* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
USB: fix oops on disconnect in cdc-acm
USB: storage: include Prolific Technology USB drive in unusual_devs list
USB: ftdi_sio: add product_id for Marvell OpenRD Base, Client
USB: ftdi_sio: add vendor and product id for Bayer glucose meter serial converter cable
USB: EHCI: fix counting of transaction error retries
USB: EHCI: fix two new bugs related to Clear-TT-Buffer
USB: usbfs: fix -ENOENT error code to be -ENODEV
USB: musb: fix the nop registration for OMAP3EVM
USB: devio: Properly do access_ok() checks
USB: pl2303: New vendor and product id
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6:
Staging: rspiusb: Fix buffer overflow
staging: add dependencies on PCI for drivers that require it
Staging: rtl8192su: fix build error
Staging: rt2870: Revert d44ca7 Removal of kernel_thread() API
Staging: rt2870: Add USB ID for Linksys, Planex Communications, Belkin
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel: (22 commits)
drm/i915: Fix read outside array bounds in restoring the SWF10 range.
drm/i915: Use our own workqueue to avoid wedging the system along with the GPU.
drm/i915: Add support for dual-channel LVDS on 8xx.
drm/i915: Return disconnected for SDVO DVI when there's no digital EDID.
drm/i915: Choose real sdvo output according to result from detection
drm/i915: Set preferred mode for integrated TV according to TV format
drm/i915: fix 845G FIFO size & burst length
drm/i915: fix VGA detect on IGDNG
drm/i915: Add eDP support on IGDNG mobile chip
drm/i915: enable DisplayPort support on IGDNG
drm/i915: Fix channel ending action for DP aux transaction
drm/i915: fix issue in display pipe setup on IGDNG
drm/i915: disable VGA plane reliably
drm/I915: Fix offset to DVO timings in LVDS data
drm/i915: hdmi detection according by reading edid
drm/i915: correct self-refresh calculation in "everything off" case
drm/i915: handle FIFO oversubsription correctly
drm/i915: FIFO watermark calculation fixes
drm/i915: ignore lvds on AOpen Mini PC MP-915
drm/i915: Allow frame buffers up to 4096x4096 on 915/945 class hardware
...
usb_buffer_map_sg() may return -1. This will result in a read from
pdx->PixelUrb[frameInfo][-1]
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds PCI dependencies to staging drivers that require it.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This fixes a build error when selecting the rtl8192su driver as a
module. This has been reported by me, and the opensuse kernel developer
team, and I finally tracked it down.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Staging: rt2870: Revert d44ca7 Removal of kernel_thread() API
The sanity check this patch introduced triggers on shutdown, apparently due to
threads having already exited by the time BUG_ON() is reached.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Cc: Peter Teoh <htmldeveloper@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes an oops caused when during an unplug a device's table
of endpoints is zeroed before the driver is notified. A pointer to
the endpoint must be cached.
this fixes a regression caused by commit
5186ffee23
Therefore it should go into 2.6.31
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a quirk entry for the Leading Driver UD-11 usb flash drive.
As Alan Stern told me, the device doesn't deal correctly with the
locking media feature of the device, and this patch incorporates it.
Compiled, tested, working.
Signed-off-by: Rogerio Brito <rbrito@ime.usp.br>
Cc: Phil Dibowitz <phil@ipom.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Robert Hancock <hancockrwd@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Attached patch adds USB vendor and product IDs for Bayer's USB to serial
converter cable used by Bayer blood glucose meters. It seems to be a
FT232RL based device and works without any problem with ftdi_sio driver
when this patch is applied. See: http://winglucofacts.com/cables/
Signed-off-by: Marko Hänninen <bugitus@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1274) simplifies the counting of transaction-error
retries. Now we will count up from 0 to QH_XACTERR_MAX instead of
down from QH_XACTERR_MAX to 0.
The patch also fixes a small bug: qh->xacterr was not getting
initialized for interrupt endpoints.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Matthijs Kooijman <matthijs@stdin.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1273) fixes two(!) bugs introduced by the new
Clear-TT-Buffer implementation in ehci-hcd.
