A few blocks of code are rearranged a bit here:
    - In rbd_header_from_disk():
	- Don't bother computing snap_count until we're sure the
	  on-disk header starts with a good signature.
	- Move a few independent lines of code so they are *after* a
	  check for a failed memory allocation.
	- Get rid of unnecessary local variable "ret".
    - Make a few other changes in rbd_read_header(), similar to the
      above--just moving things around a bit while preserving the
      functionality.
    - In rbd_rq_fn(), just assign rq in the while loop's controlling
      expression rather than duplicating it before and at the end of
      the loop body.  This allows the use of "continue" rather than
      "goto next" in a number of spots.
    - Rearrange the logic in snap_by_name().  End result is the same.
Signed-off-by: NAlex Elder <elder@dreamhost.com>

Once rbd_bus_type is registered, it allows an "add" operation via
the /sys/bus/rbd/add bus attribute, and adding a new rbd device that
way establishes a connection between the device and rbd_root_dev.
But rbd_root_dev is not registered until after the rbd_bus_type
registration is complete.  This could (in principle anyway) result
in an invalid state.

Since rbd_root_dev has no tie to rbd_bus_type we can reorder these
two initializations and never be faced with this scenario.

In addition, unregister the device in the event the bus registration
fails at module init time.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The mon_addrs buffer in rbd_add is used to hold a copy of the
monitor IP addresses supplied via /sys/bus/rbd/add.  That is
passed to rbd_get_client(), which never modifies it (nor do
any of the functions it gets passed to thereafter)--the mon_addr
parameter to rbd_get_client() is a pointer to constant data, so it
can't be modifed.  Furthermore, rbd_get_client() has the length of
the mon_addrs buffer and that is used to ensure nothing goes beyond
its end.

Based on all this, there is no reason that a buffer needs to
be used to hold a copy of the mon_addrs provided via
/sys/bus/rbd/add.   Instead, the location within that passed-in
buffer can be provided, along with the length of the "token"
therein which represents the monitor IP's.

A small change to rbd_add_parse_args() allows the address within the
buffer to be passed back, and the length is already returned.  This
now means that, at least from the perspective of this interface,
there is no such thing as a list of monitor addresses that is too
long.
Signed-off-by: NAlex Elder <elder@dreamhost.com>

The argument parsing routine already computes the size of the
mon_addrs buffer it extracts from the "command."  Pass it to the
caller so it can use it to provide the length to rbd_get_client().
Signed-off-by: NAlex Elder <elder@dreamhost.com>

This is a bit gratuitous, but there are a few things that can be
verified at build time rather than run time, so do that.
Signed-off-by: NAlex Elder <elder@dreamhost.com>

Make use of a few simple helper routines to parse the arguments
rather than sscanf().  This will treat both missing and too-long
arguments as invalid input (rather than silently truncating the
input in the too-long case).  In time this can also be used by
rbd_add() to use the passed-in buffer in place, rather than copying
its contents into new buffers.

It appears to me that the sscanf() previously used would not
correctly handle a supplied snapshot--the two final "%s" conversion
specifications were not separated by a space, and I'm not sure
how sscanf() handles that situation.  It may not be well-defined.
So that may be a bug this change fixes (but I didn't verify that).

The sizes of the mon_addrs and options buffers are now passed to
rbd_add_parse_args(), so they can be supplied to copy_token().
Signed-off-by: NAlex Elder <elder@dreamhost.com>

Move the code that parses the arguments provided to rbd_add() (which
are supplied via /sys/bus/rbd/add) into a separate function.

Also rename the "mon_dev_name" variable in rbd_add() to be
"mon_addrs".   The variable represents a list of one or more
comma-separated monitor IP addresses, each with an optional port
number.  I think "mon_addrs" captures that notion a little better.
Signed-off-by: NAlex Elder <elder@dreamhost.com>

If a couple pointers are initialized to NULL then a single
"out_nomem" label can be used for all of the memory allocation
failure cases in rbd_add().

