Re: [PATCH 7/9] nvme: apple: Add Apple A11 support
From: Sven Peter <sven@kernel.org>
Date: 2025-08-17 10:47:23
Also in:
asahi, linux-devicetree, linux-iommu, linux-nvme, lkml
On 11.08.25 15:50, Nick Chan wrote:
Add support for ANS2 NVMe on Apple A11 SoC. This version of ANS2 is less quirky than the one in M1, and does not have NVMMU or Linear SQ. However, it still requires a non-standard 128-byte SQE. Signed-off-by: Nick Chan <redacted> --- drivers/nvme/host/apple.c | 228 +++++++++++++++++++++++++++++++---------------
[...]
quoted hunk ↗ jump to hunk
} static void apple_nvme_rtkit_crashed(void *cookie, const void *crashlog, size_t crashlog_size)@@ -284,21 +294,8 @@ static void apple_nvme_submit_cmd(struct apple_nvme_queue *q, struct nvme_command *cmd) {
Please just create a separate submit function here. There's just not much code that's shared between the two variants. [...]
quoted hunk ↗ jump to hunk
}@@ -587,10 +618,17 @@ static inline void apple_nvme_handle_cqe(struct apple_nvme_queue *q, { struct apple_nvme *anv = queue_to_apple_nvme(q); struct nvme_completion *cqe = &q->cqes[idx]; - __u16 command_id = READ_ONCE(cqe->command_id); struct request *req; - apple_nvmmu_inval(q, command_id); + if (!anv->hw->has_lsq_nvmmu) + cqe->command_id--; + + __u16 command_id = READ_ONCE(cqe->command_id); + + if (anv->hw->has_lsq_nvmmu) + apple_nvmmu_inval(q, command_id); + else + command_id++;
This entire block here looks weird. First you decrease the command_id directly inside the shared memory structure, then you read it with READ_ONCE to a local variable only to increase it again. Why? Sven