File-private locks have been merged into Linux for v3.15, and *now*
people are commenting that the name and macro definitions for the new
file-private locks suck.
...and I can't even disagree. The names and command macros do suck.
We're going to have to live with these for a long time, so it's
important that we be happy with the names before we're stuck with them.
The consensus on the lists so far is that they should be rechristened as
"open file description locks".
The name isn't a big deal for the kernel, but the command macros are not
visually distinct enough from the traditional POSIX lock macros. The
glibc and documentation folks are recommending that we change them to
look like F_OFD_{GETLK|SETLK|SETLKW}. That lessens the chance that a
programmer will typo one of the commands wrong, and also makes it easier
to spot this difference when reading code.
This patch makes the following changes that I think are necessary before
v3.15 ships:
1) rename the command macros to their new names. These end up in the uapi
headers and so are part of the external-facing API. It turns out that
glibc doesn't actually use the fcntl.h uapi header, but it's hard to
be sure that something else won't. Changing it now is safest.
2) make the the /proc/locks output display these as type "OFDLCK"
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Carlos O'Donell <carlos@redhat.com>
Cc: Stefan Metzmacher <metze@samba.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Frank Filz <ffilzlnx@mindspring.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Pull file locking updates from Jeff Layton:
"Highlights:
- maintainership change for fs/locks.c. Willy's not interested in
maintaining it these days, and is OK with Bruce and I taking it.
- fix for open vs setlease race that Al ID'ed
- cleanup and consolidation of file locking code
- eliminate unneeded BUG() call
- merge of file-private lock implementation"
* 'locks-3.15' of git://git.samba.org/jlayton/linux:
locks: make locks_mandatory_area check for file-private locks
locks: fix locks_mandatory_locked to respect file-private locks
locks: require that flock->l_pid be set to 0 for file-private locks
locks: add new fcntl cmd values for handling file private locks
locks: skip deadlock detection on FL_FILE_PVT locks
locks: pass the cmd value to fcntl_getlk/getlk64
locks: report l_pid as -1 for FL_FILE_PVT locks
locks: make /proc/locks show IS_FILE_PVT locks as type "FLPVT"
locks: rename locks_remove_flock to locks_remove_file
locks: consolidate checks for compatible filp->f_mode values in setlk handlers
locks: fix posix lock range overflow handling
locks: eliminate BUG() call when there's an unexpected lock on file close
locks: add __acquires and __releases annotations to locks_start and locks_stop
locks: remove "inline" qualifier from fl_link manipulation functions
locks: clean up comment typo
locks: close potential race between setlease and open
MAINTAINERS: update entry for fs/locks.c
Pull compat time conversion changes from Peter Anvin:
"Despite the branch name this is really neither an x86 nor an
x32-specific patchset, although it the implementation of the
discussions that followed the x32 security hole a few months ago.
This removes get/put_compat_timespec/val() and replaces them with
compat_get/put_timespec/val() which are savvy as to the current status
of COMPAT_USE_64BIT_TIME.
It removes several unused and/or incorrect/misleading functions (like
compat_put_timeval_convert which doesn't in fact do any conversion)
and also replaces several open-coded implementations what is now
called compat_convert_timespec() with that function"
* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
compat: Fix sparse address space warnings
compat: Get rid of (get|put)_compat_time(val|spec)
Due to some unfortunate history, POSIX locks have very strange and
unhelpful semantics. The thing that usually catches people by surprise
is that they are dropped whenever the process closes any file descriptor
associated with the inode.
This is extremely problematic for people developing file servers that
need to implement byte-range locks. Developers often need a "lock
management" facility to ensure that file descriptors are not closed
until all of the locks associated with the inode are finished.
Additionally, "classic" POSIX locks are owned by the process. Locks
taken between threads within the same process won't conflict with one
another, which renders them useless for synchronization between threads.
This patchset adds a new type of lock that attempts to address these
issues. These locks conflict with classic POSIX read/write locks, but
have semantics that are more like BSD locks with respect to inheritance
and behavior on close.
This is implemented primarily by changing how fl_owner field is set for
these locks. Instead of having them owned by the files_struct of the
process, they are instead owned by the filp on which they were acquired.
