relay: remove unused buf_mapped and buf_unmapped callbacks

Patch series "relay: cleanup and const callbacks", v2.

None of the relay users require the use of mutable structs for callbacks,
however the relay code does.  Instead of assigning default callbacks when
there is none, add callback wrappers to conditionally call the client
callbacks if available, and fall back to default behaviour (typically
no-op) otherwise.

This lets all relay users make their struct rchan_callbacks const data.

This series starts with a number of cleanups first based on Christoph's
feedback.

This patch (of 9):

No relay client uses the buf_mapped or buf_unmapped callbacks.  Remove
them.  This makes relay's vm_operations_struct close callback a dummy,
remove it as well.

Link: https://lkml.kernel.org/r/cover.1606153547.git.jani.nikula@intel.com
Link: https://lkml.kernel.org/r/c69fff6e0cd485563604240bbfcc028434983bec.1606153547.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/relay.h b/include/linux/relay.h
index e13a333e7c3741e12f610eadbf780ae51a308a3f..b3c4f49f69510f600436d7d3aea26aecb7f826dd 100644 (file)
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -101,25 +101,6 @@ struct rchan_callbacks
                             void *prev_subbuf,
                             size_t prev_padding);
 
-       /*
-        * buf_mapped - relay buffer mmap notification
-        * @buf: the channel buffer
-        * @filp: relay file pointer
-        *
-        * Called when a relay file is successfully mmapped
-        */
-        void (*buf_mapped)(struct rchan_buf *buf,
-                          struct file *filp);
-
-       /*
-        * buf_unmapped - relay buffer unmap notification
-        * @buf: the channel buffer
-        * @filp: relay file pointer
-        *
-        * Called when a relay file is successfully unmapped
-        */
-        void (*buf_unmapped)(struct rchan_buf *buf,
-                            struct file *filp);
        /*
         * create_buf_file - create file to represent a relay channel buffer
         * @filename: the name of the file to create

diff --git a/kernel/relay.c b/kernel/relay.c
index b08d936d5fa75b58651ad40192d42373c5ff773c..b51343642bf44c542606947f1a61c5a60ab22cd1 100644 (file)
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -27,15 +27,6 @@
 static DEFINE_MUTEX(relay_channels_mutex);
 static LIST_HEAD(relay_channels);
 
-/*
- * close() vm_op implementation for relay file mapping.
- */
-static void relay_file_mmap_close(struct vm_area_struct *vma)
-{
-       struct rchan_buf *buf = vma->vm_private_data;
-       buf->chan->cb->buf_unmapped(buf, vma->vm_file);
-}
-
 /*
  * fault() vm_op implementation for relay file mapping.
  */
@@ -62,7 +53,6 @@ static vm_fault_t relay_buf_fault(struct vm_fault *vmf)
  */
 static const struct vm_operations_struct relay_file_mmap_ops = {
        .fault = relay_buf_fault,
-       .close = relay_file_mmap_close,
 };
 
 /*
@@ -96,7 +86,6 @@ static void relay_free_page_array(struct page **array)
 static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
 {
        unsigned long length = vma->vm_end - vma->vm_start;
-       struct file *filp = vma->vm_file;
 
        if (!buf)
                return -EBADF;
@@ -107,7 +96,6 @@ static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
        vma->vm_ops = &relay_file_mmap_ops;
        vma->vm_flags |= VM_DONTEXPAND;
        vma->vm_private_data = buf;
-       buf->chan->cb->buf_mapped(buf, filp);
 
        return 0;
 }
@@ -283,22 +271,6 @@ static int subbuf_start_default_callback (struct rchan_buf *buf,
        return 1;
 }
 
-/*
- * buf_mapped() default callback.  Does nothing.
- */
-static void buf_mapped_default_callback(struct rchan_buf *buf,
-                                       struct file *filp)
-{
-}
-
-/*
- * buf_unmapped() default callback.  Does nothing.
- */
-static void buf_unmapped_default_callback(struct rchan_buf *buf,
-                                         struct file *filp)
-{
-}
-
 /*
  * create_buf_file_create() default callback.  Does nothing.
  */
@@ -322,8 +294,6 @@ static int remove_buf_file_default_callback(struct dentry *dentry)
 /* relay channel default callbacks */
 static struct rchan_callbacks default_channel_callbacks = {
        .subbuf_start = subbuf_start_default_callback,
-       .buf_mapped = buf_mapped_default_callback,
-       .buf_unmapped = buf_unmapped_default_callback,
        .create_buf_file = create_buf_file_default_callback,
        .remove_buf_file = remove_buf_file_default_callback,
 };
@@ -509,10 +479,6 @@ static void setup_callbacks(struct rchan *chan,
 
        if (!cb->subbuf_start)
                cb->subbuf_start = subbuf_start_default_callback;
-       if (!cb->buf_mapped)
-               cb->buf_mapped = buf_mapped_default_callback;
-       if (!cb->buf_unmapped)
-               cb->buf_unmapped = buf_unmapped_default_callback;
        if (!cb->create_buf_file)
                cb->create_buf_file = create_buf_file_default_callback;
        if (!cb->remove_buf_file)