3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
21 * Pavel Emelianov <xemul@openvz.org>
24 #include <linux/slab.h>
26 #include <linux/hugetlb.h>
27 #include <linux/shm.h>
28 #include <linux/init.h>
29 #include <linux/file.h>
30 #include <linux/mman.h>
31 #include <linux/shmem_fs.h>
32 #include <linux/security.h>
33 #include <linux/syscalls.h>
34 #include <linux/audit.h>
35 #include <linux/capability.h>
36 #include <linux/ptrace.h>
37 #include <linux/seq_file.h>
38 #include <linux/rwsem.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41 #include <linux/ipc_namespace.h>
42 #include <linux/ima.h>
44 #include <asm/uaccess.h>
48 struct shm_file_data {
50 struct ipc_namespace *ns;
52 const struct vm_operations_struct *vm_ops;
55 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
57 static const struct file_operations shm_file_operations;
58 static const struct vm_operations_struct shm_vm_ops;
60 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
62 #define shm_unlock(shp) \
63 ipc_unlock(&(shp)->shm_perm)
65 static int newseg(struct ipc_namespace *, struct ipc_params *);
66 static void shm_open(struct vm_area_struct *vma);
67 static void shm_close(struct vm_area_struct *vma);
68 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
70 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
73 void shm_init_ns(struct ipc_namespace *ns)
75 ns->shm_ctlmax = SHMMAX;
76 ns->shm_ctlall = SHMALL;
77 ns->shm_ctlmni = SHMMNI;
79 ipc_init_ids(&shm_ids(ns));
83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
88 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
101 void shm_exit_ns(struct ipc_namespace *ns)
103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
108 void __init shm_init (void)
110 shm_init_ns(&init_ipc_ns);
111 ipc_init_proc_interface("sysvipc/shm",
112 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
113 IPC_SHM_IDS, sysvipc_shm_proc_show);
117 * shm_lock_(check_) routines are called in the paths where the rw_mutex
118 * is not necessarily held.
120 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
122 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
125 return (struct shmid_kernel *)ipcp;
127 return container_of(ipcp, struct shmid_kernel, shm_perm);
130 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
133 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
136 return (struct shmid_kernel *)ipcp;
138 return container_of(ipcp, struct shmid_kernel, shm_perm);
141 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
143 ipc_rmid(&shm_ids(ns), &s->shm_perm);
147 /* This is called by fork, once for every shm attach. */
148 static void shm_open(struct vm_area_struct *vma)
150 struct file *file = vma->vm_file;
151 struct shm_file_data *sfd = shm_file_data(file);
152 struct shmid_kernel *shp;
154 shp = shm_lock(sfd->ns, sfd->id);
156 shp->shm_atim = get_seconds();
157 shp->shm_lprid = task_tgid_vnr(current);
163 * shm_destroy - free the struct shmid_kernel
166 * @shp: struct to free
168 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
169 * but returns with shp unlocked and freed.
171 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
173 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
176 if (!is_file_hugepages(shp->shm_file))
177 shmem_lock(shp->shm_file, 0, shp->mlock_user);
178 else if (shp->mlock_user)
179 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
181 fput (shp->shm_file);
182 security_shm_free(shp);
187 * remove the attach descriptor vma.
188 * free memory for segment if it is marked destroyed.
189 * The descriptor has already been removed from the current->mm->mmap list
190 * and will later be kfree()d.
