X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fshmem.c;h=855eaf5b8d5bd964d4af0f6d1280d347b9490e8d;hb=105a048a4f35f7a74c7cc20b36dd83658b6ec232;hp=f92fea94d037b4b469cc8e55096f0e7d5f57cbf0;hpb=c9b0ed51483cc2fc42bb801b6675c4231b0e4634;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/shmem.c b/mm/shmem.c index f92fea9..855eaf5 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -14,33 +14,41 @@ * Copyright (c) 2004, Luke Kenneth Casson Leighton * Copyright (c) 2004 Red Hat, Inc., James Morris * + * tiny-shmem: + * Copyright (c) 2004, 2008 Matt Mackall + * * This file is released under the GPL. */ +#include +#include +#include +#include +#include +#include +#include +#include +#include + +static struct vfsmount *shm_mnt; + +#ifdef CONFIG_SHMEM /* * This virtual memory filesystem is heavily based on the ramfs. It * extends ramfs by the ability to use swap and honor resource limits * which makes it a completely usable filesystem. */ -#include -#include -#include #include #include +#include #include -#include #include -#include -#include -#include #include #include #include #include -#include #include -#include #include #include #include @@ -50,21 +58,34 @@ #include #include #include +#include #include #include #include -/* This magic number is used in glibc for posix shared memory */ -#define TMPFS_MAGIC 0x01021994 - +/* + * The maximum size of a shmem/tmpfs file is limited by the maximum size of + * its triple-indirect swap vector - see illustration at shmem_swp_entry(). + * + * With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel, + * but one eighth of that on a 64-bit kernel. With 8kB page size, maximum + * file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel, + * MAX_LFS_FILESIZE being then more restrictive than swap vector layout. + * + * We use / and * instead of shifts in the definitions below, so that the swap + * vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE. + */ #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) -#define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) -#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) +#define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) + +#define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) +#define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT) -#define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) -#define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) +#define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE) +#define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT)) +#define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ @@ -163,13 +184,13 @@ static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) */ static inline int shmem_acct_size(unsigned long flags, loff_t size) { - return (flags & VM_ACCOUNT)? - security_vm_enough_memory(VM_ACCT(size)): 0; + return (flags & VM_NORESERVE) ? + 0 : security_vm_enough_memory_kern(VM_ACCT(size)); } static inline void shmem_unacct_size(unsigned long flags, loff_t size) { - if (flags & VM_ACCOUNT) + if (!(flags & VM_NORESERVE)) vm_unacct_memory(VM_ACCT(size)); } @@ -181,13 +202,13 @@ static inline void shmem_unacct_size(unsigned long flags, loff_t size) */ static inline int shmem_acct_block(unsigned long flags) { - return (flags & VM_ACCOUNT)? - 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); + return (flags & VM_NORESERVE) ? + security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; } static inline void shmem_unacct_blocks(unsigned long flags, long pages) { - if (!(flags & VM_ACCOUNT)) + if (flags & VM_NORESERVE) vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); } @@ -197,11 +218,11 @@ static const struct file_operations shmem_file_operations; static const struct inode_operations shmem_inode_operations; static const struct inode_operations shmem_dir_inode_operations; static const struct inode_operations shmem_special_inode_operations; -static struct vm_operations_struct shmem_vm_ops; +static const struct vm_operations_struct shmem_vm_ops; static struct backing_dev_info shmem_backing_dev_info __read_mostly = { .ra_pages = 0, /* No readahead */ - .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK, + .