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/block/blk-sysfs.c b/block/blk-sysfs.c
index 001ab18..b014f77 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -112,6 +112,11 @@
return queue_var_show(queue_max_segments(q), (page));
}
+static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(q->limits.max_integrity_segments, (page));
+}
+
static ssize_t queue_max_segment_size_show(struct request_queue *q, char *page)
{
if (test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags))
@@ -288,6 +293,11 @@
.show = queue_max_segments_show,
};
+static struct queue_sysfs_entry queue_max_integrity_segments_entry = {
+ .attr = {.name = "max_integrity_segments", .mode = S_IRUGO },
+ .show = queue_max_integrity_segments_show,
+};
+
static struct queue_sysfs_entry queue_max_segment_size_entry = {
.attr = {.name = "max_segment_size", .mode = S_IRUGO },
.show = queue_max_segment_size_show,
@@ -375,6 +385,7 @@
&queue_max_hw_sectors_entry.attr,
&queue_max_sectors_entry.attr,
&queue_max_segments_entry.attr,
+ &queue_max_integrity_segments_entry.attr,
&queue_max_segment_size_entry.attr,
&queue_iosched_entry.attr,
&queue_hw_sector_size_entry.attr,
