From e92b0b5edfc7c83bd2d791929aa4e0c89ac029aa Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 4 Feb 2021 17:30:14 +0100 Subject: [PATCH] scsi: pmcraid: Fix 'ioarcb' alignment warning Building with 'make W=1' enables -Wpacked-not-aligned, and this warns about pmcraid because of incompatible alignment constraints for pmcraid_passthrough_ioctl_buffer: 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. Link: https://lore.kernel.org/r/20210204163020.3286210-1-arnd@kernel.org Cc: Lee Jones Reviewed-by: Lee Jones Signed-off-by: Arnd Bergmann Signed-off-by: Martin K. Petersen --- 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 15c9621..6d36deb 100644 --- a/drivers/scsi/pmcraid.h +++ b/drivers/scsi/pmcraid.h @@ -244,7 +244,7 @@ struct pmcraid_ioarcb { __u8 hrrq_id; __u8 cdb[PMCRAID_MAX_CDB_LEN]; 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 -- 2.7.4