Modify function blktrans_getgeo()'s return value to -EOPNOTSUPP when
dev->tr->getgeo == NULL.

We shouldn't make the return value to 0 when dev->tr->getgeo == NULL,
because the function blktrans_getgeo() has an output value "hd_geometry"
which is usually used by some application, if returns 0 (i.e.,
"success"), it will make some application get the wrong information.
Signed-off-by: NWenlin Kang <wenlin.kang@windriver.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

On A MIPS 32-cores machine a BUG_ON was triggered because some acesses to
mtd->usecount were done without taking mtd_table_mutex.
kernel: Call Trace:
kernel: [<ffffffff80401818>] __put_mtd_device+0x20/0x50
kernel: [<ffffffff804086f4>] blktrans_release+0x8c/0xd8
kernel: [<ffffffff802577e0>] __blkdev_put+0x1a8/0x200
kernel: [<ffffffff802579a4>] blkdev_close+0x1c/0x30
kernel: [<ffffffff8022006c>] __fput+0xac/0x250
kernel: [<ffffffff80171208>] task_work_run+0xd8/0x120
kernel: [<ffffffff8012c23c>] work_notifysig+0x10/0x18
kernel:
kernel:
        Code: 2442ffff  ac8202d8  000217fe <00020336> dc820128  10400003
               00000000  0040f809  00000000
kernel: ---[ end trace 080fbb4579b47a73 ]---

Fixed by taking the mutex in blktrans_open and blktrans_release.

Note that this locking is already suggested in
include/linux/mtd/blktrans.h:

struct mtd_blktrans_ops {
...
	/* Called with mtd_table_mutex held; no race with add/remove */
	int (*open)(struct mtd_blktrans_dev *dev);
	void (*release)(struct mtd_blktrans_dev *dev);
...
};

But we weren't following it.

Originally reported by (and patched by) Zhang and Giuseppe,
independently. Improved and rewritten.

Cc: stable@vger.kernel.org
Reported-by: NZhang Xingcai <zhangxingcai@huawei.com>
Reported-by: NGiuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Tested-by: NGiuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Acked-by: NAlexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The only exit (break) from the preceding loop is nested within a
condition which yields req == NULL. This code is dead.

Coverity CID #752669
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

Clear QUEUE_FLAG_ADD_RANDOM in all block drivers that set
QUEUE_FLAG_NONROT.

Historically, all block devices have automatically made entropy
contributions.  But as previously stated in commit e2e1a148 ("block: add
sysfs knob for turning off disk entropy contributions"):
    - On SSD disks, the completion times aren't as random as they
      are for rotational drives. So it's questionable whether they
      should contribute to the random pool in the first place.
    - Calling add_disk_randomness() has a lot of overhead.

There are more reliable sources for randomness than non-rotational block
devices.  From a security perspective it is better to err on the side of
caution than to allow entropy contributions from unreliable "random"
sources.
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

mtd_blkdevs is device with volatile cache (writeback buffer), so it should support
REQ_FLUSH to do explicit flush.

Without this patch 'sync' does not guarantee that writeback buffer will be flushed
on disk in case of power off, e.g.:

  $ cp some_file /mnt
  $ sync

  ### POWER OFF

In case of this sequence writeback buffer will not be flushed on disk.

This patch fixes this behaviour and explicitly reports to block layer that flush
requests are being supported.
Signed-off-by: NRoman Peniaev <r.peniaev@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

This was used in the olden days, back when onions were proper
yellow. Basically it mapped to the current buffer to be
transferred. With highmem being added more than a decade ago,
most drivers map pages out of a bio, and rq->buffer isn't
pointing at anything valid.

Convert old style drivers to just use bio_data().

For the discard payload use case, just reference the page
in the bio.
Signed-off-by: NJens Axboe <axboe@fb.com>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.  Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: linux-mtd@lists.infradead.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
[Brian: dropped one incorrect hunk]
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>

The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Both existing instances always return 0 and even if they didn't,
the value would be lost on the way out.  Just don't bother...
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

By replacing a kthread with a workqueue, the code is now a bit clearer.
There's also a slight reduction of code size (numbers apply for x86):
Before:
   text	   data	    bss	    dec	    hex	filename
   3248	     36	      0	   3284	    cd4	drivers/mtd/mtd_blkdevs.o

After:
   text	   data	    bss	    dec	    hex	filename
   3150	     36	      0	   3186	    c72	drivers/mtd/mtd_blkdevs.o

Due to lack of real hardware, tests have been performed on an emulated
environment with mtdswap and mtdblock over nandsim devices.
Some real testing should be done, before merging this patch.
Signed-off-by: NEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

struct mtd_blktrans_ops is a type, and mtd_blktrans_ops is a variable.
To improve code clarity it's better to not use the same names,
so we just change the latter.
Signed-off-by: NEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>

Because it is useless to call it if the device is opened in R/O mode, and also
harmful: on CFI NOR flash it may block for long time waiting for erase
operations to complete is another partition with a R/W file-system on this
chip.