192 static void shm_close(struct vm_area_struct *vma)
194 struct file * file = vma->vm_file;
195 struct shm_file_data *sfd = shm_file_data(file);
196 struct shmid_kernel *shp;
197 struct ipc_namespace *ns = sfd->ns;
199 down_write(&shm_ids(ns).rw_mutex);
200 /* remove from the list of attaches of the shm segment */
201 shp = shm_lock(ns, sfd->id);
203 shp->shm_lprid = task_tgid_vnr(current);
204 shp->shm_dtim = get_seconds();
206 if(shp->shm_nattch == 0 &&
207 shp->shm_perm.mode & SHM_DEST)
208 shm_destroy(ns, shp);
211 up_write(&shm_ids(ns).rw_mutex);
214 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
216 struct file *file = vma->vm_file;
217 struct shm_file_data *sfd = shm_file_data(file);
219 return sfd->vm_ops->fault(vma, vmf);
223 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
225 struct file *file = vma->vm_file;
226 struct shm_file_data *sfd = shm_file_data(file);
228 if (sfd->vm_ops->set_policy)
229 err = sfd->vm_ops->set_policy(vma, new);
233 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
236 struct file *file = vma->vm_file;
237 struct shm_file_data *sfd = shm_file_data(file);
238 struct mempolicy *pol = NULL;
240 if (sfd->vm_ops->get_policy)
241 pol = sfd->vm_ops->get_policy(vma, addr);
242 else if (vma->vm_policy)
243 pol = vma->vm_policy;
249 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
251 struct shm_file_data *sfd = shm_file_data(file);
254 ret = sfd->file->f_op->mmap(sfd->file, vma);
257 sfd->vm_ops = vma->vm_ops;
259 BUG_ON(!sfd->vm_ops->fault);
261 vma->vm_ops = &shm_vm_ops;
267 static int shm_release(struct inode *ino, struct file *file)
269 struct shm_file_data *sfd = shm_file_data(file);
272 shm_file_data(file) = NULL;
277 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
279 int (*fsync) (struct file *, struct dentry *, int datasync);
280 struct shm_file_data *sfd = shm_file_data(file);
283 fsync = sfd->file->f_op->fsync;
285 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
289 static unsigned long shm_get_unmapped_area(struct file *file,
290 unsigned long addr, unsigned long len, unsigned long pgoff,
293 struct shm_file_data *sfd = shm_file_data(file);
294 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
298 static const struct file_operations shm_file_operations = {
301 .release = shm_release,
304 static const struct file_operations shm_file_operations_huge = {
307 .release = shm_release,
308 .get_unmapped_area = shm_get_unmapped_area,
311 int is_file_shm_hugepages(struct file *file)
313 return file->f_op == &shm_file_operations_huge;
316 static const struct vm_operations_struct shm_vm_ops = {
317 .open = shm_open, /* callback for a new vm-area open */
318 .close = shm_close, /* callback for when the vm-area is released */
320 #if defined(CONFIG_NUMA)
321 .set_policy = shm_set_policy,
322 .get_policy = shm_get_policy,
327 * newseg - Create a new shared memory segment
329 * @params: ptr to the structure that contains key, size and shmflg
331 * Called with shm_ids.rw_mutex held as a writer.
334 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
336 key_t key = params->key;
337 int shmflg = params->flg;
338 size_t size = params->u.size;
340 struct shmid_kernel *shp;
341 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
347 if (size < SHMMIN || size > ns->shm_ctlmax)
350 if (ns->shm_tot + numpages > ns->shm_ctlall)
353 shp = ipc_rcu_alloc(sizeof(*shp));
357 shp->shm_perm.key = key;
358 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
359 shp->mlock_user = NULL;
361 shp->shm_perm.security = NULL;
362 error = security_shm_alloc(shp);
368 sprintf (name, "SYSV%08x", key);
369 if (shmflg & SHM_HUGETLB) {
370 /* hugetlb_file_setup applies strict accounting */
371 if (shmflg & SHM_NORESERVE)
372 acctflag = VM_NORESERVE;
373 file = hugetlb_file_setup(name, size, acctflag,
374 &shp->mlock_user, HUGETLB_SHMFS_INODE);
377 * Do not allow no accounting for OVERCOMMIT_NEVER, even
380 if ((shmflg & SHM_NORESERVE) &&
381 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
382 acctflag = VM_NORESERVE;
383 file = shmem_file_setup(name, size, acctflag);
385 error = PTR_ERR(file);
389 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
395 shp->shm_cprid = task_tgid_vnr(current);
397 shp->shm_atim = shp->shm_dtim = 0;
398 shp->shm_ctim = get_seconds();
399 shp->shm_segsz = size;
401 shp->shm_file = file;
403 * shmid gets reported as "inode#" in /proc/pid/maps.
404 * proc-ps tools use this. Changing this will break them.
406 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
408 ns->shm_tot += numpages;
409 error = shp->shm_perm.id;
414 if (is_file_hugepages(file) && shp->mlock_user)
415 user_shm_unlock(size, shp->mlock_user);
418 security_shm_free(shp);
424 * Called with shm_ids.rw_mutex and ipcp locked.
426 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
428 struct shmid_kernel *shp;
430 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
431 return security_shm_associate(shp, shmflg);
435 * Called with shm_ids.rw_mutex and ipcp locked.
