[PATCH 2/9] cciss: detect bad alignment of scsi commands at build time
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From: Stephen M. Cameron on 26 Feb 2010 17:00 From: Stephen M. Cameron <scameron(a)beardog.cce.hp.com> cciss: detect bad alignment of scsi commands at build time Incidentally fix some nearby c++ style comments. Signed-off-by: Stephen M. Cameron <scameron(a)beardog.cce.hp.com> --- drivers/block/cciss.c | 2 +- drivers/block/cciss_cmd.h | 9 ++++++--- drivers/block/cciss_scsi.c | 12 ++++++++---- 3 files changed, 15 insertions(+), 8 deletions(-) diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index a29e694..cd8c7c2 100644 --- a/drivers/block/cciss.c +++ b/drivers/block/cciss.c @@ -4496,7 +4496,7 @@ static int __init cciss_init(void) * boundary. Given that we use pci_alloc_consistent() to allocate an * array of them, the size must be a multiple of 8 bytes. */ - BUILD_BUG_ON(sizeof(CommandList_struct) % 8); + BUILD_BUG_ON(sizeof(CommandList_struct) % COMMANDLIST_ALIGNMENT); printk(KERN_INFO DRIVER_NAME "\n"); diff --git a/drivers/block/cciss_cmd.h b/drivers/block/cciss_cmd.h index 515c9f0..e624ff9 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) diff --git a/drivers/block/cciss_scsi.c b/drivers/block/cciss_scsi.c index 5d0e46d..f203606 100644 --- a/drivers/block/cciss_scsi.c +++ b/drivers/block/cciss_scsi.c @@ -93,11 +93,15 @@ static struct scsi_host_template cciss_driver_template = { }; #pragma pack(1) + +#define SCSI_PAD_32 4 +#define SCSI_PAD_64 4 + struct cciss_scsi_cmd_stack_elem_t { CommandList_struct cmd; ErrorInfo_struct Err; __u32 busaddr; - __u32 pad; + u8 pad[IS_32_BIT * SCSI_PAD_32 + IS_64_BIT * SCSI_PAD_64]; }; #pragma pack() @@ -202,9 +206,9 @@ scsi_cmd_stack_setup(int ctlr, struct cciss_scsi_adapter_data_t *sa) stk = &sa->cmd_stack; size = sizeof(struct cciss_scsi_cmd_stack_elem_t) * CMD_STACK_SIZE; - // pci_alloc_consistent guarantees 32-bit DMA address will - // be used - + /* Check alignment, see cciss_cmd.h near CommandList_struct def. */ + BUILD_BUG_ON((sizeof(*stk->pool) % COMMANDLIST_ALIGNMENT) != 0); + /* pci_alloc_consistent guarantees 32-bit DMA address will be used */ stk->pool = (struct cciss_scsi_cmd_stack_elem_t *) pci_alloc_consistent(hba[ctlr]->pdev, size, &stk->cmd_pool_handle); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |