[PATCH] constify pipe_buf_operations

- pipe/splice should use const pipe_buf_operations and file_operations

- struct pipe_inode_info has an unused field "start" : get rid of it.

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 11 insertions, 12 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index f8b6bdcb879a..9a06e8e48e8d 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -207,7 +207,7 @@ int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf)
         return 0;
 }
 
-static struct pipe_buf_operations anon_pipe_buf_ops = {
+static const struct pipe_buf_operations anon_pipe_buf_ops = {
         .can_merge = 1,
         .map = generic_pipe_buf_map,
         .unmap = generic_pipe_buf_unmap,
@@ -243,7 +243,7 @@ pipe_read(struct kiocb *iocb, const struct iovec *_iov,
                 if (bufs) {
                         int curbuf = pipe->curbuf;
                         struct pipe_buffer *buf = pipe->bufs + curbuf;
-                        struct pipe_buf_operations *ops = buf->ops;
+                        const struct pipe_buf_operations *ops = buf->ops;
                         void *addr;
                         size_t chars = buf->len;
                         int error, atomic;
@@ -365,7 +365,7 @@ pipe_write(struct kiocb *iocb, const struct iovec *_iov,
                 int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
                                                         (PIPE_BUFFERS-1);
                 struct pipe_buffer *buf = pipe->bufs + lastbuf;
-                struct pipe_buf_operations *ops = buf->ops;
+                const struct pipe_buf_operations *ops = buf->ops;
                 int offset = buf->offset + buf->len;
 
                 if (ops->can_merge && offset + chars <= PAGE_SIZE) {
@@ -756,7 +756,7 @@ const struct file_operations rdwr_fifo_fops = {
         .fasync         = pipe_rdwr_fasync,
 };
 
-static struct file_operations read_pipe_fops = {
+static const struct file_operations read_pipe_fops = {
         .llseek         = no_llseek,
         .read           = do_sync_read,
         .aio_read       = pipe_read,
@@ -768,7 +768,7 @@ static struct file_operations read_pipe_fops = {
         .fasync         = pipe_read_fasync,
 };
 
-static struct file_operations write_pipe_fops = {
+static const struct file_operations write_pipe_fops = {
         .llseek         = no_llseek,
         .read           = bad_pipe_r,
         .write          = do_sync_write,
@@ -780,7 +780,7 @@ static struct file_operations write_pipe_fops = {
         .fasync         = pipe_write_fasync,
 };
 
-static struct file_operations rdwr_pipe_fops = {
+static const struct file_operations rdwr_pipe_fops = {
         .llseek         = no_llseek,
         .read           = do_sync_read,
         .aio_read       = pipe_read,
diff --git a/fs/splice.c b/fs/splice.c
index bbd0aeb3f68e..2fca6ebf4cc2 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -42,7 +42,7 @@ struct splice_pipe_desc {
         struct partial_page *partial;   /* pages[] may not be contig */
         int nr_pages;                   /* number of pages in map */
         unsigned int flags;             /* splice flags */
-        struct pipe_buf_operations *ops;/* ops associated with output pipe */
+        const struct pipe_buf_operations *ops;/* ops associated with output pipe */
 };
 
 /*
@@ -139,7 +139,7 @@ error:
         return err;
 }
 
-static struct pipe_buf_operations page_cache_pipe_buf_ops = {
+static const struct pipe_buf_operations page_cache_pipe_buf_ops = {
         .can_merge = 0,
         .map = generic_pipe_buf_map,
         .unmap = generic_pipe_buf_unmap,
@@ -159,7 +159,7 @@ static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
         return generic_pipe_buf_steal(pipe, buf);
 }
 
-static struct pipe_buf_operations user_page_pipe_buf_ops = {
+static const struct pipe_buf_operations user_page_pipe_buf_ops = {
         .can_merge = 0,
         .map = generic_pipe_buf_map,
         .unmap = generic_pipe_buf_unmap,
@@ -724,7 +724,7 @@ static ssize_t __splice_from_pipe(struct pipe_inode_info *pipe,
         for (;;) {
                 if (pipe->nrbufs) {
                         struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
-                        struct pipe_buf_operations *ops = buf->ops;
+                        const struct pipe_buf_operations *ops = buf->ops;
 
                         sd.len = buf->len;
                         if (sd.len > sd.total_len)
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index ea4f7cd7bfd8..cc902d242c41 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -12,7 +12,7 @@
 struct pipe_buffer {
         struct page *page;
         unsigned int offset, len;
-        struct pipe_buf_operations *ops;
+        const struct pipe_buf_operations *ops;
         unsigned int flags;
 };
 
@@ -43,7 +43,6 @@ struct pipe_inode_info {
         unsigned int nrbufs, curbuf;
         struct pipe_buffer bufs[PIPE_BUFFERS];
         struct page *tmp_page;
-        unsigned int start;
         unsigned int readers;
         unsigned int writers;
         unsigned int waiting_writers;