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-rw-r--r--fs/pipe.c31
-rw-r--r--include/linux/pipe_fs_i.h1
2 files changed, 30 insertions, 2 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 25feaa3faac..fec5e4ad071 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 6d626ff0cfd..e1ac1ce16fb 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