Trying to compile drivers/usb/gadget/f_mass_storage.o currently fails and
spews a ton of warnings :

  CC      drivers/usb/gadget/f_mass_storage.o
drivers/usb/gadget/f_mass_storage.c:436:22: error: field ‘function’ has incomplete type
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_from_func’:
drivers/usb/gadget/f_mass_storage.c:466:9: warning: type defaults to ‘int’ in declaration of ‘__mptr’
drivers/usb/gadget/f_mass_storage.c:466:9: warning: initialization from incompatible pointer type
drivers/usb/gadget/f_mass_storage.c: At top level:
drivers/usb/gadget/f_mass_storage.c:2743:15: warning: ‘struct usb_composite_dev’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:2743:15: warning: its scope is only this definition or declaration, which is probably not what you want
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_common_init’:
drivers/usb/gadget/f_mass_storage.c:2745:34: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:2775:23: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:2779:3: error: implicit declaration of function ‘usb_string_id’
drivers/usb/gadget/f_mass_storage.c: At top level:
drivers/usb/gadget/f_mass_storage.c:2984:60: warning: ‘struct usb_configuration’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:3003:57: warning: ‘struct usb_configuration’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_bind’:
drivers/usb/gadget/f_mass_storage.c:3006:31: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:3013:2: error: implicit declaration of function ‘usb_interface_id’
drivers/usb/gadget/f_mass_storage.c:3033:3: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:3034:6: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:3043:4: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:3044:7: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c:3045:26: error: dereferencing pointer to incomplete type
drivers/usb/gadget/f_mass_storage.c: At top level:
drivers/usb/gadget/f_mass_storage.c:3067:14: warning: ‘struct usb_configuration’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:3067:14: warning: ‘struct usb_composite_dev’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_bind_config’:
drivers/usb/gadget/f_mass_storage.c:3093:2: error: implicit declaration of function ‘usb_add_function’
drivers/usb/gadget/f_mass_storage.c: At top level:
drivers/usb/gadget/f_mass_storage.c:3103:9: warning: ‘struct usb_configuration’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:3103:9: warning: ‘struct usb_composite_dev’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_add’:
drivers/usb/gadget/f_mass_storage.c:3105:2: warning: passing argument 1 of ‘fsg_bind_config’ from incompatible pointer type
drivers/usb/gadget/f_mass_storage.c:3065:12: note: expected ‘struct usb_composite_dev *’ but argument is of type ‘struct usb_composite_dev *’
drivers/usb/gadget/f_mass_storage.c:3105:2: warning: passing argument 2 of ‘fsg_bind_config’ from incompatible pointer type
drivers/usb/gadget/f_mass_storage.c:3065:12: note: expected ‘struct usb_configuration *’ but argument is of type ‘struct usb_configuration *’
drivers/usb/gadget/f_mass_storage.c: At top level:
drivers/usb/gadget/f_mass_storage.c:3190:23: warning: ‘struct usb_composite_dev’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:3195:23: warning: ‘struct usb_composite_dev’ declared inside parameter list
drivers/usb/gadget/f_mass_storage.c:3193:1: error: conflicting types for ‘fsg_common_from_params’
drivers/usb/gadget/f_mass_storage.c:3188:1: note: previous declaration of ‘fsg_common_from_params’ was here
drivers/usb/gadget/f_mass_storage.c: In function ‘fsg_common_from_params’:
drivers/usb/gadget/f_mass_storage.c:3199:2: warning: passing argument 2 of ‘fsg_common_init’ from incompatible pointer type
drivers/usb/gadget/f_mass_storage.c:2741:27: note: expected ‘struct usb_composite_dev *’ but argument is of type ‘struct usb_composite_dev *’
make[1]: *** [drivers/usb/gadget/f_mass_storage.o] Error 1
make: *** [drivers/usb/gadget/f_mass_storage.o] Error 2

This is due to the missing include of linux/usb/composite.h - this patch
adds the missing include.

