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authorLinus Torvalds <torvalds@linux-foundation.org>2022-06-04 18:52:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-06-04 18:52:00 -0700
commitdbe0ee46614016146c1b3e1fc063b44333bb2401 (patch)
treed575d487d306a8f03cceac3f930d7fd53a6079f8 /fs
parentd66016c5cd3d4c474cd24622c511dcd358645613 (diff)
parent6319194ec57b0452dcda4589d24c4e7db299c5bf (diff)
Merge tag 'pull-18-rc1-work.fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull file descriptor updates from Al Viro. - Descriptor handling cleanups * tag 'pull-18-rc1-work.fd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: Unify the primitives for file descriptor closing fs: remove fget_many and fput_many interface io_uring_enter(): don't leave f.flags uninitialized
Diffstat (limited to 'fs')
-rw-r--r--fs/file.c110
-rw-r--r--fs/file_table.c9
-rw-r--r--fs/internal.h2
-rw-r--r--fs/io_uring.c18
4 files changed, 52 insertions, 87 deletions
diff --git a/fs/file.c b/fs/file.c
index ee9317346702..dd6692048f4f 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -630,32 +630,23 @@ EXPORT_SYMBOL(fd_install);
* @files: file struct to retrieve file from
* @fd: file descriptor to retrieve file for
*
- * If this functions returns an EINVAL error pointer the fd was beyond the
- * current maximum number of file descriptors for that fdtable.
+ * Context: files_lock must be held.
*
- * Returns: The file associated with @fd, on error returns an error pointer.
+ * Returns: The file associated with @fd (NULL if @fd is not open)
*/
static struct file *pick_file(struct files_struct *files, unsigned fd)
{
+ struct fdtable *fdt = files_fdtable(files);
struct file *file;
- struct fdtable *fdt;
- spin_lock(&files->file_lock);
- fdt = files_fdtable(files);
- if (fd >= fdt->max_fds) {
- file = ERR_PTR(-EINVAL);
- goto out_unlock;
- }
+ if (fd >= fdt->max_fds)
+ return NULL;
+
file = fdt->fd[fd];
- if (!file) {
- file = ERR_PTR(-EBADF);
- goto out_unlock;
+ if (file) {
+ rcu_assign_pointer(fdt->fd[fd], NULL);
+ __put_unused_fd(files, fd);
}
- rcu_assign_pointer(fdt->fd[fd], NULL);
- __put_unused_fd(files, fd);
-
-out_unlock:
- spin_unlock(&files->file_lock);
return file;
}
@@ -664,8 +655,10 @@ int close_fd(unsigned fd)
struct files_struct *files = current->files;
struct file *file;
+ spin_lock(&files->file_lock);
file = pick_file(files, fd);
- if (IS_ERR(file))
+ spin_unlock(&files->file_lock);
+ if (!file)
return -EBADF;
return filp_close(file, files);
@@ -702,20 +695,25 @@ static inline void __range_cloexec(struct files_struct *cur_fds,
static inline void __range_close(struct files_struct *cur_fds, unsigned int fd,
unsigned int max_fd)
{
+ unsigned n;
+
+ rcu_read_lock();
+ n = last_fd(files_fdtable(cur_fds));
+ rcu_read_unlock();
+ max_fd = min(max_fd, n);
+
while (fd <= max_fd) {
struct file *file;
+ spin_lock(&cur_fds->file_lock);
file = pick_file(cur_fds, fd++);
- if (!IS_ERR(file)) {
+ spin_unlock(&cur_fds->file_lock);
+
+ if (file) {
/* found a valid file to close */
filp_close(file, cur_fds);
cond_resched();
- continue;
}
-
- /* beyond the last fd in that table */
- if (PTR_ERR(file) == -EINVAL)
- return;
}
}
@@ -795,26 +793,9 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags)
* See close_fd_get_file() below, this variant assumes current->files->file_lock
* is held.
*/
-int __close_fd_get_file(unsigned int fd, struct file **res)
+struct file *__close_fd_get_file(unsigned int fd)
{
- struct files_struct *files = current->files;
- struct file *file;
- struct fdtable *fdt;
-
- fdt = files_fdtable(files);
- if (fd >= fdt->max_fds)
- goto out_err;
- file = fdt->fd[fd];
- if (!file)
- goto out_err;
- rcu_assign_pointer(fdt->fd[fd], NULL);
- __put_unused_fd(files, fd);
- get_file(file);
- *res = file;
- return 0;
-out_err:
- *res = NULL;
- return -ENOENT;
+ return pick_file(current->files, fd);
}
/*
@@ -822,16 +803,16 @@ out_err:
* The caller must ensure that filp_close() called on the file, and then
* an fput().
*/
-int close_fd_get_file(unsigned int fd, struct file **res)
+struct file *close_fd_get_file(unsigned int fd)
{
struct files_struct *files = current->files;
- int ret;
+ struct file *file;
spin_lock(&files->file_lock);
- ret = __close_fd_get_file(fd, res);
+ file = pick_file(files, fd);
spin_unlock(&files->file_lock);
- return ret;
+ return file;
}
void do_close_on_exec(struct files_struct *files)
@@ -871,7 +852,7 @@ void do_close_on_exec(struct files_struct *files)
}
static inline struct file *__fget_files_rcu(struct files_struct *files,
- unsigned int fd, fmode_t mask, unsigned int refs)
+ unsigned int fd, fmode_t mask)
{
for (;;) {
struct file *file;
@@ -897,10 +878,9 @@ static inline struct file *__fget_files_rcu(struct files_struct *files,
* Such a race can take two forms:
*
* (a) the file ref already went down to zero,
- * and get_file_rcu_many() fails. Just try
- * again:
+ * and get_file_rcu() fails. Just try again:
*/
- if (unlikely(!get_file_rcu_many(file, refs)))
+ if (unlikely(!get_file_rcu(file)))
continue;
/*
@@ -909,11 +889,11 @@ static inline struct file *__fget_files_rcu(struct files_struct *files,
* pointer having changed, because it always goes
* hand-in-hand with 'fdt'.
