diff options
Diffstat (limited to 'include/linux/pipe_fs_i.h')
| -rw-r--r-- | include/linux/pipe_fs_i.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 96158ca80456..44f2245debda 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -32,6 +32,7 @@ struct pipe_buffer { * @wait: reader/writer wait point in case of empty/full pipe * @head: The point of buffer production * @tail: The point of buffer consumption + * @max_usage: The maximum number of slots that may be used in the ring * @ring_size: total number of buffers (should be a power of 2) * @tmp_page: cached released page * @readers: number of current readers of this pipe @@ -50,6 +51,7 @@ struct pipe_inode_info { wait_queue_head_t wait; unsigned int head; unsigned int tail; + unsigned int max_usage; unsigned int ring_size; unsigned int readers; unsigned int writers; @@ -150,9 +152,11 @@ static inline unsigned int pipe_space_for_user(unsigned int head, unsigned int t unsigned int p_occupancy, p_space; p_occupancy = pipe_occupancy(head, tail); - if (p_occupancy >= pipe->ring_size) + if (p_occupancy >= pipe->max_usage) return 0; p_space = pipe->ring_size - p_occupancy; + if (p_space > pipe->max_usage) + p_space = pipe->max_usage; return p_space; } |