linux/drivers
Stefan Richter 8e2b2b46ea firewire: cdev: improve FW_CDEV_IOC_ALLOCATE
In both the ieee1394 stack and the firewire stack, the core treats
kernelspace drivers better than userspace drivers when it comes to
CSR address range allocation:  The former may request a register to be
placed automatically at a free spot anywhere inside a specified address
range.  The latter may only request a register at a fixed offset.

Hence, userspace drivers which do not require a fixed offset potentially
need to implement a retry loop with incremented offset in each retry
until the kernel does not fail allocation with EBUSY.  This awkward
procedure is not fundamentally necessary as the core already provides a
superior allocation API to kernelspace drivers.

Therefore change the ioctl() ABI by addition of a region_end member in
the existing struct fw_cdev_allocate.  Userspace and kernelspace APIs
work the same way now.

There is a small cost to pay by clients though:  If client source code
is required to compile with older kernel headers too, then any use of
the new member fw_cdev_allocate.region_end needs to be enclosed by
#ifdef/#endif directives.  However, any client program that seriously
wants to use address range allocations will require a kernel of cdev ABI
version >= 4 at runtime and a linux/firewire-cdev.h header of >= 4
anyway.  This is because v4 brings FW_CDEV_EVENT_REQUEST2.  The only
client program in which build-time compatibility with struct
fw_cdev_allocate as found in older kernel headers makes sense is
libraw1394.

(libraw1394 uses the older broken FW_CDEV_EVENT_REQUEST to implement a
makeshift, incorrect transaction responder that does at least work
somewhat in many simple scenarios, relying on guesswork by libraw1394
and by libraw1394 based applications.  Plus, address range allocation
and transaction responder is only one of many features that libraw1394
needs to provide, and these other features need to work with kernel and
kernel-headers as old as possible.  Any new linux/firewire-cdev.h based
client that implements a transaction responder should never attempt to
do it like libraw1394;  instead it should make a header and kernel of v4
or later a hard requirement.)

While we are at it, update the struct fw_cdev_allocate documentation to
better reflect the recent fw_cdev_event_request2 ABI addition.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2010-07-23 13:36:28 +02:00
..
accessibility
acpi Merge branch 'pcc' into release 2010-02-23 00:39:00 -05:00
amba
ata [libata] Call flush_dcache_page after PIO data transfers in libata-sff.c 2010-02-04 01:04:50 -05:00
atm
auxdisplay
base class: Free the class private data in class_release 2010-02-16 15:43:00 -08:00
block cciss: Make cciss_seq_show handle holes in the h->drv[] array 2010-02-05 13:15:36 +01:00
bluetooth Bluetooth: Fix memory leak in Marvell BT-over-SDIO driver 2010-02-03 19:08:30 -08:00
cdrom
char Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-11 14:01:10 -08:00
clocksource geode-mfgpt: restore previous behavior for selecting IRQ 2010-02-22 19:50:34 -08:00
connector connector: Delete buggy notification code. 2010-02-02 15:58:48 -08:00
cpufreq
cpuidle
crypto crypto: padlock-sha - Add import/export support 2010-02-02 06:50:25 +11:00
dca
dio
dma drivers/dma: Correct NULL test 2010-02-10 12:07:28 -07:00
edac Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp 2010-02-11 14:07:13 -08:00
eisa
firewire firewire: cdev: improve FW_CDEV_IOC_ALLOCATE 2010-07-23 13:36:28 +02:00
firmware
gpio
gpu Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-02-23 18:13:34 -08:00
hid
hwmon hwmon: (w83781d) Request I/O ports individually for probing 2010-02-05 19:58:36 +01:00
i2c i2c-tiny-usb: Fix on big-endian systems 2010-02-05 17:48:13 +01:00
ide
idle
ieee1394 ieee1394: Remove unnecessary casts of private_data 2010-07-13 09:59:32 +02:00
ieee802154
infiniband Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband 2010-02-11 14:01:25 -08:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2010-02-22 08:48:06 -08:00
isdn
leds
lguest
macintosh
mca
md dm: sysfs revert add empty release function to avoid debug warning 2010-02-16 18:43:04 +00:00
media firewire: remove an unused function argument 2010-06-20 23:11:55 +02:00
memstick
message [SCSI] mptfusion : mptscsih_abort return value should be SUCCESS instead of value 0. 2010-02-08 13:40:17 -06:00
mfd mfd: Fix asic3 build 2010-01-29 21:03:09 +01:00
misc
mmc mmc_test: block addressed cards 2010-02-11 13:59:42 -08:00
mtd Merge branch 'for-linus' of git://git.infradead.org/ubi-2.6 2010-01-28 12:57:50 -08:00
net Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2010-02-23 01:27:05 -08:00
nubus
of
oprofile
parisc
parport
pci Merge branches 'bugzilla-14886', 'bugzilla-15000', 'bugzilla-15040', 'bugzilla-15108', 'pdc', 'hotplug-null-ref' and 'thinkpad' into release 2010-02-18 03:51:04 -05:00
pcmcia
platform acer-wmi: Respect current backlight level when loading 2010-02-19 00:19:26 -05:00
pnp
power wm97xx_battery: Handle missing platform data gracefully 2010-01-29 17:00:18 +03:00
pps
ps3
rapidio
regulator regulator/lp3971: vol_map out of bounds in lp3971_{ldo,dcdc}_set_voltage() 2010-02-12 11:39:49 +00:00
rtc rtc-fm3130: add missing braces 2010-02-02 18:11:21 -08:00
s390 Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6 2010-02-11 14:05:55 -08:00
sbus
scsi Merge master.kernel.org:/home/rmk/linux-2.6-arm 2010-02-20 16:55:05 -08:00
serial serial: 8250: add serial transmitter fully empty test 2010-02-16 15:55:51 -08:00
sfi
sh
sn
spi spi: spi_sh_msiof: Fixed data sampling on the correct edge 2010-02-02 11:29:15 +09:00
ssb ssb: Fix CONFIG_SSB_SDIOHOST typo 2010-02-03 16:55:20 -05:00
staging Merge branch 'drm-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 2010-02-01 10:46:49 -08:00
tc
telephony
thermal
uio
usb USB: gadget: fix EEM gadget CRC usage 2010-02-16 15:11:10 -08:00
uwb
video efifb: fix framebuffer handoff 2010-02-22 19:50:34 -08:00
virtio
vlynq
w1
watchdog [WATCHDOG] bfin: fix max timeout calculation 2010-02-21 19:16:30 +00:00
xen
zorro
Kconfig
Makefile