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Mike Marciniszyn d103c131ef RDMA/core: Fix umem iterator when PAGE_SIZE is greater then HCA pgsz 
[ Upstream commit 4fbc3a52cd ]

64k pages introduce the situation in this diagram when the HCA 4k page
size is being used:

 +-------------------------------------------+ <--- 64k aligned VA
 |                                           |
 |              HCA 4k page                  |
 |                                           |
 +-------------------------------------------+
 |                   o                       |
 |                                           |
 |                   o                       |
 |                                           |
 |                   o                       |
 +-------------------------------------------+
 |                                           |
 |              HCA 4k page                  |
 |                                           |
 +-------------------------------------------+ <--- Live HCA page
 |OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO| <--- offset
 |                                           | <--- VA
 |                MR data                    |
 +-------------------------------------------+
 |                                           |
 |              HCA 4k page                  |
 |                                           |
 +-------------------------------------------+
 |                   o                       |
 |                                           |
 |                   o                       |
 |                                           |
 |                   o                       |
 +-------------------------------------------+
 |                                           |
 |              HCA 4k page                  |
 |                                           |
 +-------------------------------------------+

The VA addresses are coming from rdma-core in this diagram can be
arbitrary, but for 64k pages, the VA may be offset by some number of HCA
4k pages and followed by some number of HCA 4k pages.

The current iterator doesn't account for either the preceding 4k pages or
the following 4k pages.

Fix the issue by extending the ib_block_iter to contain the number of DMA
pages like comment [1] says and by using __sg_advance to start the
iterator at the first live HCA page.

The changes are contained in a parallel set of iterator start and next
functions that are umem aware and specific to umem since there is one user
of the rdma_for_each_block() without umem.

These two fixes prevents the extra pages before and after the user MR
data.

Fix the preceding pages by using the __sq_advance field to start at the
first 4k page containing MR data.

Fix the following pages by saving the number of pgsz blocks in the
iterator state and downcounting on each next.

This fix allows for the elimination of the small page crutch noted in the
Fixes.

Fixes: 10c75ccb54 ("RDMA/umem: Prevent small pages from being returned by ib_umem_find_best_pgsz()")
Link: https://lore.kernel.org/r/20231129202143.1434-2-shiraz.saleem@intel.com
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-12-13 18:45:16 +01:00
arch ARM: dts: bcm2711-rpi-400: Fix delete-node of led_act 2023-12-13 18:45:14 +01:00
block block: update the stable_writes flag in bdev_add 2023-12-03 07:33:03 +01:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 17:19:42 +00:00
Documentation tee: optee: Fix supplicant based device enumeration 2023-12-13 18:45:11 +01:00
drivers RDMA/core: Fix umem iterator when PAGE_SIZE is greater then HCA pgsz 2023-12-13 18:45:16 +01:00
fs btrfs: fix 64bit compat send ioctl arguments not initializing version member 2023-12-08 08:52:20 +01:00
include RDMA/core: Fix umem iterator when PAGE_SIZE is greater then HCA pgsz 2023-12-13 18:45:16 +01:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-11-28 17:19:57 +00:00
io_uring io_uring/kbuf: recycle freed mapped buffer ring entries 2023-12-08 08:52:21 +01:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel bpf: Fix a verifier bug due to incorrect branch offset comparison with cpu=v4 2023-12-13 18:45:04 +01:00
lib zstd: Fix array-index-out-of-bounds UBSAN warning 2023-12-13 18:44:58 +01:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/damon/sysfs: eliminate potential uninitialized variable warning 2023-12-13 18:45:11 +01:00
net net/smc: fix missing byte order conversion in CLC handshake 2023-12-13 18:45:11 +01:00
rust rust: docs: fix logo replacement 2023-10-19 16:40:00 +02:00
samples samples/bpf: syscall_tp_user: Fix array out-of-bound access 2023-11-28 17:19:48 +00:00
scripts dt: dt-extract-compatibles: Don't follow symlinks when walking tree 2023-12-13 18:45:03 +01:00
security apparmor: Fix regression in mount mediation 2023-11-28 17:20:07 +00:00
sound ASoC: wm_adsp: fix memleak in wm_adsp_buffer_populate 2023-12-13 18:45:16 +01:00
tools selftests/net: mptcp: fix uninitialized variable warnings 2023-12-08 08:52:22 +01:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
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 Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.6 2023-12-11 10:40:17 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.