* 'linux-next' of git://git.infradead.org/ubifs-2.6: (25 commits)
UBIFS: clean-up commentaries
UBIFS: save 128KiB or more RAM
UBIFS: allocate orphans scan buffer on demand
UBIFS: allocate lpt dump buffer on demand
UBIFS: allocate ltab checking buffer on demand
UBIFS: allocate scanning buffer on demand
UBIFS: allocate dump buffer on demand
UBIFS: do not check data crc by default
UBIFS: simplify UBIFS Kconfig menu
UBIFS: print max. index node size
UBIFS: handle allocation failures in UBIFS write path
UBIFS: use max_write_size during recovery
UBIFS: use max_write_size for write-buffers
UBIFS: introduce write-buffer size field
UBI: incorporate LEB offset information
UBIFS: incorporate maximum write size
UBI: provide LEB offset information
UBI: incorporate maximum write size
UBIFS: fix LEB number in printk
UBIFS: restrict world-writable debugfs files
...
* 'linux-next' of git://git.infradead.org/ubi-2.6:
UBI: make tests modes dynamic
UBI: make self-checks dynamic
UBI: make debugging messages dynamic
UBI: remove UBI_IO_DEBUG macro
UBI: kill debugging buffer
UBI: allocate erase checking buffer on demand
UBI: allocate write checking buffer on demand
UBI: always re-read in case of read failures
UBI: cleanup comments about corrupted PEBs
UBI: add slab cache for ubi_scan_leb objects
UBI: use raw mtd read function in debugging code
UBI: try to reveal buggy MTD drivers
UBI: add a commentary about allocating VID header buffer on stack
UBI: cleanup LEB start calculations
UBI: fix NOR erase preparation quirk
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (47 commits)
doc: CONFIG_UNEVICTABLE_LRU doesn't exist anymore
Update cpuset info & webiste for cgroups
dcdbas: force SMI to happen when expected
arch/arm/Kconfig: remove one to many l's in the word.
asm-generic/user.h: Fix spelling in comment
drm: fix printk typo 'sracth'
Remove one to many n's in a word
Documentation/filesystems/romfs.txt: fixing link to genromfs
drivers:scsi Change printk typo initate -> initiate
serial, pch uart: Remove duplicate inclusion of linux/pci.h header
fs/eventpoll.c: fix spelling
mm: Fix out-of-date comments which refers non-existent functions
drm: Fix printk typo 'failled'
coh901318.c: Change initate to initiate.
mbox-db5500.c Change initate to initiate.
edac: correct i82975x error-info reported
edac: correct i82975x mci initialisation
edac: correct commented info
fs: update comments to point correct document
target: remove duplicate include of target/target_core_device.h from drivers/target/target_core_hba.c
...
Trivial conflict in fs/eventpoll.c (spelling vs addition)
* 'omap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6: (258 commits)
omap: zoom: host should not pull up wl1271's irq line
arm: plat-omap: iommu: fix request_mem_region() error path
OMAP2+: Common CPU DIE ID reading code reads wrong registers for OMAP4430
omap4: mux: Remove duplicate mux modes
omap: iovmm: don't check 'da' to set IOVMF_DA_FIXED flag
omap: iovmm: disallow mapping NULL address when IOVMF_DA_ANON is set
omap2+: mux: Fix compile when CONFIG_OMAP_MUX is not selected
omap4: board-omap4panda: Initialise the serial pads
omap3: board-3430sdp: Initialise the serial pads
omap4: board-4430sdp: Initialise the serial pads
omap2+: mux: Add macro for configuring static with omap_hwmod_mux_init
omap2+: mux: Remove the use of IDLE flag
omap2+: Add separate list for dynamic pads to mux
perf: add OMAP support for the new power events
OMAP4: Add IVA OPP enteries.
OMAP4: Update Voltage Rail Values for MPU, IVA and CORE
OMAP4: Enable 800 MHz and 1 GHz MPU-OPP
OMAP3+: OPP: Replace voltage values with Macros
OMAP3: wdtimer: Fix CORE idle transition
Watchdog: omap_wdt: add fine grain runtime-pm
...
