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Filename Latest commit message Latest commit date
Eric Pilmore a6b9e09403 ntb_netdev: Use dev_kfree_skb_any() in interrupt context
[ Upstream commit 5f7d78b2b12a9d561f48fa00bab29b40f4616dad ]

TX/RX callback handlers (ntb_netdev_tx_handler(),
ntb_netdev_rx_handler()) can be called in interrupt
context via the DMA framework when the respective
DMA operations have completed. As such, any calls
by these routines to free skb's, should use the
interrupt context safe dev_kfree_skb_any() function.

Previously, these callback handlers would call the
interrupt unsafe version of dev_kfree_skb(). This has
not presented an issue on Intel IOAT DMA engines as
that driver utilizes tasklets rather than a hard
interrupt handler, like the AMD PTDMA DMA driver.
On AMD systems, a kernel WARNING message is
encountered, which is being issued from
skb_release_head_state() due to in_hardirq()
being true.

Besides the user visible WARNING from the kernel,
the other symptom of this bug was that TCP/IP performance
across the ntb_netdev interface was very poor, i.e.
approximately an order of magnitude below what was
expected. With the repair to use dev_kfree_skb_any(),
kernel WARNINGs from skb_release_head_state() ceased
and TCP/IP performance, as measured by iperf, was on
par with expected results, approximately 20 Gb/s on
AMD Milan based server. Note that this performance
is comparable with Intel based servers.

Fixes: 765ccc7bc3 ("ntb_netdev: correct skb leak")
Fixes: 548c237c0a ("net: Add support for NTB virtual ethernet device")
Signed-off-by: Eric Pilmore <epilmore@gigaio.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/20221209000659.8318-1-epilmore@gigaio.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:41:16 +01:00
arch MIPS: OCTEON: warn only once if deprecated link status is being used 2023-01-18 11:40:58 +01:00
block block: unhash blkdev part inode when the part is deleted 2022-12-19 12:24:16 +01:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: akcipher - default implementation for setting a private key 2022-10-26 13:22:45 +02:00
Documentation ASoC: dt-bindings: wcd9335: fix reset line polarity in example 2023-01-18 11:41:06 +01:00
drivers ntb_netdev: Use dev_kfree_skb_any() in interrupt context 2023-01-18 11:41:16 +01:00
fs NFSv4.x: Fail client initialisation if state manager thread can't run 2023-01-18 11:41:10 +01:00
include bonding: Rename slave_arr to usable_slaves 2023-01-18 11:41:05 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel blktrace: Fix output non-blktrace event when blk_classic option enabled 2023-01-18 11:41:13 +01:00
lib lib/notifier-error-inject: fix error when writing -errno to debugfs file 2023-01-18 11:40:55 +01:00
LICENSES
mm mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page 2022-12-19 12:24:15 +01:00
net net/tunnel: wait until all sk_user_data reader finish before releasing the sock 2023-01-18 11:41:14 +01:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security ima: Fix misuse of dereference of pointer in template_desc_init_fields() 2023-01-18 11:41:03 +01:00
sound ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt 2023-01-18 11:41:09 +01:00
tools netfilter: conntrack: set icmpv6 redirects as RELATED 2023-01-18 11:41:08 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: add Chandan as xfs maintainer for 5.4.y 2022-09-28 11:03:58 +02:00
Makefile Linux 5.4.228 2022-12-19 12:24:17 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.