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Björn Töpel bbff2f321a xsk: new descriptor addressing scheme 
Currently, AF_XDP only supports a fixed frame-size memory scheme where
each frame is referenced via an index (idx). A user passes the frame
index to the kernel, and the kernel acts upon the data.  Some NICs,
however, do not have a fixed frame-size model, instead they have a
model where a memory window is passed to the hardware and multiple
frames are filled into that window (referred to as the "type-writer"
model).

By changing the descriptor format from the current frame index
addressing scheme, AF_XDP can in the future be extended to support
these kinds of NICs.

In the index-based model, an idx refers to a frame of size
frame_size. Addressing a frame in the UMEM is done by offseting the
UMEM starting address by a global offset, idx * frame_size + offset.
Communicating via the fill- and completion-rings are done by means of
idx.

In this commit, the idx is removed in favor of an address (addr),
which is a relative address ranging over the UMEM. To convert an
idx-based address to the new addr is simply: addr = idx * frame_size +
offset.

We also stop referring to the UMEM "frame" as a frame. Instead it is
simply called a chunk.

To transfer ownership of a chunk to the kernel, the addr of the chunk
is passed in the fill-ring. Note, that the kernel will mask addr to
make it chunk aligned, so there is no need for userspace to do
that. E.g., for a chunk size of 2k, passing an addr of 2048, 2050 or
3000 to the fill-ring will refer to the same chunk.

On the completion-ring, the addr will match that of the Tx descriptor,
passed to the kernel.

Changing the descriptor format to use chunks/addr will allow for
future changes to move to a type-writer based model, where multiple
frames can reside in one chunk. In this model passing one single chunk
into the fill-ring, would potentially result in multiple Rx
descriptors.

This commit changes the uapi of AF_XDP sockets, and updates the
documentation.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-06-04 17:21:02 +02:00
..
ABI Merge branch 'speck-v20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-21 11:23:26 -07:00
accelerators ocxl: Document the OCXL_IOCTL_GET_METADATA IOCTL 2018-03-02 13:02:15 +11:00
accounting
acpi ACPI / LPIT: Add Low Power Idle Table (LPIT) support 2017-10-11 15:38:10 +02:00
admin-guide Merge branch 'speck-v20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-21 11:23:26 -07:00
aoe
arm MTD changes: 2018-04-06 12:15:41 -07:00
arm64 ARM: 2018-04-09 11:42:31 -07:00
auxdisplay
backlight
block block, bfq: move debug blkio stats behind CONFIG_DEBUG_BLK_CGROUP 2017-11-14 20:13:33 -07:00
blockdev SCSI misc on 20170907 2017-09-07 21:11:05 -07:00
bpf bpf, doc: howto use/run the BPF selftests 2018-05-14 23:02:58 -07:00
bus-devices
cdrom Documentation/cdrom: fix German sharp s in LaTex 2018-03-08 19:35:29 -07:00
cgroup-v1 page cache: use xa_lock 2018-04-11 10:28:39 -07:00
cma
connector
console
core-api textsearch: fix kernel-doc warnings and add kernel-api section 2018-04-16 18:53:13 -04:00
cpu-freq cpufreq: Drop cpufreq_table_validate_and_show() 2018-04-10 08:40:45 +02:00
cpuidle cpuidle: Add definition of residency to sysfs documentation 2018-04-09 13:44:37 +02:00
crypto crypto: doc - clarify hash callbacks state machine 2018-03-31 01:33:02 +08:00
dev-tools There's been a fair amount of activity in Documentation/ this time around: 2018-04-03 13:35:51 -07:00