Artem Bityutskiy: write commit message, amend the patch to match the latest
tree (we use mtd_sync(), not mtd->sync() nowadays).
Signed-off-by: NAlexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Some error paths in mtd_blkdevs were fixed in the following commit:

    commit 94735ec4
    mtd: mtd_blkdevs: fix error path in blktrans_open

But on these error paths, the block device's `dev->open' count is
already incremented before we check for errors. This meant that, while
the error path was handled correctly on the first time through
blktrans_open(), the device is erroneously considered already open on
the second time through.

This problem can be seen, for instance, when a UBI volume is
simultaneously mounted as a UBIFS partition and read through its
corresponding gluebi mtdblockX device. This results in blktrans_open()
passing its error checks (with `dev->open > 0') without actually having
a handle on the device. Here's a summarized log of the actions and
results with nandsim:

    # modprobe nandsim
    # modprobe mtdblock
    # modprobe gluebi
    # modprobe ubifs
    # ubiattach /dev/ubi_ctrl -m 0
    ...
    # ubimkvol /dev/ubi0 -N test -s 16MiB
    ...
    # mount -t ubifs ubi0:test /mnt
    # ls /dev/mtdblock*
    /dev/mtdblock0  /dev/mtdblock1
    # cat /dev/mtdblock1 > /dev/null
    cat: can't open '/dev/mtdblock4': Device or resource busy
    # cat /dev/mtdblock1 > /dev/null

    CPU 0 Unable to handle kernel paging request at virtual address
    fffffff0, epc == 8031536c, ra == 8031f280
    Oops[#1]:
    ...
    Call Trace:
    [<8031536c>] ubi_leb_read+0x14/0x164
    [<8031f280>] gluebi_read+0xf0/0x148
    [<802edba8>] mtdblock_readsect+0x64/0x198
    [<802ecfe4>] mtd_blktrans_thread+0x330/0x3f4
    [<8005be98>] kthread+0x88/0x90
    [<8000bc04>] kernel_thread_helper+0x10/0x18

Cc: stable@kernel.org [3.0+]
Signed-off-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

This is similar to what the nbd driver does, among others.
Signed-off-by: NDan McGee <dpmcgee@gmail.com>
Signed-off-by: NArtem Bityutskiy <artem.bityutskiy@intel.com>

The 'blktrans_open()' does not handle possible '__get_mtd_device()' failures
because it does not check the error code. Moreover, the 'dev->tr->open()'
failures are not handled correctly because in this case the function just
goes ahead and gets the mtd device, then returns an error. But Instead, it
should _not_ try to get the mtd device, then it should put back the module
and the kref.

This patch fixes the issue. Note, I only compile-tested it. This patch was
inspired by a bug report about a similar issue in 2.6.34 kernels
sent by Mike Turner <admin@islandsoftware.co.uk> to the MTD mailing list:

http://lists.infradead.org/pipermail/linux-mtd/2011-April/034980.htmlSigned-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Set max_discard_sectors to UINT_MAX.
Signed-off-by: NJarkko Lavinen <jarkko.lavinen@nokia.com>
Tested-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Add a new background method into mtd_blktrans_ops, add background support
into mtd_blktrans_thread(), and add mtd_blktrans_cease_background().

If the mtd blktrans dev has the background support, the thread will
call background function when the request queue becomes empty. The background
operation may run as long as needs to until
mtd_blktrans_cease_background() tells to stop.
Signed-off-by: NJarkko Lavinen <jarkko.lavinen@nokia.com>
Tested-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

The function blktrans_dev_release and blktrans_dev_put are only used
locally in this file and should be static.
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

This one liner patch fixes double free that will occur if add_mtd_blktrans_dev
fails. On failure it frees the input argument, but all its users also free it
on error which is natural thing to do. Thus don't free it.

