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>
This commit is contained in:
parent
4790b03d30
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@ -234,7 +234,10 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
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size_t size;
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uint32_t num_sectors;
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uint64_t lba;
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#if !defined(LIBISCSI_FEATURE_IOVECTOR)
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struct iscsi_data data;
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#endif
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int ret;
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acb = qemu_aio_get(&iscsi_aiocb_info, bs, cb, opaque);
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trace_iscsi_aio_writev(iscsi, sector_num, nb_sectors, opaque, acb);
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@ -247,9 +250,10 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
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acb->status = -EINPROGRESS;
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acb->buf = NULL;
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/* XXX we should pass the iovec to write16 to avoid the extra copy */
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/* this will allow us to get rid of 'buf' completely */
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size = nb_sectors * BDRV_SECTOR_SIZE;
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#if !defined(LIBISCSI_FEATURE_IOVECTOR)
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data.size = MIN(size, acb->qiov->size);
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/* if the iovec only contains one buffer we can pass it directly */
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@ -260,6 +264,7 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
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qemu_iovec_to_buf(acb->qiov, 0, acb->buf, data.size);
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data.data = acb->buf;
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}
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#endif
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acb->task = malloc(sizeof(struct scsi_task));
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if (acb->task == NULL) {
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@ -280,16 +285,28 @@ iscsi_aio_writev(BlockDriverState *bs, int64_t sector_num,
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*(uint32_t *)&acb->task->cdb[10] = htonl(num_sectors);
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acb->task->expxferlen = size;
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if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
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#if defined(LIBISCSI_FEATURE_IOVECTOR)
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ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
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iscsi_aio_write16_cb,
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NULL,
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acb);
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#else
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ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
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iscsi_aio_write16_cb,
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&data,
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acb) != 0) {
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acb);
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#endif
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if (ret != 0) {
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scsi_free_scsi_task(acb->task);
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g_free(acb->buf);
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qemu_aio_release(acb);
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return NULL;
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}
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#if defined(LIBISCSI_FEATURE_IOVECTOR)
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scsi_task_set_iov_out(acb->task, (struct scsi_iovec*) acb->qiov->iov, acb->qiov->niov);
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#endif
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iscsi_set_events(iscsilun);
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return &acb->common;
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@ -327,7 +344,10 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
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struct iscsi_context *iscsi = iscsilun->iscsi;
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IscsiAIOCB *acb;
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size_t qemu_read_size;
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#if !defined(LIBISCSI_FEATURE_IOVECTOR)
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int i;
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#endif
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int ret;
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uint64_t lba;
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uint32_t num_sectors;
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@ -389,20 +409,25 @@ iscsi_aio_readv(BlockDriverState *bs, int64_t sector_num,
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break;
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}
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if (iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
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ret = iscsi_scsi_command_async(iscsi, iscsilun->lun, acb->task,
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iscsi_aio_read16_cb,
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NULL,
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acb) != 0) {
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acb);
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if (ret != 0) {
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scsi_free_scsi_task(acb->task);
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qemu_aio_release(acb);
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return NULL;
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}
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#if defined(LIBISCSI_FEATURE_IOVECTOR)
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scsi_task_set_iov_in(acb->task, (struct scsi_iovec*) acb->qiov->iov, acb->qiov->niov);
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#else
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for (i = 0; i < acb->qiov->niov; i++) {
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scsi_task_add_data_in_buffer(acb->task,
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acb->qiov->iov[i].iov_len,
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acb->qiov->iov[i].iov_base);
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}
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#endif
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iscsi_set_events(iscsilun);
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