diff options
Diffstat (limited to 'drivers/block/cciss_cmd.h')
| -rw-r--r-- | drivers/block/cciss_cmd.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/block/cciss_cmd.h b/drivers/block/cciss_cmd.h index 515c9f03c201..e624ff959cb6 100644 --- a/drivers/block/cciss_cmd.h +++ b/drivers/block/cciss_cmd.h @@ -167,10 +167,13 @@ typedef struct _SGDescriptor_struct { #define CMD_MSG_TIMEOUT 0x05 #define CMD_MSG_STALE 0xff -/* This structure needs to be divisible by 8 for new - * indexing method. PAD_32 and PAD_64 can be adjusted - * independently as needed for 32-bit and 64-bits systems. +/* This structure needs to be divisible by COMMANDLIST_ALIGNMENT + * because low bits of the address are used to to indicate that + * whether the tag contains an index or an address. PAD_32 and + * PAD_64 can be adjusted independently as needed for 32-bit + * and 64-bits systems. */ +#define COMMANDLIST_ALIGNMENT (8) #define IS_64_BIT ((sizeof(long) - 4)/4) #define IS_32_BIT (!IS_64_BIT) #define PAD_32 (0) |