[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>
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 61d6251..2e40799 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -49,73 +49,6 @@
return res;
}
-/*
- * locate_fd finds a free file descriptor in the open_fds fdset,
- * expanding the fd arrays if necessary. Must be called with the
- * file_lock held for write.
- */
-
-static int locate_fd(unsigned int orig_start, int cloexec)
-{
- struct files_struct *files = current->files;
- unsigned int newfd;
- unsigned int start;
- int error;
- struct fdtable *fdt;
-
- spin_lock(&files->file_lock);
-repeat:
- fdt = files_fdtable(files);
- /*
- * Someone might have closed fd's in the range
- * orig_start..fdt->next_fd
- */
- start = orig_start;
- if (start < files->next_fd)
- start = files->next_fd;
-
- newfd = start;
- if (start < fdt->max_fds)
- newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
- fdt->max_fds, start);
-
- error = expand_files(files, newfd);
- if (error < 0)
- goto out;
-
- /*
- * If we needed to expand the fs array we
- * might have blocked - try again.
- */
- if (error)
- goto repeat;
-
- if (start <= files->next_fd)
- files->next_fd = newfd + 1;
-
- FD_SET(newfd, fdt->open_fds);
- if (cloexec)
- FD_SET(newfd, fdt->close_on_exec);
- else
- FD_CLR(newfd, fdt->close_on_exec);
- error = newfd;
-
-out:
- spin_unlock(&files->file_lock);
- return error;
-}
-
-static int dupfd(struct file *file, unsigned int start, int cloexec)
-{
- int fd = locate_fd(start, cloexec);
- if (fd >= 0)
- fd_install(fd, file);
- else
- fput(file);
-
- return fd;
-}
-
asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
int err = -EBADF;
@@ -194,10 +127,15 @@
asmlinkage long sys_dup(unsigned int fildes)
{
int ret = -EBADF;
- struct file * file = fget(fildes);
+ struct file *file = fget(fildes);
- if (file)
- ret = dupfd(file, 0, 0);
+ if (file) {
+ ret = get_unused_fd();
+ if (ret >= 0)
+ fd_install(ret, file);
+ else
+ fput(file);
+ }
return ret;
}
@@ -322,8 +260,11 @@
case F_DUPFD_CLOEXEC:
if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
break;
- get_file(filp);
- err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
+ err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
+ if (err >= 0) {
+ get_file(filp);
+ fd_install(err, filp);
+ }
break;
case F_GETFD:
err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
diff --git a/fs/file.c b/fs/file.c
index d8773b1..f313314 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -6,6 +6,7 @@
* Manage the dynamic fd arrays in the process files_struct.
*/
+#include <linux/module.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/time.h>
@@ -432,3 +433,63 @@
},
.file_lock = __SPIN_LOCK_UNLOCKED(init_task.file_lock),
};
+
+/*
+ * allocate a file descriptor, mark it busy.
+ */
+int alloc_fd(unsigned start, unsigned flags)
+{
+ struct files_struct *files = current->files;
+ unsigned int fd;
+ int error;
+ struct fdtable *fdt;
+
+ spin_lock(&files->file_lock);
+repeat:
+ fdt = files_fdtable(files);
+ fd = start;
+ if (fd < files->next_fd)
+ fd = files->next_fd;
+
+ if (fd < fdt->max_fds)
+ fd = find_next_zero_bit(fdt->open_fds->fds_bits,
+ fdt->max_fds, fd);
+
+ error = expand_files(files, fd);
+ if (error < 0)
+ goto out;
+
+ /*
+ * If we needed to expand the fs array we
+ * might have blocked - try again.
+ */
+ if (error)
+ goto repeat;
+
+ if (start <= files->next_fd)
+ files->next_fd = fd + 1;
+
+ FD_SET(fd, fdt->open_fds);
+ if (flags & O_CLOEXEC)
+ FD_SET(fd, fdt->close_on_exec);
+ else
+ FD_CLR(fd, fdt->close_on_exec);
+ error = fd;
+#if 1
+ /* Sanity check */
+ if (rcu_dereference(fdt->fd[fd]) != NULL) {
+ printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ }
+#endif
+
+out:
+ spin_unlock(&files->file_lock);
+ return error;
+}
+
+int get_unused_fd(void)
+{
+ return alloc_fd(0, 0);
+}
+EXPORT_SYMBOL(get_unused_fd);
diff --git a/fs/open.c b/fs/open.c
index 52647be..07da935 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -963,62 +963,6 @@
}
EXPORT_SYMBOL(dentry_open);
-/*
- * Find an empty file descriptor entry, and mark it busy.
- */
-int get_unused_fd_flags(int flags)
-{
- struct files_struct * files = current->files;
- int fd, error;
- struct fdtable *fdt;
-
- spin_lock(&files->file_lock);
-
-repeat:
- fdt = files_fdtable(files);
- fd = find_next_zero_bit(fdt->open_fds->fds_bits, fdt->max_fds,
- files->next_fd);
-
- /* Do we need to expand the fd array or fd set? */
- error = expand_files(files, fd);
- if (error < 0)
- goto out;
-
- if (error) {
- /*
- * If we needed to expand the fs array we
- * might have blocked - try again.
- */
- goto repeat;
- }
-
- FD_SET(fd, fdt->open_fds);
- if (flags & O_CLOEXEC)
- FD_SET(fd, fdt->close_on_exec);
- else
- FD_CLR(fd, fdt->close_on_exec);
- files->next_fd = fd + 1;
-#if 1
- /* Sanity check */
- if (fdt->fd[fd] != NULL) {
- printk(KERN_WARNING "get_unused_fd: slot %d not NULL!\n", fd);
- fdt->fd[fd] = NULL;
- }
-#endif
- error = fd;
-
-out:
- spin_unlock(&files->file_lock);
- return error;
-}
-
-int get_unused_fd(void)
-{
- return get_unused_fd_flags(0);
-}
-
-EXPORT_SYMBOL(get_unused_fd);
-
static void __put_unused_fd(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = files_fdtable(files);
diff --git a/include/linux/file.h b/include/linux/file.h
index 27c64bd..a20259e 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -34,8 +34,9 @@
extern struct file *fget_light(unsigned int fd, int *fput_needed);
extern void set_close_on_exec(unsigned int fd, int flag);
extern void put_filp(struct file *);
+extern int alloc_fd(unsigned start, unsigned flags);
extern int get_unused_fd(void);
-extern int get_unused_fd_flags(int flags);
+#define get_unused_fd_flags(flags) alloc_fd(0, (flags))
extern void put_unused_fd(unsigned int fd);
extern void fd_install(unsigned int fd, struct file *file);