437 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
438 struct ipc_params *params)
440 struct shmid_kernel *shp;
442 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
443 if (shp->shm_segsz < params->u.size)
449 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
451 struct ipc_namespace *ns;
452 struct ipc_ops shm_ops;
453 struct ipc_params shm_params;
455 ns = current->nsproxy->ipc_ns;
457 shm_ops.getnew = newseg;
458 shm_ops.associate = shm_security;
459 shm_ops.more_checks = shm_more_checks;
461 shm_params.key = key;
462 shm_params.flg = shmflg;
463 shm_params.u.size = size;
465 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
468 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
472 return copy_to_user(buf, in, sizeof(*in));
477 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
478 out.shm_segsz = in->shm_segsz;
479 out.shm_atime = in->shm_atime;
480 out.shm_dtime = in->shm_dtime;
481 out.shm_ctime = in->shm_ctime;
482 out.shm_cpid = in->shm_cpid;
483 out.shm_lpid = in->shm_lpid;
484 out.shm_nattch = in->shm_nattch;
486 return copy_to_user(buf, &out, sizeof(out));
493 static inline unsigned long
494 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
498 if (copy_from_user(out, buf, sizeof(*out)))
503 struct shmid_ds tbuf_old;
505 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
508 out->shm_perm.uid = tbuf_old.shm_perm.uid;
509 out->shm_perm.gid = tbuf_old.shm_perm.gid;
510 out->shm_perm.mode = tbuf_old.shm_perm.mode;
519 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
523 return copy_to_user(buf, in, sizeof(*in));
528 if(in->shmmax > INT_MAX)
529 out.shmmax = INT_MAX;
531 out.shmmax = (int)in->shmmax;
533 out.shmmin = in->shmmin;
534 out.shmmni = in->shmmni;
535 out.shmseg = in->shmseg;
536 out.shmall = in->shmall;
538 return copy_to_user(buf, &out, sizeof(out));
546 * Called with shm_ids.rw_mutex held as a reader
548 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
557 in_use = shm_ids(ns).in_use;
559 for (total = 0, next_id = 0; total < in_use; next_id++) {
560 struct kern_ipc_perm *ipc;
561 struct shmid_kernel *shp;
564 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
567 shp = container_of(ipc, struct shmid_kernel, shm_perm);
569 inode = shp->shm_file->f_path.dentry->d_inode;
571 if (is_file_hugepages(shp->shm_file)) {
572 struct address_space *mapping = inode->i_mapping;
573 struct hstate *h = hstate_file(shp->shm_file);
574 *rss += pages_per_huge_page(h) * mapping->nrpages;
577 struct shmem_inode_info *info = SHMEM_I(inode);
578 spin_lock(&info->lock);
579 *rss += inode->i_mapping->nrpages;
580 *swp += info->swapped;
581 spin_unlock(&info->lock);
583 *rss += inode->i_mapping->nrpages;
592 * This function handles some shmctl commands which require the rw_mutex
593 * to be held in write mode.
