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.
David Hildenbrand
authored
Let's use folio_walk instead, so we can avoid taking a folio reference just to read the nid and get rid of another follow_page()/FOLL_DUMP user. Use FW_ZEROPAGE so we can return "-EFAULT" for it as documented. The possible return values for follow_page() were confusing, especially with FOLL_DUMP set. We'll handle it like documented in the man page: * -EFAULT: This is a zero page or the memory area is not mapped by the process. * -ENOENT: The page is not present. We'll keep setting -ENOENT for ZONE_DEVICE. Maybe not the right thing to do, but it likely doesn't really matter (just like for weird devmap, whereby we fake "not present"). Note that the other errors (-EACCESS, -EBUSY, -EIO, -EINVAL, -ENOMEM) so far only applied when actually moving pages, not when only querying stats. We'll effectively drop the "secretmem" check we had in follow_page(), but that shouldn't really matter here, we're not accessing folio/page content after all. Link: https://lkml.kernel.org/r/20240802155524.517137-4-david@redhat.com Signed-off-by:David Hildenbrand <david@redhat.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>