[PATCH] merge locate_fd() and get_unused_fd()
New primitive: alloc_fd(start, flags). get_unused_fd() and get_unused_fd_flags() become wrappers on top of it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Родитель
a1bc6eb4b4
Коммит
1027abe882
85
fs/fcntl.c
85
fs/fcntl.c
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@ -49,73 +49,6 @@ static int get_close_on_exec(unsigned int fd)
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return res;
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}
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/*
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* locate_fd finds a free file descriptor in the open_fds fdset,
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* expanding the fd arrays if necessary. Must be called with the
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* file_lock held for write.
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*/
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static int locate_fd(unsigned int orig_start, int cloexec)
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{
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struct files_struct *files = current->files;
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unsigned int newfd;
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unsigned int start;
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int error;
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struct fdtable *fdt;
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spin_lock(&files->file_lock);
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repeat:
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fdt = files_fdtable(files);
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/*
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* Someone might have closed fd's in the range
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* orig_start..fdt->next_fd
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*/
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start = orig_start;
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if (start < files->next_fd)
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start = files->next_fd;
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newfd = start;
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if (start < fdt->max_fds)
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newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
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fdt->max_fds, start);
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error = expand_files(files, newfd);
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if (error < 0)
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goto out;
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/*
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* If we needed to expand the fs array we
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* might have blocked - try again.
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*/
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if (error)
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goto repeat;
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if (start <= files->next_fd)
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files->next_fd = newfd + 1;
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FD_SET(newfd, fdt->open_fds);
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if (cloexec)
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FD_SET(newfd, fdt->close_on_exec);
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else
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FD_CLR(newfd, fdt->close_on_exec);
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error = newfd;
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out:
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spin_unlock(&files->file_lock);
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return error;
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}
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static int dupfd(struct file *file, unsigned int start, int cloexec)
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{
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int fd = locate_fd(start, cloexec);
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if (fd >= 0)
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fd_install(fd, file);
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else
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fput(file);
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return fd;
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}
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asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
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{
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int err = -EBADF;
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@ -194,10 +127,15 @@ asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
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asmlinkage long sys_dup(unsigned int fildes)
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{
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int ret = -EBADF;
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struct file * file = fget(fildes);
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struct file *file = fget(fildes);
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if (file)
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ret = dupfd(file, 0, 0);
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if (file) {
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ret = get_unused_fd();
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if (ret >= 0)
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fd_install(ret, file);
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else
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fput(file);
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}
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return ret;
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}
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@ -322,8 +260,11 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
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case F_DUPFD_CLOEXEC:
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if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
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break;
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get_file(filp);
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err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
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err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
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if (err >= 0) {
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get_file(filp);
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fd_install(err, filp);
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}
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break;
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case F_GETFD:
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err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
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61
fs/file.c
61
fs/file.c
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@ -6,6 +6,7 @@
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* Manage the dynamic fd arrays in the process files_struct.
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/time.h>
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@ -432,3 +433,63 @@ struct files_struct init_files = {
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},
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.file_lock = __SPIN_LOCK_UNLOCKED(init_task.file_lock),
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};
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/*
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* allocate a file descriptor, mark it busy.
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*/
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int alloc_fd(unsigned start, unsigned flags)
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{
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struct files_struct *files = current->files;
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unsigned int fd;
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int error;
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struct fdtable *fdt;
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spin_lock(&files->file_lock);
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repeat:
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fdt = files_fdtable(files);
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fd = start;
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if (fd < files->next_fd)
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fd = files->next_fd;
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if (fd < fdt->max_fds)
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fd = find_next_zero_bit(fdt->open_fds->fds_bits,
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fdt->max_fds, fd);
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error = expand_files(files, fd);
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if (error < 0)
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goto out;
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/*
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* If we needed to expand the fs array we
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* might have blocked - try again.
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*/
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if (error)
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goto repeat;
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if (start <= files->next_fd)
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files->next_fd = fd + 1;
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FD_SET(fd, fdt->open_fds);
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if (flags & O_CLOEXEC)
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FD_SET(fd, fdt->close_on_exec);
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else
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FD_CLR(fd, fdt->close_on_exec);
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error = fd;
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#if 1
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/* Sanity check */
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if (rcu_dereference(fdt->fd[fd]) != NULL) {
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printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
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rcu_assign_pointer(fdt->fd[fd], NULL);
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}
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#endif
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out:
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spin_unlock(&files->file_lock);
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return error;
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}
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int get_unused_fd(void)
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{
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return alloc_fd(0, 0);
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}
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EXPORT_SYMBOL(get_unused_fd);
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56
fs/open.c
56
fs/open.c
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@ -963,62 +963,6 @@ struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags)
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}
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EXPORT_SYMBOL(dentry_open);
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/*
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* Find an empty file descriptor entry, and mark it busy.
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*/
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int get_unused_fd_flags(int flags)
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{
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struct files_struct * files = current->files;
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int fd, error;
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struct fdtable *fdt;
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spin_lock(&files->file_lock);
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repeat:
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fdt = files_fdtable(files);
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fd = find_next_zero_bit(fdt->open_fds->fds_bits, fdt->max_fds,
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files->next_fd);
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/* Do we need to expand the fd array or fd set? */
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error = expand_files(files, fd);
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if (error < 0)
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goto out;
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if (error) {
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/*
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* If we needed to expand the fs array we
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* might have blocked - try again.
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*/
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goto repeat;
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}
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FD_SET(fd, fdt->open_fds);
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if (flags & O_CLOEXEC)
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FD_SET(fd, fdt->close_on_exec);
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else
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FD_CLR(fd, fdt->close_on_exec);
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files->next_fd = fd + 1;
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#if 1
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/* Sanity check */
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if (fdt->fd[fd] != NULL) {
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printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
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fdt->fd[fd] = NULL;
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}
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#endif
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error = fd;
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out:
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spin_unlock(&files->file_lock);
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return error;
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}
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int get_unused_fd(void)
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{
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return get_unused_fd_flags(0);
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}
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EXPORT_SYMBOL(get_unused_fd);
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static void __put_unused_fd(struct files_struct *files, unsigned int fd)
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{
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struct fdtable *fdt = files_fdtable(files);
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@ -34,8 +34,9 @@ extern struct file *fget(unsigned int fd);
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extern struct file *fget_light(unsigned int fd, int *fput_needed);
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extern void set_close_on_exec(unsigned int fd, int flag);
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extern void put_filp(struct file *);
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extern int alloc_fd(unsigned start, unsigned flags);
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extern int get_unused_fd(void);
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extern int get_unused_fd_flags(int flags);
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#define get_unused_fd_flags(flags) alloc_fd(0, (flags))
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extern void put_unused_fd(unsigned int fd);
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extern void fd_install(unsigned int fd, struct file *file);
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