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Subject[RFC PATCH 8/8] relay - Clean up remaining padding-related junk.
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Date
Clean up remaining padding-related junk.

Removes the rest of the padding-related junk. Also simplifies the
subbuf_start callback a bit.
---
block/blktrace.c | 5 +++--
include/linux/relay.h | 12 ++----------
kernel/relay.c | 19 ++++---------------
virt/kvm/kvm_trace.c | 7 ++++---
4 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/block/blktrace.c b/block/blktrace.c
index 150c5f7..271b7b7 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -334,8 +334,9 @@ static const struct file_operations blk_msg_fops = {
* Keep track of how many times we encountered a full subbuffer, to aid
* the user space app in telling how many lost events there were.
*/
-static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
- void *prev_subbuf, size_t prev_padding)
+static int blk_subbuf_start_callback(struct rchan_buf *buf,
+ void *subbuf,
+ int first_subbuf)
{
struct blk_trace *bt;

diff --git a/include/linux/relay.h b/include/linux/relay.h
index c42b2d3..85f43a0 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -51,8 +51,6 @@ struct rchan_buf
struct page **page_array; /* array of current buffer pages */
unsigned int page_count; /* number of current buffer pages */
unsigned int finalized; /* buffer has been finalized */
- size_t *padding; /* padding counts per sub-buffer */
- size_t prev_padding; /* temporary variable */
size_t bytes_consumed; /* bytes consumed in cur read subbuf */
size_t early_bytes; /* bytes consumed before VFS inited */
unsigned int cpu; /* this buf's cpu */
@@ -88,23 +86,17 @@ struct rchan_callbacks
* subbuf_start - called on buffer-switch to a new sub-buffer
* @buf: the channel buffer containing the new sub-buffer
* @subbuf: the start of the new sub-buffer
- * @prev_subbuf: the start of the previous sub-buffer
- * @prev_padding: unused space at the end of previous sub-buffer
+ * @first_subbuf: boolean, is this the first subbuf?
*
* The client should return 1 to continue logging, 0 to stop
* logging.
*
- * 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.
- *
* NOTE: the client can reserve bytes at the beginning of the new
* sub-buffer by calling subbuf_start_reserve() in this callback.
*/
int (*subbuf_start) (struct rchan_buf *buf,
void *subbuf,
- void *prev_subbuf,
- size_t prev_padding);
+ int first_subbuf);

/*
* buf_mapped - relay buffer mmap notification
diff --git a/kernel/relay.c b/kernel/relay.c
index 21b3e19..b2bf510 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -178,10 +178,6 @@ static struct rchan_buf *relay_create_buf(struct rchan *chan)
if (!buf)
return NULL;

- buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
- if (!buf->padding)
- goto free_buf;
-
buf->chan = chan;
kref_get(&buf->chan->kref);

@@ -192,7 +188,6 @@ static struct rchan_buf *relay_create_buf(struct rchan *chan)
return buf;

free_buf:
- kfree(buf->padding);
kfree(buf);
return NULL;
}
@@ -225,7 +220,6 @@ static void relay_destroy_buf(struct rchan_buf *buf)
relay_free_page_array(buf->page_array);
}
chan->buf[buf->cpu] = NULL;
- kfree(buf->padding);
kfree(buf);
kref_put(&chan->kref, relay_destroy_channel);
}
@@ -283,8 +277,7 @@ EXPORT_SYMBOL_GPL(relay_buf_full);
*/
static int subbuf_start_default_callback (struct rchan_buf *buf,
void *subbuf,
- void *prev_subbuf,
- size_t prev_padding)
+ int first_subbuf)
{
if (relay_buf_full(buf))
return 0;
@@ -374,8 +367,6 @@ static void wakeup_readers(unsigned long data)
*/
static void __relay_reset(struct rchan_buf *buf, unsigned int init)
{
- size_t i;
-
if (init) {
init_waitqueue_head(&buf->read_wait);
kref_init(&buf->kref);
@@ -390,10 +381,7 @@ static void __relay_reset(struct rchan_buf *buf, unsigned int init)
buf->data = buf->start;
buf->offset = 0;

- for (i = 0; i < buf->chan->n_subbufs; i++)
- buf->padding[i] = 0;
-
- buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0);
+ buf->chan->cb->subbuf_start(buf, buf->data, 1);
}

/**
@@ -757,7 +745,7 @@ static inline int next_subbuf_free(struct rchan_buf *buf)
* Returns either the length passed in or 0 if full.
*
* Performs sub-buffer-switch tasks such as invoking callbacks,
- * updating padding counts, waking up readers, etc.
+ * waking up readers, etc.
*/
size_t relay_switch_subbuf_default_callback(struct rchan_buf *buf,
size_t length,
@@ -788,6 +776,7 @@ size_t relay_switch_subbuf_default_callback(struct rchan_buf *buf,

buf->data = new_data;
buf->offset = 0; /* remainder will be added by caller */
+ buf->chan->cb->subbuf_start(buf, new_data, 0);

if (unlikely(relay_event_toobig(buf, length + buf->offset)))
goto toobig;
diff --git a/virt/kvm/kvm_trace.c b/virt/kvm/kvm_trace.c
index d0a9e1c..4626caa 100644
--- a/virt/kvm/kvm_trace.c
+++ b/virt/kvm/kvm_trace.c
@@ -105,13 +105,14 @@ DEFINE_SIMPLE_ATTRIBUTE(kvm_trace_lost_ops, lost_records_get, NULL, "%llu\n");
* many times we encountered a full subbuffer, to tell user space app the
* lost records there were.
*/
-static int kvm_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
- void *prev_subbuf, size_t prev_padding)
+static int kvm_subbuf_start_callback(struct rchan_buf *buf,
+ void *subbuf,
+ int first_subbuf)
{
struct kvm_trace *kt;

if (!relay_buf_full(buf)) {
- if (!prev_subbuf) {
+ if (first_subbuf) {
/*
* executed only once when the channel is opened
* save metadata as first record
--
1.5.3.5




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