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authorFam Zheng <famz@redhat.com>2014-09-16 15:20:17 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2014-09-23 15:40:51 +0200
commit61e68b3fbd3e2b7beb636bc56f78d9c1ca25e8f9 (patch)
tree94312f417d4022a681392b1526c590a18924ceb2 /include/hw/scsi
parent380f649e02f9545159dc3158d7c1b2e70c1005e3 (diff)
downloadhqemu-61e68b3fbd3e2b7beb636bc56f78d9c1ca25e8f9.zip
hqemu-61e68b3fbd3e2b7beb636bc56f78d9c1ca25e8f9.tar.gz
scsi: Optimize scsi_req_alloc
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 zeroed fields to the end of the structure and use a partial memset. The explicitly initialized fields (by scsi_req_alloc or scsi_req_new) are moved to the beginning of the structure, before sense buffer, to skip the memset. Also change g_malloc0 to g_slice_alloc. Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/hw/scsi')
-rw-r--r--include/hw/scsi/scsi.h21
1 files changed, 14 insertions, 7 deletions
diff --git a/include/hw/scsi/scsi.h b/include/hw/scsi/scsi.h
index 2e3a8f9..6271ad3 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;
+ void *hba_private;
size_t resid;
SCSICommand cmd;
+
+ /* 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];
+ uint32_t sense_len;
+ bool enqueued;
+ bool io_canceled;
+ bool retry;
+ bool dma_started;
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;
};
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