/* * linux/ipc/shm.c * Copyright (C) 1992, 1993 Krishna Balasubramanian * Many improvements/fixes by Bruno Haible. * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern int ipcperms (struct ipc_perm *ipcp, short shmflg); extern unsigned long get_swap_page (void); static int findkey (key_t key); static int newseg (key_t key, int shmflg, int size); static int shm_map (struct vm_area_struct *shmd); static void killseg (int id); static void shm_open (struct vm_area_struct *shmd); static void shm_close (struct vm_area_struct *shmd); static pte_t shm_swap_in(struct vm_area_struct *, unsigned long, unsigned long); static int shm_tot = 0; /* total number of shared memory pages */ static int shm_rss = 0; /* number of shared memory pages that are in memory */ static int shm_swp = 0; /* number of shared memory pages that are in swap */ static int max_shmid = 0; /* every used id is <= max_shmid */ static struct wait_queue *shm_lock = NULL; /* calling findkey() may need to wait */ static struct shmid_ds *shm_segs[SHMMNI]; static unsigned short shm_seq = 0; /* incremented, for recognizing stale ids */ /* some statistics */ static ulong swap_attempts = 0; static ulong swap_successes = 0; static ulong used_segs = 0; __initfunc(void shm_init (void)) { int id; for (id = 0; id < SHMMNI; id++) shm_segs[id] = (struct shmid_ds *) IPC_UNUSED; shm_tot = shm_rss = shm_seq = max_shmid = used_segs = 0; shm_lock = NULL; return; } static int findkey (key_t key) { int id; struct shmid_ds *shp; for (id = 0; id <= max_shmid; id++) { while ((shp = shm_segs[id]) == IPC_NOID) sleep_on (&shm_lock); if (shp == IPC_UNUSED) continue; if (key == shp->shm_perm.key) return id; } return -1; } /* * allocate new shmid_ds and pgtable. protected by shm_segs[id] = NOID. */ static int newseg (key_t key, int shmflg, int size) { struct shmid_ds *shp; int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; int id, i; if (size < SHMMIN) return -EINVAL; if (shm_tot + numpages >= SHMALL) return -ENOSPC; for (id = 0; id < SHMMNI; id++) if (shm_segs[id] == IPC_UNUSED) { shm_segs[id] = (struct shmid_ds *) IPC_NOID; goto found; } return -ENOSPC; found: shp = (struct shmid_ds *) kmalloc (sizeof (*shp), GFP_KERNEL); if (!shp) { shm_segs[id] = (struct shmid_ds *) IPC_UNUSED; wake_up (&shm_lock); return -ENOMEM; } shp->shm_pages = (ulong *) kmalloc (numpages*sizeof(ulong),GFP_KERNEL); if (!shp->shm_pages) { shm_segs[id] = (struct shmid_ds *) IPC_UNUSED; wake_up (&shm_lock); kfree(shp); return -ENOMEM; } for (i = 0; i < numpages; shp->shm_pages[i++] = 0); shm_tot += numpages; shp->shm_perm.key = key; shp->shm_perm.mode = (shmflg & S_IRWXUGO); shp->shm_perm.cuid = shp->shm_perm.uid = current->euid; shp->shm_perm.cgid = shp->shm_perm.gid = current->egid; shp->shm_perm.seq = shm_seq; shp->shm_segsz = size; shp->shm_cpid = current->pid; shp->attaches = NULL; shp->shm_lpid = shp->shm_nattch = 0; shp->shm_atime = shp->shm_dtime = 0; shp->shm_ctime = CURRENT_TIME; shp->shm_npages = numpages; if (id > max_shmid) max_shmid = id; shm_segs[id] = shp; used_segs++; wake_up (&shm_lock); return (unsigned int) shp->shm_perm.seq * SHMMNI + id; } asmlinkage int sys_shmget (key_t key, int size, int shmflg) { struct shmid_ds *shp; int err, id = 0; lock_kernel(); if (size < 0 || size > SHMMAX) { err = -EINVAL; } else if (key == IPC_PRIVATE) { err = newseg(key, shmflg, size); } else if ((id = findkey (key)) == -1) { if (!