Commit Graph

4 Commits

Author SHA1 Message Date
Christoph Hellwig f5e54d6e53 [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>
2006-06-28 14:59:04 -07:00
Arjan van de Ven 4b6f5d20b0 [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>
2006-03-28 09:16:06 -08:00
Nick Piggin 84097518d1 [PATCH] mm: nommu use compound pages
Now that compound page handling is properly fixed in the VM, move nommu
over to using compound pages rather than rolling their own refcounting.

nommu vm page refcounting is broken anyway, but there is no need to have
divergent code in the core VM now, nor when it gets fixed.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: David Howells <dhowells@redhat.com>

(Needs testing, please).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:54:01 -08:00
David Howells 642fb4d1f1 [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>
2006-01-06 08:33:32 -08:00