diff options
Diffstat (limited to 'fs/read_write.c')
| -rw-r--r-- | fs/read_write.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/fs/read_write.c b/fs/read_write.c index a6133241dfb8..bb0ed26a0b3a 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -169,11 +169,16 @@ generic_file_llseek_size(struct file *file, loff_t offset, int whence, if (whence == SEEK_CUR) { /* - * f_lock protects against read/modify/write race with - * other SEEK_CURs. Note that parallel writes and reads - * behave like SEEK_SET. + * If the file requires locking via f_pos_lock we know + * that mutual exclusion for SEEK_CUR on the same file + * is guaranteed. If the file isn't locked, we take + * f_lock to protect against f_pos races with other + * SEEK_CURs. */ - guard(spinlock)(&file->f_lock); + if (file_seek_cur_needs_f_lock(file)) { + guard(spinlock)(&file->f_lock); + return vfs_setpos(file, file->f_pos + offset, maxsize); + } return vfs_setpos(file, file->f_pos + offset, maxsize); } |