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, .unplug_io_fn = default_unplug_io_fn, }; @@ -412,8 +433,6 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long spin_unlock(&info->lock); page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); - if (page) - set_page_private(page, 0); spin_lock(&info->lock); if (!page) { @@ -789,7 +808,7 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) error = inode_setattr(inode, attr); #ifdef CONFIG_TMPFS_POSIX_ACL if (!error && (attr->ia_valid & ATTR_MODE)) - error = generic_acl_chmod(inode, &shmem_acl_ops); + error = generic_acl_chmod(inode); #endif if (page) page_cache_release(page); @@ -922,7 +941,11 @@ found: error = 1; if (!inode) goto out; - /* Precharge page using GFP_KERNEL while we can wait */ + /* + * Charge page using GFP_KERNEL while we can wait. + * Charged back to the user(not to caller) when swap account is used. + * add_to_page_cache() will be called with GFP_NOWAIT. + */ error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); if (error) goto out; @@ -936,7 +959,7 @@ found: spin_lock(&info->lock); ptr = shmem_swp_entry(info, idx, NULL); if (ptr && ptr->val == entry.val) { - error = add_to_page_cache(page, inode->i_mapping, + error = add_to_page_cache_locked(page, inode->i_mapping, idx, GFP_NOWAIT); /* does mem_cgroup_uncharge_cache_page on error */ } else /* we must compensate for our precharge above */ @@ -992,7 +1015,14 @@ int shmem_unuse(swp_entry_t entry, struct page *page) goto out; } mutex_unlock(&shmem_swaplist_mutex); -out: return found; /* 0 or 1 or -ENOMEM */ + /* + * Can some race bring us here? We've been holding page lock, + * so I think not; but would rather try again later than BUG() + */ + unlock_page(page); + page_cache_release(page); +out: + return (found < 0) ? found : 0; } /* @@ -1021,8 +1051,9 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) * sync from ever calling shmem_writepage; but a stacking filesystem * may use the ->writepage of its underlying filesystem, in which case * tmpfs should write out to swap only in response to memory pressure, - * and not for pdflush or sync. However, in those cases, we do still - * want to check if there's a redundant swappage to be discarded. + * and not for the writeback threads or sync. However, in those cases, + * we do still want to check if there's a redundant swappage to be + * discarded. */ if (wbc->for_reclaim) swap = get_swap_page(); @@ -1054,11 +1085,10 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) else inode = NULL; spin_unlock(&info->lock); - swap_duplicate(swap); + swap_shmem_alloc(swap); BUG_ON(page_mapped(page)); page_cache_release(page); /* pagecache ref */ - set_page_dirty(page); - unlock_page(page); + swap_writepage(page, wbc); if (inode) { mutex_lock(&shmem_swaplist_mutex); /* move instead of add in case we're racing */ @@ -1072,7 +1102,11 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) shmem_swp_unmap(entry); unlock: spin_unlock(&info->lock); - swap_free(swap); + /* + * add_to_swap_cache() doesn't return -EEXIST, so we can safely + * clear SWAP_HAS_CACHE flag. + */ + swapcache_free(swap, NULL); redirty: set_page_dirty(page); if (wbc->for_reclaim) @@ -1265,7 +1299,7 @@ repeat: } /* We have to do this with page locked to prevent races */ - if (TestSetPageLocked(swappage)) { + if (!trylock_page(swappage)) { shmem_swp_unmap(entry); spin_unlock(&info->lock); wait_on_page_locked(swappage); @@ -1301,8 +1335,8 @@ repeat: SetPageUptodate(filepage); set_page_dirty(filepage); swap_free(swap); - } else if (!(error = add_to_page_cache( - swappage, mapping, idx, GFP_NOWAIT))) { + } else if (!(error = add_to_page_cache_locked(swappage, mapping, + idx, GFP_NOWAIT))) { info->flags |= SHMEM_PAGEIN; shmem_swp_set(info, entry, 0); shmem_swp_unmap(entry); @@ -1314,22 +1348,30 @@ repeat: } else { shmem_swp_unmap(entry); spin_unlock(&info->lock); - unlock_page(swappage); - page_cache_release(swappage); if (error == -ENOMEM) { - /* allow reclaim from this memory cgroup */ - error = mem_cgroup_shrink_usage(current->mm, + /* + * reclaim from proper memory cgroup and + * call memcg's OOM if needed. + */ + error = mem_cgroup_shmem_charge_fallback( + swappage, + current->mm, gfp); - if (error) + if (error) { + unlock_page(swappage); + page_cache_release(swappage); goto failed; + } } + unlock_page(swappage); + page_cache_release(swappage); goto repeat; } } else if (sgp == SGP_READ && !filepage) { shmem_swp_unmap(entry); filepage = find_get_page(mapping, idx); if (filepage && - (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { + (!PageUptodate(filepage) || !trylock_page(filepage))) { spin_unlock(&info->lock); wait_on_page_locked(filepage); page_cache_release(filepage); @@ -1369,10 +1411,11 @@ repeat: error = -ENOMEM; goto failed; } + SetPageSwapBacked(filepage); /* Precharge page while we can wait, compensate after */ error = mem_cgroup_cache_charge(filepage, current->mm, - gfp & ~__GFP_HIGHMEM); + GFP_KERNEL); if (error) { page_cache_release(filepage); shmem_unacct_blocks(info->flags, 1); @@ -1445,7 +1488,6 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (error) return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); - mark_page_accessed(vmf->page); return