Also, get rid of the "irc" local variable there.  There is no
real need for "rc" to be type ssize_t, and it can be used in
the spot "irc" was.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The length of the string containing the monitor address
specification(s) will never exceed the length of the string passed
in to rbd_add().  The same holds true for the ceph + rbd options
string.  So reduce the amount of memory allocated for these to
that length rather than the maximum (1024 bytes).
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Since rbd_get_client() currently returns an error code.  It assigns
the rbd_client field of the rbd_device structure it is passed if
successful.  Instead, have it return the created rbd_client
structure and return a pointer-coded error if there is an error.
This makes the assignment of the client pointer more obvious at the
call site.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Here are a few very simple cleanups:
    - Add a "RBD_" prefix to the two driver name string definitions.
    - Move the definition of struct rbd_request below struct rbd_req_coll
      to avoid the need for an empty declaration of the latter.
    - Move and group the definitions of rbd_root_dev_release() and
      rbd_root_dev, as well as rbd_bus_type and rbd_bus_attrs[],
      close to the top of the file.  Arrange the latter so
      rbd_bus_type.bus_attrs can be initialized statically.
    - Get rid of an unnecessary local variable in rbd_open().
    - Rework some hokey logic in rbd_bus_add_dev(), so the value of
      "ret" at the end is either 0 or -ENOENT to avoid the need for
      the code duplication that was there.
    - Rename a goto target in rbd_add().
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The spinlock used to protect rbd_client_list is named "node_lock".
Rename it to "rbd_client_list_lock" to make it more obvious what
it's for.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Since rbd_client_create() is only called in one place, move the
acquisition of the mutex around that call inside that function.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Since rbd_get_client() is only called in one place, move the
acquisition of the mutex around that call inside that function.

Furthermore, within rbd_get_client(), it appears the mutex only
needs to be held while calling rbd_client_create().  (Moving
the lock inside that function will wait for the next patch.)
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

In rbd_get_client(), if a client is reused, a number of things
get done while still holding the list lock unnecessarily.

This just moves a few things that need no lock protection outside
the lock.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

It used to be that selecting a new unique identifier for an added
rbd device required searching all existing ones to find the highest
id is used.  A recent change made that unnecessary, but made it
so that id's used were monotonically non-decreasing.  It's a bit
more pleasant to have smaller rbd id's though, and this change
makes ids get allocated as they were before--each new id is one more
than the maximum currently in use.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The only time entries are added to or removed from the global
rbd_dev_list is exactly when a "put" or "get" operation is being
performed on a rbd_dev's id.  So just move the list management code
into get/put routines.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The rbd_dev_list is just a simple list of all the current
rbd_devices.  Using the ctl_mutex as a concurrency guard is
overkill.  Instead, use a spinlock for that specific purpose.

This also reduces the window that the ctl_mutex needs to be held in
rbd_add().
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

In order to select a new unique identifier for an added rbd device,
the list of all existing ones is searched and a value one greater
than the highest id is used.

The list search can be avoided by using an atomic variable that
keeps track of the current highest id.  Using a get/put model for
id's we can limit the boundless growth of id numbers a bit by
arranging to reuse the current highest id once it gets released.
Add these calls to "put" the id when an rbd is getting removed.

Note that this changes the pattern of device id's used--new values
will never be below the highest one seen so far (even if there
exists an unused lower one).  I assert this is OK because the key
property of an rbd id is its uniqueness, not its magnitude.

Regardless, a follow-on patch will restore the old way of doing
things, I just think this commit just makes the incremental change
to atomics a little easier to understand.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Move the loop that finds a new unique rbd id to use into
its own helper function.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

There's already a constant for this anyway.

Since rbd_header_set_snap() is only used to set the rbd device
snap_name field, just do that within that function rather than
having it take the snap_name as an argument.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

v2: Changed interface rbd_header_set_snap() so it explicitly updates
    the snap_name in the rbd_device.  Also added a BUILD_BUG_ON()
    to verify the size of the snap_name field is sufficient for
    SNAP_HEAD_NAME.

