X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Fpipe.c;h=37ba29ff3158aca16ff0febd65fdb3cce24152d6;hb=274a24c16fa97a1fc67437b191274db2286c7ac3;hp=b89c878588a9ecabe59b5bc417e3b8ea660ba0bf;hpb=d4e82042c4cfa87a7d51710b71f568fe80132551;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/pipe.c b/fs/pipe.c index b89c878..37ba29f 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -37,6 +37,42 @@ * -- Manfred Spraul 2002-05-09 */ +static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass) +{ + if (pipe->inode) + mutex_lock_nested(&pipe->inode->i_mutex, subclass); +} + +void pipe_lock(struct pipe_inode_info *pipe) +{ + /* + * pipe_lock() nests non-pipe inode locks (for writing to a file) + */ + pipe_lock_nested(pipe, I_MUTEX_PARENT); +} +EXPORT_SYMBOL(pipe_lock); + +void pipe_unlock(struct pipe_inode_info *pipe) +{ + if (pipe->inode) + mutex_unlock(&pipe->inode->i_mutex); +} +EXPORT_SYMBOL(pipe_unlock); + +void pipe_double_lock(struct pipe_inode_info *pipe1, + struct pipe_inode_info *pipe2) +{ + BUG_ON(pipe1 == pipe2); + + if (pipe1 < pipe2) { + pipe_lock_nested(pipe1, I_MUTEX_PARENT); + pipe_lock_nested(pipe2, I_MUTEX_CHILD); + } else { + pipe_lock_nested(pipe2, I_MUTEX_PARENT); + pipe_lock_nested(pipe1, I_MUTEX_CHILD); + } +} + /* Drop the inode semaphore and wait for a pipe event, atomically */ void pipe_wait(struct pipe_inode_info *pipe) { @@ -47,12 +83,10 @@ void pipe_wait(struct pipe_inode_info *pipe) * is considered a noninteractive wait: */ prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE); - if (pipe->inode) - mutex_unlock(&pipe->inode->i_mutex); + pipe_unlock(pipe); schedule(); finish_wait(&pipe->wait, &wait); - if (pipe->inode) - mutex_lock(&pipe->inode->i_mutex); + pipe_lock(pipe); } static int @@ -268,6 +302,20 @@ int generic_pipe_buf_confirm(struct pipe_inode_info *info, return 0; } +/** + * generic_pipe_buf_release - put a reference to a &struct pipe_buffer + * @pipe: the pipe that the buffer belongs to + * @buf: the buffer to put a reference to + * + * Description: + * This function releases a reference to @buf. + */ +void generic_pipe_buf_release(struct pipe_inode_info *pipe, + struct pipe_buffer *buf) +{ + page_cache_release(buf->page); +} + static const struct pipe_buf_operations anon_pipe_buf_ops = { .can_merge = 1, .map = generic_pipe_buf_map, @@ -667,10 +715,7 @@ pipe_read_fasync(int fd, struct file *filp, int on) retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers); mutex_unlock(&inode->i_mutex); - if (retval < 0) - return retval; - - return 0; + return retval; } @@ -684,10 +729,7 @@ pipe_write_fasync(int fd, struct file *filp, int on) retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers); mutex_unlock(&inode->i_mutex); - if (retval < 0) - return retval; - - return 0; + return retval; } @@ -699,18 +741,14 @@ pipe_rdwr_fasync(int fd, struct file *filp, int on) int retval; mutex_lock(&inode->i_mutex); - retval = fasync_helper(fd, filp, on, &pipe->fasync_readers); - - if (retval >= 0) + if (retval >= 0) { retval = fasync_helper(fd, filp, on, &pipe->fasync_writers); - + if (retval < 0) /* this can happen only if on == T */ + fasync_helper(-1, filp, 0, &pipe->fasync_readers); + } mutex_unlock(&inode->i_mutex); - - if (retval < 0) - return retval; - - return 0; + return retval; } @@ -739,36 +777,55 @@ pipe_rdwr_release(struct inode *inode, struct file *filp) static int pipe_read_open(struct inode *inode, struct file *filp) { - /* We could have perhaps used atomic_t, but this and friends - below are the only places. So it doesn't seem worthwhile. */ + int ret = -ENOENT; + mutex_lock(&inode->i_mutex); - inode->i_pipe->readers++; + + if (inode->i_pipe) { + ret = 0; + inode->i_pipe->readers++; + } + mutex_unlock(&inode->i_mutex); - return 0; + return ret; } static int pipe_write_open(struct inode *inode, struct file *filp) { + int ret = -ENOENT; + mutex_lock(&inode->i_mutex); - inode->i_pipe->writers++; + + if (inode->i_pipe) { + ret = 0; + inode->i_pipe->writers++; + } + mutex_unlock(&inode->i_mutex); - return 0; + return ret; } static int pipe_rdwr_open(struct inode *inode, struct file *filp) { + int ret = -ENOENT; + mutex_lock(&inode->i_mutex); - if (filp->f_mode & FMODE_READ) - inode->i_pipe->readers++; - if (filp->f_mode & FMODE_WRITE) - inode->i_pipe->writers++; + + if (inode->i_pipe) { + ret = 0; + if (filp->f_mode & FMODE_READ) + inode->i_pipe->readers++; + if (filp->f_mode & FMODE_WRITE) + inode->i_pipe->writers++; + } + mutex_unlock(&inode->i_mutex); - return 0; + return ret; } /* @@ -849,17 +906,6 @@ void free_pipe_info(struct inode *inode) } static struct vfsmount *pipe_mnt __read_mostly; -static int pipefs_delete_dentry(struct dentry *dentry) -{ - /* - * At creation time, we pretended this dentry was hashed - * (by clearing DCACHE_UNHASHED bit in d_flags) - * At delete time, we restore the truth : not hashed. - * (so that dput() can proceed correctly) - */ - dentry->d_flags |= DCACHE_UNHASHED; - return 0; -} /* * pipefs_dname() is called from d_path(). @@ -870,8 +916,7 @@ static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen) dentry->d_inode->i_ino); } -static struct dentry_operations pipefs_dentry_operations = { - .d_delete = pipefs_delete_dentry, +static const struct dentry_operations pipefs_dentry_operations = { .d_dname = pipefs_dname, }; @@ -917,7 +962,7 @@ struct file *create_write_pipe(int flags) int err; struct inode *inode; struct file *f; - struct dentry *dentry; + struct path path; struct qstr name = { .name = "" }; err = -ENFILE; @@ -926,21 +971,16 @@ struct file *create_write_pipe(int flags) goto err; err = -ENOMEM; - dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); - if (!dentry) + path.dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name); + if (!path.dentry) goto err_inode; + path.mnt = mntget(pipe_mnt); - dentry->d_op = &pipefs_dentry_operations; - /* - * We dont want to publish this dentry into global dentry hash table. - * We pretend dentry is already hashed, by unsetting DCACHE_UNHASHED - * This permits a working /proc/$pid/fd/XXX on pipes - */ - dentry->d_flags &= ~DCACHE_UNHASHED; - d_instantiate(dentry, inode); + path.dentry->d_op = &pipefs_dentry_operations; + d_instantiate(path.dentry, inode); err = -ENFILE; - f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipefifo_fops); + f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops); if (!f) goto err_dentry; f->f_mapping = inode->i_mapping; @@ -952,7 +992,7 @@ struct file *create_write_pipe(int flags) err_dentry: free_pipe_info(inode); - dput(dentry); + path_put(&path); return ERR_PTR(err); err_inode: @@ -971,20 +1011,14 @@ void free_write_pipe(struct file *f) struct file *create_read_pipe(struct file *wrf, int flags) { - struct file *f = get_empty_filp(); + /* Grab pipe from the writer */ + struct file *f = alloc_file(&wrf->f_path, FMODE_READ, + &read_pipefifo_fops); if (!f) return ERR_PTR(-ENFILE); - /* Grab pipe from the writer */ - f->f_path = wrf->f_path; path_get(&wrf->f_path); - f->f_mapping = wrf->f_path.dentry->d_inode->i_mapping; - - f->f_pos = 0; f->f_flags = O_RDONLY | (flags & O_NONBLOCK); - f->f_op = &read_pipefifo_fops; - f->f_mode = FMODE_READ; - f->f_version = 0; return f; } @@ -1034,11 +1068,6 @@ int do_pipe_flags(int *fd, int flags) return error; } -int do_pipe(int *fd) -{ - return do_pipe_flags(fd, 0); -} - /* * sys_pipe() is the normal C calling standard for creating * a pipe. It's not the way Unix traditionally does this, though. @@ -1059,7 +1088,7 @@ SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) return error; } -asmlinkage long sys_pipe(int __user *fildes) +SYSCALL_DEFINE1(pipe, int __user *, fildes) { return sys_pipe2(fildes, 0); }