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Linux kernel source tree
99bda20d6d
mmap() calls on the DRM file pointer currently always end up using mm_get_unmapped_area() to get a free mapping region. On builds with CONFIG_TRANSPARENT_HUGEPAGE enabled, this isn't ideal for GEM objects backed by shmem buffers on mountpoints setting the 'huge=' option because it can't correctly figure out the potentially huge address alignment required. This commit introduces the drm_gem_get_unmapped_area() function which is meant to be used as a get_unmapped_area file operation on the DRM file pointer to lookup GEM objects based on their fake offsets and get a properly aligned region by calling shmem_get_unmapped_area() with the right file pointer. If a GEM object isn't available at the given offset or if the caller isn't granted access to it, the function falls back to mm_get_unmapped_area(). This also makes drm_gem_get_unmapped_area() part of the default GEM file operations so that all the DRM drivers can benefit from more efficient mappings thanks to the huge page fault handler introduced in previous commit 'drm/shmem-helper: Add huge page fault handler'. The shmem_get_unmapped_area() function needs to be exported so that it can be used from the DRM subsystem. v3: - include <linux/sched/mm.h> in drm_gem.c - forward to shmem layer in builds with CONFIG_TRANSPARENT_HUGEPAGE=n v6: - use GPL variant to export drm_gem_get_unmapped_area() - don't export shmem_get_unmapped_area() anymore (use f_op instead) v11: - rename drm_gem_object_lookup_from_offset() to drm_gem_object_lookup_at_offset() - add Boris R-b Signed-off-by: Loïc Molinari <loic.molinari@collabora.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> Link: https://patch.msgid.link/20251205182231.194072-4-loic.molinari@collabora.com Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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.