Merge branch 'akpm' (patches from Andrew)

NOTE: At the moment DMA_ATTR_ALLOC_SINGLE_PAGES is only implemented on ARM,

though ARM64 patches will likely be posted soon.

DMA_ATTR_NO_WARN

----------------

This tells the DMA-mapping subsystem to suppress allocation failure reports

(similarly to __GFP_NOWARN).

On some architectures allocation failures are reported with error messages

to the system logs.  Although this can help to identify and debug problems,

drivers which handle failures (eg, retry later) have no problems with them,

and can actually flood the system logs with error messages that aren't any

problem at all, depending on the implementation of the retry mechanism.

So, this provides a way for drivers to avoid those error messages on calls

where allocation failures are not a problem, and shouldn't bother the logs.

NOTE: At the moment DMA_ATTR_NO_WARN is only implemented on PowerPC.

 [<ffffffff817db154>] kernel_thread_helper+0x4/0x10

 [<ffffffff81066430>] ? finish_task_switch+0x80/0x110

 [<ffffffff817d9c04>] ? retint_restore_args+0xe/0xe

 [<ffffffff81097510>] ? __init_kthread_worker+0x70/0x70

 [<ffffffff81097510>] ? __kthread_init_worker+0x70/0x70

 [<ffffffff817db150>] ? gs_change+0xb/0xb

Line 2776 of block/cfq-iosched.c in v3.0-rc5 is as follows:

- ``kmemleak_alloc_recursive`` - as kmemleak_alloc but checks the recursiveness

- ``kmemleak_free_recursive``	 - as kmemleak_free but checks the recursiveness

The following functions take a physical address as the object pointer

and only perform the corresponding action if the address has a lowmem

mapping:

- ``kmemleak_alloc_phys``

- ``kmemleak_free_part_phys``

- ``kmemleak_not_leak_phys``

- ``kmemleak_ignore_phys``

Dealing with false positives/negatives

--------------------------------------

				 * including this struct */

	__s32 ioctlfd;          /* automount command fd */

	__u32 arg1;             /* Command parameters */

	__u32 arg2;

	union {

		struct args_protover		protover;

		struct args_protosubver		protosubver;

		struct args_openmount		openmount;

		struct args_ready		ready;

		struct args_fail		fail;

		struct args_setpipefd		setpipefd;

		struct args_timeout		timeout;

		struct args_requester		requester;

		struct args_expire		expire;

		struct args_askumount		askumount;

		struct args_ismountpoint	ismountpoint;

	};

	char path[0];

};

mount point file descriptor, and when requesting the uid and gid of the

last successful mount on a directory within the autofs file system.

The fields arg1 and arg2 are used to communicate parameters and results of

calls made as described below.

The union is used to communicate parameters and results of calls made

as described below.

The path field is used to pass a path where it is needed and the size field

is used account for the increased structure length when translating the

Get the major and minor version of the autofs4 protocol version understood

by loaded module. This call requires an initialized struct autofs_dev_ioctl

with the ioctlfd field set to a valid autofs mount point descriptor

and sets the requested version number in structure field arg1. These

commands return 0 on success or one of the negative error codes if

validation fails.

and sets the requested version number in version field of struct args_protover

or sub_version field of struct args_protosubver. These commands return

0 on success or one of the negative error codes if validation fails.

AUTOFS_DEV_IOCTL_OPENMOUNT and AUTOFS_DEV_IOCTL_CLOSEMOUNT

Obtain and release a file descriptor for an autofs managed mount point

path. The open call requires an initialized struct autofs_dev_ioctl with

the path field set and the size field adjusted appropriately as well

as the arg1 field set to the device number of the autofs mount. The

device number can be obtained from the mount options shown in

/proc/mounts. The close call requires an initialized struct

as the devid field of struct args_openmount set to the device number of

the autofs mount. The device number can be obtained from the mount options

shown in /proc/mounts. The close call requires an initialized struct

autofs_dev_ioct with the ioctlfd field set to the descriptor obtained

from the open call. The release of the file descriptor can also be done

with close(2) so any open descriptors will also be closed at process exit.

