From 13f05c8d8e98bbdce89158bfdb2e380940695a88 Mon Sep 17 00:00:00 2001 From: "Martin K. Petersen" Date: Fri, 10 Sep 2010 20:50:10 +0200 Subject: block/scsi: Provide a limit on the number of integrity segments Some controllers have a hardware limit on the number of protection information scatter-gather list segments they can handle. Introduce a max_integrity_segments limit in the block layer and provide a new scsi_host_template setting that allows HBA drivers to provide a value suitable for the hardware. Add support for honoring the integrity segment limit when merging both bios and requests. Signed-off-by: Martin K. Petersen Signed-off-by: Jens Axboe --- include/scsi/scsi.h | 6 ++++++ include/scsi/scsi_host.h | 7 +++++++ 2 files changed, 13 insertions(+) (limited to 'include/scsi') diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h index 8fcb6e0e9e72..d63533a4a59e 100644 --- a/include/scsi/scsi.h +++ b/include/scsi/scsi.h @@ -31,6 +31,12 @@ struct scsi_cmnd; #define SCSI_MAX_SG_CHAIN_SEGMENTS SCSI_MAX_SG_SEGMENTS #endif +/* + * DIX-capable adapters effectively support infinite chaining for the + * protection information scatterlist + */ +#define SCSI_MAX_PROT_SG_SEGMENTS 0xFFFF + /* * Special value for scanning to specify scanning or rescanning of all * possible channels, (target) ids, or luns on a given shost. diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index b7bdecb7b76e..d0a6a845f204 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -388,6 +388,7 @@ struct scsi_host_template { * of scatter-gather. */ unsigned short sg_tablesize; + unsigned short sg_prot_tablesize; /* * Set this if the host adapter has limitations beside segment count. @@ -599,6 +600,7 @@ struct Scsi_Host { int can_queue; short cmd_per_lun; short unsigned int sg_tablesize; + short unsigned int sg_prot_tablesize; short unsigned int max_sectors; unsigned long dma_boundary; /* @@ -823,6 +825,11 @@ static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost) return shost->prot_capabilities; } +static inline int scsi_host_prot_dma(struct Scsi_Host *shost) +{ + return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION; +} + static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type) { static unsigned char cap[] = { 0, -- cgit v1.2.3