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linux/drivers
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Jesper Dangaard Brouer 99c07c43c4 xdp: tracking page_pool resources and safe removal 
This patch is needed before we can allow drivers to use page_pool for
DMA-mappings. Today with page_pool and XDP return API, it is possible to
remove the page_pool object (from rhashtable), while there are still
in-flight packet-pages. This is safely handled via RCU and failed lookups in
__xdp_return() fallback to call put_page(), when page_pool object is gone.
In-case page is still DMA mapped, this will result in page note getting
correctly DMA unmapped.

To solve this, the page_pool is extended with tracking in-flight pages. And
XDP disconnect system queries page_pool and waits, via workqueue, for all
in-flight pages to be returned.

To avoid killing performance when tracking in-flight pages, the implement
use two (unsigned) counters, that in placed on different cache-lines, and
can be used to deduct in-flight packets. This is done by mapping the
unsigned "sequence" counters onto signed Two's complement arithmetic
operations. This is e.g. used by kernel's time_after macros, described in
kernel commit 1ba3aab303 and 5a581b367b, and also explained in RFC1982.

The trick is these two incrementing counters only need to be read and
compared, when checking if it's safe to free the page_pool structure. Which
will only happen when driver have disconnected RX/alloc side. Thus, on a
non-fast-path.

It is chosen that page_pool tracking is also enabled for the non-DMA
use-case, as this can be used for statistics later.

After this patch, using page_pool requires more strict resource "release",
e.g. via page_pool_release_page() that was introduced in this patchset, and
previous patches implement/fix this more strict requirement.

