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scsi: annotate unlikely checks in read/write

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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: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/393700
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: <shuhei.matsumoto.xt@hitachi.com>
This commit is contained in:
Daniel Verkamp 2018-01-04 13:52:10 -07:00 committed by Jim Harris
parent a06daa1bfa
commit 683eeb59b8
1 changed files with 6 additions and 5 deletions
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11
lib/scsi/scsi_bdev.c
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@ -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,