[lkml]   [2021]   [Feb]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH] scsi: pmcraid: fix 'ioarcb' alignment warning
From: Arnd Bergmann <>

Building with 'make W=1' enables -Wpacked-not-aligned, and this
warns about pmcraid because of incompatible alignment constraints for

drivers/scsi/pmcraid.h:1044:1: warning: alignment 1 of 'struct pmcraid_passthrough_ioctl_buffer' is less than 32 [-Wpacked-not-aligned]
1044 | } __attribute__ ((packed));
| ^
drivers/scsi/pmcraid.h:1041:24: warning: 'ioarcb' offset 16 in 'struct pmcraid_passthrough_ioctl_buffer' isn't aligned to 32 [-Wpacked-not-aligned]
1041 | struct pmcraid_ioarcb ioarcb;

The inner structure is documented as having 32 byte alignment here,
but is starts at a 16 byte offset in the outer structure, so it's never
actually aligned, as the outer structure is also marked 'packed'.

Lee Jones point this out as one of the last files that need to be changed
before the warning can be enabled by default.

Change the annotations in a way that avoids the warning but leaves the
layout unchanged, by removing the packing on the inner structure and
adding it to the outer one. The one-byte request_buffer[] array should
have been a flexible array member here, which is how I change it to
avoid extra padding from the alignment attribute.

Cc: Lee Jones <>
Signed-off-by: Arnd Bergmann <>
drivers/scsi/pmcraid.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/pmcraid.h b/drivers/scsi/pmcraid.h
index 15c962108075..6d36debde18e 100644
--- a/drivers/scsi/pmcraid.h
+++ b/drivers/scsi/pmcraid.h
@@ -244,7 +244,7 @@ struct pmcraid_ioarcb {
__u8 hrrq_id;
struct pmcraid_ioarcb_add_data add_data;
-} __attribute__((packed, aligned(PMCRAID_IOARCB_ALIGNMENT)));

/* well known resource handle values */
#define PMCRAID_IOA_RES_HANDLE 0xffffffff
@@ -1040,8 +1040,8 @@ struct pmcraid_passthrough_ioctl_buffer {
struct pmcraid_ioctl_header ioctl_header;
struct pmcraid_ioarcb ioarcb;
struct pmcraid_ioasa ioasa;
- u8 request_buffer[1];
-} __attribute__ ((packed));
+ u8 request_buffer[];
+} __attribute__ ((packed, aligned(PMCRAID_IOARCB_ALIGNMENT)));

* keys to differentiate between driver handled IOCTLs and passthrough
 \ /
  Last update: 2021-02-04 17:41    [W:0.069 / U:1.368 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site