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Daniel Vetter 01ce605a7b drm/prime: remove cargo-cult locking from map_sg helper 
I've checked both implementations (radeon/nouveau) and they both grab
the page array from ttm simply by dereferencing it and then wrapping
it up with drm_prime_pages_to_sg in the callback and map it with
dma_map_sg (in the helper).

Only the grabbing of the underlying page array is anything we need to
be concerned about, and either those pages are pinned independently,
or we're screwed no matter what.

And indeed, nouveau/radeon pin the backing storage in their
attach/detach functions.

Since I've created this patch cma prime support for dma_buf was added.
drm_gem_cma_prime_get_sg_table only calls kzalloc and the creates&maps
the sg table with dma_get_sgtable. It doesn't touch any gem object
state otherwise. So the cma helpers also look safe.

The only thing we might claim it does is prevent concurrent mapping of
dma_buf attachments. But a) that's not allowed and b) the current code
is racy already since it checks whether the sg mapping exists _before_
grabbing the lock.

So the dev->struct_mutex locking here does absolutely nothing useful,
but only distracts. Remove it.

This should also help Maarten's work to eventually pin the backing
storage more dynamically by preventing locking inversions around
dev->struct_mutex.

v2: Add analysis for recently added cma helper prime code.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
 		2013-08-19 10:46:16 +10:00
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accessibility
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acpi Revert "ACPI / video / i915: No ACPI backlight if firmware expects Windows 8" 2013-07-26 14:59:20 +02:00
amba
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ata ahci_imx: depend on CONFIG_MFD_SYSCON 2013-07-26 08:57:56 -04:00
atm
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auxdisplay
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base Driver core patches for 3.11-rc2 2013-07-18 12:48:40 -07:00
bcma bcma: add support for BCM43142 2013-06-27 13:42:16 -04:00
block Merge branch 'for-3.11/drivers' of git://git.kernel.dk/linux-block 2013-07-22 19:02:52 -07:00
bluetooth
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bus ARM SoC device tree changes 2013-07-02 14:23:01 -07:00
cdrom drivers/cdrom/cdrom.c: use kzalloc() for failing hardware 2013-07-03 16:07:25 -07:00
char Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
clk Power management and ACPI updates for 3.11-rc1 2013-07-03 14:35:40 -07:00
clocksource clocksource+irqchip: delete __cpuinit usage from all related files 2013-07-14 19:36:57 -04:00
connector
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cpufreq cpufreq / intel_pstate: Change to scale off of max P-state 2013-07-23 04:18:28 +02:00
cpuidle Power management and ACPI updates for 3.11-rc1 2013-07-03 14:35:40 -07:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2013-07-24 11:05:18 -07:00
dca
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devfreq Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
dio
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dma drivers/dma/iop-adma.c: fix new warnings 2013-07-09 10:33:19 -07:00
edac EDAC: Fix lockdep splat 2013-07-23 16:01:28 -07:00
eisa
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extcon drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
firewire
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firmware efivars: check for EFI_RUNTIME_SERVICES 2013-07-11 11:00:31 +01:00
fmc
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gpio drivers: gpio: msm: Fix the error condition for reading ngpio 2013-07-20 23:33:33 +02:00
gpu drm/prime: remove cargo-cult locking from map_sg helper 2013-08-19 10:46:16 +10:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-07-04 15:35:08 -07:00
hsi drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
hv Drivers: hv: balloon: Do not post pressure status if interrupted 2013-07-16 23:19:19 -07:00
hwmon Single patch to staticize a local variable 2013-07-18 11:32:36 -07:00
hwspinlock
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i2c Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
ide Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide 2013-07-10 18:15:41 -07:00
idle
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iio The first round of IIO fixes for the 3.11 cycle. 2013-07-16 22:41:38 -07:00
infiniband Main batch of InfiniBand/RDMA changes for 3.11 merge window: 2013-07-13 12:57:21 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2013-07-13 18:05:13 -07:00
iommu IOMMU Updates for Linux 3.11 2013-07-10 14:46:40 -07:00
ipack
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irqchip clocksource+irqchip: delete __cpuinit usage from all related files 2013-07-14 19:36:57 -04:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
leds leds: mc13783: Fix "uninitialized variable" warning 2013-07-02 08:44:02 -07:00
lguest Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
macintosh macintosh/windfarm: Remove obsolete cleanup for clientdata 2013-07-01 11:46:56 +10:00
mailbox
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md 2 more bugfixes for md in 3.11 2013-07-26 11:20:10 -07:00
media [media] saa7134: Fix unlocked snd_pcm_stop() call 2013-07-15 21:25:14 +02:00
memory
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memstick drivers/memstick/host/r592.c: convert to module_pci_driver 2013-07-03 16:08:06 -07:00
message drivers: avoid format strings in names passed to alloc_workqueue() 2013-07-03 16:07:41 -07:00
mfd For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
misc Char/Misc patches for 3.11-rc3 2013-07-26 11:36:12 -07:00
mmc ARM: pxa: propagate errors from regulator_enable() to pxamci 2013-07-23 12:15:15 -07:00
mtd A couple of fixes and clean-ups, allow for assigning user-defined 2013-07-05 12:09:48 -07:00
net macvtap: do not zerocopy if iov needs more pages than MAX_SKB_FRAGS 2013-07-18 13:04:25 -07:00
nfc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2013-07-09 18:24:39 -07:00
ntb
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nubus
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of of/irq: init struct resource to 0 in of_irq_to_resource() 2013-07-22 19:40:38 +01:00
oprofile drivers: delete __cpuinit usage from all remaining drivers files 2013-07-14 19:36:59 -04:00
parisc parisc: fix LMMIO mismatch between PAT length and MASK register 2013-07-09 22:09:16 +02:00
parport Merge branch 'akpm' (updates from Andrew Morton) 2013-07-03 17:12:13 -07:00
pci powerpc/pci/hotplug: Don't need to remove from EEH cache twice 2013-07-24 14:18:47 +10:00
pcmcia Driver core patches for 3.11-rc1 2013-07-02 11:44:19 -07:00
pinctrl pinctrl: fix a memleak when freeing maps 2013-07-25 17:18:36 +02:00
platform x86 platform drivers: fix gpio leak 2013-07-10 15:42:51 -04:00
pnp PNP / ACPI: avoid garbage in resource name 2013-07-18 01:38:59 +02:00
power Nothing exciting this time, just assorted fixes and cleanups. 2013-07-10 11:13:00 -07:00
pps pps-gpio: add device-tree binding and support 2013-07-03 16:08:06 -07:00
ps3
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ptp
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pwm pwm: pwm-tiehrpwm: Use clk_enable/disable instead clk_prepare/unprepare. 2013-06-26 23:23:54 +02:00
rapidio Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
regulator For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
remoteproc Trivial remoteproc fixes by Suman Anna, Wei Yongjun and Thomas Meyer. 2013-07-11 12:35:09 -07:00
reset
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rpmsg
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rtc For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
s390 s390/zcrypt: Alias for new zcrypt device driver base module 2013-07-19 08:37:39 +02:00
sbus
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scsi [SCSI] isci: fix breakage caused by >16byte CDB patch 2013-07-24 14:18:12 -07:00
sfi
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sh Merge branch 'pm-assorted' 2013-06-28 13:01:40 +02:00
sn
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spi Merge remote-tracking branch 'spi/fix/xilinx' into spi-linus 2013-07-15 11:46:16 +01:00
ssb Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
staging drm: remove FASYNC support 2013-08-19 10:05:17 +10:00
target Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2013-07-11 12:57:19 -07:00
tc
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thermal Thermal: Fix lockup of cpu_down() 2013-07-22 09:34:46 +08:00
tty serial: tegra: correct help message in Kconfig from 'ttyHS' to 'ttyTHS' 2013-07-24 15:23:38 -07:00
uio uio: use vma_pages() to replace (vm_end - vm_start) >> PAGE_SHIFT 2013-07-03 16:07:26 -07:00
usb usb: Clear both buffers when clearing a control transfer TT buffer. 2013-07-25 11:37:13 -07:00
uwb drivers: avoid format string in dev_set_name 2013-07-03 16:07:41 -07:00
vfio vfio Updates for v3.11 2013-07-10 14:50:08 -07:00
vhost vhost: more fixes for 3.11 2013-07-23 14:38:20 -07:00
video mfd: max8925: fix dt code for backlight 2013-07-25 16:57:00 -07:00
virt
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virtio No real surprises. 2013-07-10 14:50:58 -07:00
vlynq
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vme
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w1 drivers/w1/slaves/w1_ds2408.c: add magic sequence to disable P0 test mode 2013-07-03 16:08:06 -07:00
watchdog Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus 2013-07-13 14:52:21 -07:00
xen drivers: delete __cpuinit usage from all remaining drivers files 2013-07-14 19:36:59 -04:00
zorro zorro: switch to fixed_size_llseek() 2013-06-29 12:57:28 +04:00
Kconfig For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00
Makefile For the 3.11 merge we only have one new MFD driver for the Kontron PLD. 2013-07-10 11:10:27 -07:00