ret | VM_FAULT_LOCKED; } @@ -1478,12 +1520,16 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user) if (!user_shm_lock(inode->i_size, user)) goto out_nomem; info->flags |= VM_LOCKED; + mapping_set_unevictable(file->f_mapping); } if (!lock && (info->flags & VM_LOCKED) && user) { user_shm_unlock(inode->i_size, user); info->flags &= ~VM_LOCKED; + mapping_clear_unevictable(file->f_mapping); + scan_mapping_unevictable_pages(file->f_mapping); } retval = 0; + out_nomem: spin_unlock(&info->lock); return retval; @@ -1497,8 +1543,8 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) return 0; } -static struct inode * -shmem_get_inode(struct super_block *sb, int mode, dev_t dev) +static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, + int mode, dev_t dev, unsigned long flags) { struct inode *inode; struct shmem_inode_info *info; @@ -1509,18 +1555,17 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) inode = new_inode(sb); if (inode) { - inode->i_mode = mode; - inode->i_uid = current->fsuid; - inode->i_gid = current->fsgid; + inode_init_owner(inode, dir, mode); inode->i_blocks = 0; - inode->i_mapping->a_ops = &shmem_aops; inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_generation = get_seconds(); info = SHMEM_I(inode); memset(info, 0, (char *)inode - (char *)info); spin_lock_init(&info->lock); + info->flags = flags & VM_NORESERVE; INIT_LIST_HEAD(&info->swaplist); + cache_no_acl(inode); switch (mode & S_IFMT) { default: @@ -1528,6 +1573,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev) init_special_inode(inode, mode, dev); break; case S_IFREG: + inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_inode_operations; inode->i_fop = &shmem_file_operations; mpol_shared_policy_init(&info->policy, @@ -1591,8 +1637,8 @@ shmem_write_end(struct file *file, struct address_space *mapping, if (pos + copied > inode->i_size) i_size_write(inode, pos + copied); - unlock_page(page); set_page_dirty(page); + unlock_page(page); page_cache_release(page); return copied; @@ -1761,9 +1807,10 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) static int shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) { - struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); + struct inode *inode; int error = -ENOSPC; + inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); if (inode) { error = security_inode_init_security(inode, dir, NULL, NULL, NULL); @@ -1773,16 +1820,15 @@ shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) return error; } } - error = shmem_acl_init(inode, dir); +#ifdef CONFIG_TMPFS_POSIX_ACL + error = generic_acl_init(inode, dir); if (error) { iput(inode); return error; } - if (dir->i_mode & S_ISGID) { - inode->i_gid = dir->i_gid; - if (S_ISDIR(mode)) - inode->i_mode |= S_ISGID; - } +#else + error = 0; +#endif dir->i_size += BOGO_DIRENT_SIZE; dir->i_ctime = dir->i_mtime = CURRENT_TIME; d_instantiate(dentry, inode); @@ -1902,7 +1948,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s if (len > PAGE_CACHE_SIZE) return -ENAMETOOLONG; - inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); + inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); if (!inode) return -ENOSPC; @@ -1928,16 +1974,15 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s iput(inode); return error; } - unlock_page(page); + inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; kaddr = kmap_atomic(page, KM_USER0); memcpy(kaddr, symname, len); kunmap_atomic(kaddr, KM_USER0); set_page_dirty(page); + unlock_page(page); page_cache_release(page); } - if (dir->i_mode & S_ISGID) - inode->i_gid = dir->i_gid; dir->i_size += BOGO_DIRENT_SIZE; dir->i_ctime = dir->i_mtime = CURRENT_TIME; d_instantiate(dentry, inode); @@ -1991,39 +2036,40 @@ static const struct inode_operations shmem_symlink_inode_operations = { * filesystem level, though. */ -static size_t shmem_xattr_security_list(struct inode *inode, char *list, +static size_t shmem_xattr_security_list(struct dentry *dentry, char *list, size_t list_len, const char *name, - size_t name_len) + size_t name_len, int handler_flags) { - return security_inode_listsecurity(inode, list, list_len); + return security_inode_listsecurity(dentry->d_inode, list, list_len); } -static int shmem_xattr_security_get(struct inode *inode, const char *name, - void *buffer, size_t size) +static int shmem_xattr_security_get(struct dentry *dentry, const char *name, + void *buffer, size_t size, int handler_flags) { if (strcmp(name, "") == 0) return -EINVAL; - return xattr_getsecurity(inode, name, buffer, size); + return xattr_getsecurity(dentry->d_inode, name, buffer, size); } -static int