From: "Lynch, Nathan" <nathan.lynch@amd.com>
To: Frank Li <Frank.li@nxp.com>
Cc: Vinod Koul <vkoul@kernel.org>, Wei Huang <wei.huang2@amd.com>,
Mario Limonciello <mario.limonciello@amd.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Jonathan Cameron <jonathan.cameron@huawei.com>,
Stephen Bates <Stephen.Bates@amd.com>,
PradeepVineshReddy.Kodamati@amd.com, John.Kariuki@amd.com,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
dmaengine@vger.kernel.org
Subject: Re: [PATCH 12/23] dmaengine: sdxi: Add descriptor ring management
Date: Mon, 20 Apr 2026 17:42:46 -0500 [thread overview]
Message-ID: <839d1fb4-8519-4fdd-b04b-b2a9e88bbaf9@amd.com> (raw)
In-Reply-To: <aeXkrudhvhTRtS9d@lizhi-Precision-Tower-5810>
On 4/20/2026 3:32 AM, Frank Li wrote:
>> +
>> +static u64 sdxi_ring_state_load_ridx(struct sdxi_ring_state *rs)
>> +{
>> + lockdep_assert_held(&rs->lock);
>> + return le64_to_cpu(READ_ONCE(*rs->read_index_ptr));
>> +}
>> +
>> +static void sdxi_ring_state_store_widx(struct sdxi_ring_state *rs, u64 new_widx)
>> +{
>> + lockdep_assert_held(&rs->lock);
>> + *rs->write_index_ptr = cpu_to_le64(rs->write_index = new_widx);
>
> Does it need WRITE_ONCE() ? you load_ridx() use READ_ONCE. I just not sure
>
> suppose doorbell will drain write buffer, most likely it is okay without
> WRITE_ONCE()
The SDXI implementation is free to sample the write index before software
hits the doorbell, so I believe WRITE_ONCE() is required here, thanks.
next prev parent reply other threads:[~2026-04-20 22:42 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 13:07 [PATCH 00/23] dmaengine: Smart Data Accelerator Interface (SDXI) basic support Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 01/23] PCI: Add SNIA SDXI accelerator sub-class Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 02/23] MAINTAINERS: Add entry for SDXI driver Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 03/23] dmaengine: sdxi: Add PCI initialization Nathan Lynch via B4 Relay
2026-04-20 6:36 ` Frank Li
2026-04-20 15:29 ` Lynch, Nathan
2026-04-10 13:07 ` [PATCH 04/23] dmaengine: sdxi: Feature discovery and initial configuration Nathan Lynch via B4 Relay
2026-04-20 6:51 ` Frank Li
2026-04-20 19:31 ` Lynch, Nathan
2026-04-10 13:07 ` [PATCH 05/23] dmaengine: sdxi: Configure context tables Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 06/23] dmaengine: sdxi: Allocate DMA pools Nathan Lynch via B4 Relay
2026-04-20 7:03 ` Frank Li
2026-04-20 22:16 ` Lynch, Nathan
2026-04-10 13:07 ` [PATCH 07/23] dmaengine: sdxi: Allocate administrative context Nathan Lynch via B4 Relay
2026-04-20 7:11 ` Frank Li
2026-04-10 13:07 ` [PATCH 08/23] dmaengine: sdxi: Install " Nathan Lynch via B4 Relay
2026-04-20 7:16 ` Frank Li
2026-04-10 13:07 ` [PATCH 09/23] dmaengine: sdxi: Start functions on probe, stop on remove Nathan Lynch via B4 Relay
2026-04-20 7:18 ` Frank Li
2026-04-10 13:07 ` [PATCH 10/23] dmaengine: sdxi: Complete administrative context jump start Nathan Lynch via B4 Relay
2026-04-20 7:33 ` Frank Li
2026-04-10 13:07 ` [PATCH 11/23] dmaengine: sdxi: Add client context alloc and release APIs Nathan Lynch via B4 Relay
2026-04-20 8:19 ` Frank Li
2026-04-10 13:07 ` [PATCH 12/23] dmaengine: sdxi: Add descriptor ring management Nathan Lynch via B4 Relay
2026-04-20 8:32 ` Frank Li
2026-04-20 22:42 ` Lynch, Nathan [this message]
2026-04-10 13:07 ` [PATCH 13/23] dmaengine: sdxi: Add unit tests for descriptor ring reservations Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 14/23] dmaengine: sdxi: Attach descriptor ring state to contexts Nathan Lynch via B4 Relay
2026-04-20 8:34 ` Frank Li
2026-04-10 13:07 ` [PATCH 15/23] dmaengine: sdxi: Per-context access key (AKey) table entry allocator Nathan Lynch via B4 Relay
2026-04-20 8:39 ` Frank Li
2026-04-10 13:07 ` [PATCH 16/23] dmaengine: sdxi: Generic descriptor manipulation helpers Nathan Lynch via B4 Relay
2026-04-20 8:40 ` Frank Li
2026-04-10 13:07 ` [PATCH 17/23] dmaengine: sdxi: Add completion status block API Nathan Lynch via B4 Relay
2026-04-20 8:44 ` Frank Li
2026-04-10 13:07 ` [PATCH 18/23] dmaengine: sdxi: Encode context start, stop, and sync descriptors Nathan Lynch via B4 Relay
2026-04-20 8:48 ` Frank Li
2026-04-10 13:07 ` [PATCH 19/23] dmaengine: sdxi: Provide context start and stop APIs Nathan Lynch via B4 Relay
2026-04-20 8:50 ` Frank Li
2026-04-10 13:07 ` [PATCH 20/23] dmaengine: sdxi: Encode nop, copy, and interrupt descriptors Nathan Lynch via B4 Relay
2026-04-20 8:52 ` Frank Li
2026-04-10 13:07 ` [PATCH 21/23] dmaengine: sdxi: Add unit tests for descriptor encoding Nathan Lynch via B4 Relay
2026-04-10 13:07 ` [PATCH 22/23] dmaengine: sdxi: MSI/MSI-X vector allocation and mapping Nathan Lynch via B4 Relay
2026-04-20 8:54 ` Frank Li
2026-04-10 13:07 ` [PATCH 23/23] dmaengine: sdxi: Add DMA engine provider Nathan Lynch via B4 Relay
2026-04-20 9:08 ` Frank Li
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