linux.git/fs/aio.c, branch v2.6.32

aio.c: move EXPORT* macros to line after function

2009-09-23T14:39:29+00:00

As mentioned in Documentation/CodingStyle, move EXPORT* macro's
to the line immediately after the closing function brace line.

Also, move the __initcall() similarly.

Signed-off-by: H Hartley Sweeten 
Cc: Zach Brown 
Cc: Benjamin LaHaise 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move use_mm/unuse_mm from aio.c to mm/

2009-09-22T14:17:42+00:00

Anyone who wants to do copy to/from user from a kernel thread, needs
use_mm (like what fs/aio has).  Move that into mm/, to make reusing and
exporting easier down the line, and make aio use it.  Next intended user,
besides aio, will be vhost-net.

Acked-by: Andrea Arcangeli 
Signed-off-by: Michael S. Tsirkin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eventfd: revised interface and cleanups

2009-07-01T01:55:58+00:00

Change the eventfd interface to de-couple the eventfd memory context, from
the file pointer instance.

Without such change, there is no clean way to racely free handle the
POLLHUP event sent when the last instance of the file* goes away.  Also,
now the internal eventfd APIs are using the eventfd context instead of the
file*.

This patch is required by KVM's IRQfd code, which is still under
development.

Signed-off-by: Davide Libenzi 
Cc: Gregory Haskins 
Cc: Rusty Russell 
Cc: Benjamin LaHaise 
Cc: Avi Kivity 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

aio: lookup_ioctx can return the wrong value when looking up a bogus context

2009-03-19T22:57:18+00:00

The libaio test harness turned up a problem whereby lookup_ioctx on a
bogus io context was returning the 1 valid io context from the list
(harness/cases/3.p).

Because of that, an extra put_iocontext was done, and when the process
exited, it hit a BUG_ON in the put_iocontext macro called from exit_aio
(since we expect a users count of 1 and instead get 0).

The problem was introduced by "aio: make the lookup_ioctx() lockless"
(commit abf137dd7712132ee56d5b3143c2ff61a72a5faa).

Thanks to Zach for pointing out that hlist_for_each_entry_rcu will not
return with a NULL tpos at the end of the loop, even if the entry was
not found.

Signed-off-by: Jeff Moyer 
Acked-by: Zach Brown 
Acked-by: Jens Axboe 
Cc: Benjamin LaHaise 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eventfd: remove fput() call from possible IRQ context

2009-03-19T22:57:18+00:00

Remove a source of fput() call from inside IRQ context.  Myself, like Eric,
wasn't able to reproduce an fput() call from IRQ context, but Jeff said he was
able to, with the attached test program.  Independently from this, the bug is
conceptually there, so we might be better off fixing it.  This patch adds an
optimization similar to the one we already do on ->ki_filp, on ->ki_eventfd.
Playing with ->f_count directly is not pretty in general, but the alternative
here would be to add a brand new delayed fput() infrastructure, that I'm not
sure is worth it.

Signed-off-by: Davide Libenzi 
Cc: Benjamin LaHaise 
Cc: Trond Myklebust 
Cc: Eric Dumazet 
Signed-off-by: Jeff Moyer 
Cc: Zach Brown 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[CVE-2009-0029] System call wrappers part 16

2009-01-14T13:15:25+00:00

Signed-off-by: Heiko Carstens

aio: make the lookup_ioctx() lockless

2008-12-29T07:29:50+00:00

The mm->ioctx_list is currently protected by a reader-writer lock,
so we always grab that lock on the read side for doing ioctx
lookups. As the workload is extremely reader biased, turn this into
an rcu hlist so we can make lookup_ioctx() lockless. Get rid of
the rwlock and use a spinlock for providing update side exclusion.

There's usually only 1 entry on this list, so it doesn't make sense
to look into fancier data structures.

Reviewed-by: Jeff Moyer 
Signed-off-by: Jens Axboe

[PATCH] f_count may wrap around

2008-07-27T00:53:40+00:00

make it atomic_long_t; while we are at it, get rid of useless checks in affs,
hfs and hpfs - ->open() always has it equal to 1, ->release() - to 0.

Signed-off-by: Al Viro

kill PF_BORROWED_MM in favour of PF_KTHREAD

2008-07-25T17:53:39+00:00

Kill PF_BORROWED_MM.  Change use_mm/unuse_mm to not play with ->flags, and
do s/PF_BORROWED_MM/PF_KTHREAD/ for a couple of other users.

No functional changes yet.  But this allows us to do further
fixes/cleanups.

oom_kill/ptrace/etc often check "p->mm != NULL" to filter out the
kthreads, this is wrong because of use_mm().  The problem with
PF_BORROWED_MM is that we need task_lock() to avoid races.  With this
patch we can check PF_KTHREAD directly, or use a simple lockless helper:

	/* The result must not be dereferenced !!! */
	struct mm_struct *__get_task_mm(struct task_struct *tsk)
	{
		if (tsk->flags & PF_KTHREAD)
			return NULL;
		return tsk->mm;
	}

Note also ecard_task().  It runs with ->mm != NULL, but it's the kernel
thread without PF_BORROWED_MM.

Signed-off-by: Oleg Nesterov 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uml: activate_mm: remove the dead PF_BORROWED_MM check

2008-06-06T18:36:22+00:00

use_mm() was changed to use switch_mm() instead of activate_mm(), since
then nobody calls (and nobody should call) activate_mm() with
PF_BORROWED_MM bit set.

As Jeff Dike pointed out, we can also remove the "old != new" check, it is
always true.

Signed-off-by: Oleg Nesterov 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds