Commit 0720ad35 authored by Daniel Verkamp's avatar Daniel Verkamp
Browse files

scsi: allow zero-length read and write 



The SCSI spec says that zero transfer length shouldn't be considered an
error.

Change-Id: I98958cc393e0e487e25fdbb0eb7fc8126aff9945
Signed-off-by: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/374320


Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
parent 75a3ee3f

lib/scsi/scsi_bdev.c

+5 −9
Original line number Diff line number Diff line
@@ -1338,15 +1338,6 @@ spdk_bdev_scsi_write(struct spdk_bdev *bdev, 
	int rc;

	struct spdk_scsi_task *primary = task->parent;



	if (len == 0) {

		task->data_transferred = 0;

		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,

					  SPDK_SCSI_SENSE_NO_SENSE,

					  SPDK_SCSI_ASC_NO_ADDITIONAL_SENSE,

					  SPDK_SCSI_ASCQ_CAUSE_NOT_REPORTABLE);

		return SPDK_SCSI_TASK_COMPLETE;

	}



	blen = spdk_bdev_get_block_size(bdev);

	offset = lba * blen;

	nbytes = ((uint64_t)len) * blen;
@@ -1461,6 +1452,11 @@ spdk_bdev_scsi_readwrite(struct spdk_bdev *bdev, 
		return SPDK_SCSI_TASK_COMPLETE;

	}



	if (xfer_len == 0) {

		task->status = SPDK_SCSI_STATUS_GOOD;

		return SPDK_SCSI_TASK_COMPLETE;

	}



	/* Transfer Length is limited to the Block Limits VPD page Maximum Transfer Length */

	max_xfer_len = SPDK_WORK_BLOCK_SIZE / spdk_bdev_get_block_size(bdev);

	if (xfer_len > max_xfer_len) {

test/unit/lib/scsi/scsi_bdev.c/scsi_bdev_ut.c

+18 −0
Original line number Diff line number Diff line
@@ -672,6 +672,24 @@ xfer_len_test(void) 
	CU_ASSERT((task.sense_data[2] & 0xf) == SPDK_SCSI_SENSE_ILLEGAL_REQUEST);

	CU_ASSERT(task.sense_data[12] == SPDK_SCSI_ASC_INVALID_FIELD_IN_CDB);



	/* zero transfer length (valid) */

	to_be64(&cdb[2], 0); /* LBA */

	to_be32(&cdb[10], 0); /* transfer length */

	task.transfer_len = 0;

	rc = spdk_bdev_scsi_execute(&bdev, &task);

	CU_ASSERT(rc == SPDK_SCSI_TASK_COMPLETE);

	CU_ASSERT(task.status == SPDK_SCSI_STATUS_GOOD);

	CU_ASSERT(task.data_transferred == 0);



	/* zero transfer length past end of disk (invalid) */

	to_be64(&cdb[2], g_test_bdev_num_blocks); /* LBA */

	to_be32(&cdb[10], 0); /* transfer length */

	task.transfer_len = 0;

	rc = spdk_bdev_scsi_execute(&bdev, &task);

	CU_ASSERT(rc == SPDK_SCSI_TASK_COMPLETE);

	CU_ASSERT(task.status == SPDK_SCSI_STATUS_CHECK_CONDITION);

	CU_ASSERT(task.sense_data[12] == SPDK_SCSI_ASC_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE);



	spdk_put_task(&task);

}