On Mon, 01 Feb 2021, Arnd Bergmann wrote: > From: Arnd Bergmann <arnd@xxxxxxxx> > > 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. Looks good to me. Reviewed-by: Lee Jones <lee.jones@xxxxxxxxxx> -- Lee Jones [李琼斯] Senior Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
