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[v6,29/30] lib/vhost: replace packed attributes

Message ID 1732668761-5556-30-git-send-email-andremue@linux.microsoft.com (mailing list archive)
State Superseded
Delegated to: David Marchand
Headers
Series fix packing of structs when building with MSVC |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Andre Muezerie Nov. 27, 2024, 12:52 a.m. UTC 
MSVC struct packing is not compatible with GCC. Replace macro
__rte_packed with __rte_packed_begin to push existing pack value
and set packing to 1-byte and macro __rte_packed_end to restore
the pack value prior to the push.

Macro __rte_packed_end is deliberately utilized to trigger a
MSVC compiler warning if no existing packing has been pushed allowing
easy identification of locations where the __rte_packed_begin is
missing.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 lib/vhost/vhost_user.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff mbox series

Patch

diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h
index edf7adb3c0..d48542e72f 100644
--- a/lib/vhost/vhost_user.h
+++ b/lib/vhost/vhost_user.h
@@ -143,7 +143,7 @@  struct vhost_user_config {
 	uint8_t region[VHOST_USER_MAX_CONFIG_SIZE];
 };
 
-typedef struct VhostUserMsg {
+typedef __rte_packed_begin struct VhostUserMsg {
 	union {
 		uint32_t frontend; /* a VhostUserRequest value */
 		uint32_t backend;  /* a VhostUserBackendRequest value*/
@@ -169,16 +169,16 @@  typedef struct VhostUserMsg {
 		struct vhost_user_config cfg;
 	} payload;
 	/* Nothing should be added after the payload */
-} __rte_packed VhostUserMsg;
+} __rte_packed_end VhostUserMsg;
 
 /* Note: this structure and VhostUserMsg can't be changed carelessly as
  * external message handlers rely on them.
  */
-struct __rte_packed vhu_msg_context {
+__rte_packed_begin struct vhu_msg_context {
 	VhostUserMsg msg;
 	int fds[VHOST_MEMORY_MAX_NREGIONS];
 	int fd_num;
-};
+} __rte_packed_end;
 
 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)