Fix up various conflicts in
- arch/arm/mach-omap2/board-omap3evm.c
- arch/arm/mach-omap2/clock3xxx_data.c
- arch/arm/mach-omap2/usb-musb.c
- arch/arm/plat-omap/include/plat/usb.h
- drivers/usb/musb/musb_core.h
* 'devel-stable' of master.kernel.org:/home/rmk/linux-2.6-arm: (289 commits)
davinci: DM644x EVM: register MUSB device earlier
davinci: add spi devices on tnetv107x evm
davinci: add ssp config for tnetv107x evm board
davinci: add tnetv107x ssp platform device
spi: add ti-ssp spi master driver
mfd: add driver for sequencer serial port
ARM: EXYNOS4: Implement Clock gating for System MMU
ARM: EXYNOS4: Enhancement of System MMU driver
ARM: EXYNOS4: Add support for gpio interrupts
ARM: S5P: Add function to register gpio interrupt bank data
ARM: S5P: Cleanup S5P gpio interrupt code
ARM: EXYNOS4: Add missing GPYx banks
ARM: S3C64XX: Fix section mismatch from cpufreq init
ARM: EXYNOS4: Add keypad device to the SMDKV310
ARM: EXYNOS4: Update clocks for keypad
ARM: EXYNOS4: Update keypad base address
ARM: EXYNOS4: Add keypad device helpers
ARM: EXYNOS4: Add support for SATA on ARMLEX4210
plat-nomadik: make GPIO interrupts work with cpuidle ApSleep
mach-u300: define a dummy filter function for coh901318
...
Fix up various conflicts in
- arch/arm/mach-exynos4/cpufreq.c
- arch/arm/mach-mxs/gpio.c
- drivers/net/Kconfig
- drivers/tty/serial/Kconfig
- drivers/tty/serial/Makefile
- drivers/usb/gadget/fsl_mxc_udc.c
- drivers/video/Kconfig
Similarly to the debugging checks and message, make the test modes
be dynamically selected via the "debug_tsts" module parameter or
via the "/sys/module/ubi/parameters/debug_tsts" sysfs file. This
is consistent with UBIFS as well.
And now, since all the Kconfig knobs became dynamic, we can remove
the Kconfig.debug file completely.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This patch adds a possibility to dynamically switch UBI self-checks
on and off, instead of toggling them compile-time from the configuration
menu. This is much more flexible, and consistent with UBIFS, and this
also simplifies UBI Kconfig menu and the code.
This patch introduces two levels of self-checks - general, which
includes all self-checks which are relatively fast, and I/O, which
includes write-verify checks and erase-verify checks, which are
relatively slow and involve flash I/O.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This patch adds a possibility to dynamically select UBI debugging
messages, instead of selecting them compile-time from the configuration
menu. This is much more flexible, and consistent with UBIFS, and this
also simplifies UBI Kconfig menu and the code.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This additional little macro is used to print a bit more messages
while scanning the media. However, we have the 'dbg_bld()' macro
for this, so we better us 'dbg_bld()' and kill UBI_IO_DEBUG. This
simplifies the code a tiny bit.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This patch kills the 'ubi->dbg_peb_buf' debugging buffer and the
associated mutex, because all users of this buffer are now gone.
We are killing this buffer because we are going to switch to
dynamic debugging control, just like in UBIFS, which means that
CONFIG_MTD_UBI_DEBUG_PARANOID will be removed. In this case we'd
end up always allocating 'ubi->dbg_peb_buf', which is rather large
(128KiB or more), and this would be wasteful. Thus, we are just
killing it.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Instead of using pre-allocated 'ubi->dbg_peb_buf' buffer in
'ubi_dbg_check_all_ff()', dynamically allocate it when needed. The
intend is to get rid of the pre-allocated 'ubi->dbg_peb_buf' buffer
completely. And the need for this arises because we want to change
to dynamic debugging control instead of compile-time control, i.e.,
we are going to kill the CONFIG_MTD_UBI_DEBUG_PARANOID Kconfig
option, which would mean that 'ubi->dbg_peb_buf' is always allocated,
which would be wasteful.
