Commit b0e15190 authored by David Howells's avatar David Howells Committed by Linus Torvalds
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[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: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 642fb4d1
...@@ -654,9 +654,18 @@ static inline struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, ...@@ -654,9 +654,18 @@ static inline struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
} }
#endif #endif
struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags); 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 *); 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) static inline int can_do_mlock(void)
{ {
if (capable(CAP_IPC_LOCK)) if (capable(CAP_IPC_LOCK))
......
...@@ -105,7 +105,6 @@ config SWAP ...@@ -105,7 +105,6 @@ config SWAP
config SYSVIPC config SYSVIPC
bool "System V IPC" bool "System V IPC"
depends on MMU
---help--- ---help---
Inter Process Communication is a suite of library functions and Inter Process Communication is a suite of library functions and
system calls which let processes (running programs) synchronize and system calls which let processes (running programs) synchronize and
......
...@@ -157,14 +157,22 @@ static void shm_close (struct vm_area_struct *shmd) ...@@ -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) static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{ {
file_accessed(file); int ret;
vma->vm_ops = &shm_vm_ops;
shm_inc(file->f_dentry->d_inode->i_ino); ret = shmem_mmap(file, vma);
return 0; 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 = { 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 = { static struct vm_operations_struct shm_vm_ops = {
......
...@@ -1177,3 +1177,10 @@ int in_gate_area_no_task(unsigned long addr) ...@@ -1177,3 +1177,10 @@ int in_gate_area_no_task(unsigned long addr)
{ {
return 0; return 0;
} }
struct page *filemap_nopage(struct vm_area_struct *area,
unsigned long address, int *type)
{
BUG();
return NULL;
}
...@@ -1270,7 +1270,7 @@ out_nomem: ...@@ -1270,7 +1270,7 @@ out_nomem:
return retval; 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); file_accessed(file);
vma->vm_ops = &shmem_vm_ops; vma->vm_ops = &shmem_vm_ops;
......
...@@ -81,13 +81,19 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) ...@@ -81,13 +81,19 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
goto close_file; goto close_file;
d_instantiate(dentry, inode); d_instantiate(dentry, inode);
inode->i_size = size;
inode->i_nlink = 0; /* It is unlinked */ inode->i_nlink = 0; /* It is unlinked */
file->f_vfsmnt = mntget(shm_mnt); file->f_vfsmnt = mntget(shm_mnt);
file->f_dentry = dentry; file->f_dentry = dentry;
file->f_mapping = inode->i_mapping; file->f_mapping = inode->i_mapping;
file->f_op = &ramfs_file_operations; file->f_op = &ramfs_file_operations;
file->f_mode = FMODE_WRITE | FMODE_READ; 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; return file;
close_file: close_file:
...@@ -123,3 +129,24 @@ int shmem_unuse(swp_entry_t entry, struct page *page) ...@@ -123,3 +129,24 @@ int shmem_unuse(swp_entry_t entry, struct page *page)
{ {
return 0; 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
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