The rbd_device structure maintains a duplicate copy of the
ceph_client pointer maintained in its rbd_client structure.  There
appears to be no good reason for this, and its presence presents a
risk of them getting out of synch or otherwise misused.  So kill it
off, and use the rbd_client copy only.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

ceph_parse_options() takes the address of a pointer as an argument
and uses it to return the address of an allocated structure if
successful.  With this interface is not evident at call sites that
the pointer is always initialized.  Change the interface to return
the address instead (or a pointer-coded error code) to make the
validity of the returned pointer obvious.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Some minor cleanups in "drivers/block/rbd.c:
    - Use the more meaningful "RBD_MAX_OBJ_NAME_LEN" in place if "96"
      in the definition of RBD_MAX_MD_NAME_LEN.
    - Use DEFINE_SPINLOCK() to define and initialize node_lock.
    - Drop a needless (char *) cast in parse_rbd_opts_token().
    - Make a few minor formatting changes.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

Fix setting bio flags in drivers (sd_dif/floppy).
Signed-off-by: NMuthukumar R <muthur@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

"mem" is type u8.  We need parenthesis here or it screws up the pointer
math probably leading to an oops.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Cc: stable@kernel.org
Acked-by: NJeff Garzik <jgarzik@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Set CommandMailbox with memset before use it. Fix for:

drivers/block/DAC960.c: In function ‘DAC960_V1_EnableMemoryMailboxInterface’:
arch/x86/include/asm/io.h:61:1: warning: ‘CommandMailbox.Bytes[12]’
 may be used uninitialized in this function [-Wuninitialized]
drivers/block/DAC960.c:1175:30: note: ‘CommandMailbox.Bytes[12]’
 was declared here
Signed-off-by: NDanny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Fixed compiler warning:

comparison between ‘DAC960_V2_IOCTL_Opcode_T’ and ‘enum <anonymous>’

Renamed enum, added a new enum for SCSI_10.CommandOpcode in
DAC960_V2_ProcessCompletedCommand().
Signed-off-by: NDanny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Fix setting bio flags in drivers (sd_dif/floppy).
Signed-off-by: NMuthukumar R <muthur@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This provides unified readq()/writeq() helper functions for 32-bit
drivers.

For some cases, readq/writeq without atomicity is harmful, and order of
io access has to be specified explicitly.  So in this patch, new two
header files which contain non-atomic readq/writeq are added.

 - <asm-generic/io-64-nonatomic-lo-hi.h> provides non-atomic readq/
   writeq with the order of lower address -> higher address

 - <asm-generic/io-64-nonatomic-hi-lo.h> provides non-atomic readq/
   writeq with reversed order

This allows us to remove some readq()s that were added drivers when the
default non-atomic ones were removed in commit dbee8a0a ("x86:
remove 32-bit versions of readq()/writeq()")

The drivers which need readq/writeq but can do with the non-atomic ones
must add the line:

  #include <asm-generic/io-64-nonatomic-lo-hi.h> /* or hi-lo.h */

But this will be nop in 64-bit environments, and no other #ifdefs are
required.  So I believe that this patch can solve the problem of
 1. driver-specific readq/writeq
 2. atomicity and order of io access

This patch is tested with building allyesconfig and allmodconfig as
ARCH=x86 and ARCH=i386 on top of tip/master.

Cc: Kashyap Desai <Kashyap.Desai@lsi.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Ravi Anand <ravi.anand@qlogic.com>
Cc: Vikas Chaudhary <vikas.chaudhary@qlogic.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Jason Uhlenkott <juhlenko@akamai.com>
Cc: James Bottomley <James.Bottomley@parallels.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHitoshi Mitake <h.mitake@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

commit 8268f5a7 ("deny partial write for loop dev fd") tried to fix the
loop device partial read information leak problem.  But it changed the
semantics of read behavior.  When we read beyond the end of the device we
should get 0 bytes, which is normal behavior, we should not just return
-EIO

Instead of returning -EIO, zero out the bio to avoid information leak in
case of partail read.
Signed-off-by: NDave Young <dyoung@redhat.com>
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Tested-by: NJeff Moyer <jmoyer@redhat.com>
Cc: Dmitry Monakhov <dmonakhov@sw.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

floppy driver does not call add_disk() on all the drives hence we don't take
gendisk reference on request queue for these drives. Don't call put_disk()
with disk->queue set, otherwise we try to put the reference we never took.
Reported-and-tested-by: NDirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de>
Signed-off-by: Vivek Goyal<vgoyal@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

add_disk() takes gendisk reference on request queue. If driver failed during
initialization and never called add_disk() then that extra reference is not
taken. That reference is put in put_disk(). floppy driver allocates the
disk, allocates queue, sets disk->queue and then relizes that floppy
controller is not present. It tries to tear down everything and tries to
put a reference down in put_disk() which was never taken.

In such error cases cleanup disk->queue before calling put_disk() so that
we never try to put down a reference which was never taken in first place.
Reported-and-tested-by: NSuresh Jayaraman <sjayaraman@suse.com>
Tested-by: NDirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de>
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

mtip32xx: removed the irrelevant argument of mtip_hw_submit_io() and the unused member of struct driver_data

Removed the following:
	* irrelevant argument 'barrier' of mtip_hw_submit_io()
	* unused member 'eh_active' of struct driver_data
Signed-off-by: NAsai Thambi S P <asamymuthupa@micron.com>
Signed-off-by: NSam Bradshaw <sbradshaw@micron.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

The rbd_client structure uses a kref to arrange for cleaning up and
freeing an instance when its last reference is dropped.  The cleanup
routine is rbd_client_release(), and one of the things it does is
delete the rbd_client from rbd_client_list.  It acquires node_lock
to do so, but the way it is done is still not safe.

The problem is that when attempting to reuse an existing rbd_client,
the structure found might already be in the process of getting
destroyed and cleaned up.

Here's the scenario, with "CLIENT" representing an existing
rbd_client that's involved in the race:

 Thread on CPU A                | Thread on CPU B
 ---------------                | ---------------
 rbd_put_client(CLIENT)         | rbd_get_client()
   kref_put()                   |   (acquires node_lock)
     kref->refcount becomes 0   |   __rbd_client_find() returns CLIENT
     calls rbd_client_release() |   kref_get(&CLIENT->kref);
                                |   (releases node_lock)
       (acquires node_lock)     |
       deletes CLIENT from list | ...and starts using CLIENT...
       (releases node_lock)     |
       and frees CLIENT         | <-- but CLIENT gets freed here

Fix this by having rbd_put_client() acquire node_lock.  The result
could still be improved, but at least it avoids this problem.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

If an existing rbd client is found to be suitable for use in
rbd_get_client(), the rbd_options structure is not being
freed as it should.  Fix that.
Signed-off-by: NAlex Elder <elder@dreamhost.com>
Signed-off-by: NSage Weil <sage@newdream.net>

The type of 'make_request_fn' changed in 5a7bbad2 ("block: remove
support for bio remapping from ->make_request"), but the merge of the
nvme driver didn't take that into account, and as a result the driver
would compile with a warning:

  drivers/block/nvme.c: In function 'nvme_alloc_ns':
  drivers/block/nvme.c:1336:2: warning: passing argument 2 of 'blk_queue_make_request' from incompatible pointer type [enabled by default]
  include/linux/blkdev.h:830:13: note: expected 'void (*)(struct request_queue *, struct bio *)' but argument is of type 'int (*)(struct request_queue *, struct bio *)'

It's benign, but the warning is annoying.
Reported-by: NStephen Rothwell <sfr@canb.auug.org>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce a wrapper around scsi_cmd_ioctl that takes a block device.

The function will then be enhanced to detect partition block devices
and, in that case, subject the ioctls to whitelisting.

Cc: linux-scsi@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: James Bottomley <JBottomley@parallels.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Dan Carpenter points out that it's an int, not a bool:

pcd.c:427:				if (verbose > 1)
pcd.c:433:				if (verbose > 1)
pcd.c:437:				if (verbose < 2)
pcd.c:506:#define DBMSG(msg)	((verbose>1)?(msg):NULL)
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Dan Carpenter <dan.carpenter@oracle.com>

module_param(bool) used to counter-intuitively take an int.  In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.

It's time to remove the int/unsigned int option.  For this version
it'll simply give a warning, but it'll break next kernel version.
Acked-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>