splice: add SPLICE_F_NONBLOCK flag

It doesn't make the splice itself necessarily nonblocking (because the
actual file descriptors that are spliced from/to may block unless they
have the O_NONBLOCK flag set), but it makes the splice pipe operations
nonblocking.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 21 insertions, 4 deletions

diff --git a/fs/splice.c b/fs/splice.c
index 7c2bbf18d7a7..6081cf7d2d1b 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -106,7 +106,7 @@ static struct pipe_buf_operations page_cache_pipe_buf_ops = {
 
 static ssize_t move_to_pipe(struct inode *inode, struct page **pages,
                             int nr_pages, unsigned long offset,
-                            unsigned long len)
+                            unsigned long len, unsigned int flags)
 {
         struct pipe_inode_info *info;
         int ret, do_wakeup, i;
@@ -159,6 +159,12 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages,
                         break;
                 }
 
+                if (flags & SPLICE_F_NONBLOCK) {
+                        if (!ret)
+                                ret = -EAGAIN;
+                        break;
+                }
+
                 if (signal_pending(current)) {
                         if (!ret)
                                 ret = -ERESTARTSYS;
@@ -191,7 +197,7 @@ static ssize_t move_to_pipe(struct inode *inode, struct page **pages,
 }
 
 static int __generic_file_splice_read(struct file *in, struct inode *pipe,
-                                      size_t len)
+                                      size_t len, unsigned int flags)
 {
         struct address_space *mapping = in->f_mapping;
         unsigned int offset, nr_pages;
@@ -279,7 +285,7 @@ static int __generic_file_splice_read(struct file *in, struct inode *pipe,
          * Now we splice them into the pipe..
          */
 splice_them:
-        return move_to_pipe(pipe, pages, i, offset, len);
+        return move_to_pipe(pipe, pages, i, offset, len, flags);
 }
 
 ssize_t generic_file_splice_read(struct file *in, struct inode *pipe,
@@ -291,7 +297,7 @@ ssize_t generic_file_splice_read(struct file *in, struct inode *pipe,
         ret = 0;
         spliced = 0;
         while (len) {
-                ret = __generic_file_splice_read(in, pipe, len);
+                ret = __generic_file_splice_read(in, pipe, len, flags);
 
                 if (ret <= 0)
                         break;
@@ -299,6 +305,11 @@ ssize_t generic_file_splice_read(struct file *in, struct inode *pipe,
                 in->f_pos += ret;
                 len -= ret;
                 spliced += ret;
+
+                if (!(flags & SPLICE_F_NONBLOCK))
+                        continue;
+                ret = -EAGAIN;
+                break;
         }
 
         if (spliced)
@@ -527,6 +538,12 @@ static ssize_t move_from_pipe(struct inode *inode, struct file *out,
                                 break;
                 }
 
+                if (flags & SPLICE_F_NONBLOCK) {
+                        if (!ret)
+                                ret = -EAGAIN;
+                        break;
+                }
+
                 if (signal_pending(current)) {
                         if (!ret)
                                 ret = -ERESTARTSYS;