device-mapper dm thin: update Documentation to clarify when "read_only" is valid 2018-05-10 11:18:49 -04:00
devicetree net: dsa: qca8k: Add QCA8334 binding documentation 2018-05-23 15:45:55 -04:00
doc-guide MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
driver-api Driver core fixes for 4.17-rc3 2018-04-27 10:12:20 -07:00
driver-model serdev: Introduce devm_serdev_device_open() 2018-01-08 10:08:34 +00:00
early-userspace
EDID
extcon
fault-injection Documentation: nvme: Documentation for nvme fault injection 2018-03-26 08:53:43 -06:00
fb documentation: fb: update list of available compiled-in fonts 2017-11-08 03:39:52 -07:00
features arch: remove obsolete architecture ports 2018-04-02 20:20:12 -07:00
filesystems ipconfig: Write NTP server IPs to /proc/net/ipconfig/ntp_servers 2018-04-24 13:40:42 -04:00
firmware_class
fmc
fpga fpga: mgr: separate getting/locking FPGA manager 2017-11-28 16:30:37 +01:00
gpio Documentation: gpio: Move drivers-on-gpio.txt to driver-api 2018-03-23 04:22:29 +01:00
gpu Linux 4.16-rc7 2018-03-28 14:30:41 +10:00
hid Documentation: fix input related doc refs 2017-10-12 11:14:06 -06:00
hwmon hwmon: (lm92) Add max6635 to lm92_id[] 2018-03-22 09:33:24 -07:00
i2c Documentation/i2c: adopt kernel commenting style in examples 2018-04-18 10:09:44 +02:00
ia64 ia64: doc: tweak whitespace for 'console=' parameter 2018-03-05 14:41:38 -08:00
ide
iio iio: adc: New driver for Cirrus Logic EP93xx ADC 2017-07-25 19:56:23 +01:00
infiniband Documentation/ABI: update infiniband sysfs interfaces 2018-02-23 08:18:33 -07:00
input Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input 2018-04-05 13:21:57 -07:00
ioctl staging: irda: remove remaining remants of irda code removal 2018-04-16 11:26:49 +02:00
isdn Documentation/isdn: check and fix dead links ... 2018-03-26 12:31:13 -04:00
kbuild Kconfig updates for v4.17 2018-04-03 16:28:01 -07:00
kdump kexec/kdump: minor Documentation updates for arm64 and Image 2017-07-12 16:26:00 -07:00
kernel-hacking Documentation: Fix misconversion of #if 2018-01-17 16:45:01 -07:00
laptops Documentation: fix admin-guide doc refs 2017-10-12 11:13:28 -06:00
leds Documentation: leds: Update 00-INDEX file 2017-10-23 20:17:03 +02:00
lightnvm
livepatch livepatch: Allow to call a custom callback when freeing shadow variables 2018-04-17 13:42:48 +02:00
locking Linux 4.16-rc2 2018-02-21 09:57:55 +01:00
m68k
maintainer docs: Add an intro note to the maintainers handbook 2017-12-11 14:46:10 -07:00
md raid5-ppl: PPL support for disks with write-back cache enabled 2018-01-15 14:29:42 -08:00
media MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
memory-devices
mic
mips Documentation: mips: Update AU1xxx_IDE Kconfig dependencies 2018-02-01 12:45:35 -07:00
misc-devices
mmc
mtd mtd: spi-nor: add an API to restore the status of SPI flash chip 2017-12-13 00:36:00 +01:00
namespaces
netlabel
networking xsk: new descriptor addressing scheme 2018-06-04 17:21:02 +02:00
nfc
nios2
nvdimm
nvmem NVMEM documentation fix: A minor typo 2017-08-24 13:31:58 -06:00
openrisc Documentation: openrisc: Updates to README 2017-10-30 21:37:53 +09:00
parisc
PCI PCI: Update location of pci.ids file 2018-02-22 15:00:43 -06:00
pcmcia
perf drivers/bus: Move Arm CCN PMU driver 2018-03-06 17:26:15 +01:00
phy
platform
power firmware: Fix firmware documentation for recent file renames 2018-04-23 13:03:26 +02:00
powerpc powerpc updates for 4.13 2017-07-07 13:55:45 -07:00
pps drivers/pps: aesthetic tweaks to PPS-related content 2017-09-08 18:26:51 -07:00