*
- * If so, we need to put our refs and try again.
+ * If so, we need to put our ref and try again.
*/
if (unlikely(rcu_dereference_raw(files->fdt) != fdt) ||
unlikely(rcu_dereference_raw(*fdentry) != file)) {
- fput_many(file, refs);
+ fput(file);
continue;
}
@@ -926,37 +906,31 @@ static inline struct file *__fget_files_rcu(struct files_struct *files,
}
static struct file *__fget_files(struct files_struct *files, unsigned int fd,
- fmode_t mask, unsigned int refs)
+ fmode_t mask)
{
struct file *file;
rcu_read_lock();
- file = __fget_files_rcu(files, fd, mask, refs);
+ file = __fget_files_rcu(files, fd, mask);
rcu_read_unlock();
return file;
}
-static inline struct file *__fget(unsigned int fd, fmode_t mask,
- unsigned int refs)
-{
- return __fget_files(current->files, fd, mask, refs);
-}
-
-struct file *fget_many(unsigned int fd, unsigned int refs)
+static inline struct file *__fget(unsigned int fd, fmode_t mask)
{
- return __fget(fd, FMODE_PATH, refs);
+ return __fget_files(current->files, fd, mask);
}
struct file *fget(unsigned int fd)
{
- return __fget(fd, FMODE_PATH, 1);
+ return __fget(fd, FMODE_PATH);
}
EXPORT_SYMBOL(fget);
struct file *fget_raw(unsigned int fd)
{
- return __fget(fd, 0, 1);
+ return __fget(fd, 0);
}
EXPORT_SYMBOL(fget_raw);
@@ -966,7 +940,7 @@ struct file *fget_task(struct task_struct *task, unsigned int fd)
task_lock(task);
if (task->files)
- file = __fget_files(task->files, fd, 0, 1);
+ file = __fget_files(task->files, fd, 0);
task_unlock(task);
return file;
@@ -1035,7 +1009,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask)
return 0;
return (unsigned long)file;
} else {
- file = __fget(fd, mask, 1);
+ file = __fget(fd, mask);
if (!file)
return 0;
return FDPUT_FPUT | (unsigned long)file;
diff --git a/fs/file_table.c b/fs/file_table.c
index ada8fe814db9..5424e3a8df5f 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -368,9 +368,9 @@ EXPORT_SYMBOL_GPL(flush_delayed_fput);
static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput);
-void fput_many(struct file *file, unsigned int refs)
+void fput(struct file *file)
{
- if (atomic_long_sub_and_test(refs, &file->f_count)) {
+ if (atomic_long_dec_and_test(&file->f_count)) {
struct task_struct *task = current;
if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) {
@@ -389,11 +389,6 @@ void fput_many(struct file *file, unsigned int refs)
}
}
-void fput(struct file *file)
-{
- fput_many(file, 1);
-}
-
/*
* synchronous analog of fput(); for kernel threads that might be needed
* in some umount() (and thus can't use flush_delayed_fput() without
diff --git a/fs/internal.h b/fs/internal.h
index 9a6c233ee7f1..ad77723779f9 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -125,7 +125,7 @@ extern struct file *do_file_open_root(const struct path *,
const char *, const struct open_flags *);
extern struct open_how build_open_how(int flags, umode_t mode);
extern int build_open_flags(const struct open_how *how, struct open_flags *op);
-extern int __close_fd_get_file(unsigned int fd, struct file **res);
+extern struct file *__close_fd_get_file(unsigned int fd);
long do_sys_ftruncate(unsigned int fd, loff_t length, int small);
int chmod_common(const struct path *path, umode_t mode);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2a9b9a24fc22..86f9df56526b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6039,13 +6039,10 @@ static int io_close(struct io_kiocb *req, unsigned int issue_flags)
return -EAGAIN;
}
- ret = __close_fd_get_file(close->fd, &file);
+ file = __close_fd_get_file(close->fd);
spin_unlock(&files->file_lock);
- if (ret < 0) {
- if (ret == -ENOENT)
- ret = -EBADF;
+ if (!file)
goto err;
- }
/* No ->flush() or already async, safely close from here */
ret = filp_close(file, current->files);
@@ -12053,14 +12050,14 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
return -EINVAL;
fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
f.file = tctx->registered_rings[fd];
- if (unlikely(!f.file))
- return -EBADF;
+ f.flags = 0;
} else {
f = fdget(fd);
- if (unlikely(!f.file))
- return -EBADF;
}
+ if (unlikely(!f.file))
+ return -EBADF;
+
ret = -EOPNOTSUPP;
if (unlikely(f.file->f_op != &io_uring_fops))
goto out_fput;
@@ -12158,8 +12155,7 @@ iopoll_locked:
out:
percpu_ref_put(&ctx->refs);
out_fput:
- if (!(flags & IORING_ENTER_REGISTERED_RING))
- fdput(f);
+ fdput(f);
return ret;
}