594 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
596 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
597 struct shmid_ds __user *buf, int version)
599 struct kern_ipc_perm *ipcp;
600 struct shmid64_ds shmid64;
601 struct shmid_kernel *shp;
604 if (cmd == IPC_SET) {
605 if (copy_shmid_from_user(&shmid64, buf, version))
609 ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
611 return PTR_ERR(ipcp);
613 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
615 err = security_shm_shmctl(shp, cmd);
620 do_shm_rmid(ns, ipcp);
623 ipc_update_perm(&shmid64.shm_perm, ipcp);
624 shp->shm_ctim = get_seconds();
632 up_write(&shm_ids(ns).rw_mutex);
636 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
638 struct shmid_kernel *shp;
640 struct ipc_namespace *ns;
642 if (cmd < 0 || shmid < 0) {
647 version = ipc_parse_version(&cmd);
648 ns = current->nsproxy->ipc_ns;
650 switch (cmd) { /* replace with proc interface ? */
653 struct shminfo64 shminfo;
655 err = security_shm_shmctl(NULL, cmd);
659 memset(&shminfo, 0, sizeof(shminfo));
660 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
661 shminfo.shmmax = ns->shm_ctlmax;
662 shminfo.shmall = ns->shm_ctlall;
664 shminfo.shmmin = SHMMIN;
665 if(copy_shminfo_to_user (buf, &shminfo, version))
668 down_read(&shm_ids(ns).rw_mutex);
669 err = ipc_get_maxid(&shm_ids(ns));
670 up_read(&shm_ids(ns).rw_mutex);
678 struct shm_info shm_info;
680 err = security_shm_shmctl(NULL, cmd);
684 memset(&shm_info, 0, sizeof(shm_info));
685 down_read(&shm_ids(ns).rw_mutex);
686 shm_info.used_ids = shm_ids(ns).in_use;
687 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
688 shm_info.shm_tot = ns->shm_tot;
689 shm_info.swap_attempts = 0;
690 shm_info.swap_successes = 0;
691 err = ipc_get_maxid(&shm_ids(ns));
692 up_read(&shm_ids(ns).rw_mutex);
693 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
698 err = err < 0 ? 0 : err;
704 struct shmid64_ds tbuf;
707 if (cmd == SHM_STAT) {
708 shp = shm_lock(ns, shmid);
713 result = shp->shm_perm.id;
715 shp = shm_lock_check(ns, shmid);
723 if (ipcperms (&shp->shm_perm, S_IRUGO))
725 err = security_shm_shmctl(shp, cmd);
728 memset(&tbuf, 0, sizeof(tbuf));
729 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
730 tbuf.shm_segsz = shp->shm_segsz;
731 tbuf.shm_atime = shp->shm_atim;
732 tbuf.shm_dtime = shp->shm_dtim;
733 tbuf.shm_ctime = shp->shm_ctim;
734 tbuf.shm_cpid = shp->shm_cprid;
735 tbuf.shm_lpid = shp->shm_lprid;
736 tbuf.shm_nattch = shp->shm_nattch;
738 if(copy_shmid_to_user (buf, &tbuf, version))
747 struct file *uninitialized_var(shm_file);
749 lru_add_drain_all(); /* drain pagevecs to lru lists */
751 shp = shm_lock_check(ns, shmid);
757 audit_ipc_obj(&(shp->shm_perm));
759 if (!capable(CAP_IPC_LOCK)) {
760 uid_t euid = current_euid();
762 if (euid != shp->shm_perm.uid &&
763 euid != shp->shm_perm.cuid)
765 if (cmd == SHM_LOCK &&
766 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
770 err = security_shm_shmctl(shp, cmd);
775 struct user_struct *user = current_user();
776 if (!is_file_hugepages(shp->shm_file)) {
777 err = shmem_lock(shp->shm_file, 1, user);
778 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
779 shp->shm_perm.mode |= SHM_LOCKED;
780 shp->mlock_user = user;
783 } else if (!is_file_hugepages(shp->shm_file)) {
784 shmem_lock(shp->shm_file, 0, shp->mlock_user);
785 shp->shm_perm.mode &= ~SHM_LOCKED;
786 shp->mlock_user = NULL;
793 err = shmctl_down(ns, shmid, cmd, buf, version);
806 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
808 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
809 * "raddr" thing points to kernel space, and there has to be a wrapper around
812 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
814 struct shmid_kernel *shp;
822 unsigned long user_addr;
823 struct ipc_namespace *ns;
824 struct shm_file_data *sfd;
831 else if ((addr = (ulong)shmaddr)) {
832 if (addr & (SHMLBA-1)) {
833 if (shmflg & SHM_RND)
834 addr &= ~(SHMLBA-1); /* round down */
836 #ifndef __ARCH_FORCE_SHMLBA
837 if (addr & ~PAGE_MASK)
841 flags = MAP_SHARED | MAP_FIXED;
843 if ((shmflg & SHM_REMAP))
849 if (shmflg & SHM_RDONLY) {
854 prot = PROT_READ | PROT_WRITE;
855 acc_mode = S_IRUGO | S_IWUGO;
856 f_mode = FMODE_READ | FMODE_WRITE;
858 if (shmflg & SHM_EXEC) {
864 * We cannot rely on the fs check since SYSV IPC does have an
865 * additional creator id...
