2 files changed, 30 insertions, 2 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index 25feaa3faac0..fec5e4ad071a 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -346,6 +346,16 @@ static const struct pipe_buf_operations anon_pipe_buf_ops = {
         .get = generic_pipe_buf_get,
 };
 
+static const struct pipe_buf_operations packet_pipe_buf_ops = {
+        .can_merge = 0,
+        .map = generic_pipe_buf_map,
+        .unmap = generic_pipe_buf_unmap,
+        .confirm = generic_pipe_buf_confirm,
+        .release = anon_pipe_buf_release,
+        .steal = generic_pipe_buf_steal,
+        .get = generic_pipe_buf_get,
+};
+
 static ssize_t
 pipe_read(struct kiocb *iocb, const struct iovec *_iov,
            unsigned long nr_segs, loff_t pos)
@@ -407,6 +417,13 @@ redo:
                         ret += chars;
                         buf->offset += chars;
                         buf->len -= chars;
+
+                        /* Was it a packet buffer? Clean up and exit */
+                        if (buf->flags & PIPE_BUF_FLAG_PACKET) {
+                                total_len = chars;
+                                buf->len = 0;
+                        }
+
                         if (!buf->len) {
                                 buf->ops = NULL;
                                 ops->release(pipe, buf);
@@ -459,6 +476,11 @@ redo:
         return ret;
 }
 
+static inline int is_packetized(struct file *file)
+{
+        return (file->f_flags & O_DIRECT) != 0;
+}
+
 static ssize_t
 pipe_write(struct kiocb *iocb, const struct iovec *_iov,
             unsigned long nr_segs, loff_t ppos)
@@ -593,6 +615,11 @@ redo2:
                         buf->ops = &anon_pipe_buf_ops;
                         buf->offset = 0;
                         buf->len = chars;
+                        buf->flags = 0;
+                        if (is_packetized(filp)) {
+                                buf->ops = &packet_pipe_buf_ops;
+                                buf->flags = PIPE_BUF_FLAG_PACKET;
+                        }
                         pipe->nrbufs = ++bufs;
                         pipe->tmp_page = NULL;
 
@@ -1013,7 +1040,7 @@ struct file *create_write_pipe(int flags)
                 goto err_dentry;
         f->f_mapping = inode->i_mapping;
 
-        f->f_flags = O_WRONLY | (flags & O_NONBLOCK);
+        f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT));
         f->f_version = 0;
 
         return f;
@@ -1057,7 +1084,7 @@ int do_pipe_flags(int *fd, int flags)
         int error;
         int fdw, fdr;
 
-        if (flags & ~(O_CLOEXEC | O_NONBLOCK))
+        if (flags & ~(O_CLOEXEC | O_NONBLOCK | O_DIRECT))
                 return -EINVAL;
 
         fw = create_write_pipe(flags);
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 6d626ff0cfd0..e1ac1ce16fb0 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -6,6 +6,7 @@
 #define PIPE_BUF_FLAG_LRU       0x01    /* page is on the LRU */
 #define PIPE_BUF_FLAG_ATOMIC    0x02    /* was atomically mapped */
 #define PIPE_BUF_FLAG_GIFT      0x04    /* page is a gift */
+#define PIPE_BUF_FLAG_PACKET    0x08    /* read() as a packet */
 
 /**
  *      struct pipe_buffer - a linux kernel pipe buffer