process staging: irda: remove remaining remants of irda code removal 2018-04-16 11:26:49 +02:00
pti
ptp ptp: Fix documentation to match code. 2018-03-26 12:13:21 -04:00
rapidio Documentation: rapidio: move sysfs interface to ABI 2018-02-23 08:25:45 -07:00
RCU Merge branches 'cond_resched.2017.12.04a', 'dyntick.2017.11.28a', 'fixes.2017.12.11a', 'srbd.2017.12.05a' and 'torture.2017.12.11a' into HEAD 2017-12-11 09:21:58 -08:00
s390 vfio-ccw: update documentation 2018-03-01 17:32:14 +01:00
scheduler sched/deadline: Fix the description of runtime accounting in the documentation 2017-11-16 09:00:35 +01:00
scsi scsi: documentation: Obsolete documentation references 2018-03-21 18:34:20 -04:00
security selinux: Update SELinux SCTP documentation 2018-03-20 16:26:15 -04:00
serial
sh
sound sound updates for 4.15-rc1 2017-11-14 18:01:46 -08:00
sparc sparc64: Add support for ADI (Application Data Integrity) 2018-03-18 07:38:48 -07:00
sphinx MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
sphinx-static docs RTD theme: code-block with line nos - lines and line numbers don't line up. 2017-07-17 13:48:45 -06:00
spi
sysctl bpf, x86_32: add eBPF JIT compiler for ia32 2018-05-03 18:15:25 +02:00
target
thermal thermal: Add cooling device's statistics in sysfs 2018-04-02 21:49:01 +08:00
timers sched/isolation: Eliminate NO_HZ_FULL_ALL 2018-02-15 15:40:37 -08:00
trace Revert: Unify CLOCK_MONOTONIC and CLOCK_BOOTTIME 2018-04-26 14:53:32 +02:00
translations MAINTAINERS & files: Canonize the e-mails I use at files 2018-05-04 06:21:06 -04:00
usb Documentation updates for 4.16. New stuff includes refcount_t 2018-01-31 19:25:25 -08:00
userspace-api Documentation/spec_ctrl: Do some minor cleanups 2018-05-09 21:41:38 +02:00
virtual kvm: rename KVM_HINTS_DEDICATED to KVM_HINTS_REALTIME 2018-05-17 19:12:13 +02:00
vm page cache: use xa_lock 2018-04-11 10:28:39 -07:00
w1 Documentation updates for 4.16. New stuff includes refcount_t 2018-01-31 19:25:25 -08:00
watchdog watchdog: remove bfin_wdt driver 2018-03-26 15:57:04 +02:00
wimax
x86 Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-04-15 16:12:35 -07:00
xtensa xtensa: add support for KASAN 2017-12-16 22:37:12 -08:00
.gitignore
00-INDEX CRIS: Drop support for the CRIS port 2018-03-16 10:56:05 +01:00
atomic_bitops.txt locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit() 2018-02-13 14:55:53 +01:00
atomic_t.txt Documentation/locking/atomic: Finish the document... 2017-08-25 11:06:33 +02:00
bcache.txt bcache.txt: standardize document format 2017-07-14 13:51:27 -06:00
bt8xxgpio.txt bt8xxgpio.txt: standardize document format 2017-07-14 13:51:27 -06:00
btmrvl.txt btmrvl.txt: standardize document format 2017-07-14 13:51:27 -06:00
bus-virt-phys-mapping.txt bus-virt-phys-mapping.txt: standardize document format 2017-07-14 13:51:28 -06:00
cachetlb.txt cachetlb.txt: standardize document format 2017-07-14 13:51:28 -06:00
cgroup-v2.txt cgroup, docs: document the root cgroup behavior of cpu and io controllers 2018-01-16 08:07:09 -08:00
Changes
circular-buffers.txt doc: De-emphasize smp_read_barrier_depends 2017-12-05 11:57:53 -08:00
clearing-warn-once.txt kernel debug: support resetting WARN*_ONCE 2017-11-17 16:10:00 -08:00
clk.txt Documentation: clk: enable lock is not held for clk_is_enabled API 2018-03-16 15:44:43 -07:00
CodingStyle
conf.py docs: Remove "could not extract kernel version" warning 2017-12-11 15:20:04 -07:00
cpu-load.txt cpu-load: standardize document format 2017-07-14 13:51:30 -06:00