All credit for finding that bug belongs to reporters of the bug in the android bugzilla
http://code.google.com/p/android/issues/detail?id=13761

Commit message tweaked by Artem.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org

In commit 2a48fc0a ('block: autoconvert
trivial BKL users to private mutex'), Arnd replaced the BKL usage with a
mutex. However, Maxim has already provided a better fix in commit
480792b7 ('mtd: blktrans: kill BKL'),
which was simply to remove the BKL without replacing it — since he'd
already made it do all necessary locking for itself.
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

register_blkdev return 1..255 when major = 0.

if (ret ) {
	printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
		tr->name, tr->major, ret);
	      mutex_unlock(&mtd_table_mutex);
	return ret;
}

Above code will return fail when register_blkdev return allocated major number.
Signed-off-by: NFrank Li <Frank.Li@freescale.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

There is small race window that could make kthread_stop hang forever.
I found that while hacking the IR subsystem.
Signed-off-by: NMaxim Levitsky <maximlevisky@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

It not needed, because I already added locking for all fops
methods.
Signed-off-by: NMaxim Levitsky <maximlevisky@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Now it once again possible to remove mtdtrans module.
You still need to ensure that block devices of that module aren't mounted.
This is due to the fact that as long as a block device is open, it still exists,
therefore if we were to allow module removal, this block device might became used again.

This time in addition to code review, I also made the code
pass some torture tests like module reload in  a loop + read in a loop +
card insert/removal all at same time.

The blktrans_open/blktrans_release don't take the mtd table lock because:

While device is added (that includes execution of add_mtd_blktrans_dev)
the lock is already taken

Now suppose the device will never be removed. In this case even if we have changes
in mtd table, the entry that we need will stay exactly the same. (Note that we don't
look at table at all, just following private pointer of block device).

Now suppose that someone tries to remove the mtd device.
This will be propagated to trans driver which _ought_ to call del_mtd_blktrans_dev
which will take the per device lock, release the mtd device and set trans->mtd = NULL.
>From this point on, following opens won't even be able to know anything about that mtd device
(which at that point is likely not to exist)
Also the same care is taken not to trip over NULL mtd pointer in blktrans_dev_release.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Tested-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.

This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.

This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.

The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.

Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

As a preparation for the removal of the big kernel
lock in the block layer, this removes the BKL
from the common ioctl handling code, moving it
into every single driver still using it.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NChristoph Hellwig <hch@infradead.org>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests.  This allows much easier grepping for different request
types instead of unwinding through macros.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Remove the attributes group before disk to avoid use after free
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

There was a break missing so we returned -ENOTTY on success instead of
zero.  This was introduced by 048d8719: "mtd: blktrans: Hotplug fixes"
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

I was calling it in del_mtd_blktrans_dev, but ->request_fn could
still be running at that point, thus defer this call
to blktrans_dev_release
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

* Test results of few functions that were declared with __must_check
* Fix bogus gcc warning about uinitialized variable 'ret'
* Remove unused variable from mtdblock_remove_dev
* Don't use deprecated DMA_32BIT_MASK
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

This patch adds an ability to export sysfs attributes below
the block disk device.

This can be used to pass the udev an information about the FTL
and could include the vendor, serial, version, etc...
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

* Add locking where it was missing.

* Don't do a get_mtd_device in blktrans_open because it would lead to a
  deadlock; instead do that in add_mtd_blktrans_dev.

* Only free the mtd_blktrans_dev structure when the last user exits.

* Flush request queue on device removal.

* Track users, and call tr->release in del_mtd_blktrans_dev
  Due to that ->open and release aren't called more that once.

Now it is safe to call del_mtd_blktrans_dev while the device is still in use.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

This is the biggest change. To make hotplug possible, and this layer 
clean, the mtd_blktrans_dev now contains everything for a single mtd 
block translation device. Also removed some very old leftovers.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

add_mtd_blktrans_dev() imposes a maximum of 257 devices per block
translator.  This was presumably meant to prevent overflow back in the
days of 8-bit minor numbers.  Instead, check against MINORMASK and the
limits of the partition naming scheme.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
memory, anyone must not prevent it. Otherwise the system cause
mysterious hang-up and/or OOM Killer invokation.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Mtdblock driver doesn't call flush_dcache_page for pages in request.  So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases.  The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op.  Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.
Signed-off-by: NIlya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>