tree: https://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git work.open head: 956b068e4bed1c13d0218ea7afaaa9ea0d345fc2 commit: 2e0cc644dea0b2f616879145cc0dd6c43373c475 [39/44] new wrapper: alloc_file_pseudo() config: i386-tinyconfig (attached as .config) compiler: gcc-7 (Debian 7.3.0-16) 7.3.0 reproduce: git checkout 2e0cc644dea0b2f616879145cc0dd6c43373c475 # save the attached .config to linux build tree make ARCH=i386 All errors (new ones prefixed by >>): In file included from fs/file_table.c:10:0: include/linux/file.h:23:46: warning: 'struct inode' declared inside parameter list will not be visible outside of this definition or declaration extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *, ^~~~~ >> fs/file_table.c:185:14: error: conflicting types for 'alloc_file_pseudo' struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt, ^~~~~~~~~~~~~~~~~ In file included from fs/file_table.c:10:0: include/linux/file.h:23:21: note: previous declaration of 'alloc_file_pseudo' was here extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *, ^~~~~~~~~~~~~~~~~ vim +/alloc_file_pseudo +185 fs/file_table.c > 10 #include <linux/file.h> 11 #include <linux/fdtable.h> 12 #include <linux/init.h> 13 #include <linux/module.h> 14 #include <linux/fs.h> 15 #include <linux/security.h> 16 #include <linux/cred.h> 17 #include <linux/eventpoll.h> 18 #include <linux/rcupdate.h> 19 #include <linux/mount.h> 20 #include <linux/capability.h> 21 #include <linux/cdev.h> 22 #include <linux/fsnotify.h> 23 #include <linux/sysctl.h> 24 #include <linux/percpu_counter.h> 25 #include <linux/percpu.h> 26 #include <linux/task_work.h> 27 #include <linux/ima.h> 28 #include <linux/swap.h> 29 30 #include <linux/atomic.h> 31 32 #include "internal.h" 33 34 /* sysctl tunables... */ 35 struct files_stat_struct files_stat = { 36 .max_files = NR_FILE 37 }; 38 39 /* SLAB cache for file structures */ 40 static struct kmem_cache *filp_cachep __read_mostly; 41 42 static struct percpu_counter nr_files __cacheline_aligned_in_smp; 43 44 static void file_free_rcu(struct rcu_head *head) 45 { 46 struct file *f = container_of(head, struct file, f_u.fu_rcuhead); 47 48 put_cred(f->f_cred); 49 kmem_cache_free(filp_cachep, f); 50 } 51 52 static inline void file_free(struct file *f) 53 { 54 percpu_counter_dec(&nr_files); 55 call_rcu(&f->f_u.fu_rcuhead, file_free_rcu); 56 } 57 58 /* 59 * Return the total number of open files in the system 60 */ 61 static long get_nr_files(void) 62 { 63 return percpu_counter_read_positive(&nr_files); 64 } 65 66 /* 67 * Return the maximum number of open files in the system 68 */ 69 unsigned long get_max_files(void) 70 { 71 return files_stat.max_files; 72 } 73 EXPORT_SYMBOL_GPL(get_max_files); 74 75 /* 76 * Handle nr_files sysctl 77 */ 78 #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) 79 int proc_nr_files(struct ctl_table *table, int write, 80 void __user *buffer, size_t *lenp, loff_t *ppos) 81 { 82 files_stat.nr_files = get_nr_files(); 83 return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); 84 } 85 #else 86 int proc_nr_files(struct ctl_table *table, int write, 87 void __user *buffer, size_t *lenp, loff_t *ppos) 88 { 89 return -ENOSYS; 90 } 91 #endif 92 93 /* Find an unused file structure and return a pointer to it. 94 * Returns an error pointer if some error happend e.g. we over file 95 * structures limit, run out of memory or operation is not permitted. 96 * 97 * Be very careful using this. You are responsible for 98 * getting write access to any mount that you might assign 99 * to this filp, if it is opened for write. If this is not 100 * done, you will imbalance int the mount's writer count 101 * and a warning at __fput() time. 102 */ 103 struct file *get_empty_filp(void) 104 { 105 const struct cred *cred = current_cred(); 106 static long old_max; 107 struct file *f; 108 int error; 109 110 /* 111 * Privileged users can go above max_files 112 */ 113 if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) { 114 /* 115 * percpu_counters are inaccurate. Do an expensive check before 116 * we go and fail. 117 */ 118 if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files) 119 goto over; 120 } 121 122 f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL); 123 if (unlikely(!f)) 124 return ERR_PTR(-ENOMEM); 125 126 percpu_counter_inc(&nr_files); 127 f->f_cred = get_cred(cred); 128 error = security_file_alloc(f); 129 if (unlikely(error)) { 130 file_free(f); 131 return ERR_PTR(error); 132 } 133 134 atomic_long_set(&f->f_count, 1); 135 rwlock_init(&f->f_owner.lock); 136 spin_lock_init(&f->f_lock); 137 mutex_init(&f->f_pos_lock); 138 eventpoll_init_file(f); 139 /* f->f_version: 0 */ 140 return f; 141 142 over: 143 /* Ran out of filps - report that */ 144 if (get_nr_files() > old_max) { 145 pr_info("VFS: file-max limit %lu reached\n", get_max_files()); 146 old_max = get_nr_files(); 147 } 148 return ERR_PTR(-ENFILE); 149 } 150 151 /** 152 * alloc_file - allocate and initialize a 'struct file' 153 * 154 * @path: the (dentry, vfsmount) pair for the new file 155 * @mode: the mode with which the new file will be opened 156 * @fop: the 'struct file_operations' for the new file 157 */ 158 struct file *alloc_file(const struct path *path, fmode_t mode, 159 const struct file_operations *fop) 160 { 161 struct file *file; 162 163 file = get_empty_filp(); 164 if (IS_ERR(file)) 165 return file; 166 167 file->f_path = *path; 168 file->f_inode = path->dentry->d_inode; 169 file->f_mapping = path->dentry->d_inode->i_mapping; 170 file->f_wb_err = filemap_sample_wb_err(file->f_mapping); 171 if ((mode & FMODE_READ) && 172 likely(fop->read || fop->read_iter)) 173 mode |= FMODE_CAN_READ; 174 if ((mode & FMODE_WRITE) && 175 likely(fop->write || fop->write_iter)) 176 mode |= FMODE_CAN_WRITE; 177 file->f_mode = mode; 178 file->f_op = fop; 179 if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) 180 i_readcount_inc(path->dentry->d_inode); 181 return file; 182 } 183 EXPORT_SYMBOL(alloc_file); 184 > 185 struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt, 186 const char *name, fmode_t mode, 187 const struct file_operations *fops) 188 { 189 static const struct dentry_operations anon_ops = { 190 .d_dname = simple_dname 191 }; 192 struct qstr this = QSTR_INIT(name, strlen(name)); 193 struct path path; 194 struct file *file; 195 196 path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this); 197 if (!path.dentry) 198 return ERR_PTR(-ENOMEM); 199 if (!mnt->mnt_sb->s_d_op) 200 d_set_d_op(path.dentry, &anon_ops); 201 path.mnt = mntget(mnt); 202 d_instantiate(path.dentry, inode); 203 file = alloc_file(&path, mode | FMODE_OPENED, fops); 204 if (IS_ERR(file)) { 205 ihold(inode); 206 path_put(&path); 207 } 208 return file; 209 } 210 EXPORT_SYMBOL(alloc_file_pseudo); 211 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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