From: Arnd Bergmann <arnd@xxxxxxxx>
clang points out that the lpfc_name structure has an 8-byte alignement 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@xxxxxxxx>
---
drivers/scsi/lpfc/lpfc_hw.h | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_hw.h b/drivers/scsi/lpfc/lpfc_hw.h
index 663755842e4a4..aaea3e31944d0 100644
--- 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)
--
2.39.2