It is now possible for an idle QH to have some URBs on its
queue -- this will happen if a Clear-TT-Buffer is pending for
the QH's endpoint. Consequently we should not issue a warning
when someone tries to unlink an URB from an idle QH; instead
we should process the request immediately.
The refcounts for QHs could get messed up, because
submit_async() would increment the refcount when calling
qh_link_async() and qh_link_async() would then refuse to link
the QH into the schedule if a Clear-TT-Buffer was pending.
Instead we should increment the refcount only when the QH
actually is added to the schedule. The current code tries to
be clever by leaving the refcount alone if an unlink is
immediately followed by a relink; the patch changes this to an
unconditional decrement and increment (although they occur in
the opposite order).
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Tested-by: Manuel Lauss <manuel.lauss@gmail.com>
Tested-by: Matthijs Kooijman <matthijs@stdin.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1272) changes the error code returned when an open call
for a USB device node fails to locate the corresponding device. The
appropriate error code is -ENODEV, not -ENOENT.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
OMAP3EVM uses ISP1504 phy which doesn't require any programming and
thus has to use NOP otg transceiver.
Cleanups being done:
- Remove unwanted code in usb-musb.c file
- Register NOP in OMAP3EVM board file using
usb_nop_xceiv_register().
- Select NOP_USB_XCEIV for OMAP3EVM boards.
- Don't enable TWL4030_USB in omap3_evm_defconfig
Signed-off-by: Ajay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: Eino-Ville Talvala <talvala@stanford.edu>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
access_ok() checks must be done on every part of the userspace structure
that is accessed. If access_ok() on one part of the struct succeeded, it
does not imply it will succeed on other parts of the struct. (Does
depend on the architecture implementation of access_ok()).
This changes the __get_user() users to first check access_ok() on the
data structure.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: stable <stable@kernel.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
I am submitting a patch for the pl2303 driver. This patch adds support
for the "Sony QN-3USB" cable (vendor=0x054c, product=0x0437). This USB
cable is a so-called data cable used to connect a Sony mobile phone to a
computer. Supported models are Sony CMD-J5, J6, J7, J16, J26, J70 and
Z7.
I have used this patch with my Sony CMD-J70 for several days and I
haven't encountered any kernel/hardware issue.
From: Khanh-Dang Nguyen Thu Lam <kdntl@yahoo.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* git://git.infradead.org/mtd-2.6:
jffs2: Fix return value from jffs2_do_readpage_nolock()
mtd: mtdblock: introduce mtdblks_lock
mtd: remove 'SBC8240 Wind River' Device Driver Code
mtd: OneNAND: OMAP2/3: free GPMC CS on module removal
mtd: OneNAND: fix incorrect bufferram offset
mtd: blkdevs: do not forget to get MTD devices
mtd: fix the conversion from dev to mtd_info
mtd: let include/linux/mtd/partitions.h stand on its own
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon/kms: setup MC/VRAM the same way for suspend/resume
drm/radeon/kms: Fix caching mode selection for GTT object
sdhci_alloc_host returns an ERR_PTR value in an error case instead of NULL.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@match exists@
expression x, E;
statement S1, S2;
@@
x = sdhci_alloc_host(...)
... when != x = E
(
* if (x == NULL || ...) S1 else S2
|
* if (x == NULL && ...) S1 else S2
)
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: Ian Molton <ian@mnementh.co.uk>
Cc: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>
Cc: Philip Langdale <philipl@overt.org>
Cc: Pierre Ossman <pierre@ossman.eu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recent framebuffer locking patches first made affected systems unbootable,
then the dead-lock has been fixed but as of 2.6.31-rc4 the framebuffer on
mx3 machines doesn't work. Fix this.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Catalin and kmemleak spotted a leak of a VC screen buffer in
vc_allocate() due to the following chain of events:
vc_allocate()
visual_init(init=1)
vc->vc_sw->con_init(init=1)
fbcon_init()
vc_resize()
vc->screen_buf = kmalloc()
vc->screen_buf = kmalloc()
The common way for the VC drivers is to set the screen dimension
parameters manually in the init case and only call vc_resize() for
!init - which allocates a screen buffer according to the new
dimensions.
fbcon instead would do vc_resize() unconditionally and afterwards set
the dimensions manually (again) for !init - i.e. completely upside
down. The vc_resize() allocated buffer would then get lost by
vc_allocate() allocating a fresh one.
