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authorDavid Howells <dhowells@redhat.com>2006-01-06 00:11:42 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-06 08:33:32 -0800
commitb0e15190ead07056ab0c3844a499ff35e66d27cc (patch)
tree0601a8d68fa051a7ee85d22640e982c0a64f0efc
parent642fb4d1f1dd2417aa69189fe5ceb81e4fb72900 (diff)
downloadlinux-b0e15190ead07056ab0c3844a499ff35e66d27cc.tar.bz2
[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>
-rw-r--r--include/linux/mm.h9
-rw-r--r--init/Kconfig1
-rw-r--r--ipc/shm.c18
-rw-r--r--mm/nommu.c7
-rw-r--r--mm/shmem.c2
-rw-r--r--mm/tiny-shmem.c29
6 files changed, 58 insertions, 8 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 75ec04e2f184..26f3094911a5 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -654,9 +654,18 @@ static inline struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
}
#endif
struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags);
+extern int shmem_mmap(struct file *file, struct vm_area_struct *vma);
int shmem_zero_setup(struct vm_area_struct *);
+#ifndef CONFIG_MMU
+extern unsigned long shmem_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags);
+#endif
+
static inline int can_do_mlock(void)
{
if (capable(CAP_IPC_LOCK))
diff --git a/init/Kconfig b/init/Kconfig
index ce737e02c5a2..24e0f7c756c0 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -105,7 +105,6 @@ config SWAP
config SYSVIPC
bool "System V IPC"
- depends on MMU
---help---
Inter Process Communication is a suite of library functions and
system calls which let processes (running programs) synchronize and
diff --git a/ipc/shm.c b/ipc/shm.c
index 587d836d80d9..0ef4a1cf3e27 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -157,14 +157,22 @@ static void shm_close (struct vm_area_struct *shmd)
static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
- file_accessed(file);
- vma->vm_ops = &shm_vm_ops;
- shm_inc(file->f_dentry->d_inode->i_ino);
- return 0;
+ int ret;
+
+ ret = shmem_mmap(file, vma);
+ if (ret == 0) {
+ vma->vm_ops = &shm_vm_ops;
+ shm_inc(file->f_dentry->d_inode->i_ino);
+ }
+
+ return ret;
}
static struct file_operations shm_file_operations = {
- .mmap = shm_mmap
+ .mmap = shm_mmap,
+#ifndef CONFIG_MMU
+ .get_unmapped_area = shmem_get_unmapped_area,
+#endif
};
static struct vm_operations_struct shm_vm_ops = {
diff --git a/mm/nommu.c b/mm/nommu.c
index c1196812876b..c10262d68232 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1177,3 +1177,10 @@ int in_gate_area_no_task(unsigned long addr)
{
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 65c148efa2ed..a1f2f02af724 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1270,7 +1270,7 @@ out_nomem:
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 b58abcf44ed6..cdc6d431972b 100644
--- a/mm/tiny-shmem.c
+++ b/mm/tiny-shmem.c
@@ -81,13 +81,19 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
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 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
{
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