In addition there's also a problem in fsg_common_init() where we memset
'common', but we use the size of a pointer to 'struct fsg_common' as the
size argument to memset(), not the actual size of the struct. This patch
fixes the sizeof so we zero the entire struct as intended.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit is purely style clean ups.
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit removes call to the complete() function done in
fsg_unbind() which was never needed there but was a leftover
form file_storage.c.
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit drops START_TRANSFER_OR() and START_TRANSFER()
macros with a pair of nice inline functions which are actually
more readable and easier to use.
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit removes an "OR" macro defined in Mass Storage
Function in favour of a two argument version of "?:" operator
(which is a GCC extension).
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit fixes an issue with error recovery after
device_register() fails in Mass Storage Function.  The device
needs to be put to avoid resource leakage.
Signed-off-by: NRahul Ruikar <rahul.ruikar@gmail.com>
[mina86@mina86.com: updated commit message]
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This commit changes storage_common.h, file_storage.c and
f_mass_storage.c to use definitions of SCSI commands from
scsi/scsi.h file instead of redefining the commands in
storage_common.c.

scsi/scsi.h header file was missing READ_FORMAT_CAPACITIES and
READ_HEADER so this commit also add those to the header.
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The nofua parameter (optionally ignore SCSI WRITE FUA) was added
to the File Storage Gadget some time ago.  This patch adds the
same functionality to the Mass Storage Function.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Added pre_eject() and post_eject() callbacks which are
called before and after removable logical unit is ejected.
The first can prevent logical unit from being ejected.

This commit also changes the way callbacks are passed to
the function from gadget.  A fsg_operations structure has
been created which lists all callbacks -- this is passed
to the fsg_config.

This is important because it changes the way thread_exits()
callback is passed.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The ep0req_name was never used in f_mass_storage hence it may
be safely removed from the code.  It was a leftover from File
Storage Gadget which used it for debug messages.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Mass Storage Function had a bit unique name for function
used to add it to USB configuration.  Renamed as to match
naming convention of other functions.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

On fsg_unbind the common->fsg pointer was not NULLed if the
unbound fsg_dev instance was the current one.  As an effect,
the incorrect pointer was preserved in all further operations
which caused do_set_interface to reference an invalid region.

This commit fixes this by raising an exception in fsg_bind
which will change the common->fsg pointer.  This also requires
an wait queue so that the thread in fsg_bind can wait till the
worker thread handles the exception.

This commit removes also a config and new_config fields of
fsg_common as they are no longer needed since fsg can be
used to determine whether function is active or not.

Moreover, this commit removes possible race condition where
the fsg field was modified in both the worker thread and
form various other contexts.  This is fixed by replacing
prev_fsg with new_fsg.  At this point, fsg is assigned only
in worker thread.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The full speed descriptors were copied to the usb_function structure
in the fsg_bind_config function before call to the usb_ep_autoconfig.
The usb_ep_autoconfig was called in fsg_bind using the original
descriptors.  In effect copied descriptors were not updated.

This patch changes the copy full speed descriptors after the call to
usb_op_autoconfig is performed.  This way, copied full speed
descriptors have updated values.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Reported-by: NDries Van Puymbroeck <Dries.VanPuymbroeck@dekimo.com>
Tested-by: NDries Van Puymbroeck <Dries.VanPuymbroeck@dekimo.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In to places in fsg_common_init() an unconditional call to kfree()
on common was performed in error recovery which is not a valid
behaviour since fsg_common structure is not always allocated by
fsg_common_init().

To fix, the calls has been replaced with a goto to a proper error
recovery which does the correct thing.

Also, refactored fsg_common_release() function.
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Reviewed-by: NViral Mehta <viral.mehta@lntinfotech.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

__init, __initdata and __exit tags have have been removed from
various files to make it possible for gadgets that do not use
the __init/__exit tags to use those.

Files in question are related to:
* the core composite framework,
* the mass storage function (fixing a section mismatch) and
* ethernet driver (ACM, ECM, RNDIS).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch adds handling of the "Start/Stop Unit" SCSI request
to simulate media ejection.
Signed-off-by: NFabien Chouteau <fabien.chouteau@barco.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Mass Storage Function (MSF) used the same descriptors for each
usb_function instance (meaning usb_function::descriptors of different
functions pointed to the same static area (the same was true for
usb_function::hs_descriptors)).

This would leads to problems if MSF were used in several USB
configurations with different interface and/or endpoint numbers.
Descriptors for all configurations would have interface/endpoint
numbers overwritten by the values valid for the last configuration.

This patch adds code that copies the descriptors each time MSF is
added to USB configuration (that is for each usb_function).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>

"Static" buffers in fsg_buffhd structure (ie. fields which are arrays
rather then pointers to dynamically allocated memory) are not aligned
to any "big" power of two which may lead to poor DMA performance
(copying "by hand" of head or tail) or no DMA at all even if otherwise
hardware supports it.

Therefore, this patch makes mass storage function use kmalloc()ed
buffers which are (because of their size) page aligned (which should
be enough for any hardware).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Contrary to the comment in fsg_add, fsg_bind calls fsg_unbind on errors,
which decreases refcount and frees the fsg_dev structure, causing trouble
when fsg_add does the same.

Fix it by simply leaving up cleanup to fsg_add().
Signed-off-by: NPeter Korsgaard <jacmet@sunsite.dk>
Acked-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The recent commit (0e530b45) that moved usb_ep_autoconfig from the
__devinit section to the __init section missed the mass storage device.
Its fsg_bind() function uses the usb_ep_autoconfig() function from non
__init context leading to:
WARNING: drivers/usb/gadget/g_mass_storage.o(.text): Section mismatch in
	reference from the function _fsg_bind()
	            to the function .init.text:_usb_ep_autoconfig()

So move fsg_bind() into __init as well.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

No one is calling this anymore as everyone has switched to
invalidate_mapping_pages long time ago.  Also update a few
references to it in comments.  nfs has two more, but I can't
easily figure what they are actually referring to, so I left
them as-is.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

A bunch of USB gadget drivers where never ported from the linux 2.4
series to 2.6 kernels. However there's some code still in the tree for
them which isn't used and is probably untested for ages.

As the chance of these drivers being forward ported is probably quite
small now it might be time to get rid of them.
Signed-off-by: NChristoph Egger <siccegge@stud.informatik.uni-erlangen.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

init_completion() hasn't been called yet and the thread isn't created
if we end up here, so don't call complete() on thread_notifier.
Signed-off-by: NPeter Korsgaard <jacmet@sunsite.dk>
Acked-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch fixes warning caused by calling min() macro
with arguments of different types:

  drivers/usb/gadget/f_mass_storage.c:623: warning: \
  comparison of distinct pointer types lacks a cast
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Marek Szyprowski <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The mass storage function responded needlessly to a set
configuration packet.  This was a leftover from converting
gadget (file storage gadget) into a composite function.

Moreover, it has failed to respond to get max LUN request.
Adding request queueing made the function work better.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Adds a fallback which forces all LUNs ejection (including
non-removable and with prevent_medium_removal flag) when mass storage
function (MSF) worker thread exits and gadget fails to handle the
situation.

Previously, if thread_exits was not specified mass storage function
(MSF) did nothing when exiting thread as it's unclear for *function*
what to do when it's thread terminates so responsibility of handling
this situation was left to the *gadget* using the function.

The g_mass_storage handled the situation by unregistering itself (the
same thing that file storage gadget does).  However, g_multi did
nothing and so MSF did not eject LUNs which prevented file system
unmounting.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Reviewed-by: NKyungmin Park <kyungmin.park@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

thread_exits callback has been added to fsg_common structure.
This callback is called when MSF's thread exits (is terminated
by a signal or function is unregistered).  It's then gadget's
responsibility to unregister the gadget.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Most of the data from fsg_dev have been moved to fsg_common
structure.  The fsg_dev structure holds only endpoint dependent
data.  The fsg_common structure has a fsg pointer which points
to active fsg_dev structure -- endpoints are referenced via this
pointer.