Thus, we are getting rid of 'ubi->dbg_peb_buf', and this is a
preparation for that.
signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Instead of using pre-allocated 'ubi->dbg_peb_buf' buffer in
'ubi_dbg_check_write()', dynamically allocate it when needed. The
intend is to get rid of the pre-allocated 'ubi->dbg_peb_buf' buffer
completely. And the need for this arises because we want to change
to dynamic debugging control instead of compile-time control, i.e.,
we are going to kill the CONFIG_MTD_UBI_DEBUG_PARANOID Kconfig
option, which would mean that 'ubi->dbg_peb_buf' is always allocated,
which would be wasteful.
Thus, we are getting rid of 'ubi->dbg_peb_buf', and this is a
preparation for that.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* git://git.infradead.org/users/dwmw2/mtd-2.6.38:
mtd: add "platform:" prefix for platform modalias
mtd: mtd_blkdevs: fix double free on error path
mtd: amd76xrom: fix oops at boot when resources are not available
mtd: fix race in cfi_cmdset_0001 driver
mtd: jedec_probe: initialise make sector erase command variable
mtd: jedec_probe: Change variable name from cfi_p to cfi
Since 43cc71eed1 (platform: prefix MODALIAS
with "platform:"), the platform modalias is prefixed with "platform:".
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
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: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
For some unknown reasons resources needed by amd76xrom driver can be
unavailable. And instead of returning an error, the driver keeps going
and crash the kernel. This patch fixes the problem by making the driver
return -EBUSY if the resources are not available.
Commit messages tweaked by Artem.
Reported-by: Russell Whitaker <russ@ashlandhome.net>
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
As inval_cache_and_wait_for_operation() drop and reclaim the lock
to invalidate the cache, some other thread may suspend the operation
before reaching the for(;;) loop. Therefore the loop must start with
checking the chip->state before reading status from the chip.
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Acked-by: Michael Cashwell <mboards@prograde.net>
Acked-by: Stefan Bigler <stefan.bigler@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Cc: stable@kernel.org
In the commit 08968041be
(mtd: cfi_cmdset_0002: make sector erase command variable)
introdused a field sector_erase_cmd. In the same commit initialisation
of cfi->sector_erase_cmd made in cfi_chip_setup()
(file drivers/mtd/chips/cfi_probe.c), so the CFI chip has no problem:
...
cfi->cfi_mode = CFI_MODE_CFI;
cfi->sector_erase_cmd = CMD(0x30);
...
But for the JEDEC chips this initialisation is not carried out,
so the JEDEC chips have sector_erase_cmd == 0.
This patch adds the missing initialisation.
Signed-off-by: Antony Pavlov <antony@niisi.msk.ru>
Acked-by: Guillaume LECERF <glecerf@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
CC: stable@kernel.org
In the following commit, we'll need to use the CMD() macro in order to
fix the initialisation of the sector_erase_cmd field. That requires the
local variable to be called 'cfi', so change it first in a simple patch.
Signed-off-by: Antony Pavlov <antony@niisi.msk.ru>
Acked-by: Guillaume LECERF <glecerf@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
CC: stable@kernel.org
Provide the LEB offset information in the UBI device information data
structure. This piece of information is required by UBIFS to find out
what are the LEB offsets which are aligned to the max. write size.
If LEB offset not aligned to max. write size, then UBIFS has to take
this into account to write more optimally.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Incorporate MTD write buffer size into UBI device information
because UBIFS needs this field. UBI does not use it ATM, just
provides to upper layers in 'struct ubi_device_info'.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Move to SOC_SOC_IMX5X. Leave only places which prevent multi-soc
using ARCH_MX5X.
Signed-off-by: Richard Zhao <richard.zhao@freescale.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Final step to eliminate of_platform_bus_type. They're all just
platform drivers now.
v2: fix type in pasemi_nand.c (thanks to Stephen Rothwell)
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This patch updates EXYNOS4 OneNAND support according to the change of
ARCH name, EXYNOS4.