shmem_xattr_security_set(struct inode *inode, const char *name, - const void *value, size_t size, int flags) +static int shmem_xattr_security_set(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, int handler_flags) { if (strcmp(name, "") == 0) return -EINVAL; - return security_inode_setsecurity(inode, name, value, size, flags); + return security_inode_setsecurity(dentry->d_inode, name, value, + size, flags); } -static struct xattr_handler shmem_xattr_security_handler = { +static const struct xattr_handler shmem_xattr_security_handler = { .prefix = XATTR_SECURITY_PREFIX, .list = shmem_xattr_security_list, .get = shmem_xattr_security_get, .set = shmem_xattr_security_set, }; -static struct xattr_handler *shmem_xattr_handlers[] = { - &shmem_xattr_acl_access_handler, - &shmem_xattr_acl_default_handler, +static const struct xattr_handler *shmem_xattr_handlers[] = { + &generic_acl_access_handler, + &generic_acl_default_handler, &shmem_xattr_security_handler, NULL }; @@ -2257,8 +2303,7 @@ static void shmem_put_super(struct super_block *sb) sb->s_fs_info = NULL; } -static int shmem_fill_super(struct super_block *sb, - void *data, int silent) +int shmem_fill_super(struct super_block *sb, void *data, int silent) { struct inode *inode; struct dentry *root; @@ -2266,17 +2311,14 @@ static int shmem_fill_super(struct super_block *sb, int err = -ENOMEM; /* Round up to L1_CACHE_BYTES to resist false sharing */ - sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), + sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), L1_CACHE_BYTES), GFP_KERNEL); if (!sbinfo) return -ENOMEM; - sbinfo->max_blocks = 0; - sbinfo->max_inodes = 0; sbinfo->mode = S_IRWXUGO | S_ISVTX; - sbinfo->uid = current->fsuid; - sbinfo->gid = current->fsgid; - sbinfo->mpol = NULL; + sbinfo->uid = current_fsuid(); + sbinfo->gid = current_fsgid(); sb->s_fs_info = sbinfo; #ifdef CONFIG_TMPFS @@ -2313,7 +2355,7 @@ static int shmem_fill_super(struct super_block *sb, sb->s_flags |= MS_POSIXACL; #endif - inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0); + inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); if (!inode) goto failed; inode->i_uid = sbinfo->uid; @@ -2348,19 +2390,14 @@ static void shmem_destroy_inode(struct inode *inode) /* only struct inode is valid if it's an inline symlink */ mpol_free_shared_policy(&SHMEM_I(inode)->policy); } - shmem_acl_destroy_inode(inode); kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); } -static void init_once(struct kmem_cache *cachep, void *foo) +static void init_once(void *foo) { struct shmem_inode_info *p = (struct shmem_inode_info *) foo; inode_init_once(&p->vfs_inode); -#ifdef CONFIG_TMPFS_POSIX_ACL - p->i_acl = NULL; - p->i_default_acl = NULL; -#endif } static int init_inodecache(void) @@ -2385,6 +2422,7 @@ static const struct address_space_operations shmem_aops = { .write_end = shmem_write_end, #endif .migratepage = migrate_page, + .error_remove_page = generic_error_remove_page, }; static const struct file_operations shmem_file_operations = { @@ -2410,7 +2448,7 @@ static const struct inode_operations shmem_inode_operations = { .getxattr = generic_getxattr, .listxattr = generic_listxattr, .removexattr = generic_removexattr, - .permission = shmem_permission, + .check_acl = generic_check_acl, #endif }; @@ -2433,7 +2471,7 @@ static const struct inode_operations shmem_dir_inode_operations = { .getxattr = generic_getxattr, .listxattr = generic_listxattr, .removexattr = generic_removexattr, - .permission = shmem_permission, + .check_acl = generic_check_acl, #endif }; @@ -2444,7 +2482,7 @@ static const struct inode_operations shmem_special_inode_operations = { .getxattr = generic_getxattr, .listxattr = generic_listxattr, .removexattr = generic_removexattr, - .permission = shmem_permission, + .check_acl = generic_check_acl, #endif }; @@ -2461,7 +2499,7 @@ static const struct super_operations shmem_ops = { .put_super = shmem_put_super, }; -static struct vm_operations_struct shmem_vm_ops = { +static const struct vm_operations_struct shmem_vm_ops = { .fault = shmem_fault, #ifdef CONFIG_NUMA .set_policy = shmem_set_policy, @@ -2482,9 +2520,8 @@ static struct file_system_type tmpfs_fs_type = { .get_sb = shmem_get_sb, .kill_sb = kill_litter_super, }; -static struct vfsmount *shm_mnt; -static int __init init_tmpfs(void) +int __init init_tmpfs(void) { int error; @@ -2521,20 +2558,134 @@ out4: shm_mnt = ERR_PTR(error); return error; } -module_init(init_tmpfs) + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +/** + * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file + * @inode: the inode to be searched + * @pgoff: the offset to be searched + * @pagep: the pointer for the found page to be stored + * @ent: the pointer for the found swap entry to be stored + * + * If a page is found, refcount of it is incremented. Callers should handle + * these refcount. + */ +void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, + struct page **pagep, swp_entry_t *ent) +{ + swp_entry_t entry = { .val = 0 }, *ptr; + struct page *page = NULL; + struct shmem_inode_info *info = SHMEM_I(inode); + + if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) + goto out; + + spin_lock(&info->lock); + ptr = shmem_swp_entry(info, pgoff, NULL); +#ifdef CONFIG_SWAP + if (ptr && ptr->val) { + entry.val = ptr->val; + page = find_get_page(&swapper_space, entry.val); + } else +#endif + page = find_get_page(inode->i_mapping, pgoff); + if (ptr) + shmem_swp_unmap(ptr); + spin_unlock(&info->lock); +out: + *pagep = page; + *ent = entry; +} +#endif + +#else /* !CONFIG_SHMEM */ + +/* + * tiny-shmem: simple shmemfs and tmpfs using ramfs code + * + * This is intended for small system where the benefits of the full + * shmem code (swap-backed and resource-limited) are outweighed by + * their complexity. On systems without swap this code should be + * effectively equivalent, but much lighter weight. + */ + +#include + +static struct file_system_type tmpfs_fs_type = { + .name = "tmpfs", + .get_sb = ramfs_get_sb, + .kill_sb = kill_litter_super, +}; + +int __init init_tmpfs(void) +{ + BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); + + shm_mnt = kern_mount(&tmpfs_fs_type); + BUG_ON(IS_ERR(shm_mnt)); + + return 0; +} + +int shmem_unuse(swp_entry_t entry, struct page *page) +{ + return 0; +} + +int shmem_lock(struct file *file, int lock, struct user_struct *user) +{ + return 0; +} + +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +/** + * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file + * @inode: the inode to be searched + * @pgoff: the offset to be searched + * @pagep: the pointer for the found page to be stored + * @ent: the pointer for the found swap entry to be stored + * + * If a page is found, refcount of it is incremented. Callers should handle + * these refcount. + */ +void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, + struct page **pagep, swp_entry_t *ent) +{ + struct page *page = NULL; + + if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) + goto out; + page = find_get_page(inode->i_mapping, pgoff); +out: + *pagep = page; + *ent = (swp_entry_t){ .val = 0 }; +} +#endif + +#define shmem_vm_ops generic_file_vm_ops +#define shmem_file_operations ramfs_file_operations +#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) +#define shmem_acct_size(flags, size) 0 +#define shmem_unacct_size(flags, size) do {} while (0) +#define SHMEM_MAX_BYTES MAX_LFS_FILESIZE + +#endif /* CONFIG_SHMEM */ + +/* common code */ /** * shmem_file_setup - get an unlinked file living in tmpfs * @name: name for dentry (to be seen in /proc//maps * @size: size to be set for the file - * @flags: vm_flags + * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size */ -struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) +struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) { int error; struct file *file; struct inode *inode; - struct dentry *dentry, *root; + struct path path; + struct dentry *root; struct qstr this; if (IS_ERR(shm_mnt)) @@ -2551,36 +2702,40 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) this.len = strlen(name); this.hash = 0; /* will go */ root = shm_mnt->mnt_root; - dentry = d_alloc(root, &this); - if (!dentry) + path.dentry = d_alloc(root, &this); + if (!path.dentry) goto put_memory; - - error = -ENFILE; - file = get_empty_filp(); - if (!file) - goto put_dentry; + path.mnt = mntget(shm_mnt); error = -ENOSPC; - inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); + inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); if (!inode) - goto close_file; + goto put_dentry; - SHMEM_I(inode)->flags = flags & VM_ACCOUNT; - d_instantiate(dentry, inode); + d_instantiate(path.dentry, inode); inode->i_size = size; inode->i_nlink = 0; /* It is unlinked */ - init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, - &shmem_file_operations); +#ifndef CONFIG_MMU + error = ramfs_nommu_expand_for_mapping(inode, size); + if (error) + goto put_dentry; +#endif + + error = -ENFILE; + file = alloc_file(&path, FMODE_WRITE | FMODE_READ, + &shmem_file_operations); + if (!file) + goto put_dentry; + return file; -close_file: - put_filp(file); put_dentry: - dput(dentry); + path_put(&path); put_memory: shmem_unacct_size(flags, size); return ERR_PTR(error); } +EXPORT_SYMBOL_GPL(shmem_file_setup); /** * shmem_zero_setup - setup a shared anonymous mapping