cputopology.txt cputopology.txt: standardize document format 2017-07-14 13:51:30 -06:00
crc32.txt crc32.txt: standardize document format 2017-07-14 13:51:30 -06:00
dcdbas.txt dcdbas.txt: standardize document format 2017-07-14 13:51:31 -06:00
debugging-modules.txt
debugging-via-ohci1394.txt debugging-via-ohci1394.txt: standardize document format 2017-07-14 13:51:34 -06:00
dell_rbu.txt dell_rbu.txt: standardize document format 2017-07-14 13:58:12 -06:00
digsig.txt digsig.txt: standardize document format 2017-07-14 13:51:31 -06:00
DMA-API-HOWTO.txt DMA-API-HOWTO.txt: standardize document format 2017-07-14 13:51:32 -06:00
DMA-API.txt dma-coherent: remove the DMA_MEMORY_MAP and DMA_MEMORY_IO flags 2017-09-01 11:59:17 +02:00
DMA-attributes.txt DMA-attributes.txt: standardize document format 2017-07-14 13:51:33 -06:00
DMA-ISA-LPC.txt DMA-ISA-LPC.txt: standardize document format 2017-07-14 13:51:33 -06:00
docutils.conf
dontdiff Remove gperf usage from toolchain 2017-08-19 11:02:53 -07:00
efi-stub.txt efi-stub.txt: standardize document format 2017-07-14 13:51:34 -06:00
eisa.txt eisa.txt: standardize document format 2017-07-14 13:51:34 -06:00
flexible-arrays.txt flexible-arrays.txt: standardize document format 2017-07-14 13:51:35 -06:00
futex-requeue-pi.txt futex-requeue-pi.txt: standardize document format 2017-07-14 13:51:35 -06:00
gcc-plugins.txt gcc-plugins.txt: standardize document format 2017-07-14 13:51:36 -06:00
highuid.txt highuid.txt: standardize document format 2017-07-14 13:51:36 -06:00
hw_random.txt hw_random.txt: standardize document format 2017-07-14 13:51:37 -06:00
hwspinlock.txt hwspinlock.txt: standardize document format 2017-07-14 13:51:37 -06:00
index.rst Documentation: add Linux tracing to Sphinx TOC tree 2018-03-07 10:22:53 -07:00
intel_txt.txt intel_txt.txt: standardize document format 2017-07-14 13:51:38 -06:00
Intel-IOMMU.txt Intel-IOMMU.txt: standardize document format 2017-07-14 13:51:38 -06:00
io_ordering.txt io_ordering.txt: standardize document format 2017-07-14 13:51:39 -06:00
io-mapping.txt io-mapping.txt: standardize document format 2017-07-14 13:51:38 -06:00
iostats.txt iostats.txt: update it to cover recent Kernels 2017-07-14 13:51:40 -06:00
IPMI.txt ipmi: Make IPMI panic strings always available 2017-09-27 16:03:45 -05:00
IRQ-affinity.txt IRQ-affinity.txt: standardize document format 2017-07-14 13:51:41 -06:00
IRQ-domain.txt irqdomain: Kill CONFIG_IRQ_DOMAIN_DEBUG 2018-01-24 12:32:58 +01:00
IRQ.txt IRQ.txt: add a markup for its title 2017-07-14 13:51:42 -06:00
irqflags-tracing.txt irqflags-tracing.txt: standardize document format 2017-07-14 13:51:42 -06:00
isa.txt isa.txt: standardize document format 2017-07-14 13:51:43 -06:00
isapnp.txt isapnp.txt: promote title level 2017-07-14 13:51:43 -06:00
kernel-per-CPU-kthreads.txt kernel-per-CPU-kthreads.txt: standardize document format 2017-07-14 13:51:43 -06:00
kobject.txt kobject.txt: standardize document format 2017-07-14 13:51:44 -06:00
kprobes.txt kprobes/docs: Remove jprobes related documents 2017-10-20 11:02:55 +02:00
kref.txt kref.txt: standardize document format 2017-07-14 13:51:45 -06:00
ldm.txt ldm.txt: standardize document format 2017-07-14 13:51:45 -06:00
lockup-watchdogs.txt lockup-watchdogs.txt: standardize document format 2017-07-14 13:51:46 -06:00
logo.gif
logo.txt
lsm.txt
lzo.txt lzo.txt: standardize document format 2017-07-14 13:51:46 -06:00
mailbox.txt mailbox.txt: standardize document format 2017-07-14 13:51:47 -06:00
