-----Original Message-----
From: Paolo Abeni <pabeni@redhat.com>
Sent: Monday, December 29, 2025 9:45 PM
To: Vimlesh Kumar <redacted>; netdev@vger.kernel.org; linux-
kernel@vger.kernel.org
Cc: Sathesh B Edara <sedara@marvell.com>; Shinas Rasheed
[off-list ref]; Haseeb Gani [off-list ref];
Veerasenareddy Burru [off-list ref]; Andrew Lunn
[off-list ref]; David S. Miller [off-list ref]; Eric
Dumazet [off-list ref]; Jakub Kicinski [off-list ref];
Satananda Burla [off-list ref]; Abhijit Ayarekar
[off-list ref]
Subject: [EXTERNAL] Re: [PATCH net v1 1/2] octeon_ep: avoid compiler and
IQ/OQ reordering
On 12/19/25 8:29 AM, Vimlesh Kumar wrote:

quoted

Utilize READ_ONCE and WRITE_ONCE APIs for IO queue Tx/Rx variable
access to prevent compiler optimization and reordering.
Additionally, ensure IO queue OUT/IN_CNT registers are flushed by
performing a read-back after writing.

Please explain why such _ONCE() annotation are required, and what could be
reordered otherwise.

I don't think they are needed,

We use READ_ONCE and WRITE_ONCE APIs in the data path to prevent the compiler from optimizing or reordering read/write operations.
The APIs are used to access RX and TX queue counter fields that are shared between the Octeon hardware device and its device driver. These APIs ensure that the driver always reads the most current values from the hardware for various RX and TX counter fields. Additionally, they prevent the compiler from optimizing or reordering read/write operations on these counter fields.
 

/P