File kvm-qemu-preXX-scsi-disk-commonize-iovec-creation-between-reads-and.patch of Package kvm.openSUSE_12.1_Update

From 103b40f51e4012b3b0ad20f615562a1806d7f49a Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Fri, 16 Sep 2011 16:40:03 +0200
Subject: [PATCH] scsi-disk: commonize iovec creation between reads and writes

Also, consistently use qiov.size instead of iov.iov_len.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/scsi-disk.c |   42 ++++++++++++++++++------------------------
 1 files changed, 18 insertions(+), 24 deletions(-)

Index: qemu-kvm-0.15.1/hw/scsi-disk.c
===================================================================
--- qemu-kvm-0.15.1.orig/hw/scsi-disk.c
+++ qemu-kvm-0.15.1/hw/scsi-disk.c
@@ -134,6 +134,13 @@ static void scsi_cancel_io(SCSIRequest *
     r->req.aiocb = NULL;
 }
 
+static uint32_t scsi_init_iovec(SCSIDiskReq *r)
+{
+    r->iov.iov_len = MIN(r->sector_count * 512, SCSI_DMA_BUF_SIZE);
+    qemu_iovec_init_external(&r->qiov, &r->iov, 1);
+    return r->qiov.size / 512;
+}
+
 static void scsi_read_complete(void * opaque, int ret)
 {
     SCSIDiskReq *r = (SCSIDiskReq *)opaque;
@@ -147,12 +154,12 @@ static void scsi_read_complete(void * op
         }
     }
 
-    DPRINTF("Data ready tag=0x%x len=%zd\n", r->req.tag, r->iov.iov_len);
+    DPRINTF("Data ready tag=0x%x len=%zd\n", r->req.tag, r->qiov.size);
 
-    n = r->iov.iov_len / 512;
+    n = r->qiov.size / 512;
     r->sector += n;
     r->sector_count -= n;
-    scsi_req_data(&r->req, r->iov.iov_len);
+    scsi_req_data(&r->req, r->qiov.size);
 }
 
 
@@ -184,12 +191,7 @@ static void scsi_read_data(SCSIRequest *
         return;
     }
 
-    n = r->sector_count;
-    if (n > SCSI_DMA_BUF_SIZE / 512)
-        n = SCSI_DMA_BUF_SIZE / 512;
-
-    r->iov.iov_len = n * 512;
-    qemu_iovec_init_external(&r->qiov, &r->iov, 1);
+    n = scsi_init_iovec(r);
     r->req.aiocb = bdrv_aio_readv(s->bs, r->sector, &r->qiov, n,
                               scsi_read_complete, r);
     if (r->req.aiocb == NULL) {
@@ -242,7 +244,6 @@ static int scsi_handle_rw_error(SCSIDisk
 static void scsi_write_complete(void * opaque, int ret)
 {
     SCSIDiskReq *r = (SCSIDiskReq *)opaque;
-    uint32_t len;
     uint32_t n;
 
     r->req.aiocb = NULL;
@@ -253,19 +254,15 @@ static void scsi_write_complete(void * o
         }
     }
 
-    n = r->iov.iov_len / 512;
+    n = r->qiov.size / 512;
     r->sector += n;
     r->sector_count -= n;
     if (r->sector_count == 0) {
         scsi_command_complete(r, GOOD, SENSE_CODE(NO_SENSE));
     } else {
-        len = r->sector_count * 512;
-        if (len > SCSI_DMA_BUF_SIZE) {
-            len = SCSI_DMA_BUF_SIZE;
-        }
-        r->iov.iov_len = len;
-        DPRINTF("Write complete tag=0x%x more=%d\n", r->req.tag, len);
-        scsi_req_data(&r->req, len);
+        scsi_init_iovec(r);
+        DPRINTF("Write complete tag=0x%x more=%d\n", r->req.tag, r->qiov.size);
+        scsi_req_data(&r->req, r->qiov.size);
     }
 }
 
@@ -284,16 +281,15 @@ static void scsi_write_data(SCSIRequest
         return;
     }
 
-    n = r->iov.iov_len / 512;
+    n = r->qiov.size / 512;
     if (n) {
-        qemu_iovec_init_external(&r->qiov, &r->iov, 1);
         r->req.aiocb = bdrv_aio_writev(s->bs, r->sector, &r->qiov, n,
-                                   scsi_write_complete, r);
+                                       scsi_write_complete, r);
         if (r->req.aiocb == NULL) {
             scsi_write_complete(r, -ENOMEM);
         }
     } else {
-        /* Invoke completion routine to fetch data from host.  */
+        /* Called for the first time.  Ask the driver to send us more data.  */
         scsi_write_complete(r, 0);
     }
 }