From b0e15190ead07056ab0c3844a499ff35e66d27cc Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 6 Jan 2006 00:11:42 -0800 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 9 +++++++++ init/Kconfig | 1 - ipc/shm.c | 18 +++++++++++++----- mm/nommu.c | 7 +++++++ mm/shmem.c | 2 +- mm/tiny-shmem.c | 29 ++++++++++++++++++++++++++++- 6 files changed, 58 insertions(+), 8 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 75ec04e..26f3094 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 ce737e0..24e0f7c7 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 587d836..0ef4a1c 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 c119681..c10262d 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 65c148e..a1f2f02 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 b58abcf..cdc6d43 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 -- cgit v1.1