Makefile Documentation: add script and build target to check for broken file references 2017-10-12 11:07:42 -06:00
memory-barriers.txt locking/memory-barriers: De-emphasize smp_read_barrier_depends() some more 2018-03-10 10:22:22 +01:00
memory-hotplug.txt memory-hotplug.txt: standardize document format 2017-07-14 13:57:53 -06:00
men-chameleon-bus.txt men-chameleon-bus.txt: standardize document format 2017-07-14 13:57:54 -06:00
nommu-mmap.txt nommu-mmap.txt: don't use all upper case on titles 2017-07-14 13:57:55 -06:00
ntb.txt This series converts a number of top-level documents to the RST format 2017-07-15 12:58:58 -07:00
numastat.txt numastat.txt: standardize document format 2017-07-14 13:57:56 -06:00
padata.txt padata.txt: standardize document format 2017-07-14 13:57:56 -06:00
parport-lowlevel.txt parport-lowlevel.txt: standardize document format 2017-07-14 13:57:57 -06:00
percpu-rw-semaphore.txt percpu-rw-semaphore.txt: standardize document format 2017-07-14 13:57:58 -06:00
phy.txt phy.txt: standardize document format 2017-07-14 13:57:58 -06:00
pi-futex.txt Documentation: fix locking rt-mutex doc refs 2017-10-19 12:56:44 -06:00
pnp.txt pnp.txt: standardize document format 2017-07-14 13:57:59 -06:00
preempt-locking.txt preempt-locking.txt: standardize document format 2017-07-14 13:58:00 -06:00
pwm.txt pwm: Standardize document format 2017-07-06 08:23:30 +02:00
rbtree.txt rbtree: cache leftmost node internally 2017-09-08 18:26:48 -07:00
remoteproc.txt remoteproc.txt: standardize document format 2017-07-14 13:58:02 -06:00
rfkill.txt rfkill.txt: standardize document format 2017-07-14 13:58:02 -06:00
robust-futex-ABI.txt robust-futex-ABI.txt: standardize document format 2017-07-14 13:58:03 -06:00
robust-futexes.txt robust-futexes.txt: standardize document format 2017-07-14 13:58:03 -06:00
rpmsg.txt rpmsg.txt: standardize document format 2017-07-14 13:58:04 -06:00
rtc.txt Documentation: rtc: move iotcl interface documentation to ABI 2018-01-12 00:20:41 +01:00
SAK.txt SAK.txt: standardize document format 2017-07-14 13:58:04 -06:00
sgi-ioc4.txt sgi-ioc4.txt: standardize document format 2017-07-14 13:58:05 -06:00
siphash.txt siphash.txt: standardize document format 2017-07-14 13:58:06 -06:00
SM501.txt SM501.txt: standardize document format 2017-07-14 13:58:06 -06:00
smsc_ece1099.txt smsc_ece1099.txt: standardize document format 2017-07-14 13:58:07 -06:00
speculation.txt Documentation: Document array_index_nospec 2018-01-30 21:54:28 +01:00
static-keys.txt jump_label: Provide hotplug context variants 2017-08-10 12:28:59 +02:00
SubmittingPatches
svga.txt documentation/svga.txt: update outdated file 2017-11-20 10:45:50 -07:00
switchtec.txt NTB: switchtec_ntb: Update switchtec documentation with notes for NTB 2017-11-18 20:37:13 -05:00
sync_file.txt
tee.txt tee.txt: standardize document format 2017-07-14 13:58:14 -06:00
this_cpu_ops.txt this_cpu_ops.txt: standardize document format 2017-07-14 13:58:08 -06:00
unaligned-memory-access.txt unaligned-memory-access.txt: standardize document format 2017-07-14 13:58:09 -06:00
vfio-mediated-device.txt vfio-mediated-device.txt: standardize document format 2017-07-14 13:58:10 -06:00
vfio.txt vfio.txt: standardize document format 2017-07-14 13:58:10 -06:00
video-output.txt
xillybus.txt xillybus.txt: standardize document format 2017-07-14 13:58:11 -06:00
xz.txt xz.txt: standardize document format 2017-07-14 13:58:11 -06:00
zorro.txt zorro.txt: standardize document format 2017-07-14 13:58:12 -06:00