Thus, they are inherited across fork() and are only released when the
last reference to a filp is put.
These new semantics prevent them from being merged with classic POSIX
locks, even if they are acquired by the same process. These locks will
also conflict with classic POSIX locks even if they are acquired by
the same process or on the same file descriptor.
The new locks are managed using a new set of cmd values to the fcntl()
syscall. The initial implementation of this converts these values to
"classic" cmd values at a fairly high level, and the details are not
exposed to the underlying filesystem. We may eventually want to push
this handing out to the lower filesystem code but for now I don't
see any need for it.
Also, note that with this implementation the new cmd values are only
available via fcntl64() on 32-bit arches. There's little need to
add support for legacy apps on a new interface like this.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Some fs compat system calls have unsigned long parameters instead of
compat_ulong_t.
In order to allow the COMPAT_SYSCALL_DEFINE macro generate code that
performs proper zero and sign extension convert all 64 bit parameters
their corresponding 32 bit counterparts.
compat_sys_io_getevents() is a bit different: the non-compat version
has signed parameters for the "min_nr" and "nr" parameters while the
compat version has unsigned parameters.
So change this as well. For all practical purposes this shouldn't make
any difference (doesn't fix a real bug).
Also introduce a generic compat_aio_context_t type which can be used
everywhere.
The access_ok() check within compat_sys_io_getevents() got also removed
since the non-compat sys_io_getevents() should be able to handle
everything anyway.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Convert all compat system call functions where all parameter types
have a size of four or less than four bytes, or are pointer types
to COMPAT_SYSCALL_DEFINE.
The implicit casts within COMPAT_SYSCALL_DEFINE will perform proper
zero and sign extension to 64 bit of all parameters if needed.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
For architecture dependent compat syscalls in common code an architecture
must define something like __ARCH_WANT_<WHATEVER> if it wants to use the
code.
This however is not true for compat_sys_getdents64 for which architectures
must define __ARCH_OMIT_COMPAT_SYS_GETDENTS64 if they do not want the code.
This leads to the situation where all architectures, except mips, get the
compat code but only x86_64, arm64 and the generic syscall architectures
actually use it.
So invert the logic, so that architectures actively must do something to
get the compat code.
This way a couple of architectures get rid of otherwise dead code.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
We have two APIs for compatiblity timespec/val, with confusingly
similar names. compat_(get|put)_time(val|spec) *do* handle the case
where COMPAT_USE_64BIT_TIME is set, whereas
(get|put)_compat_time(val|spec) do not. This is an accident waiting
to happen.
Clean it up by favoring the full-service version; the limited version
is replaced with double-underscore versions static to kernel/compat.c.
A common pattern is to convert a struct timespec to kernel format in
an allocation on the user stack. Unfortunately it is open-coded in
several places. Since this allocation isn't actually needed if
COMPAT_USE_64BIT_TIME is true (since user format == kernel format)
encapsulate that whole pattern into the function
compat_convert_timespec(). An equivalent function should be written
for struct timeval if it is needed in the future.
Finally, get rid of compat_(get|put)_timeval_convert(): each was only
used once, and the latter was not even doing what the function said
(no conversion actually was being done.) Moving the conversion into
compat_sys_settimeofday() itself makes the code much more similar to
sys_settimeofday() itself.
v3: Remove unused compat_convert_timeval().
v2: Drop bogus "const" in the destination argument for
compat_convert_time*().
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Tested-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
New method - ->iterate(file, ctx). That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...). It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.
Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
iterate_dir(): new helper, replacing vfs_readdir().
struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/compat.c doesn't need it anymore, so let's just move the remaining
contents (two typedefs) into fs/read_write.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
Pull compat cleanup from Al Viro:
"Mostly about syscall wrappers this time; there will be another pile
with patches in the same general area from various people, but I'd
rather push those after both that and vfs.git pile are in."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
syscalls.h: slightly reduce the jungles of macros
get rid of union semop in sys_semctl(2) arguments
make do_mremap() static
sparc: no need to sign-extend in sync_file_range() wrapper
ppc compat wrappers for add_key(2) and request_key(2) are pointless
x86: trim sys_ia32.h
x86: sys32_kill and sys32_mprotect are pointless
get rid of compat_sys_semctl() and friends in case of ARCH_WANT_OLD_COMPAT_IPC
merge compat sys_ipc instances
consolidate compat lookup_dcookie()
convert vmsplice to COMPAT_SYSCALL_DEFINE
switch getrusage() to COMPAT_SYSCALL_DEFINE
switch epoll_pwait to COMPAT_SYSCALL_DEFINE
convert sendfile{,64} to COMPAT_SYSCALL_DEFINE
switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE
make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
make HAVE_SYSCALL_WRAPPERS unconditional
consolidate cond_syscall and SYSCALL_ALIAS declarations
teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long
get rid of duplicate logics in __SC_....[1-6] definitions
Looking at mm/process_vm_access.c:process_vm_rw() and comparing it to
compat_process_vm_rw() shows that the compatibility code requires an
explicit "access_ok()" check before calling
compat_rw_copy_check_uvector(). The same difference seems to appear when
we compare fs/read_write.c:do_readv_writev() to
fs/compat.c:compat_do_readv_writev().
This subtle difference between the compat and non-compat requirements
should probably be debated, as it seems to be error-prone. In fact,
there are two others sites that use this function in the Linux kernel,
and they both seem to get it wrong:
Now shifting our attention to fs/aio.c, we see that aio_setup_iocb()
also ends up calling compat_rw_copy_check_uvector() through
aio_setup_vectored_rw(). Unfortunately, the access_ok() check appears to
be missing. Same situation for
security/keys/compat.c:compat_keyctl_instantiate_key_iov().
I propose that we add the access_ok() check directly into
compat_rw_copy_check_uvector(), so callers don't have to worry about it,
and it therefore makes the compat call code similar to its non-compat
counterpart. Place the access_ok() check in the same location where
copy_from_user() can trigger a -EFAULT error in the non-compat code, so
the ABI behaviors are alike on both compat and non-compat.
While we are here, fix compat_do_readv_writev() so it checks for
compat_rw_copy_check_uvector() negative return values.
And also, fix a memory leak in compat_keyctl_instantiate_key_iov() error
handling.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
getname() is intended to copy pathname strings from userspace into a
kernel buffer. The result is just a string in kernel space. It would
however be quite helpful to be able to attach some ancillary info to
the string.
For instance, we could attach some audit-related info to reduce the
amount of audit-related processing needed. When auditing is enabled,
we could also call getname() on the string more than once and not
need to recopy it from userspace.
This patchset converts the getname()/putname() interfaces to return
a struct instead of a string. For now, the struct just tracks the
string in kernel space and the original userland pointer for it.
Later, we'll add other information to the struct as it becomes
convenient.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This function is used by sparc, powerpc and arm64 for compat support.
The patch adds a generic implementation which calls do_sendfile()
directly and avoids set_fs().
The sparc architecture has wrappers for the sign extensions while
powerpc relies on the compiler to do the this. The patch adds wrappers
for powerpc to handle the u32->int type conversion.
compat_sys_sendfile64() can be replaced by a sys_sendfile() call since
compat_loff_t has the same size as off_t on a 64-bit system.
On powerpc, the patch also changes the 64-bit sendfile call from
sys_sendile64 to sys_sendfile.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
compat_sys_{read,write}v() need the same "pass a copy of file->f_pos" thing
as sys_{read,write}{,v}().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull third pile of signal handling patches from Al Viro:
"This time it's mostly helpers and conversions to them; there's a lot
of stuff remaining in the tree, but that'll either go in -rc2
(isolated bug fixes, ideally via arch maintainers' trees) or will sit
there until the next cycle."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
x86: get rid of calling do_notify_resume() when returning to kernel mode
blackfin: check __get_user() return value
whack-a-mole with TIF_FREEZE
FRV: Optimise the system call exit path in entry.S [ver #2]
FRV: Shrink TIF_WORK_MASK [ver #2]
FRV: Prevent syscall exit tracing and notify_resume at end of kernel exceptions
new helper: signal_delivered()
powerpc: get rid of restore_sigmask()
most of set_current_blocked() callers want SIGKILL/SIGSTOP removed from set
set_restore_sigmask() is never called without SIGPENDING (and never should be)
TIF_RESTORE_SIGMASK can be set only when TIF_SIGPENDING is set
don't call try_to_freeze() from do_signal()
pull clearing RESTORE_SIGMASK into block_sigmask()
sh64: failure to build sigframe != signal without handler
openrisc: tracehook_signal_handler() is supposed to be called on success
new helper: sigmask_to_save()
new helper: restore_saved_sigmask()
new helpers: {clear,test,test_and_clear}_restore_sigmask()
HAVE_RESTORE_SIGMASK is defined on all architectures now
Pull vfs changes from Al Viro.
