make priority class support conditional

Author: ashwin-simplyblock

lib/blob/blobstore.c

@@ -3915,7 +3915,7 @@ bs_alloc(struct spdk_bs_dev *dev, struct spdk_bs_opts *opts, struct spdk_blob_st
 	bs->md_thread = spdk_get_thread();
 	assert(bs->md_thread != NULL);
 
-	bs->priority_class = MAX_PRIORITY_CLASS; // max priority for metadata I/O
+	bs->priority_class = 0;
 
 	/*
 	 * Do not use bs_lba_to_cluster() here since blockcnt may not be an
@@ -10302,6 +10302,7 @@ void
 spdk_blob_set_priority_class(struct spdk_blob* blob, int priority_class)
 {
 	blob->priority_class = priority_class;
+	if (priority_class) { blob->bs->priority_class = MAX_PRIORITY_CLASS; } // max priority for metadata I/O if priority is supported
 }
 
 SPDK_LOG_REGISTER_COMPONENT(blob)

module/bdev/raid/bdev_raid.c

@@ -922,6 +922,7 @@ raid_bdev_submit_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_i
 			  bdev_io->u.bdev.iovs, bdev_io->u.bdev.iovcnt, bdev_io->u.bdev.md_buf,
 			  bdev_io->u.bdev.memory_domain, bdev_io->u.bdev.memory_domain_ctx);
 	raid_io->priority_class = (bdev_io->u.bdev.offset_blocks & PRIORITY_CLASS_MASK) >> PRIORITY_CLASS_BITS_POS;
+	if (raid_io->priority_class) { raid_io->raid_bdev->supports_priority_class = 1; }
 
 	switch (bdev_io->type) {
 	case SPDK_BDEV_IO_TYPE_READ:
@@ -1539,6 +1540,8 @@ _raid_bdev_create(const char *name, uint32_t strip_size, uint8_t num_base_bdevs,
 		base_info->raid_bdev = raid_bdev;
 	}
 
+	raid_bdev->supports_priority_class = 0;
+
 	/* strip_size_kb is from the rpc param.  strip_size is in blocks and used
 	 * internally and set later.
 	 */

module/bdev/raid/bdev_raid.h

@@ -195,6 +195,8 @@ struct raid_bdev {
 	/* array of base bdev info */
 	struct raid_base_bdev_info	*base_bdev_info;
 
+	uint8_t supports_priority_class; // whether lvol priority is supported, default 0 (false)
+
 	/* strip size of raid bdev in blocks */
 	uint32_t			strip_size;
 

module/bdev/raid/raid1.c

@@ -489,7 +489,7 @@ raid1_submit_process_request(struct raid_bdev_process_request *process_req,
 			  process_req->offset_blocks, process_req->num_blocks,
 			  &process_req->iov, 1, process_req->md_buf, NULL, NULL);
 	raid_io->completion_cb = raid1_process_read_completed;
-	raid_io->priority_class = MAX_PRIORITY_CLASS;
+	raid_io->priority_class = raid_io->raid_bdev->supports_priority_class ? MAX_PRIORITY_CLASS : 0;
 
 	ret = raid1_submit_read_request(raid_io);
 	if (spdk_likely(ret == 0)) {

module/bdev/raid/raid5f.c

@@ -1223,7 +1223,7 @@ raid5f_submit_process_request(struct raid_bdev_process_request *process_req,
 	raid_bdev_io_init(raid_io, raid_ch, SPDK_BDEV_IO_TYPE_READ,
 			  process_req->offset_blocks, raid_bdev->strip_size,
 			  &process_req->iov, 1, process_req->md_buf, NULL, NULL);
-	raid_io->priority_class = MAX_PRIORITY_CLASS;
+	raid_io->priority_class = raid_io->raid_bdev->supports_priority_class ? MAX_PRIORITY_CLASS : 0;
 
 	ret = raid5f_submit_reconstruct_read(raid_io, stripe_index, chunk_idx, 0,
 					     raid5f_process_stripe_request_reconstruct_xor_done);