scsi: lpfc: Fix lpfc_name struct packing

clang points out that the lpfc_name structure has an 8-byte alignment
requirement on most architectures, but is embedded in a number of other
structures that are forced to be only 1-byte aligned:

drivers/scsi/lpfc/lpfc_hw.h:1516:30: error: field pe within 'struct lpfc_fdmi_reg_port_list' is less aligned than 'struct lpfc_fdmi_port_entry' and is usually due to 'struct lpfc_fdmi_reg_port_list' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
        struct lpfc_fdmi_port_entry pe;
drivers/scsi/lpfc/lpfc_hw.h:850:19: error: field portName within 'struct _ADISC' is less aligned than 'struct lpfc_name' and is usually due to 'struct _ADISC' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
drivers/scsi/lpfc/lpfc_hw.h:851:19: error: field nodeName within 'struct _ADISC' is less aligned than 'struct lpfc_name' and is usually due to 'struct _ADISC' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
drivers/scsi/lpfc/lpfc_hw.h:922:19: error: field portName within 'struct _RNID' is less aligned than 'struct lpfc_name' and is usually due to 'struct _RNID' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]
drivers/scsi/lpfc/lpfc_hw.h:923:19: error: field nodeName within 'struct _RNID' is less aligned than 'struct lpfc_name' and is usually due to 'struct _RNID' being packed, which can lead to unaligned accesses [-Werror,-Wunaligned-access]

From the git history, I can see that all the __packed annotations were done
specifically to avoid introducing implicit padding around the lpfc_name
instances, though this was probably the wrong approach.

To improve this, only annotate the one uint64_t field inside of lpfc_name
as packed, with an explicit 4-byte alignment, as is the default already on
the 32-bit x86 ABI but not on most others. With this, the other __packed
annotations can be removed again, as this avoids the incorrect padding.

Two other structures change their layout as a result of this change:

 - struct _LOGO never gained a __packed annotation even though it has the
   same alignment problem as the others but is not used anywhere in the
   driver today.

 - struct serv_param similarly has this issue, and it is used, my guess is
   that this is only an internal structure rather than part of a binary
   interface, so the padding has no negative effect here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230616090705.2623408-1-arnd@kernel.org
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/lpfc/lpfc_hw.h b/drivers/scsi/lpfc/lpfc_hw.h
index 6637558..aaea3e3 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_hw.h
+++ b/drivers/scsi/lpfc/lpfc_hw.h
@@ -365,7 +365,7 @@ struct lpfc_name {
                        uint8_t IEEE[6];        /* FC IEEE address */
                } s;
                uint8_t wwn[8];
-               uint64_t name;
+               uint64_t name __packed __aligned(4);
        } u;
 };
 
@@ -850,7 +850,7 @@ typedef struct _ADISC {             /* Structure is in Big Endian format */
        struct lpfc_name portName;
        struct lpfc_name nodeName;
        uint32_t DID;
-} __packed ADISC;
+} ADISC;
 
 typedef struct _FARP {         /* Structure is in Big Endian format */
        uint32_t Mflags:8;
@@ -880,7 +880,7 @@ typedef struct _FAN {               /* Structure is in Big Endian format */
        uint32_t Fdid;
        struct lpfc_name FportName;
        struct lpfc_name FnodeName;
-} __packed FAN;
+} FAN;
 
 typedef struct _SCR {          /* Structure is in Big Endian format */
        uint8_t resvd1;
@@ -924,7 +924,7 @@ typedef struct _RNID {              /* Structure is in Big Endian format */
        union {
                RNID_TOP_DISC topologyDisc;     /* topology disc (0xdf) */
        } un;
-} __packed RNID;
+} RNID;
 
 struct RLS {                   /* Structure is in Big Endian format */
        uint32_t rls;
@@ -1514,7 +1514,7 @@ struct lpfc_fdmi_hba_ident {
 struct lpfc_fdmi_reg_port_list {
        __be32 EntryCnt;
        struct lpfc_fdmi_port_entry pe;
-} __packed;
+};
 
 /*
  * Register HBA(RHBA)