"A lot of misc stuff. The obvious groups:
* Miklos' atomic_open series; kills the damn abuse of
->d_revalidate() by NFS, which was the major stumbling block for
all work in that area.
* ripping security_file_mmap() and dealing with deadlocks in the
area; sanitizing the neighborhood of vm_mmap()/vm_munmap() in
general.
* ->encode_fh() switched to saner API; insane fake dentry in
mm/cleancache.c gone.
* assorted annotations in fs (endianness, __user)
* parts of Artem's ->s_dirty work (jff2 and reiserfs parts)
* ->update_time() work from Josef.
* other bits and pieces all over the place.
Normally it would've been in two or three pull requests, but
signal.git stuff had eaten a lot of time during this cycle ;-/"
Fix up trivial conflicts in Documentation/filesystems/vfs.txt (the
'truncate_range' inode method was removed by the VM changes, the VFS
update adds an 'update_time()' method), and in fs/btrfs/ulist.[ch] (due
to sparse fix added twice, with other changes nearby).
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (95 commits)
nfs: don't open in ->d_revalidate
vfs: retry last component if opening stale dentry
vfs: nameidata_to_filp(): don't throw away file on error
vfs: nameidata_to_filp(): inline __dentry_open()
vfs: do_dentry_open(): don't put filp
vfs: split __dentry_open()
vfs: do_last() common post lookup
vfs: do_last(): add audit_inode before open
vfs: do_last(): only return EISDIR for O_CREAT
vfs: do_last(): check LOOKUP_DIRECTORY
vfs: do_last(): make ENOENT exit RCU safe
vfs: make follow_link check RCU safe
vfs: do_last(): use inode variable
vfs: do_last(): inline walk_component()
vfs: do_last(): make exit RCU safe
vfs: split do_lookup()
Btrfs: move over to use ->update_time
fs: introduce inode operation ->update_time
reiserfs: get rid of resierfs_sync_super
reiserfs: mark the superblock as dirty a bit later
...
Everyone either defines it in arch thread_info.h or has TIF_RESTORE_SIGMASK
and picks default set_restore_sigmask() in linux/thread_info.h. Kill the
ifdefs, slap #error in linux/thread_info.h to catch breakage when new ones
get merged.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
A cleanup of rw_copy_check_uvector and compat_rw_copy_check_uvector after
changes made to support CMA in an earlier patch.
Rather than having an additional check_access parameter to these
functions, the first paramater type is overloaded to allow the caller to
specify CHECK_IOVEC_ONLY which means check that the contents of the iovec
are valid, but do not check the memory that they point to. This is used
by process_vm_readv/writev where we need to validate that a iovec passed
to the syscall is valid but do not want to check the memory that it points
to at this point because it refers to an address space in another process.
Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Store uids and gids with kuid_t and kgid_t in struct kstat
- Convert uid and gids to userspace usable values with
from_kuid and from_kgid
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Pull x32 support for x86-64 from Ingo Molnar:
"This tree introduces the X32 binary format and execution mode for x86:
32-bit data space binaries using 64-bit instructions and 64-bit kernel
syscalls.
This allows applications whose working set fits into a 32 bits address
space to make use of 64-bit instructions while using a 32-bit address
space with shorter pointers, more compressed data structures, etc."
Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c}
* 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits)
x32: Fix alignment fail in struct compat_siginfo
x32: Fix stupid ia32/x32 inversion in the siginfo format
x32: Add ptrace for x32
x32: Switch to a 64-bit clock_t
x32: Provide separate is_ia32_task() and is_x32_task() predicates
x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls
x86/x32: Fix the binutils auto-detect
x32: Warn and disable rather than error if binutils too old
x32: Only clear TIF_X32 flag once
x32: Make sure TS_COMPAT is cleared for x32 tasks
fs: Remove missed ->fds_bits from cessation use of fd_set structs internally
fs: Fix close_on_exec pointer in alloc_fdtable
x32: Drop non-__vdso weak symbols from the x32 VDSO
x32: Fix coding style violations in the x32 VDSO code
x32: Add x32 VDSO support
x32: Allow x32 to be configured
x32: If configured, add x32 system calls to system call tables
x32: Handle process creation
x32: Signal-related system calls
x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h>
...
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
For 32-bit ABIs which have real 64-bit registers, we don't want to
break the position argument into two. However, we still need compat
support to deal with 32-bit pointers, so we can't just use
sys_p{read,write} directly.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Massaged cp_compat_stat() into form closer to cp_new_stat(); the only
real issue had been in handling of st_nlink overflows - native 32bit
stat(2) returns -EOVERFLOW in such situations, compat one silently
loses upper bits.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The basic idea behind cross memory attach is to allow MPI programs doing
intra-node communication to do a single copy of the message rather than a
double copy of the message via shared memory.
The following patch attempts to achieve this by allowing a destination
process, given an address and size from a source process, to copy memory
directly from the source process into its own address space via a system
call. There is also a symmetrical ability to copy from the current
process's address space into a destination process's address space.
- Use of /proc/pid/mem has been considered, but there are issues with
using it:
- Does not allow for specifying iovecs for both src and dest, assuming
preadv or pwritev was implemented either the area read from or
written to would need to be contiguous.
- Currently mem_read allows only processes who are currently
ptrace'ing the target and are still able to ptrace the target to read
from the target. This check could possibly be moved to the open call,
but its not clear exactly what race this restriction is stopping
(reason appears to have been lost)
- Having to send the fd of /proc/self/mem via SCM_RIGHTS on unix
domain socket is a bit ugly from a userspace point of view,
especially when you may have hundreds if not (eventually) thousands
of processes that all need to do this with each other
- Doesn't allow for some future use of the interface we would like to
consider adding in the future (see below)
- Interestingly reading from /proc/pid/mem currently actually
involves two copies! (But this could be fixed pretty easily)
As mentioned previously use of vmsplice instead was considered, but has
problems. Since you need the reader and writer working co-operatively if
the pipe is not drained then you block. Which requires some wrapping to
do non blocking on the send side or polling on the receive. In all to all
communication it requires ordering otherwise you can deadlock. And in the
example of many MPI tasks writing to one MPI task vmsplice serialises the
copying.
There are some cases of MPI collectives where even a single copy interface
does not get us the performance gain we could. For example in an
MPI_Reduce rather than copy the data from the source we would like to
instead use it directly in a mathops (say the reduce is doing a sum) as
this would save us doing a copy. We don't need to keep a copy of the data
from the source. I haven't implemented this, but I think this interface
could in the future do all this through the use of the flags - eg could
specify the math operation and type and the kernel rather than just
copying the data would apply the specified operation between the source
and destination and store it in the destination.
Although we don't have a "second user" of the interface (though I've had
some nibbles from people who may be interested in using it for intra
process messaging which is not MPI). This interface is something which
hardware vendors are already doing for their custom drivers to implement
fast local communication. And so in addition to this being useful for
OpenMPI it would mean the driver maintainers don't have to fix things up
when the mm changes.
There was some discussion about how much faster a true zero copy would
go. Here's a link back to the email with some testing I did on that:
http://marc.info/?l=linux-mm&m=130105930902915&w=2
There is a basic man page for the proposed interface here:
http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt
This has been implemented for x86 and powerpc, other architecture should
mainly (I think) just need to add syscall numbers for the process_vm_readv
and process_vm_writev. There are 32 bit compatibility versions for
64-bit kernels.
