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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

include/linux/mm.h

+9 −0
Original line number Diff line number Diff line
@@ -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))

init/Kconfig

+0 −1
Original line number Diff line number Diff line
@@ -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

ipc/shm.c

+13 −5
Original line number Diff line number Diff line
@@ -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);

	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 0;

	}



	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 = {

mm/nommu.c

+7 −0
Original line number Diff line number Diff line
@@ -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;

}

mm/shmem.c

+1 −1
Original line number Diff line number Diff line
@@ -1270,7 +1270,7 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user) 
	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;