Use vc_resize() only for actual resizing to close the leak.
Set the dimensions manually only in initialization mode to remove the
redundant setting in resize mode.
The kmemleak trace from Catalin:
unreferenced object 0xde158000 (size 12288):
comm "Xorg", pid 1439, jiffies 4294961016
hex dump (first 32 bytes):
20 00 20 00 20 00 20 00 20 00 20 00 20 00 20 00 . . . . . . . .
20 00 20 00 20 00 20 00 20 00 20 00 20 00 20 00 . . . . . . . .
backtrace:
[<c006f74b>] __save_stack_trace+0x17/0x1c
[<c006f81d>] create_object+0xcd/0x188
[<c01f5457>] kmemleak_alloc+0x1b/0x3c
[<c006e303>] __kmalloc+0xdb/0xe8
[<c012cc4b>] vc_do_resize+0x73/0x1e0
[<c012cdf1>] vc_resize+0x15/0x18
[<c011afc1>] fbcon_init+0x1f9/0x2b8
[<c0129e87>] visual_init+0x9f/0xdc
[<c012aff3>] vc_allocate+0x7f/0xfc
[<c012b087>] con_open+0x17/0x80
[<c0120e43>] tty_open+0x1f7/0x2e4
[<c0072fa1>] chrdev_open+0x101/0x118
[<c006ffad>] __dentry_open+0x105/0x1cc
[<c00700fd>] nameidata_to_filp+0x2d/0x38
[<c00788cd>] do_filp_open+0x2c1/0x54c
[<c006fdff>] do_sys_open+0x3b/0xb4
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Tested-by: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a bug caused by changing pointers (viafb_mode, viafb_mode1)
assigned by module_param. It reduces driver complexity by not needlessly
changing these vars as they are only read once and removing now
superfluous code.
On unpatched kernels loading viafb with viafb_mode or viafb_mode1 option
used and afterwards unloading it results in:
kernel BUG at mm/slub.c:2926!
invalid opcode: 0000 [#1] PREEMPT
last sysfs file: /sys/devices/virtual/block/loop0/removable
Modules linked in: snd_hda_codec_realtek snd_hda_intel snd_hda_codec
snd_hwdep snd_pcm rtl8187 snd_timer eeprom_93cx6 mmc_block snd soundcore
via_sdmmc fb snd_page_alloc i2c_algo_bit i2c_viapro ehci_hcd uhci_hcd
cfbcopyarea mmc_core cfbimgblt cfbfillrect video output [last unloaded:
viafb]
Pid: 3355, comm: rmmod Not tainted (2.6.31-rc1 #0)
EIP: 0060:[<c106a759>] EFLAGS: 00010246 CPU: 0
EIP is at kfree+0x80/0xda
EAX: c17c2da0 EBX: dc7edbdc ECX: 0000010f EDX: 00000000
ESI: c102c700 EDI: dc7ed8fa EBP: d703ff2c ESP: d703ff20
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
Process rmmod (pid: 3355, ti=d703e000 task=db1412c0 task.ti=d703e000)
Stack:
dc7edbdc 00000014 00000016 d703ff40 c102c700 dc7f45d4 dc7f45d4 00000880
d703ff4c c103e571 00000000 d703ffac c103e751 66616976 da140062 db89ba80
00000328 d702edf8 db89ba80 d703ff9c c105d0f0 00000200 da14f898 00000014
Call Trace:
[<c102c700>] ? destroy_params+0x1e/0x2b
[<c103e571>] ? free_module+0xa2/0xd7
[<c103e751>] ? sys_delete_module+0x1ab/0x1da
[<c105d0f0>] ? do_munmap+0x20a/0x225
[<c10029b4>] ? sysenter_do_call+0x12/0x26
Code: 10 76 7a 8d 87 00 00 00 40 c1 e8 0c c1 e0 05 03 05 1c 87 41 c1 66 83 38 00 79 03 8b 40 0c 8b 10 84 d2 78 12 66 f7 c2 00 c0 75 04 <0f> 0b eb fe e8 6f 5a fe ff eb 47 8b 55 04 8b 58 0c 9c 5e fa 3b
EIP: [<c106a759>] kfree+0x80/0xda SS:ESP 0068:d703ff20
This is caused by the current code changing the pointers assigned by
module_param. During unload it tries to free the memory the pointers
point at which is now part of an internal structure.
The patch simply avoids changing the pointers. This is okay as they are
read only once during the initialization process.
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Cc: Scott Fang <ScottFang@viatech.com.cn>
Cc: Joseph Chan <JosephChan@via.com.tw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the rotate_ud() function not to crash in case of a font which has not
a width of multiple by 8: The inner loop of the font pixel copy should not
access a bit outside the font memory area. Subtract the shift offset from
the font width will prevent this.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was found using a semantic patch, more info can be found at:
http://www.emn.fr/x-info/coccinelle/
Signed-off-by: Stoyan Gaydarov <sgayda2@uiuc.edu>
Acked-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
we should align the GTT after VRAM no matter what, as we can
come back from resume and put in a different place and bad things happen.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Two defects work together result in KVM device passthrough randomly can't
work:
1. iommu_snooping is not initialized to zero when vm_iommu_init() called.
So it is possible to get a random value.
2. One line added by commit 2c2e2c38("IOMMU Identity Mapping Support")
change the code path, let it bypass domain_update_iommu_cap(), as well as
missing the increment of domain iommu reference count.
The latter is also likely to cause a leak of domains on repeated VMM
assignment and deassignment.
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Remove assumption on the shift and size of rows/columns form
matrix_keypad driver.
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
The Prestigio 157, an old no-name clone laptop uses input keys very
similar to the Wistron 1557/MS2141 with the addition of BIOS-controlled
wireless radio frequency kill switch.
This patch adds support for the RF kill switch control and adds manual
identification of the model.
The Prestigio does not expose any recognisable identity via dmidecode
and so requires manual selection at module init using
force=1 keymap=prestigio
Signed-off-by: TJ <ubuntu@tjworld.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
GTT object can either be cached,uncached or wc just let core ttm
pick the best mode according to how the bo driver and GTT memory
type was initialized.
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Stop referencing CLOCK_TICK_RATE in the KS8695 drivers, rather refer
to a KS8695_CLOCK_RATE.
Issue pointed out by Russell King on arm-linux-kernel mailing list.
Signed-off-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dev_priv->saveSWF1 is a 16 element array, but this reads up to index 22,
and restored values from the wrong registers.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
The physical address passed to domain_pfn_mapping() should be rounded
down to the start of the MM page, not the VT-d page.
This issue causes kernel panic on PAGE_SIZE>VTD_PAGE_SIZE platforms e.g. ia64
platforms.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
In domain_sg_mapping(), use aligned_nrpages() instead of hand-coded
rounding code for calculating the size of each sg elem. This means that
on IA64 we correctly round up to the MM page size, not just to the VT-d
page size.
Also remove the incorrect mm_to_dma_pfn() when intel_map_sg() calls
domain_sg_mapping() -- the 'size' variable is in VT-d pages already.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
The synaptic touchpad on the Asus G1S is not properly detected when
rebooting machine or on cold boot from time to time. Adding the Asus
G1S to the noloop exception table resolves the issue.
# dmidecode 2.10
SMBIOS 2.4 present.
Handle 0x0001, DMI type 1, 27 bytes
System Information
Manufacturer: ASUSTeK Computer Inc.
Product Name: G1S
Version: 1.0
Wake-up Type: Power Switch
SKU Number:
Family:
Signed-off-by: Jory A. Pratt <geekypenguin@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty-2.6:
tty-ldisc: be more careful in 'put_ldisc' locking
tty-ldisc: turn ldisc user count into a proper refcount
tty-ldisc: make refcount be atomic_t 'users' count
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6: (23 commits)
[SCSI] sd: Avoid sending extended inquiry to legacy devices
[SCSI] libsas: fix wide port hotplug issues
[SCSI] libfc: fix a circular locking warning during sending RRQ
[SCSI] qla4xxx: Remove hiwat code so scsi eh does not get escalated when we can make progress
[SCSI] qla4xxx: Fix srb lookup in qla4xxx_eh_device_reset
[SCSI] qla4xxx: Fix Driver Fault Recovery Completion
[SCSI] qla4xxx: add timeout handler
[SCSI] qla4xxx: Correct Extended Sense Data Errors
[SCSI] libiscsi: disable bh in and abort handler.
[SCSI] zfcp: Fix tracing of request id for abort requests
[SCSI] zfcp: Fix wka port processing
[SCSI] zfcp: avoid double notify in lowmem scenario
[SCSI] zfcp: Add port only once to FC transport class
[SCSI] zfcp: Recover from stalled outbound queue
[SCSI] zfcp: Fix erp escalation procedure
[SCSI] zfcp: Fix logic for physical port close
[SCSI] zfcp: Use -EIO for SBAL allocation failures
[SCSI] zfcp: Use unchained mode for small ct and els requests
[SCSI] zfcp: Use correct flags for zfcp_erp_notify
[SCSI] zfcp: Return -ENOMEM for allocation failures in zfcp_fsf
...
Use 'atomic_dec_and_lock()' to make sure that we always hold the
tty_ldisc_lock when the ldisc count goes to zero. That way we can never
race against 'tty_ldisc_try()' increasing the count again.
Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
By using the user count for the actual lifetime rules, we can get rid of
the silly "wait_for_idle" logic, because any busy ldisc will
automatically stay around until the last user releases it. This avoids
a host of odd issues, and simplifies the code.
So now, when the last ldisc reference is dropped, we just release the
ldisc operations struct reference, and free the ldisc.
It looks obvious enough, and it does work for me, but the counting
_could_ be off. It probably isn't (bad counting in the new version would
generally imply that the old code did something really bad, like free an
ldisc with a non-zero count), but it does need some testing, and
preferably somebody looking at it.
With this change, both 'tty_ldisc_put()' and 'tty_ldisc_deref()' are
just aliases for the new ref-counting 'put_ldisc()'. Both of them
decrement the ldisc user count and free it if it goes down to zero.
They're identical functions, in other words.
But the reason they still exist as sepate functions is that one of them
was exported (tty_ldisc_deref) and had a stupid name (so I don't want to
use it as the main name), and the other one was used in multiple places
(and I didn't want to make the patch larger just to rename the users).
In addition to the refcounting, I did do some minimal cleanup. For
example, now "tty_ldisc_try()" actually returns the ldisc it got under
the lock, rather than returning true/false and then the caller would
look up the ldisc again (now without the protection of the lock).
That said, there's tons of dubious use of 'tty->ldisc' without obviously
proper locking or refcounting left. I expressly did _not_ want to try to
fix it all, keeping the patch minimal. There may or may not be bugs in
that kind of code, but they wouldn't be _new_ bugs.
That said, even if the bugs aren't new, the timing and lifetime will
change. For example, some silly code may depend on the 'tty->ldisc'
pointer not changing because they hold a refcount on the 'ldisc'. And
that's no longer true - if you hold a ref on the ldisc, the 'ldisc'
itself is safe, but tty->ldisc may change.
So the proper locking (remains) to hold tty->ldisc_mutex if you expect
tty->ldisc to be stable. That's not really a _new_ rule, but it's an
example of something that the old code might have unintentionally
depended on and hidden bugs.
Whatever. The patch _looks_ sensible to me. The only users of
ldisc->users are:
- get_ldisc() - atomically increment the count
- put_ldisc() - atomically decrements the count and releases if zero
- tty_ldisc_try_get() - creates the ldisc, and sets the count to 1.
The ldisc should then either be released, or be attached to a tty.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Tested-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Linus Torvalds