Commit 683eeb59 authored by Daniel Verkamp's avatar Daniel Verkamp Committed by Jim Harris
Browse files

scsi: annotate unlikely checks in read/write 



The normal execution path for read/write commands is that none of the
checks fail; annotate all of the checks in spdk_bdev_scsi_readwrite()
with spdk_unlikely to encourage the compiler to generate the happy path
as straight-line code and move the error handling out of line.

Change-Id: Id0e606c78f0b99662e5c27e3bfa32535de20aa13
Signed-off-by: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/393700


Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
Reviewed-by: default avatar <shuhei.matsumoto.xt@hitachi.com>
parent a06daa1b

lib/scsi/scsi_bdev.c

+6 −5
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ 
#include "spdk/env.h"

#include "spdk/bdev.h"

#include "spdk/endian.h"

#include "spdk/likely.h"

#include "spdk/string.h"

#include "spdk/util.h"
@@ -1430,8 +1431,8 @@ spdk_bdev_scsi_readwrite(struct spdk_bdev *bdev, 


	task->data_transferred = 0;



	if (task->dxfer_dir != SPDK_SCSI_DIR_NONE &&

	    task->dxfer_dir != (is_read ? SPDK_SCSI_DIR_FROM_DEV : SPDK_SCSI_DIR_TO_DEV)) {

	if (spdk_unlikely(task->dxfer_dir != SPDK_SCSI_DIR_NONE &&

			  task->dxfer_dir != (is_read ? SPDK_SCSI_DIR_FROM_DEV : SPDK_SCSI_DIR_TO_DEV))) {

		SPDK_ERRLOG("Incorrect data direction\n");

		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,

					  SPDK_SCSI_SENSE_NO_SENSE,
@@ -1441,7 +1442,7 @@ spdk_bdev_scsi_readwrite(struct spdk_bdev *bdev, 
	}



	bdev_num_blocks = spdk_bdev_get_num_blocks(bdev);

	if (bdev_num_blocks <= lba || bdev_num_blocks - lba < xfer_len) {

	if (spdk_unlikely(bdev_num_blocks <= lba || bdev_num_blocks - lba < xfer_len)) {

		SPDK_DEBUGLOG(SPDK_LOG_SCSI, "end of media\n");

		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,

					  SPDK_SCSI_SENSE_ILLEGAL_REQUEST,
@@ -1450,14 +1451,14 @@ spdk_bdev_scsi_readwrite(struct spdk_bdev *bdev, 
		return SPDK_SCSI_TASK_COMPLETE;

	}



	if (xfer_len == 0) {

	if (spdk_unlikely(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) {

	if (spdk_unlikely(xfer_len > max_xfer_len)) {

		SPDK_ERRLOG("xfer_len %" PRIu32 " > maximum transfer length %" PRIu32 "\n",

			    xfer_len, max_xfer_len);

		spdk_scsi_task_set_status(task, SPDK_SCSI_STATUS_CHECK_CONDITION,