For arch maintainers there are some simple tests to be able to quickly
verify that the syscalls are working correctly here:
http://ozlabs.org/~cyeoh/cma/cma-test-20110718.tgz
Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: <linux-man@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hch/vfs-queue: (21 commits)
leases: fix write-open/read-lease race
nfs: drop unnecessary locking in llseek
ext4: replace cut'n'pasted llseek code with generic_file_llseek_size
vfs: add generic_file_llseek_size
vfs: do (nearly) lockless generic_file_llseek
direct-io: merge direct_io_walker into __blockdev_direct_IO
direct-io: inline the complete submission path
direct-io: separate map_bh from dio
direct-io: use a slab cache for struct dio
direct-io: rearrange fields in dio/dio_submit to avoid holes
direct-io: fix a wrong comment
direct-io: separate fields only used in the submission path from struct dio
vfs: fix spinning prevention in prune_icache_sb
vfs: add a comment to inode_permission()
vfs: pass all mask flags check_acl and posix_acl_permission
vfs: add hex format for MAY_* flag values
vfs: indicate that the permission functions take all the MAY_* flags
compat: sync compat_stats with statfs.
vfs: add "device" tag to /proc/self/mountstats
cleanup: vfs: small comment fix for block_invalidatepage
...
Fix up trivial conflict in fs/gfs2/file.c (llseek changes)
This was found by inspection while tracking a similar
bug in compat_statfs64, that has been fixed in mainline
since decemeber.
- This fixes a bug where not all of the f_spare fields
were cleared on mips and s390.
- Add the f_flags field to struct compat_statfs
- Copy f_flags to userspace in case someone cares.
- Use __clear_user to copy the f_spare field to userspace
to ensure that all of the elements of f_spare are cleared.
On some architectures f_spare is has 5 ints and on some
architectures f_spare only has 4 ints. Which makes
the previous technique of clearing each int individually
broken.
I don't expect anyone actually uses the old statfs system
call anymore but if they do let them benefit from having
the compat and the native version working the same.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
* 'for-3.2' of git://linux-nfs.org/~bfields/linux: (103 commits)
nfs41: implement DESTROY_CLIENTID operation
nfsd4: typo logical vs bitwise negate for want_mask
nfsd4: allow NFS4_SHARE_SIGNAL_DELEG_WHEN_RESRC_AVAIL | NFS4_SHARE_PUSH_DELEG_WHEN_UNCONTENDED
nfsd4: seq->status_flags may be used unitialized
nfsd41: use SEQ4_STATUS_BACKCHANNEL_FAULT when cb_sequence is invalid
nfsd4: implement new 4.1 open reclaim types
nfsd4: remove unneeded CLAIM_DELEGATE_CUR workaround
nfsd4: warn on open failure after create
nfsd4: preallocate open stateid in process_open1()
nfsd4: do idr preallocation with stateid allocation
nfsd4: preallocate nfs4_file in process_open1()
nfsd4: clean up open owners on OPEN failure
nfsd4: simplify process_open1 logic
nfsd4: make is_open_owner boolean
nfsd4: centralize renew_client() calls
nfsd4: typo logical vs bitwise negate
nfs: fix bug about IPv6 address scope checking
nfsd4: more robust ignoring of WANT bits in OPEN
nfsd4: move name-length checks to xdr
nfsd4: move access/deny validity checks to xdr code
...
The nfsservctl system call is now gone, so we should remove all
linkage for it.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As promised in feature-removal-schedule.txt it is time to
remove the nfsctl system call.
Userspace has perferred to not use this call throughout 2.6 and it has been
excluded in the default configuration since 2.6.36 (9 months ago).
So this patch removes all the code that was being compiled out.
There are still references to sys_nfsctl in various arch systemcall tables
and related code. These should be cleaned out too, probably in the next
merge window.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Add the appropriate members into struct user_arg_ptr and teach
get_user_arg_ptr() to handle is_compat = T case correctly.
This allows us to remove the compat_do_execve() code from fs/compat.c
and reimplement compat_do_execve() as the trivial wrapper on top of
do_execve_common(is_compat => true).
In fact, this fixes another (minor) bug. "compat_uptr_t str" can
overflow after "str += len" in compat_copy_strings() if a 64bit
application execs via sys32_execve().
Unexport acct_arg_size() and get_arg_page(), fs/compat.c doesn't
need them any longer.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Remove the leftover from the commit 8ff3e8e85f ("select:
switch select() and poll() over to hrtimers").
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