This fixes the problem of several threads created when a single
instance of MSF is used in several USB configurations.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fixed most of the errors and warnings in f_mass_storage.c and
storage_common.c reported by checkpatch.pl as well as updated
comments.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

A two fsg_config fields were added:
* lun_name_format which lets one specify format of a name
  used when registering LUN devices.  It is useful if there
  would be ever need for two MSFs to be used in a single
  composite gadget (as opposed to single MSF in two
  configuration); and
* thread_name which lets one specify the name of a kernel
  thread used by MSF.  This is not required since two or more
  threads can have the same name but nevertheless it's here
  for consistency.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Removed all references to mod_data in f_mass_storage.c and
instead created fsg_config structure fsg_common_init() takes
as an argument -- it stores all configuration options that
were previously taken from mod_data.

Moreover, The fsg_config structure allows per-LUN
configuration of removable and CD-ROM emulation.

Module parameters are handled by defining an object of
fsg_module_parameters structure and then declaring module
parameters via FSG_MODULE_PARAMETERS() macro.  It adds proper
declarations to the code making specified object be populated
from module parameters.

To use values stored there one may use either
fsg_config_from_params() which will will a fsg_config structure
with values taken from fsg_module_parameters structure or
fsg_common_from_params() which will initialise fsg_common
structure directly.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The f_mass_storage.c has been changed into a composite function.
mass_storage.c file has been introduced which defines a
g_mass_storage gadget based on composite framework.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Moved code initialising fsg_common structure to fsg_common_init()
function which is called from fsg_bind().  Moreover, changed
reference counting mechanism: fsg_common has a reference counter
which counts how many fsg_dev structures uses it.  When this
reaches zero fsg_common_release() is run which unregisters
LUN devices and frees memory.

fsg_common_init() takes pointer to fsg_common structure as an
argument.  If it is NULL function allocates storage otherwise
uses pointed to memory (handy if fsg_common is a field of another
structure or a static variable).

fsg_common_release() will free storage only if
free_storage_on_release is set -- it is initialised by
fsg_common_init(): set if allocation was done, unset
otherwise (one may overwrite it of course).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Using version of fsg_buffhd structure with buf field being an
array of characters with predefined size.  Since mass storage
function does not define changing buffer size on run-time it is
not required for the field to be a pointer to void and allocating
space dynamically.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In the final version, many fsg_dev structures will (be able to)
refer to a single fsg_common structure and so it is required
to move common data to another object which can be shared.

Situation where many fsg_dev structures refer single fsg_common
structure is when a single instance of MSF is used in several
USB configurations.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Removed code that was included when CONFIG_USB_FILE_STORAGE_TEST
was defined.  If this functionality is required one may still use
the original File-backed Storage Gadget.  It has been agreed that
testing functionality is not required in the composite function.

Also removed fsg_suspend() and fsg_resume() which were no
operations.

Moreover, storage_common.c has been modified in such a way that
defining certain macros skips parts of the file.  Those macros
are:
* FSG_NO_INTR_EP -- skips interrupt endpoint descriptors
* FSG_NO_DEVICE_STRINGS -- skips certain strings
* FSG_NO_OTG -- skips OTG descriptor
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Copied file_storage.c to f_mass_storage.c which will be used as
template for the Mass Storage composite Function.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Since storage_common.c no longer references mod_data object
it is now possible to include it before mod_data object is
defined.  This makes it possible to move some defines that
are used as default values of mod_data fields to be defined
in storage_common.c file (where they should be set from
the beginning).

Also, show_ro(), show_file(), store_ro() and store_file()
have been moved to storage_common.c with LUN's device's
drvdata changed from pointing to fsg_dev to pointing to
rw_semaphore (&fsg->filesem).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

removable and cdrom flag has been added to the fsg_lun structure
removing any references to mod_data object from storage_common.c.

As of read-only flag, previously it was set if a read-only
backing file was specified (which is good) and remained set
even after the file has been closed (which may be considered an
issue).  Currently, the initial read-only flag is preserved so
if it was unset each time file is opened code will try to open
it read-write even if previous file was opened read-only.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Prefixed some identifiers that were defined in storage_common.c file
with "fsg_".  Not all identifiers were prefixed but the ones that are
most likely to produce conflicts when used with other USB functions.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>