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Krzysztof Karas 2e0438f9c3 drm/i915: ensure segment offset never exceeds allowed max Commit `255fc1703e` ("drm/i915/gem: Calculate object page offset for partial memory mapping") introduced a new offset, which accounts for userspace mapping not starting from the beginning of object's scatterlist. This works fine for cases where first object pte is larger than the new offset - "r->sgt.curr" counter is set to the offset to match the difference in the number of total pages. However, if object's first pte's size is equal to or smaller than the offset, then information about the offset in userspace is covered up by moving "r->sgt" pointer in remap_sg(): r->sgt.curr += PAGE_SIZE; if (r->sgt.curr >= r->sgt.max) r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase)); This means that two or more pages from virtual memory are counted for only one page in object's memory, because after moving "r->sgt" pointer "r->sgt.curr" will be 0. We should account for this mismatch by moving "r->sgt" pointer to the next pte. For that we may use "r.sgt.max", which already holds the max allowed size. This change also eliminates possible confusion, when looking at i915_scatterlist.h and remap_io_sg() code: former has scatterlist pointer definition, which differentiates "s.max" value based on "dma" flag (sg_dma_len() is used only when the flag is enabled), while latter uses sg_dma_len() indiscriminately. This patch aims to resolve issue: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12031 v3: - instead of checking if r.sgt.curr would exceed allowed max, changed the value in the while loop to be aligned with `dma` value v4: - remove unnecessary parent relation v5: - update commit message with explanation about page counting mismatch and link to the issue Signed-off-by: Krzysztof Karas <krzysztof.karas@intel.com> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/upbjdavlbcxku63ns4vstp5kgbn2anxwewpmnppszgb67fn66t@tfclfgkqijue		2024-12-05 14:29:48 +01:00
arch	Linux 6.9-rc6	2024-04-29 20:22:39 +02:00
block	vfs-6.9-rc6.fixes	2024-04-26 11:01:28 -07:00
certs	This update includes the following changes:	2023-11-02 16:15:30 -10:00
crypto	This push fixes a regression that broke iwd as well as a divide by	2024-03-25 10:48:23 -07:00
Documentation	drm/i915/hwmon: expose fan speed	2024-08-28 12:06:07 +05:30
drivers	drm/i915: ensure segment offset never exceeds allowed max	2024-12-05 14:29:48 +01:00
fs	three smb3 client fixes, all also for stable	2024-04-27 11:35:40 -07:00
include	drm/i915: Support replaying GPU hangs with captured context image	2024-05-16 07:37:05 +00:00
init	Rust fixes for v6.9	2024-04-27 12:11:55 -07:00
io_uring	io_uring/net: restore msg_control on sendzc retry	2024-04-08 21:48:41 -06:00
ipc	sysctl changes for v6.9-rc1	2024-03-18 14:59:13 -07:00
kernel	Misc fixes:	2024-04-28 12:11:26 -07:00
lib	11 hotfixes. 8 are cc:stable and the remaining 3 (nice ratio!) address	2024-04-26 13:48:03 -07:00
LICENSES	LICENSES: Add the copyleft-next-0.3.1 license	2022-11-08 15:44:01 +01:00
mm	mm/hugetlb: fix DEBUG_LOCKS_WARN_ON(1) when dissolve_free_hugetlb_folio()	2024-04-25 10:07:27 -07:00
net	Including fixes from netfilter, wireless and bluetooth.	2024-04-25 11:19:38 -07:00
rust	rust: remove `params` from `module` macro example	2024-04-25 17:34:33 +02:00
samples	Tracing updates for 6.9:	2024-03-18 15:11:44 -07:00
scripts	Rust fixes for v6.9	2024-04-27 12:11:55 -07:00
security	security: Place security_path_post_mknod() where the original IMA call was	2024-04-03 10:21:32 -07:00
sound	ALSA: seq: ump: Fix conversion from MIDI2 to MIDI1 UMP messages	2024-04-19 12:07:14 +02:00
tools	RISC-V Fixes for 6.9-rc6	2024-04-27 12:02:55 -07:00
usr	Kbuild updates for v6.8	2024-01-18 17:57:07 -08:00
virt	KVM: Drop unused @may_block param from gfn_to_pfn_cache_invalidate_start()	2024-04-11 12:58:53 -07:00
.clang-format	clang-format: Update with v6.7-rc4's `for_each` macro list	2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig	Add .editorconfig file for basic formatting	2023-12-28 16:22:47 +09:00
.get_maintainer.ignore	Add Jeff Kirsher to .get_maintainer.ignore	2024-03-08 11:36:54 +00:00
.gitattributes	.gitattributes: set diff driver for Rust source code files	2023-05-31 17:48:25 +02:00
.gitignore	kbuild: create a list of all built DTB files	2024-02-19 18:20:39 +09:00
.mailmap	Including fixes from netfilter, wireless and bluetooth.	2024-04-25 11:19:38 -07:00
.rustfmt.toml	rust: add `.rustfmt.toml`	2022-09-28 09:02:20 +02:00
COPYING
CREDITS	MAINTAINERS: Drop Gustavo Pimentel as PCI DWC Maintainer	2024-03-27 13:41:02 -05:00
Kbuild	Kbuild updates for v6.1	2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS	Merge tag 'drm-msm-next-2024-05-07' of https://gitlab.freedesktop.org/drm/msm into drm-next	2024-05-10 10:22:59 +10:00
Makefile	Linux 6.9-rc6	2024-04-28 13:47:24 -07:00
README	README: Fix spelling	2024-03-18 03:36:32 -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 reStructuredText 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.