diff options
| author | Jens Axboe <axboe@kernel.dk> | 2018-11-21 10:32:39 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-12-08 08:46:55 +0100 |
| commit | 1d8e40836044aeff3192f072425ea19f5c5807eb (patch) | |
| tree | 935cd65cbb4353568237f2b8a8dbf1234d6e8a1c /fs | |
| parent | b63ee2febedce876d31baa2bf345850e3b00b5ee (diff) | |
fs: add fget_many() and fput_many()
commit 091141a42e15fe47ada737f3996b317072afcefb upstream.
Some uses cases repeatedly get and put references to the same file, but
the only exposed interface is doing these one at the time. As each of
these entail an atomic inc or dec on a shared structure, that cost can
add up.
Add fget_many(), which works just like fget(), except it takes an
argument for how many references to get on the file. Ditto fput_many(),
which can drop an arbitrary number of references to a file.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/file.c | 15 | ||||
| -rw-r--r-- | fs/file_table.c | 9 |
2 files changed, 17 insertions, 7 deletions
diff --git a/fs/file.c b/fs/file.c index 97c6f0df39da..c0e7bc2c6ca0 100644 --- a/fs/file.c +++ b/fs/file.c @@ -679,7 +679,7 @@ void do_close_on_exec(struct files_struct *files) spin_unlock(&files->file_lock); } -static struct file *__fget(unsigned int fd, fmode_t mask) +static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs) { struct files_struct *files = current->files; struct file *file; @@ -694,7 +694,7 @@ loop: */ if (file->f_mode & mask) file = NULL; - else if (!get_file_rcu(file)) + else if (!get_file_rcu_many(file, refs)) goto loop; } rcu_read_unlock(); @@ -702,15 +702,20 @@ loop: return file; } +struct file *fget_many(unsigned int fd, unsigned int refs) +{ + return __fget(fd, FMODE_PATH, refs); +} + struct file *fget(unsigned int fd) { - return __fget(fd, FMODE_PATH); + return __fget(fd, FMODE_PATH, 1); } EXPORT_SYMBOL(fget); struct file *fget_raw(unsigned int fd) { - return __fget(fd, 0); + return __fget(fd, 0, 1); } EXPORT_SYMBOL(fget_raw); @@ -741,7 +746,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask) return 0; return (unsigned long)file; } else { - file = __fget(fd, mask); + file = __fget(fd, mask, 1); if (!file) return 0; return FDPUT_FPUT | (unsigned long)file; diff --git a/fs/file_table.c b/fs/file_table.c index 61517f57f8ef..4ceb4982ffea 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -261,9 +261,9 @@ void flush_delayed_fput(void) static DECLARE_DELAYED_WORK(delayed_fput_work, delayed_fput); -void fput(struct file *file) +void fput_many(struct file *file, unsigned int refs) { - if (atomic_long_dec_and_test(&file->f_count)) { + if (atomic_long_sub_and_test(refs, &file->f_count)) { struct task_struct *task = current; if (likely(!in_interrupt() && !(task->flags & PF_KTHREAD))) { @@ -282,6 +282,11 @@ void fput(struct file *file) } } +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 |