The patch titled
Subject: relay: make create_buf_file and remove_buf_file callbacks mandatory
has been added to the -mm tree. Its filename is
relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Jani Nikula <jani.nikula@xxxxxxxxx>
Subject: relay: make create_buf_file and remove_buf_file callbacks mandatory
All clients provide create_buf_file and remove_buf_file callbacks, and
they're required for relay to make sense. There is no point in them being
optional.
Also document whether each callback is mandatory/optional.
Link: https://lkml.kernel.org/r/88003c1527386b93036e286e7917f1e33aec84ac.1606153547.git.jani.nikula@xxxxxxxxx
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Suggested-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/relay.h | 6 ++++++
kernel/relay.c | 26 +-------------------------
2 files changed, 7 insertions(+), 25 deletions(-)
--- a/include/linux/relay.h~relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory
+++ a/include/linux/relay.h
@@ -89,6 +89,8 @@ struct rchan_callbacks
* The client should return 1 to continue logging, 0 to stop
* logging.
*
+ * This callback is optional.
+ *
* NOTE: subbuf_start will also be invoked when the buffer is
* created, so that the first sub-buffer can be initialized
* if necessary. In this case, prev_subbuf will be NULL.
@@ -122,6 +124,8 @@ struct rchan_callbacks
* cause relay_open() to create a single global buffer rather
* than the default set of per-cpu buffers.
*
+ * This callback is mandatory.
+ *
* See Documentation/filesystems/relay.rst for more info.
*/
struct dentry *(*create_buf_file)(const char *filename,
@@ -139,6 +143,8 @@ struct rchan_callbacks
* channel buffer.
*
* The callback should return 0 if successful, negative if not.
+ *
+ * This callback is mandatory.
*/
int (*remove_buf_file)(struct dentry *dentry);
};
--- a/kernel/relay.c~relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory
+++ a/kernel/relay.c
@@ -271,26 +271,6 @@ static int subbuf_start_default_callback
return 1;
}
-/*
- * create_buf_file_create() default callback. Does nothing.
- */
-static struct dentry *create_buf_file_default_callback(const char *filename,
- struct dentry *parent,
- umode_t mode,
- struct rchan_buf *buf,
- int *is_global)
-{
- return NULL;
-}
-
-/*
- * remove_buf_file() default callback. Does nothing.
- */
-static int remove_buf_file_default_callback(struct dentry *dentry)
-{
- return -EINVAL;
-}
-
/**
* wakeup_readers - wake up readers waiting on a channel
* @work: contains the channel buffer
@@ -467,10 +447,6 @@ static void setup_callbacks(struct rchan
{
if (!cb->subbuf_start)
cb->subbuf_start = subbuf_start_default_callback;
- if (!cb->create_buf_file)
- cb->create_buf_file = create_buf_file_default_callback;
- if (!cb->remove_buf_file)
- cb->remove_buf_file = remove_buf_file_default_callback;
chan->cb = cb;
}
@@ -530,7 +506,7 @@ struct rchan *relay_open(const char *bas
return NULL;
if (subbuf_size > UINT_MAX / n_subbufs)
return NULL;
- if (!cb)
+ if (!cb || !cb->create_buf_file || !cb->remove_buf_file)
return NULL;
chan = kzalloc(sizeof(struct rchan), GFP_KERNEL);
_
Patches currently in -mm which might be from jani.nikula@xxxxxxxxx are
relay-remove-unused-buf_mapped-and-buf_unmapped-callbacks.patch
relay-require-non-null-callbacks-in-relay_open.patch
relay-make-create_buf_file-and-remove_buf_file-callbacks-mandatory.patch
relay-allow-the-use-of-const-callback-structs.patch
drm-i915-make-relay-callbacks-const.patch
ath10k-make-relay-callbacks-const.patch
ath11k-make-relay-callbacks-const.patch
ath9k-make-relay-callbacks-const.patch
blktrace-make-relay-callbacks-const.patch
