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| author | Stephen M. Cameron <scameron@beardog.cce.hp.com> | 2010-02-25 14:03:22 -0600 |
|---|---|---|
| committer | James Bottomley <James.Bottomley@suse.de> | 2010-03-03 18:37:08 +0530 |
| commit | db61bfcfe2a68dc71402c270686cd73b80971efc (patch) | |
| tree | 2888902956cd899d924070f559f6fcac8595d490 /drivers/scsi/hpsa_cmd.h | |
| parent | ff9fea94546afa2a496c15354533f06088347f6e (diff) | |
| download | lwn-db61bfcfe2a68dc71402c270686cd73b80971efc.tar.gz lwn-db61bfcfe2a68dc71402c270686cd73b80971efc.zip | |
[SCSI] hpsa: Clarify calculation of padding for commandlist structure
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/scsi/hpsa_cmd.h')
| -rw-r--r-- | drivers/scsi/hpsa_cmd.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/scsi/hpsa_cmd.h b/drivers/scsi/hpsa_cmd.h index 3e0abdf76689..43b6f1cffe34 100644 --- a/drivers/scsi/hpsa_cmd.h +++ b/drivers/scsi/hpsa_cmd.h @@ -313,12 +313,18 @@ struct CommandList { void *scsi_cmd; /* on 64 bit architectures, to get this to be 32-byte-aligned - * it so happens we need no padding, on 32 bit systems, - * we need 8 bytes of padding. This does that. + * it so happens we need PAD_64 bytes of padding, on 32 bit systems, + * we need PAD_32 bytes of padding (see below). This does that. + * If it happens that 64 bit and 32 bit systems need different + * padding, PAD_32 and PAD_64 can be set independently, and. + * the code below will do the right thing. */ -#define COMMANDLIST_PAD ((8 - sizeof(long))/4 * 8) +#define IS_32_BIT ((8 - sizeof(long))/4) +#define IS_64_BIT (!IS_32_BIT) +#define PAD_32 (8) +#define PAD_64 (0) +#define COMMANDLIST_PAD (IS_32_BIT * PAD_32 + IS_64_BIT * PAD_64) u8 pad[COMMANDLIST_PAD]; - }; /* Configuration Table Structure */ |