(shmflg & IPC_CREAT)) err = -ENOENT; else err = newseg(key, shmflg, size); } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) { err = -EEXIST; } else { shp = shm_segs[id]; if (shp->shm_perm.mode & SHM_DEST) err = -EIDRM; else if (size > shp->shm_segsz) err = -EINVAL; else if (ipcperms (&shp->shm_perm, shmflg)) err = -EACCES; else err = (int) shp->shm_perm.seq * SHMMNI + id; } unlock_kernel(); return err; } /* * Only called after testing nattch and SHM_DEST. * Here pages, pgtable and shmid_ds are freed. */ static void killseg (int id) { struct shmid_ds *shp; int i, numpages; shp = shm_segs[id]; if (shp == IPC_NOID || shp == IPC_UNUSED) { printk ("shm nono: killseg called on unused seg id=%d\n", id); return; } shp->shm_perm.seq++; /* for shmat */ shm_seq = (shm_seq+1) % ((unsigned)(1<<31)/SHMMNI); /* increment, but avoid overflow */ shm_segs[id] = (struct shmid_ds *) IPC_UNUSED; used_segs--; if (id == max_shmid) while (max_shmid && (shm_segs[--max_shmid] == IPC_UNUSED)); if (!shp->shm_pages) { printk ("shm nono: killseg shp->pages=NULL. id=%d\n", id); return; } numpages = shp->shm_npages; for (i = 0; i < numpages ; i++) { pte_t pte; pte = __pte(shp->shm_pages[i]); if (pte_none(pte)) continue; if (pte_present(pte)) { free_page (pte_page(pte)); shm_rss--; } else { swap_free(pte_val(pte)); shm_swp--; } } kfree(shp->shm_pages); shm_tot -= numpages; kfree(shp); return; } asmlinkage int sys_shmctl (int shmid, int cmd, struct shmid_ds *buf) { struct shmid_ds tbuf; struct shmid_ds *shp; struct ipc_perm *ipcp; int id, err = -EINVAL; lock_kernel(); if (cmd < 0 || shmid < 0) goto out; if (cmd == IPC_SET) { err = -EFAULT; if (!buf) goto out; err = verify_area (VERIFY_READ, buf, sizeof (*buf)); if (err) goto out; copy_from_user (&tbuf, buf, sizeof (*buf)); } switch (cmd) { /* replace with proc interface ? */ case IPC_INFO: { struct shminfo shminfo; err = -EFAULT; if (!buf) goto out; shminfo.shmmni = SHMMNI; shminfo.shmmax = SHMMAX; shminfo.shmmin = SHMMIN; shminfo.shmall = SHMALL; shminfo.shmseg = SHMSEG; err = verify_area (VERIFY_WRITE, buf, sizeof (struct shminfo)); if (err) goto out; copy_to_user (buf, &shminfo, sizeof(struct shminfo)); err = max_shmid; goto out; } case SHM_INFO: { struct shm_info shm_info; err = -EFAULT; if (!buf) goto out; err = verify_area (VERIFY_WRITE, buf, sizeof (shm_info)); if (err) goto out; shm_info.used_ids = used_segs; shm_info.shm_rss = shm_rss; shm_info.shm_tot = shm_tot; shm_info.shm_swp = shm_swp; shm_info.swap_attempts = swap_attempts; shm_info.swap_successes = swap_successes; copy_to_user (buf, &shm_info, sizeof(shm_info)); err = max_shmid; goto out; } case SHM_STAT: err = -EFAULT; if (!buf) goto out; err = verify_area (VERIFY_WRITE, buf, sizeof (*buf)); if (err) goto out; err = -EINVAL; if (shmid > max_shmid) goto out; shp = shm_segs[shmid]; if (shp == IPC_UNUSED || shp == IPC_NOID) goto out; if (ipcperms (&shp->shm_perm, S_IRUGO)) goto out; id = (unsigned int) shp->shm_perm.seq * SHMMNI + shmid; tbuf.shm_perm = shp->shm_perm; tbuf.shm_segsz = shp->shm_segsz; tbuf.shm_atime = shp->shm_atime; tbuf.shm_dtime = shp->shm_dtime; tbuf.shm_ctime = shp->shm_ctime; tbuf.shm_cpid = shp->shm_cpid; tbuf.shm_lpid = shp->shm_lpid; tbuf.shm_nattch = shp->shm_nattch; copy_to_user (buf, &tbuf, sizeof(*buf)); err = id; goto out; } shp = shm_segs[id = (unsigned int) shmid % SHMMNI]; err = -EINVAL; if (shp == IPC_UNUSED || shp == IPC_NOID) goto out; err = -EIDRM; if (shp->shm_perm.seq != (unsigned int) shmid / SHMMNI) goto out; ipcp = &shp->shm_perm; switch (cmd) { case SHM_UNLOCK: err = -EPERM; if (!suser()) goto out; err = -EINVAL; if (!(ipcp->mode & SHM_LOCKED)) goto out; ipcp->mode &= ~SHM_LOCKED; break; case SHM_LOCK: /* Allow superuser to lock segment in memory */ /* Should the pages be faulted in here or leave it to user? */ /* need to determine interaction with current->swappable */ err = -EPERM; if (!suser()) goto out; err = -EINVAL; if (ipcp->mode & SHM_LOCKED) goto out; ipcp->mode |= SHM_LOCKED; break; case IPC_STAT: err = -EACCES; if (ipcperms (ipcp, S_IRUGO)) goto out; err = -EFAULT; if (!buf) goto out; err = verify_area (VERIFY_WRITE, buf, sizeof (*buf)); if (err) goto out; tbuf.shm_perm = shp->shm_perm; tbuf.shm_segsz = shp->shm_segsz; tbuf.shm_atime = shp->shm_atime; tbuf.shm_dtime = shp->shm_dtime; tbuf.shm_ctime = shp->shm_ctime; tbuf.shm_cpid = shp->shm_cpid; tbuf.shm_lpid = shp->shm_lpid; tbuf.shm_nattch = shp->shm_nattch; copy_to_user (buf, &tbuf, sizeof(*buf)); break; case IPC_SET: if (suser() || current->euid == shp->shm_perm.uid || current->euid == shp->shm_perm.cuid) { ipcp->uid = tbuf.shm_perm.uid; ipcp->gid = tbuf.shm_perm.gid; ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | (tbuf.shm_perm.mode & S_IRWXUGO); shp->shm_ctime = CURRENT_TIME; break; } err = -EPERM; goto out; case IPC_RMID: if (suser() || current->euid == shp->shm_perm.uid || current->euid == shp->shm_perm.cuid) { shp->shm_perm.mode |= SHM_DEST; if (shp->shm_nattch <= 0) killseg (id); break; } err = -EPERM; goto out; default: err = -EINVAL; goto out; } err = 0; out: unlock_kernel(); return err; } /* * The per process internal structure for managing segments is * `struct vm_area_struct'. * A shmat will add to and shmdt will remove from the list. * shmd->vm_mm the attacher * shmd->vm_start virt addr of attach, multiple of SHMLBA * shmd->vm_end multiple of SHMLBA * shmd->vm_next next attach for task * shmd->vm_next_share next attach for segment * shmd->vm_offset offset into segment * shmd->vm_pte signature for this attach */ static struct vm_operations_struct shm_vm_ops = { shm_open, /* open - callback for a new vm-area open */ shm_close, /* close - callback for when the vm-area is released */ NULL, /* no need to sync pages at unmap */ NULL, /* protect */ NULL, /* sync */ NULL, /* advise */ NULL, /* nopage (done with swapin) */ NULL, /* wppage */ NULL, /* swapout (hardcoded right now) */ shm_swap_in /* swapin */ }; /* Insert shmd into the list shp->attaches */ static inline void insert_attach (struct shmid_ds * shp, struct vm_area_struct * shmd) { if((shmd->vm_next_share = shp->attaches) != NULL) shp->attaches->vm_pprev_share = &shmd->vm_next_share; shp->attaches = shmd; shmd->vm_pprev_share = &shp->attaches; } /* Remove shmd from list shp->attaches */ static inline void remove_attach (struct shmid_ds * shp, struct vm_area_struct * shmd) { if(shmd->vm_next_share) shmd->vm_next_share->vm_pprev_share = shmd->vm_pprev_share; *shmd->vm_pprev_share = shmd->vm_next_share; } /* * ensure page tables exist * mark page table entries with shm_sgn. */ static int shm_map (struct vm_area_struct *shmd) { pgd_t *page_dir; pmd_t *page_middle; pte_t *page_table; unsigned long tmp, shm_sgn; int error; /* clear old mappings */ do_munmap(shmd->vm_start, shmd->vm_end - shmd->vm_start); /* add new mapping */ tmp = shmd->vm_end - shmd->vm_start; if((current->mm->total_vm << PAGE_SHIFT) + tmp > (unsigned long) current->rlim[RLIMIT_AS].rlim_cur) return -ENOMEM; current->mm->total_vm += tmp >> PAGE_SHIFT; insert_vm_struct(current->mm, shmd); merge_segments(current->mm, shmd->vm_start, shmd->vm_end); /* map page range */ error = 0; shm_sgn = shmd->vm_pte + SWP_ENTRY(0, (shmd->vm_offset >> PAGE_SHIFT) << SHM_IDX_SHIFT); flush_cache_range(shmd->vm_mm, shmd->vm_start, shmd->vm_end); for (tmp = shmd->vm_start; tmp < shmd->vm_end; tmp += PAGE_SIZE, shm_sgn += SWP_ENTRY(0, 1 << SHM_IDX_SHIFT)) { page_dir = pgd_offset(shmd->vm_mm,tmp); page_middle = pmd_alloc(page_dir,tmp); if (!page_middle) { error = -ENOMEM; break; } page_table = pte_alloc(page_middle,tmp); if (!page_table) { error = -ENOMEM; break; } set_pte(page_table, __pte(shm_sgn)); } flush_tlb_range(shmd->vm_mm, shmd->vm_start, shmd->vm_end); return error; } /* * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. */ asmlinkage int sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr) { struct shmid_ds *shp; struct vm_area_struct *shmd; int err = -EINVAL; unsigned int id; unsigned long addr; unsigned long len; lock_kernel(); if (shmid < 0) { /* printk("shmat() -> EINVAL because shmid = %d < 0\n",shmid); */ goto out; } shp = shm_segs[id = (unsigned int) shmid % SHMMNI]; if (shp == IPC_UNUSED || shp == IPC_NOID) { /* printk("shmat() -> EINVAL because shmid = %d is invalid\n",shmid); */ goto out; } if (!(addr = (ulong) shmaddr)) { if (shmflg & SHM_REMAP) goto out; err = -ENOMEM; addr = 0; again: if (!(addr = get_unmapped_area(addr, shp->shm_segsz))) goto out; if(addr & (SHMLBA - 1)) { addr = (addr + (SHMLBA - 1)) & ~(SHMLBA - 1); goto again; } } else if (addr & (SHMLBA-1)) { if (shmflg & SHM_RND) addr &= ~(SHMLBA-1); /* round down */ else goto out; } /* * Check if addr exceeds TASK_SIZE (from do_mmap) */ len = PAGE_SIZE*shp->shm_npages; err = -EINVAL; if (addr >= TASK_SIZE || len > TASK_SIZE || addr > TASK_SIZE - len) goto out; /* * If shm segment goes below stack, make sure there is some * space left for the stack to grow (presently 4 pages). */ if (addr < current->mm->start_stack && addr > current->mm->start_stack - PAGE_SIZE*(shp->shm_npages + 4)) { /* printk("shmat() -> EINVAL because segment intersects stack\n"); */ goto out; } if (!(shmflg & SHM_REMAP)) if ((shmd = find_vma_intersection(current->mm, addr, addr + shp->shm_segsz))) { /* printk("shmat() -> EINVAL because the interval [0x%lx,0x%lx) intersects an already mapped interval [0x%lx,0x%lx).\n", addr, addr + shp->shm_segsz, shmd->vm_start, shmd->vm_end); */ goto out; } err = -EACCES; if (ipcperms(&shp->shm_perm, shmflg & SHM_RDONLY ? S_IRUGO : S_IRUGO|S_IWUGO)) goto out; err = -EIDRM; if (shp->shm_perm.seq != (unsigned int) shmid / SHMMNI) goto out; err = -ENOMEM; shmd = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); if (!shmd) goto out; if ((shp != shm_segs[id]) || (shp->shm_perm.seq != (unsigned int) shmid / SHMMNI)) { kmem_cache_free(vm_area_cachep, shmd); err = -EIDRM; goto out; } shmd->vm_pte = SWP_ENTRY(SHM_SWP_TYPE, id); shmd->vm_start = addr; shmd->vm_end = addr + shp->shm_npages * PAGE_SIZE; shmd->vm_mm = current->mm; shmd->vm_page_prot = (shmflg & SHM_RDONLY) ? PAGE_READONLY : PAGE_SHARED; shmd->vm_flags = VM_SHM | VM_MAYSHARE | VM_SHARED | VM_MAYREAD | VM_MAYEXEC | VM_READ | VM_EXEC | ((shmflg & SHM_RDONLY) ? 0 : VM_MAYWRITE | VM_WRITE); shmd->vm_dentry = NULL; shmd->vm_offset = 0; shmd->vm_ops = &shm_vm_ops; shp->shm_nattch++; /* prevent destruction */ if ((err = shm_map (shmd))) { if (--shp->shm_nattch <= 0 && shp->shm_perm.mode & SHM_DEST) killseg(id); kmem_cache_free(vm_area_cachep, shmd); goto out; } insert_attach(shp,shmd); /* insert shmd into shp->attaches */ shp->shm_lpid = current->pid; shp->shm_atime = CURRENT_TIME; *raddr = addr; err = 0; out: unlock_kernel(); return err; } /* This is called by fork, once for every shm attach. */ static void shm_open (struct vm_area_struct *shmd) { unsigned int id; struct shmid_ds *shp; id = SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK; shp = shm_segs[id]; if (shp == IPC_UNUSED) { printk("shm_open: unused id=%d PANIC\n", id); return; } insert_attach(shp,shmd); /* insert shmd into shp->attaches */ shp->shm_nattch++; shp->shm_atime = CURRENT_TIME; shp->shm_lpid = current->pid; } /* * remove the attach descriptor shmd. * free memory for segment if it is marked destroyed. * The descriptor has already been removed from the current->mm->mmap list * and will later be kfree()d. */ static void shm_close (struct vm_area_struct *shmd) { struct shmid_ds *shp; int id; /* remove from the list of attaches of the shm segment */ id = SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK; shp = shm_segs[id]; remove_attach(shp,shmd); /* remove from shp->attaches */ shp->shm_lpid = current->pid; shp->shm_dtime = CURRENT_TIME; if (--shp->shm_nattch <= 0 && shp->shm_perm.mode & SHM_DEST) killseg (id); } /* * detach and kill segment if marked destroyed. * The work is done in shm_close. */ asmlinkage int sys_shmdt (char *shmaddr) { struct vm_area_struct *shmd, *shmdnext; for (shmd = current->mm->mmap; shmd; shmd = shmdnext) { shmdnext = shmd->vm_next; if (shmd->vm_ops == &shm_vm_ops && shmd->vm_start - shmd->vm_offset == (ulong) shmaddr) do_munmap(shmd->vm_start, shmd->vm_end - shmd->vm_start); } return 0; } /* * page not present ... go through shm_pages */ static pte_t shm_swap_in(struct vm_area_struct * shmd, unsigned long offset, unsigned long code) { pte_t pte; struct shmid_ds *shp; unsigned int id, idx; id = SWP_OFFSET(code) & SHM_ID_MASK; if (id != (SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK)) { printk ("shm_swap_in: code id = %d and shmd id = %ld differ\n", id, SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK); return BAD_PAGE; } if (id > max_shmid) { printk ("shm_swap_in: id=%d too big. proc mem corrupted\n", id); return BAD_PAGE; } shp = shm_segs[id]; if (shp == IPC_UNUSED || shp == IPC_NOID) { printk ("shm_swap_in: id=%d invalid. Race.\n", id); return BAD_PAGE; } idx = (SWP_OFFSET(code) >> SHM_IDX_SHIFT) & SHM_IDX_MASK; if (idx != (offset >> PAGE_SHIFT)) { printk ("shm_swap_in: code idx = %u and shmd idx = %lu differ\n", idx, offset >> PAGE_SHIFT); return BAD_PAGE; } if (idx >= shp->shm_npages) { printk ("shm_swap_in : too large page index. id=%d\n", id); return BAD_PAGE; } pte = __pte(shp->shm_pages[idx]); if (!pte_present(pte)) { unsigned long page = get_free_page(GFP_KERNEL); if (!page) { oom(current); return BAD_PAGE; } pte = __pte(shp->shm_pages[idx]); if (pte_present(pte)) { free_page (page); /* doesn't sleep */ goto done; } if (!pte_none(pte)) { read_swap_page(pte_val(pte), (char *) page); pte = __pte(shp->shm_pages[idx]); if (pte_present(pte)) { free_page (page); /* doesn't sleep */ goto done; } swap_free(pte_val(pte)); shm_swp--; } shm_rss++; pte = pte_mkdirty(mk_pte(page, PAGE_SHARED)); shp->shm_pages[idx] = pte_val(pte); } else --current->maj_flt; /* was incremented in do_no_page */ done: /* pte_val(pte) == shp->shm_pages[idx] */ current->min_flt++; atomic_inc(&mem_map[MAP_NR(pte_page(pte))].count); return pte_modify(pte, shmd->vm_page_prot); } /* * Goes through counter = (shm_rss >> prio) present shm pages. */ static unsigned long swap_id = 0; /* currently being swapped */ static unsigned long swap_idx = 0; /* next to swap */ int shm_swap (int prio, int dma) { pte_t page; struct shmid_ds *shp; struct vm_area_struct *shmd; unsigned long swap_nr; unsigned long id, idx; int loop = 0; int counter; counter = shm_rss >> prio; if (!counter || !(swap_nr = get_swap_page())) return 0; check_id: shp = shm_segs[swap_id]; if (shp == IPC_UNUSED || shp == IPC_NOID || shp->shm_perm.mode & SHM_LOCKED ) { next_id: swap_idx = 0; if (++swap_id > max_shmid) { if (loop) goto failed; loop = 1; swap_id = 0; } goto check_id; } id = swap_id; check_table: idx = swap_idx++; if (idx >= shp->shm_npages) goto next_id; page = __pte(shp->shm_pages[idx]); if (!pte_present(page)) goto check_table; if (dma && !PageDMA(&mem_map[MAP_NR(pte_page(page))])) goto check_table; swap_attempts++; if (--counter < 0) { /* failed */ failed: swap_free (swap_nr); return 0; } if (shp->attaches) for (shmd = shp->attaches; ; ) { do { pgd_t *page_dir; pmd_t *page_middle; pte_t *page_table, pte; unsigned long tmp; if ((SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK) != id) { printk ("shm_swap: id=%ld does not match shmd->vm_pte.id=%ld\n", id, SWP_OFFSET(shmd->vm_pte) & SHM_ID_MASK); continue; } tmp = shmd->vm_start + (idx << PAGE_SHIFT) - shmd->vm_offset; if (!(tmp >= shmd->vm_start && tmp < shmd->vm_end)) continue; page_dir = pgd_offset(shmd->vm_mm,tmp); if (pgd_none(*page_dir) || pgd_bad(*page_dir)) { printk("shm_swap: bad pgtbl! id=%ld start=%lx idx=%ld\n", id, shmd->vm_start, idx); pgd_clear(page_dir); continue; } page_middle = pmd_offset(page_dir,tmp); if (pmd_none(*page_middle) || pmd_bad(*page_middle)) { printk("shm_swap: bad pgmid! id=%ld start=%lx idx=%ld\n", id, shmd->vm_start, idx); pmd_clear(page_middle); continue; } page_table = pte_offset(page_middle,tmp); pte = *page_table; if (!pte_present(pte)) continue; if (pte_young(pte)) { set_pte(page_table, pte_mkold(pte)); continue; } if (pte_page(pte) != pte_page(page)) printk("shm_swap_out: page and pte mismatch %lx %lx\n", pte_page(pte),pte_page(page)); flush_cache_page(shmd, tmp); set_pte(page_table, __pte(shmd->vm_pte + SWP_ENTRY(0, idx << SHM_IDX_SHIFT))); atomic_dec(&mem_map[MAP_NR(pte_page(pte))].count); if (shmd->vm_mm->rss > 0) shmd->vm_mm->rss--; flush_tlb_page(shmd, tmp); /* continue looping through the linked list */ } while (0); shmd = shmd->vm_next_share; if (!shmd) break; } if (atomic_read(&mem_map[MAP_NR(pte_page(page))].count) != 1) goto check_table; shp->shm_pages[idx] = swap_nr; write_swap_page (swap_nr, (char *) pte_page(page)); free_page(pte_page(page)); swap_successes++; shm_swp++; shm_rss--; return 1; }