treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ramfs: move ramfs_aops to inode.c

ramfs_aops is identical in file-mmu.c and file-nommu.c. Thus move it to
fs/ramfs/inode.c and make it static.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ramfs/ extern cleanup

- internal.h shouldn't duplicate the extern declaration for
ramfs_file_operations already in include/linux/ramfs.h
- file-mmu.c needs two #include's for seeing the extern declarations
of it's global struct's

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] mark struct inode_operations const 3

Many struct inode_operations in the kernel can be "const". Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data. In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] mark address_space_operations const

Same as with already do with the file operations: keep them in .rodata and
prevents people from doing runtime patching.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] Make most file operations structs in fs/ const

This is a conversion to make the various file_operations structs in fs/
const. Basically a regexp job, with a few manual fixups

The goal is both to increase correctness (harder to accidentally write to
shared datastructures) and reducing the false sharing of cachelines with
things that get dirty in .data (while .rodata is nicely read only and thus
cache clean)

Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] NOMMU: Provide shared-writable mmap support on ramfs

The attached patch makes ramfs support shared-writable mmaps by:

(1) Attempting to perform a contiguous block allocation to the requested size
when truncate attempts to increase the file from zero size, such as
happens when:

fd = shm_open("/file/on/ramfs", ...):
ftruncate(fd, size_requested);
addr = mmap(NULL, subsize, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_SHARED,
fd, offset);

(2) Permitting any shared-writable mapping over any contiguous set of extant
pages. get_unmapped_area() will return the address into the actual ramfs
pages. The mapping may start anywhere and be of any size, but may not go
over the end of file. Multiple mappings may overlap in any way.

(3) Not permitting a file to be shrunk if it would truncate any shared
mappings (private mappings are copied).

Thus this patch provides support for POSIX shared memory on NOMMU kernels,
with certain limitations such as there being a large enough block of pages
available to support the allocation and it only working on directly mappable
filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>