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 <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
diff --git a/include/scsi/scsi.h b/include/scsi/scsi.h
index 8fcb6e0..d63533a 100644
--- a/include/scsi/scsi.h
+++ b/include/scsi/scsi.h
@@ -32,6 +32,12 @@
#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.
*/