David Hildenbrand
46d6a9b445
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>
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.