pipe: add support for shrinking and growing pipes
This patch adds F_GETPIPE_SZ and F_SETPIPE_SZ fcntl() actions for
growing and shrinking the size of a pipe and adjusts pipe.c and splice.c
(and relay and network splice) usage to work with these larger (or smaller)
pipes.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h
index 8603740..afc00af 100644
--- a/include/linux/fcntl.h
+++ b/include/linux/fcntl.h
@@ -22,6 +22,12 @@
#define F_NOTIFY (F_LINUX_SPECIFIC_BASE+2)
/*
+ * Set and get of pipe page size array
+ */
+#define F_SETPIPE_SZ (F_LINUX_SPECIFIC_BASE + 7)
+#define F_GETPIPE_SZ (F_LINUX_SPECIFIC_BASE + 8)
+
+/*
* Types of directory notifications that may be requested.
*/
#define DN_ACCESS 0x00000001 /* File accessed */
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index b43a9e0..65f4282 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -3,7 +3,7 @@
#define PIPEFS_MAGIC 0x50495045
-#define PIPE_BUFFERS (16)
+#define PIPE_DEF_BUFFERS 16
#define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */
#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */
@@ -44,17 +44,17 @@
**/
struct pipe_inode_info {
wait_queue_head_t wait;
- unsigned int nrbufs, curbuf;
- struct page *tmp_page;
+ unsigned int nrbufs, curbuf, buffers;
unsigned int readers;
unsigned int writers;
unsigned int waiting_writers;
unsigned int r_counter;
unsigned int w_counter;
+ struct page *tmp_page;
struct fasync_struct *fasync_readers;
struct fasync_struct *fasync_writers;
struct inode *inode;
- struct pipe_buffer bufs[PIPE_BUFFERS];
+ struct pipe_buffer *bufs;
};
/*
@@ -154,4 +154,7 @@
int generic_pipe_buf_steal(struct pipe_inode_info *, struct pipe_buffer *);
void generic_pipe_buf_release(struct pipe_inode_info *, struct pipe_buffer *);
+/* for F_SETPIPE_SZ and F_GETPIPE_SZ */
+long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
+
#endif
diff --git a/include/linux/splice.h b/include/linux/splice.h
index 18e7c7c..997c3b4 100644
--- a/include/linux/splice.h
+++ b/include/linux/splice.h
@@ -82,4 +82,11 @@
extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
splice_direct_actor *);
+/*
+ * for dynamic pipe sizing
+ */
+extern int splice_grow_spd(struct pipe_inode_info *, struct splice_pipe_desc *);
+extern void splice_shrink_spd(struct pipe_inode_info *,
+ struct splice_pipe_desc *);
+
#endif