuilder/build/1340/dev/ptmx: target is busy
(In some cases useful info about processes that
use the device is found by lsof(8) or fuser(1).)"
apparently pbuilder tries to unmount the /dev/pts filesystem while still
holding at least one master node open, which is arguably not very nice,
but we don't break user space even when fixing other bugs.
So this commit has to be reverted.
I'll try to figure out a way to avoid caching the path to the slave pty
in the master pty. The only thing that actually wants that slave pty
path is the "TIOCGPTPEER" ioctl, and I think we could just recreate the
path at that time.
Reported-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Eric W Biederman <ebiederm@xmission.com>
Cc: Christian Brauner <christian.brauner@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