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
The current multiblock erase verify read timeout 100us is the maximum
for none-error case. If errors happen during multibock erase then
the specification recommends to run multiblock erase verify command
with maximum timeout 10ms (see specs. for KFM4G16Q2A and KFN8G16Q2A).
For the most common non-error case we wait 100us in udelay polling
loop. In case of timeout the interrupt mode is used to wait for the
command end.
Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Acked-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
OneNAND frequency is determined when calculating
GPMC timings. Return that value instead of determining it
again in the OMAP OneNAND driver.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch overrides nand ecc layout and bad block descriptor (for 8-bit
device) to support hw ecc in romcode layout. So as to have in sync with ecc
layout throughout; i.e. x-loader, u-boot and kernel.
This enables to flash x-loader, u-boot, kernel, FS images from kernel itself
and compatiable with other tools.
This patch does not enables this feature by default and need to pass from
board file to enable for any board.
Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch makes it possible to select sw or hw (different layout options)
ecc scheme supported by omap nand driver.
Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Configure the FIFO THREASHOLD value different for read and write to keep busy
both filling and to drain out of FIFO at reading and writing.
Signed-off-by: Vimal Singh <vimalsingh@ti.com>
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
nand transfer type (sDMA, Polled, prefetch) can be select from board file,
enabling all transfer type in driver, by default.
this helps in multi-omap build and to select different transfer type for
different board.
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
zoom3 and 3630-sdp having the x16 nand device.
This patch configure gpmc as x16 and select the currect function in driver
for polled mode (without prefetch enable) transfer.
Signed-off-by: Sukumar Ghorai <s-ghorai@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
There are two spellings in use for 'freeze' + 'able' - 'freezable' and
'freezeable'. The former is the more prominent one. The latter is
mostly used by workqueue and in a few other odd places. Unify the
spelling to 'freezable'.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Steven Whitehouse <swhiteho@redhat.com>
When the read operation fails, UBI tries to re-read several times in
a hope that one of the subsequent reads may succeed. However, currently
UBI re-reads only if MTD failed to read all data, but does not re-reads
if all the data were read, but with an integrity error (-EBADMSB). This
patch makes UBI to always re-try reading.
This should be useful for reading NAND pages with unstable bits -
re-reading may help to get correct data.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
During scanning UBI allocates one struct ubi_scan_leb object for each PEB,
so it can end up allocating thousands of them. Use slab cache to reduce
memory consumption for these 48-byte objects, because currently used
'kmalloc()' ends up allocating 64 bytes per object, instead of 48.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This change affects only the debugging code. Namely, use mtd->read()
function instead of ubi_io_read() to avoid bit-flips injection
(ubi_dbg_is_bitflip()) which we do not want on the debugging path.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
When reading data from the flash, corrupt the buffer we are about to
read to. The idea is to fix the following possible situation:
1. The buffer contains data from previous operation, e.g., read from
another PEB previously. The data looks like expected, e.g., if we
just do not read anything and return - the caller would not
notice this. E.g., if we are reading a VID header, the buffer may
contain a valid VID header from another PEB.
2. The driver is buggy and returns use success or -EBADMSG or
-EUCLEAN, but it does not actually put any data to the buffer.
This may confuse UBI or upper layers - they may think the buffer
contains valid data while in fact it is just old data.
Thus, try to reveal such buggy MTD drivers with simple debugging
code which fills the read buffer with 0x12 constant.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
This reverts commit a121f64399.
Unfortunately, this commit breaks UBIFS backward compatibility and
makes new UBIFS refuse older UBIFS-formatted media:
UBIFS error: validate_sb: min. I/O unit mismatch: 8 in superblock, 64 real
Thus, we have to revert this patch and work on a better solution.
Reported-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Wrong macro was used in calculating the data offset: UBI_EC_HDR_SIZE instead of
UBI_VID_HDR_SIZE. The data offset should be VID header offset + VID header size
(aligned to the minimum I/O unit).
This was not a bug only because currently UBI_EC_HDR_SIZE and UBI_VID_HDR_SIZE
have the same value of 64 bytes.
