Hello,
On 7/23/25 15:47, Paul E. McKenney wrote:
On Mon, Jul 21, 2025 at 11:47:25AM +0900, Akira Yokosawa wrote:
+CC David and Paul, who are the authors of this doc.
On Sun, 20 Jul 2025 11:02:43 -0500, Carlos Bilbao wrote:
From: Carlos Bilbao <carlos.bilbao@xxxxxxxxxx>
Fix circular buffer usage in producer/consumer examples in
circular-buffers.rst. They incorrectly access items using buffer[head] and
buffer[tail], as if buffer was a flat array; but the examples also use
buffer->head and buffer->tail, so it's a struct. Use buffer->vals[head] and
buffer->vals[tail] instead to match the intended layout.>
Signed-off-by: Carlos Bilbao <carlos.bilbao@xxxxxxxxxx>
Hello, Carlos, and thank you for your attention to detail!
This one could likely use more help, as the last substantive change was
more than ten years ago.
But are you referring to a particular use of CIRC_SPACE() and CIRC_CNT()
for this change? If so, could you please identify it in the commit log?
No, it's just the uses of the structure. Take a look at the patch, you'll
see. The mistake was introduced in this commit:
commit 90fddabf5818367c6bd1fe1b256a10e01827862f
Author: David Howells <dhowells@xxxxxxxxxx>
Date: Wed Mar 24 09:43:00 2010 +0000
Document Linux's circular buffering capabilities
Document the circular buffering capabilities available in Linux.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
Reviewed-by: Stefan Richter <stefanr@xxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Thanx, Paul
---
Documentation/core-api/circular-buffers.rst | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/Documentation/core-api/circular-buffers.rst b/Documentation/core-api/circular-buffers.rst
index 50966f66e398..b697915a2bd0 100644
--- a/Documentation/core-api/circular-buffers.rst
+++ b/Documentation/core-api/circular-buffers.rst
@@ -161,7 +161,7 @@ The producer will look something like this::
if (CIRC_SPACE(head, tail, buffer->size) >= 1) {
/* insert one item into the buffer */
- struct item *item = buffer[head];
+ struct item *item = buffer->vals[head];
produce_item(item);
@@ -203,7 +203,7 @@ The consumer will look something like this::
if (CIRC_CNT(head, tail, buffer->size) >= 1) {
/* extract one item from the buffer */
- struct item *item = buffer[tail];
+ struct item *item = buffer->vals[tail];
consume_item(item);
--
2.43.0
Thanks, Akira
Thanks,
Carlos
