linux.git/mm/tiny-shmem.c, branch master

shmem: unify regular and tiny shmem

2009-01-06T23:59:08+00:00

tiny-shmem shares most of its 130 lines of code with shmem and tends to
break when particular bits of shmem get modified.  Unifying saves code and
makes keeping these two in sync much easier.

before:
  14367	    392	     24	  14783	   39bf	mm/shmem.o
    396      72       8     476	    1dc	mm/tiny-shmem.o

after:
  14367	    392	     24	  14783	   39bf	mm/shmem.o
    412	     72       8     492	    1ec	mm/shmem.o tiny

Signed-off-by: Matt Mackall 
Acked-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Export tiny shmem_file_setup for DRM-GEM

2008-10-20T23:17:42+00:00

We're trying to keep the !CONFIG_SHMEM tiny-shmem.c (using ramfs without
swap) in synch with CONFIG_SHMEM shmem.c (and mpm is preparing patches
to combine them).  I was glad to see EXPORT_SYMBOL_GPL(shmem_file_setup)
go into shmem.c, but why not support DRM-GEM when !CONFIG_SHMEM too?
But caution says still depend on MMU, since !CONFIG_MMU is.. different.

Signed-off-by: Hugh Dickins 
Acked-by: Matt Mackall 
Acked-by: Dave Airlie 
Signed-off-by: Linus Torvalds

mm: tiny-shmem nommu fix

2008-10-02T22:53:13+00:00

The previous patch db203d53d474aa068984e409d807628f5841da1b ("mm:
tiny-shmem fix lock ordering: mmap_sem vs i_mutex") to fix the lock
ordering in tiny-shmem breaks shared anonymous and IPC memory on NOMMU
architectures because it was using the expanding truncate to signal ramfs
to allocate a physically contiguous RAM backing the inode (otherwise it is
unusable for "memory mapping" it to userspace).

However do_truncate is what caused the lock ordering error, due to it
taking i_mutex.  In this case, we can actually just call ramfs directly to
allocate memory for the mapping, rather than go via truncate.

Acked-by: David Howells 
Acked-by: Hugh Dickins 
Signed-off-by: Nick Piggin 
Cc: Matt Mackall 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: tiny-shmem fix lock ordering: mmap_sem vs i_mutex

2008-09-23T15:09:14+00:00

tiny-shmem calls do_truncate in shmem_file_setup.  do_truncate takes
i_mutex, and shmem_file_setup is called with mmap_sem held.  However
i_mutex nests outside mmap_sem.

Copy the code in shmem.c to avoid this problem.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Nick Piggin 
Reported-and-tested-by: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Matt Mackall 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2008-03-25T15:57:47+00:00

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [PATCH] get stack footprint of pathname resolution back to relative sanity
  [PATCH] double iput() on failure exit in hugetlb
  [PATCH] double dput() on failure exit in tiny-shmem
  [PATCH] fix up new filp allocators
  [PATCH] check for null vfsmount in dentry_open()
  [PATCH] reiserfs: eliminate private use of struct file in xattr
  [PATCH] sanitize hppfs
  hppfs pass vfsmount to dentry_open()
  [PATCH] restore export of do_kern_mount()

mm/shmem and tiny-shmem: fix some kernel-doc

2008-03-20T01:53:35+00:00

Convert tiny-shmem.c function comments to kernel-doc.  Add parameters and
convert/fix other kernel-doc in shmem.c.

Signed-off-by: Randy Dunlap 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] double dput() on failure exit in tiny-shmem

2008-03-19T10:54:36+00:00

Signed-off-by: Al Viro

Remove unused code from mm/tiny-shmem.c

2008-02-05T17:44:17+00:00

This code in mm/tiny-shmem.c is under #if 0 - remove it.

Signed-off-by: Balbir Singh 
Acked-by: Matt Mackall 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

r/o bind mounts: filesystem helpers for custom 'struct file's

2007-10-17T15:43:04+00:00

Why do we need r/o bind mounts?

This feature allows a read-only view into a read-write filesystem.  In the
process of doing that, it also provides infrastructure for keeping track of
the number of writers to any given mount.

This has a number of uses.  It allows chroots to have parts of filesystems
writable.  It will be useful for containers in the future because users may
have root inside a container, but should not be allowed to write to
somefilesystems.  This also replaces patches that vserver has had out of the
tree for several years.

It allows security enhancement by making sure that parts of your filesystem
read-only (such as when you don't trust your FTP server), when you don't want
to have entire new filesystems mounted, or when you want atime selectively
updated.  I've been using the following script to test that the feature is
working as desired.  It takes a directory and makes a regular bind and a r/o
bind mount of it.  It then performs some normal filesystem operations on the
three directories, including ones that are expected to fail, like creating a
file on the r/o mount.

This patch:

Some filesystems forego the vfs and may_open() and create their own 'struct
file's.

This patch creates a couple of helper functions which can be used by these
filesystems, and will provide a unified place which the r/o bind mount code
may patch.

Also, rename an existing, static-scope init_file() to a less generic name.

Signed-off-by: Dave Hansen 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm/{,tiny-}shmem.c cleanups

2007-03-01T22:53:35+00:00

shmem_{nopage,mmap} are no longer used in ipc/shm.c

Signed-off-by: Adrian Bunk 
Cc: "Eric W. Biederman" 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds