git: ebcfab998e63 - main - nvme: Explicitly align struct nvme_command on an 8 byte boundary

From: John Baldwin <jhb_at_FreeBSD.org>
Date: Wed, 08 May 2024 23:05:54 UTC
The branch main has been updated by jhb:

URL: https://cgit.FreeBSD.org/src/commit/?id=ebcfab998e631fa7e29e1c0694868d745fc085ee

commit ebcfab998e631fa7e29e1c0694868d745fc085ee
Author:     John Baldwin <jhb@FreeBSD.org>
AuthorDate: 2024-05-08 23:05:39 +0000
Commit:     John Baldwin <jhb@FreeBSD.org>
CommitDate: 2024-05-08 23:05:39 +0000

    nvme: Explicitly align struct nvme_command on an 8 byte boundary
    
    This was already true for most architectures due to uint64_t structure
    members.  However, i386 is special in that it only requires 4 byte
    alignment for uint64_t.  As a result, casts from struct nvme_command
    to struct nvmf_fabric_cmd were raising a "cast increases alignment"
    warning on i386.  Explicitly aligning struct nvme_command pacifies
    this warning on i386.
    
    Reported by:    rscheff
    Sponsored by:   Chelsio Communications
---
 sys/dev/nvme/nvme.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/dev/nvme/nvme.h b/sys/dev/nvme/nvme.h
index 6ef7a2bd8aad..bca4df92cb25 100644
--- a/sys/dev/nvme/nvme.h
+++ b/sys/dev/nvme/nvme.h
@@ -832,7 +832,7 @@ struct nvme_command {
 	uint32_t cdw13;		/* command-specific */
 	uint32_t cdw14;		/* command-specific */
 	uint32_t cdw15;		/* command-specific */
-};
+} __aligned(8);
 
 _Static_assert(sizeof(struct nvme_command) == 16 * 4, "bad size for nvme_command");