On 01/06/24 07:53AM, Christoph Hellwig wrote:
On Mon, May 20, 2024 at 03:50:14PM +0530, Nitesh Shetty wrote:
Add device limits as sysfs entries,
- copy_max_bytes (RW)
- copy_max_hw_bytes (RO)
Above limits help to split the copy payload in block layer.
copy_max_bytes: maximum total length of copy in single payload.
copy_max_hw_bytes: Reflects the device supported maximum limit.
That's a bit of a weird way to phrase the commit log as the queue_limits
are the main thing (and there are three of them as required for the
scheme to work). The sysfs attributes really are just an artifact.
Acked, we will update commit log.
@@ -231,10 +237,11 @@ int blk_set_default_limits(struct queue_limits *lim)
{
/*
* Most defaults are set by capping the bounds in blk_validate_limits,
- * but max_user_discard_sectors is special and needs an explicit
- * initialization to the max value here.
+ * but max_user_discard_sectors and max_user_copy_sectors are special
+ * and needs an explicit initialization to the max value here.
s/needs/need/
Acked.
+/*
+ * blk_queue_max_copy_hw_sectors - set max sectors for a single copy payload
+ * @q: the request queue for the device
+ * @max_copy_sectors: maximum number of sectors to copy
+ */
+void blk_queue_max_copy_hw_sectors(struct request_queue *q,
+ unsigned int max_copy_sectors)
+{
+ struct queue_limits *lim = &q->limits;
+
+ if (max_copy_sectors > (BLK_COPY_MAX_BYTES >> SECTOR_SHIFT))
+ max_copy_sectors = BLK_COPY_MAX_BYTES >> SECTOR_SHIFT;
+
+ lim->max_copy_hw_sectors = max_copy_sectors;
+ lim->max_copy_sectors =
+ min(max_copy_sectors, lim->max_user_copy_sectors);
+}
+EXPORT_SYMBOL_GPL(blk_queue_max_copy_hw_sectors);
Please don't add new blk_queue_* helpers, everything should go through
the atomic queue limits API now. Also capping the hardware limit
here looks odd.
This was a mistake, we are not using this function. We will remove this
function in next version.
+ if (max_copy_bytes & (queue_logical_block_size(q) - 1))
+ return -EINVAL;
This should probably go into blk_validate_limits and just round down.
Bart also pointed out similar thing. We do same check before issuing
copy offload, so we will remove this check.
Also most block limits are in kb. Not that I really know why we are
doing that, but is there a good reason to deviate from that scheme?
We followed discard as a reference, but we can move to kb, if that helps
with overall readability.
Thank you,
Nitesh Shetty
