[PATCH] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU
The attached patch makes the SYSV IPC shared memory facilities use the new
ramfs facilities on a no-MMU kernel.
The following changes are made:
(1) There are now shmem_mmap() and shmem_get_unmapped_area() functions to
allow the IPC SHM facilities to commune with the tiny-shmem and shmem
code.
(2) ramfs files now need resizing using do_truncate() rather than by modifying
the inode size directly (see shmem_file_setup()). This causes ramfs to
attempt to bind a block of pages of sufficient size to the inode.
(3) CONFIG_SYSVIPC is no longer contingent on CONFIG_MMU.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/nommu.c b/mm/nommu.c
index c119681..c10262d 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1177,3 +1177,10 @@
{
return 0;
}
+
+struct page *filemap_nopage(struct vm_area_struct *area,
+ unsigned long address, int *type)
+{
+ BUG();
+ return NULL;
+}
diff --git a/mm/shmem.c b/mm/shmem.c
index 65c148e..a1f2f02 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1270,7 +1270,7 @@
return retval;
}
-static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &shmem_vm_ops;
diff --git a/mm/tiny-shmem.c b/mm/tiny-shmem.c
index b58abcf..cdc6d43 100644
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -81,13 +81,19 @@
goto close_file;
d_instantiate(dentry, inode);
- inode->i_size = size;
inode->i_nlink = 0; /* It is unlinked */
+
file->f_vfsmnt = mntget(shm_mnt);
file->f_dentry = dentry;
file->f_mapping = inode->i_mapping;
file->f_op = &ramfs_file_operations;
file->f_mode = FMODE_WRITE | FMODE_READ;
+
+ /* notify everyone as to the change of file size */
+ error = do_truncate(dentry, size, file);
+ if (error < 0)
+ goto close_file;
+
return file;
close_file:
@@ -123,3 +129,24 @@
{
return 0;
}
+
+int shmem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ file_accessed(file);
+#ifndef CONFIG_MMU
+ return ramfs_nommu_mmap(file, vma);
+#else
+ return 0;
+#endif
+}
+
+#ifndef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags)
+{
+ return ramfs_nommu_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif