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Horatiu Vultur 4a4b6848d1 net: lan966x: Stop replacing tx dcbs and dcbs_buf when changing MTU
When a frame is sent using FDMA, the skb is mapped and then the mapped
address is given to an tx dcb that is different than the last used tx
dcb. Once the HW finish with this frame, it would generate an interrupt
and then the dcb can be reused and memory can be freed. For each dcb
there is an dcb buf that contains some meta-data(is used by PTP, is
it free). There is 1 to 1 relationship between dcb and dcb_buf.
The following issue was observed. That sometimes after changing the MTU
to allocate new tx dcbs and dcbs_buf, two frames were not
transmitted. The frames were not transmitted because when reloading the
tx dcbs, it was always presuming to use the first dcb but that was not
always happening. Because it could be that the last tx dcb used before
changing MTU was first dcb and then when it tried to get the next dcb it
would take dcb 1 instead of 0. Because it is supposed to take a
different dcb than the last used one. This can be fixed simply by
changing tx->last_in_use to -1 when the fdma is disabled to reload the
new dcb and dcbs_buff.
But there could be a different issue. For example, right after the frame
is sent, the MTU is changed. Now all the dcbs and dcbs_buf will be
cleared. And now get the interrupt from HW that it finished with the
frame. So when we try to clear the skb, it is not possible because we
lost all the dcbs_buf.
The solution here is to stop replacing the tx dcbs and dcbs_buf when
changing MTU because the TX doesn't care what is the MTU size, it is
only the RX that needs this information.

Fixes: 2ea1cbac26 ("net: lan966x: Update FDMA to change MTU.")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Link: https://lore.kernel.org/r/20221021090711.3749009-1-horatiu.vultur@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-10-24 21:04:51 -07:00
arch Including fixes from bpf. 2022-10-24 12:43:51 -07:00
block block-6.1-2022-10-20 2022-10-21 15:14:14 -07:00
certs certs: make system keyring depend on built-in x509 parser 2022-09-24 04:31:18 +09:00
crypto treewide: use get_random_bytes() when possible 2022-10-11 17:42:58 -06:00
Documentation Including fixes from bpf. 2022-10-24 12:43:51 -07:00
drivers net: lan966x: Stop replacing tx dcbs and dcbs_buf when changing MTU 2022-10-24 21:04:51 -07:00
fs First batch of EFI fixes for v6.1 2022-10-21 18:02:36 -07:00
include genetlink: piggy back on resv_op to default to a reject policy 2022-10-24 19:08:46 -07:00
init init: Kconfig: fix spelling mistake "satify" -> "satisfy" 2022-10-20 21:27:22 -07:00
io_uring io_uring/net: fail zc sendmsg when unsupported by socket 2022-10-22 08:43:03 -06:00
ipc - hfs and hfsplus kmap API modernization from Fabio Francesco 2022-10-12 11:00:22 -07:00
kernel Including fixes from bpf. 2022-10-24 12:43:51 -07:00
lib kunit: update NULL vs IS_ERR() tests 2022-10-18 15:08:42 -06:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm/huge_memory: do not clobber swp_entry_t during THP split 2022-10-20 21:27:24 -07:00
net genetlink: piggy back on resv_op to default to a reject policy 2022-10-24 19:08:46 -07:00
rust Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
samples VFIO updates for v6.1-rc1 2022-10-12 14:46:48 -07:00
scripts Kbuild fixes for v6.1 2022-10-16 11:12:22 -07:00
security selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context() 2022-10-19 09:55:53 -04:00
sound sound fixes for 6.1-rc1 2022-10-14 13:22:14 -07:00
tools Including fixes from bpf. 2022-10-24 12:43:51 -07:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm: Add support for arch compat vm ioctls 2022-10-22 05:15:23 -04:00
.clang-format PCI/DOE: Add DOE mailbox support functions 2022-07-19 15:38:04 -07:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
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COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS drm for 5.20/6.0 2022-08-03 19:52:08 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Including fixes from bpf. 2022-10-24 12:43:51 -07:00
Makefile Linux 6.1-rc2 2022-10-23 15:27:33 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.