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authorPeter Lieven <pl@dlhnet.de>2012-12-03 20:35:15 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2013-01-24 15:37:55 +0100
commit7371d56fb2759f52106c76692440d0c29731ef9c (patch)
tree308fc4416e7c54ef3c4f937ee7ac585ddbfd94ca /block
parent4790b03d308f6c7dea7dc6941ddab9867c9530b8 (diff)
downloadhqemu-7371d56fb2759f52106c76692440d0c29731ef9c.zip
hqemu-7371d56fb2759f52106c76692440d0c29731ef9c.tar.gz
iscsi: add support for iovectors
This patch adds support for directly passing the iovec array from QEMUIOVector if libiscsi supports it (1.8.0 or newer). Signed-off-by: Peter Lieven <pl@kamp.de> [Preserve the improvements from commit 4cc841b, iscsi: partly avoid iovec linearization in iscsi_aio_writev, 2012-11-19 - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/iscsi.c43
1 files changed, 34 insertions, 9 deletions
diff --git a/block/iscsi.c b/block/iscsi.c
index b647201..deb3b68 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -234,7 +234,10 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
size_t size;
uint32_t num_sectors;
uint64_t lba;
+#if !defined(LIBISCSI_FEATURE_IOVECTOR)
struct iscsi_data data;
+#endif
+ int ret;
acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
trace_iscsi_aio_writev(iscsi, sector_num, nb_sectors, opaque, acb);
@@ -247,9 +250,10 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
acb->status = -EINPROGRESS;
acb->buf = NULL;
- /* XXX we should pass the iovec to write16 to avoid the extra copy */
/* this will allow us to get rid of 'buf' completely */
size = nb_sectors * BDRV_SECTOR_SIZE;
+
+#if !defined(LIBISCSI_FEATURE_IOVECTOR)
data.size = MIN(size, acb->qiov->size);
/* if the iovec only contains one buffer we can pass it directly */
@@ -260,6 +264,7 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
qemu_iovec_to_buf(acb->qiov, 0, acb->buf, data.size);
data.data = acb->buf;
}
+#endif
acb->task = malloc(sizeof(struct scsi_task));
if (acb->task == NULL) {
@@ -280,16 +285,28 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
*(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);
acb->task->expxferlen = size;
- if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
- iscsi_aio_write16_cb,
- &data,
- acb) != 0) {
+#if defined(LIBISCSI_FEATURE_IOVECTOR)
+ ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ iscsi_aio_write16_cb,
+ NULL,
+ acb);
+#else
+ ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ iscsi_aio_write16_cb,
+ &data,
+ acb);
+#endif
+ if (ret != 0) {
scsi_free_scsi_task(acb->task);
g_free(acb->buf);
qemu_aio_release(acb);
return NULL;
}
+#if defined(LIBISCSI_FEATURE_IOVECTOR)
+ scsi_task_set_iov_out(acb->task, (struct scsi_iovec*) acb->qiov->iov, acb->qiov->niov);
+#endif
+
iscsi_set_events(iscsilun);
return &acb->common;
@@ -327,7 +344,10 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
struct iscsi_context *iscsi = iscsilun->iscsi;
IscsiAIOCB *acb;
size_t qemu_read_size;
+#if !defined(LIBISCSI_FEATURE_IOVECTOR)
int i;
+#endif
+ int ret;
uint64_t lba;
uint32_t num_sectors;
@@ -389,20 +409,25 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
break;
}
- if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
- iscsi_aio_read16_cb,
- NULL,
- acb) != 0) {
+ ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
+ iscsi_aio_read16_cb,
+ NULL,
+ acb);
+ if (ret != 0) {
scsi_free_scsi_task(acb->task);
qemu_aio_release(acb);
return NULL;
}
+#if defined(LIBISCSI_FEATURE_IOVECTOR)
+ scsi_task_set_iov_in(acb->task, (struct scsi_iovec*) acb->qiov->iov, acb->qiov->niov);
+#else
for (i = 0; i < acb->qiov->niov; i++) {
scsi_task_add_data_in_buffer(acb->task,
acb->qiov->iov[i].iov_len,
acb->qiov->iov[i].iov_base);
}
+#endif
iscsi_set_events(iscsilun);
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