867 ns = current->nsproxy->ipc_ns;
868 shp = shm_lock_check(ns, shmid);
875 if (ipcperms(&shp->shm_perm, acc_mode))
878 err = security_shm_shmat(shp, shmaddr, shmflg);
882 path.dentry = dget(shp->shm_file->f_path.dentry);
883 path.mnt = shp->shm_file->f_path.mnt;
885 size = i_size_read(path.dentry->d_inode);
889 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
893 file = alloc_file(path.mnt, path.dentry, f_mode,
894 is_file_hugepages(shp->shm_file) ?
895 &shm_file_operations_huge :
896 &shm_file_operations);
899 ima_counts_get(file);
901 file->private_data = sfd;
902 file->f_mapping = shp->shm_file->f_mapping;
903 sfd->id = shp->shm_perm.id;
904 sfd->ns = get_ipc_ns(ns);
905 sfd->file = shp->shm_file;
908 down_write(¤t->mm->mmap_sem);
909 if (addr && !(shmflg & SHM_REMAP)) {
911 if (find_vma_intersection(current->mm, addr, addr + size))
914 * If shm segment goes below stack, make sure there is some
915 * space left for the stack to grow (at least 4 pages).
917 if (addr < current->mm->start_stack &&
918 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
922 user_addr = do_mmap (file, addr, size, prot, flags, 0);
925 if (IS_ERR_VALUE(user_addr))
926 err = (long)user_addr;
928 up_write(¤t->mm->mmap_sem);
933 down_write(&shm_ids(ns).rw_mutex);
934 shp = shm_lock(ns, shmid);
937 if(shp->shm_nattch == 0 &&
938 shp->shm_perm.mode & SHM_DEST)
939 shm_destroy(ns, shp);
942 up_write(&shm_ids(ns).rw_mutex);
958 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
963 err = do_shmat(shmid, shmaddr, shmflg, &ret);
966 force_successful_syscall_return();
971 * detach and kill segment if marked destroyed.
972 * The work is done in shm_close.
974 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
976 struct mm_struct *mm = current->mm;
977 struct vm_area_struct *vma;
978 unsigned long addr = (unsigned long)shmaddr;
979 int retval = -EINVAL;
982 struct vm_area_struct *next;
985 if (addr & ~PAGE_MASK)
988 down_write(&mm->mmap_sem);
991 * This function tries to be smart and unmap shm segments that
992 * were modified by partial mlock or munmap calls:
993 * - It first determines the size of the shm segment that should be
994 * unmapped: It searches for a vma that is backed by shm and that
995 * started at address shmaddr. It records it's size and then unmaps
997 * - Then it unmaps all shm vmas that started at shmaddr and that
998 * are within the initially determined size.
999 * Errors from do_munmap are ignored: the function only fails if
1000 * it's called with invalid parameters or if it's called to unmap
1001 * a part of a vma. Both calls in this function are for full vmas,
1002 * the parameters are directly copied from the vma itself and always
1003 * valid - therefore do_munmap cannot fail. (famous last words?)
1006 * If it had been mremap()'d, the starting address would not
1007 * match the usual checks anyway. So assume all vma's are
1008 * above the starting address given.
1010 vma = find_vma(mm, addr);
1014 next = vma->vm_next;
1017 * Check if the starting address would match, i.e. it's
1018 * a fragment created by mprotect() and/or munmap(), or it
1019 * otherwise it starts at this address with no hassles.
1021 if ((vma->vm_ops == &shm_vm_ops) &&
1022 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1025 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1026 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1028 * We discovered the size of the shm segment, so
1029 * break out of here and fall through to the next
1030 * loop that uses the size information to stop
1031 * searching for matching vma's.
1041 * We need look no further than the maximum address a fragment
1042 * could possibly have landed at. Also cast things to loff_t to
1043 * prevent overflows and make comparisions vs. equal-width types.
1045 size = PAGE_ALIGN(size);
1046 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1047 next = vma->vm_next;
1049 /* finding a matching vma now does not alter retval */
1050 if ((vma->vm_ops == &shm_vm_ops) &&
1051 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1053 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1057 #else /* CONFIG_MMU */
1058 /* under NOMMU conditions, the exact address to be destroyed must be
1061 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1062 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1068 up_write(&mm->mmap_sem);
1072 #ifdef CONFIG_PROC_FS
1073 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1075 struct shmid_kernel *shp = it;
1077 #if BITS_PER_LONG <= 32
1078 #define SIZE_SPEC "%10lu"
1080 #define SIZE_SPEC "%21lu"
1083 return seq_printf(s,
1084 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1085 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",