Zeroing sense buffer for each scsi request is not efficient, we can just
leave it uninitialized because sense_len is set to 0.
Move the implicitly zeroes fields to the end of the structure and use a
partial memset.
Also change g_malloc0 to g_slice_alloc.
Signed-off-by: Fam Zheng <f...@redhat.com>
---
hw/scsi/scsi-bus.c | 7 +++++--
include/hw/scsi/scsi.h | 21 ++++++++++++++-------
2 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 954c607..71b45c0 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -551,8 +551,11 @@ SCSIRequest *scsi_req_alloc(const SCSIReqOps *reqops,
SCSIDevice *d,
SCSIRequest *req;
SCSIBus *bus = scsi_bus_from_device(d);
BusState *qbus = BUS(bus);
+ const int memset_off = offsetof(SCSIRequest, sense)
+ + sizeof(req->sense);
- req = g_malloc0(reqops->size);
+ req = g_slice_alloc(reqops->size);
+ memset((uint8_t *)req + memset_off, 0, reqops->size - memset_off);
req->refcount = 1;
req->bus = bus;
req->dev = d;
@@ -1603,7 +1606,7 @@ void scsi_req_unref(SCSIRequest *req)
}
object_unref(OBJECT(req->dev));
object_unref(OBJECT(qbus->parent));
- g_free(req);
+ g_slice_free1(req->ops->size, req);
}
}
diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 2e3a8f9..889f659 100644
--- a/include/hw/scsi/scsi.h
+++ b/include/hw/scsi/scsi.h
@@ -50,17 +50,24 @@ struct SCSIRequest {
uint32_t tag;
uint32_t lun;
uint32_t status;
+ uint32_t sense_len;
+
+ /* Note:
+ * - fields before sense are initialized by scsi_req_alloc;
+ * - sense[] is uninitialized;
+ * - fields after sense are memset to 0 by scsi_req_alloc.
+ * */
+
+ uint8_t sense[SCSI_SENSE_BUF_SIZE];
+ bool enqueued;
+ bool io_canceled;
+ bool retry;
+ bool dma_started;
+ void *hba_private;
size_t resid;
SCSICommand cmd;
BlockDriverAIOCB *aiocb;
QEMUSGList *sg;
- bool dma_started;
- uint8_t sense[SCSI_SENSE_BUF_SIZE];
- uint32_t sense_len;
- bool enqueued;
- bool io_canceled;
- bool retry;
- void *hba_private;
QTAILQ_ENTRY(SCSIRequest) next;
};
--
1.9.3