Drivers no-longer call page_pool_destroy(). Drivers already call
xdp_rxq_info_unreg() which call xdp_rxq_info_unreg_mem_model(), which will
attempt to disconnect the mem id, and if attempt fails schedule the
disconnect for later via delayed workqueue.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-19 11:23:13 -04:00
..
accessibility treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 70 2019-05-24 17:36:47 +02:00
acpi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
amba treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
android treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
ata libata: Extend quirks for the ST1000LM024 drives with NOLPM quirk 2019-06-13 03:17:11 -06:00
atm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
auxdisplay treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
base drivers/base/devres: introduce devm_release_action() 2019-06-13 17:34:56 -10:00
bcma
block block/ps3vram: Use %llu to format sector_t after LBDAF removal 2019-06-13 03:17:50 -06:00
bluetooth treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
bus treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
cdrom treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 1 2019-05-21 11:28:39 +02:00
char treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 445 2019-06-05 17:37:18 +02:00
clk treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 445 2019-06-05 17:37:18 +02:00
clocksource Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-16 07:22:56 -10:00
connector treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
counter treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
cpufreq treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
cpuidle treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
crypto treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 442 2019-06-05 17:37:17 +02:00
dax mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
dca treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 33 2019-05-24 17:27:11 +02:00
devfreq treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
dio treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
dma SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
dma-buf SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
edac treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
eisa treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 210 2019-05-30 11:29:53 -07:00
extcon treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
firewire treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
firmware treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
fmc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 60 2019-05-24 17:36:45 +02:00
fpga SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
fsi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 174 2019-05-30 11:26:41 -07:00
gnss treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
gpio A single fix for the PCA953x driver affecting some fringe 2019-06-14 05:48:29 -10:00
gpu Merge branch 'drm-fixes-5.2' of git://people.freedesktop.org/~agd5f/linux into drm-fixes 2019-06-14 17:55:22 +02:00
hid Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid 2019-06-13 05:59:05 -10:00
hsi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 336 2019-06-05 17:37:07 +02:00
hv treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 320 2019-06-05 17:37:05 +02:00
hwmon SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
hwspinlock
hwtracing treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
i2c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 20:20:36 -07:00
i3c treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
ide treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
idle treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
iio treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
infiniband ipoib: correcly show a VF hardware address 2019-06-18 10:41:27 -07:00
input treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
interconnect treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
iommu IOMMU Fixes for Linux v5.2-rc4 2019-06-14 05:49:35 -10:00
ipack treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
irqchip treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
isdn Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
leds treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
lightnvm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 410 2019-06-05 17:37:14 +02:00
macintosh treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 375 2019-06-05 17:37:10 +02:00
mailbox treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
mcb treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
md bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached 2019-06-13 03:09:15 -06:00
media Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 20:20:36 -07:00
memory treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 340 2019-06-05 17:37:07 +02:00
memstick memstick: mspro_block: Fix an error code in mspro_block_issue_req() 2019-05-28 09:53:54 +02:00
message treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
mfd treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 450 2019-06-05 17:37:18 +02:00
misc SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
mmc SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
mtd treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
mux
net xdp: tracking page_pool resources and safe removal 2019-06-19 11:23:13 -04:00
nfc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 417 2019-06-05 17:37:15 +02:00
ntb treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
nubus treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
nvdimm mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
nvme Merge branch 'nvme-5.2-rc-next' of git://git.infradead.org/nvme into for-linus 2019-06-07 14:04:28 -06:00
nvmem treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295 2019-06-05 17:36:38 +02:00
of treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
opp treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
oprofile
parisc SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
parport Char/Misc driver fixes for 5.2-rc4 2019-06-08 12:50:36 -07:00
pci mm/devm_memremap_pages: fix final page put race 2019-06-13 17:34:56 -10:00
pcmcia treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 256 2019-06-05 17:30:27 +02:00
perf treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284 2019-06-05 17:36:37 +02:00
phy treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
pinctrl treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
platform platform/mellanox: mlxreg-hotplug: Add devm_free_irq call to remove flow 2019-06-12 11:49:20 +03:00
pnp treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 150 2019-05-30 11:25:19 -07:00
power treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 450 2019-06-05 17:37:18 +02:00
powercap treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 309 2019-06-05 17:37:04 +02:00
pps treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
ps3 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 167 2019-05-30 11:26:39 -07:00
ptp ptp: add QorIQ PTP support for DPAA2 2019-06-15 13:43:06 -07:00
pwm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372 2019-06-05 17:37:10 +02:00
rapidio treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
ras RAS/CEC: Convert the timer callback to a workqueue 2019-06-07 23:21:39 +02:00
regulator regulator: Fix for v5.2 2019-06-10 07:35:55 -10:00
remoteproc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
reset treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 422 2019-06-05 17:37:15 +02:00
rpmsg
rtc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
s390 s390/qeth: allocate a single cmd on read channel 2019-06-13 22:39:32 -07:00
sbus treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
scsi Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 20:20:36 -07:00
sfi treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
sh treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
siox treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
slimbus
sn treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
soc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 409 2019-06-05 17:37:14 +02:00
soundwire treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
spi spi: Fixes for v5.2 2019-06-10 07:19:56 -10:00
spmi treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284 2019-06-05 17:36:37 +02:00
ssb treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
staging Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
target Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 20:20:36 -07:00
tc treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
tee treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 282 2019-06-05 17:36:37 +02:00
thermal treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 422 2019-06-05 17:37:15 +02:00
thunderbolt treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
tty vt/fbcon: deinitialize resources in visual_init() after failed memory allocation 2019-05-24 17:08:18 +02:00
uio treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
usb usb: typec: Make sure an alt mode exist before getting its partner 2019-06-12 17:13:02 +02:00
uwb treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 268 2019-06-05 17:30:29 +02:00
vfio vfio/mdev: Synchronize device create/remove with parent removal 2019-06-06 12:32:37 -06:00
vhost vhost_net: disable zerocopy by default 2019-06-17 13:58:02 -07:00
video treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
virt treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
virtio virtio: Fix indentation of VIRTIO_MMIO 2019-05-27 11:08:22 -04:00
visorbus treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
vlynq treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 102 2019-05-24 17:39:00 +02:00
vme treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
w1 SPDX update for 5.2-rc4 2019-06-08 12:52:42 -07:00
watchdog treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 446 2019-06-05 17:37:18 +02:00
xen Merge branch 'stable/for-linus-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2019-06-11 15:38:34 -10:00
zorro treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
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