Commit message was amended by Artem.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
In 'nor_erase_prepare()' we want to make sure the UBI headers are
corrupted. But it is possible that one of the headers just contains
all 0xFFs, which is also OK, because UBI will erase it in case of
a power cut.
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
* git://git.infradead.org/mtd-2.6: (59 commits)
mtd: mtdpart: disallow reading OOB past the end of the partition
mtd: pxa3xx_nand: NULL dereference in pxa3xx_nand_probe
UBI: use mtd->writebufsize to set minimal I/O unit size
mtd: initialize writebufsize in the MTD object of a partition
mtd: onenand: add mtd->writebufsize initialization
mtd: nand: add mtd->writebufsize initialization
mtd: cfi: add writebufsize initialization
mtd: add writebufsize field to mtd_info struct
mtd: OneNAND: OMAP2/3: prevent regulator sleeping while OneNAND is in use
mtd: OneNAND: add enable / disable methods to onenand_chip
mtd: m25p80: Fix JEDEC ID for AT26DF321
mtd: txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)
mtd: cfi_cmdset_0002: add support for Samsung K8D3x16UxC NOR chips
mtd: cfi_cmdset_0002: add support for Samsung K8D6x16UxM NOR chips
mtd: nand: ams-delta: drop omap_read/write, use ioremap
mtd: m25p80: add debugging trace in sst_write
mtd: nand: ams-delta: select for built-in by default
mtd: OneNAND: lighten scary initial bad block messages
mtd: OneNAND: OMAP2/3: add support for command line partitioning
mtd: nand: rearrange ONFI revision checking, add ONFI 2.3
...
Fix up trivial conflict in drivers/mtd/Kconfig as per DavidW.
This patch fixes the mtdpart bug which allows users reading OOB past the
end of the partition. This happens because 'part_read_oob()' allows reading
multiple OOB areas in one go, and mtdparts does not validate the OOB
length in the request.
Although there is such check in 'nand_do_read_oob()' in nand_base.c, but
it checks that we do not read past the flash chip, not the partition,
because in nand_base.c we work with the whole chip (e.g., mtd->size
in nand_base.c is the size of the whole chip). So this check cannot
be done correctly in nand_base.c and should be instead done in mtdparts.c.
This problem was reported by Jason Liu <r64343@freescale.com> and reproduced
with nandsim:
$ modprobe nandsim first_id_byte=0x20 second_id_byte=0xaa third_id_byte=0x00 \
fourth_id_byte=0x15 parts=0x400,0x400
$ modprobe nandsim mtd_oobtest.ko dev=0
$ dmesg
= snip =
mtd_oobtest: attempting to read past end of device
mtd_oobtest: an error is expected...
mtd_oobtest: error: read past end of device
= snip =
mtd_oobtest: finished with 2 errors
Reported-by: Jason Liu <liu.h.jason@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Instead of splitting refcount between (per-cpu) mnt_count
and (SMP-only) mnt_longrefs, make all references contribute
to mnt_count again and keep track of how many are longterm
ones.
Accounting rules for longterm count:
* 1 for each fs_struct.root.mnt
* 1 for each fs_struct.pwd.mnt
* 1 for having non-NULL ->mnt_ns
* decrement to 0 happens only under vfsmount lock exclusive
That allows nice common case for mntput() - since we can't drop the
final reference until after mnt_longterm has reached 0 due to the rules
above, mntput() can grab vfsmount lock shared and check mnt_longterm.
If it turns out to be non-zero (which is the common case), we know
that this is not the final mntput() and can just blindly decrement
percpu mnt_count. Otherwise we grab vfsmount lock exclusive and
do usual decrement-and-check of percpu mnt_count.
For fs_struct.c we have mnt_make_longterm() and mnt_make_shortterm();
namespace.c uses the latter in places where we don't already hold
vfsmount lock exclusive and opencodes a few remaining spots where
we need to manipulate mnt_longterm.
Note that we mostly revert the code outside of fs/namespace.c back
to what we used to have; in particular, normal code doesn't need
to care about two kinds of references, etc. And we get to keep
the optimization Nick's variant had bought us...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
