Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

both on aio and non-aio sides

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

If ffs_epfile_io() fails in AIO case, we end up leaking io_data
(and iovec_copy in case of AIO read).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Add eventfd which notifies userspace about ep0 events and AIO completion
events. It simplifies using of FunctionFS with event loop, because now
we need to poll on single file (instead of polling on ep0 and eventfd's
supplied to AIO layer).

FunctionFS eventfd is not triggered if another eventfd is supplied to
AIO layer (in AIO request). It can be useful, for example, when we want
to handle AIO transations for chosen endpoint in separate thread.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Use if-loop variable 'epfile' instead of start variable 'epfiles'. Now the
correct endpoint file name is stored.

Signed-off-by: Mario Schuknecht <mario.schuknecht@dresearch-fe.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Since we can compose gadgets from many functions, there is the problem
related to gadget breakage while FunctionFS daemon being closed. FFS
function is userspace code so there is no way to know when it will close
files (it doesn't matter what is the reason of this situation, it can
be daemon logic, program breakage, process kill or any other). So when
we have another function in gadget which, for example, sends some amount
of data, does some software update or implements some real-time functionality,
we may want to keep the gadget connected despite FFS function is no longer
functional.

We can't just remove one of functions from gadget since it has been
enumerated, so the only way to keep entire gadget working is to make
broken FFS function deactivated but still visible to host. For this
purpose this patch introduces "no_disconnect" mode. It can be enabled
by setting mount option "no_disconnect=1", and results with defering
function disconnect to the moment of reopen ep0 file or filesystem
unmount. After closing all endpoint files, FunctionFS is set to state
FFS_DEACTIVATED.

When ffs->state == FFS_DEACTIVATED:
- function is still bound and visible to host,
- setup requests are automatically stalled,
- transfers on other endpoints are refused,
- epfiles, except ep0, are deleted from the filesystem,
- opening ep0 causes the function to be closed, and then FunctionFS
  is ready for descriptors and string write,
- altsetting change causes the function to be closed - we want to keep
  function alive until another functions are potentialy used, altsetting
  change means that another configuration is being selected or USB cable
  was unplugged, which indicates that we don't need to stay longer in
  FFS_DEACTIVATED state
- unmounting of the FunctionFS instance causes the function to be closed.

Tested-by: David Cohen <david.a.cohen@linux.intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Instead of using variable length array, use a static length equal to
the size of the ffs->ev.types array.  This gets rid of a sparse warning:

	drivers/usb/gadget/function/f_fs.c:401:44: warning:
	Variable length array is used.

and makes it more explicit that the array has a very tight upper size
limit.  Also add some more documentation about the ev.types array and
how its size is limited and affects the rest of the code.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reported-by: Rohith Seelaboyina <rseelaboyina@nvidia.com>
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

The commit '2e4c7553cd usb: gadget: f_fs: add aio support' broke the
quirk implemented to align buffer size to maxpacketsize on out endpoint.
As result, functionfs does not work on Intel platforms using dwc3 driver
(i.e. Bay Trail and Merrifield). This patch fixes the issue.

This code is based on a previous Qiuxu's patch.

Fixes: 2e4c7553cd (usb: gadget: f_fs: add aio support)
Cc: <stable@vger.kernel.org> # v3.16+
Signed-off-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

During FunctionFS bind, ffs_data_get() function was called twice
(in functionfs_bind() and in ffs_do_functionfs_bind()), while on unbind
ffs_data_put() was called once (in functionfs_unbind() function).
In result refcount never reached value 0, and ffs memory resources has
been never released.

Since ffs_data_get() call in ffs_do_functionfs_bind() is redundant
and not neccessary, we remove it to have equal number of gets ans puts,
and free allocated memory after refcount reach 0.

Fixes: 5920cda (usb: gadget: FunctionFS: convert to new function
	interface with backward compatibility)
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Pull vfs updates from Al Viro:
 "The big thing in this pile is Eric's unmount-on-rmdir series; we
  finally have everything we need for that.  The final piece of prereqs
  is delayed mntput() - now filesystem shutdown always happens on
  shallow stack.

  Other than that, we have several new primitives for iov_iter (Matt
  Wilcox, culled from his XIP-related series) pushing the conversion to
  ->read_iter()/ ->write_iter() a bit more, a bunch of fs/dcache.c
  cleanups and fixes (including the external name refcounting, which
  gives consistent behaviour of d_move() wrt procfs symlinks for long
  and short names alike) and assorted cleanups and fixes all over the
  place.

  This is just the first pile; there's a lot of stuff from various
  people that ought to go in this window.  Starting with
  unionmount/overlayfs mess...  ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (60 commits)
  fs/file_table.c: Update alloc_file() comment
  vfs: Deduplicate code shared by xattr system calls operating on paths
  reiserfs: remove pointless forward declaration of struct nameidata
  don't need that forward declaration of struct nameidata in dcache.h anymore
  take dname_external() into fs/dcache.c
  let path_init() failures treated the same way as subsequent link_path_walk()
  fix misuses of f_count() in ppp and netlink
  ncpfs: use list_for_each_entry() for d_subdirs walk
  vfs: move getname() from callers to do_mount()
  gfs2_atomic_open(): skip lookups on hashed dentry
  [infiniband] remove pointless assignments
  gadgetfs: saner API for gadgetfs_create_file()
  f_fs: saner API for ffs_sb_create_file()
  jfs: don't hash direct inode
  [s390] remove pointless assignment of ->f_op in vmlogrdr ->open()
  ecryptfs: ->f_op is never NULL
  android: ->f_op is never NULL
  nouveau: __iomem misannotations
  missing annotation in fs/file.c
  fs: namespace: suppress 'may be used uninitialized' warnings
  ...