Return mount and expire result status from user space to the kernel.

Both of these calls require an initialized struct autofs_dev_ioctl

with the ioctlfd field set to the descriptor obtained from the open

call and the arg1 field set to the wait queue token number, received

by user space in the foregoing mount or expire request. The arg2 field

is set to the status to be returned. For the ready call this is always

0 and for the fail call it is set to the errno of the operation.

call and the token field of struct args_ready or struct args_fail set

to the wait queue token number, received by user space in the foregoing

mount or expire request. The status field of struct args_fail is set to

the errno of the operation. It is set to 0 on success.

AUTOFS_DEV_IOCTL_SETPIPEFD_CMD

The call requires an initialized struct autofs_dev_ioctl with the

ioctlfd field set to the descriptor obtained from the open call and

the arg1 field set to descriptor of the pipe. On success the call

also sets the process group id used to identify the controlling process

(eg. the owning automount(8) daemon) to the process group of the caller.

the pipefd field of struct args_setpipefd set to descriptor of the pipe.

On success the call also sets the process group id used to identify the

controlling process (eg. the owning automount(8) daemon) to the process

group of the caller.

AUTOFS_DEV_IOCTL_CATATONIC_CMD

The call requires an initialized struct autofs_dev_ioctl with the path

field set to the mount point in question and the size field adjusted

appropriately as well as the arg1 field set to the device number of the

containing autofs mount. Upon return the struct field arg1 contains the

uid and arg2 the gid.

appropriately. Upon return the uid field of struct args_requester contains

the uid and gid field the gid.

When reconstructing an autofs mount tree with active mounts we need to

re-connect to mounts that may have used the original process uid and

The call requires an initialized struct autofs_dev_ioctl with the

ioctlfd field set to the descriptor obtained from the open call. In

addition an immediate expire, independent of the mount timeout, can be

requested by setting the arg1 field to 1. If no expire candidates can

be found the ioctl returns -1 with errno set to EAGAIN.

requested by setting the how field of struct args_expire to 1. If no

expire candidates can be found the ioctl returns -1 with errno set to

EAGAIN.

This call causes the kernel module to check the mount corresponding

to the given ioctlfd for mounts that can be expired, issues an expire

The call requires an initialized struct autofs_dev_ioctl with the

ioctlfd field set to the descriptor obtained from the open call and

it returns the result in the arg1 field, 1 for busy and 0 otherwise.

it returns the result in the may_umount field of struct args_askumount,

1 for busy and 0 otherwise.

AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD

possible variations. Both use the path field set to the path of the mount

point to check and the size field adjusted appropriately. One uses the

ioctlfd field to identify a specific mount point to check while the other

variation uses the path and optionally arg1 set to an autofs mount type.

The call returns 1 if this is a mount point and sets arg1 to the device

number of the mount and field arg2 to the relevant super block magic

number (described below) or 0 if it isn't a mountpoint. In both cases

the the device number (as returned by new_encode_dev()) is returned

in field arg1.

variation uses the path and optionally in.type field of struct args_ismountpoint

set to an autofs mount type. The call returns 1 if this is a mount point

and sets out.devid field to the device number of the mount and out.magic

field to the relevant super block magic number (described below) or 0 if

it isn't a mountpoint. In both cases the the device number (as returned

by new_encode_dev()) is returned in out.devid field.

If supplied with a file descriptor we're looking for a specific mount,

not necessarily at the top of the mounted stack. In this case the path

Mountpoint expiry

-----------------

The VFS has a mechansim for automatically expiring unused mounts,

The VFS has a mechanism for automatically expiring unused mounts,

much as it can expire any unused dentry information from the dcache.

This is guided by the MNT_SHRINKABLE flag.  This only applies to

mounts that were created by `d_automount()` returning a filesystem to be

autofs knows whether a process requesting some operation is the daemon

or not based on its process-group id number (see getpgid(1)).

When an autofs filesystem it mounted the pgid of the mounting

When an autofs filesystem is mounted the pgid of the mounting

processes is recorded unless the "pgrp=" option is given, in which

case that number is recorded instead.  Any request arriving from a

process in that process group is considered to come from the daemon.