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[Qemu-devel] [RFC PATCH 9/9] scsi: Cancel request asynchronously
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [RFC PATCH 9/9] scsi: Cancel request asynchronously |
Date: |
Thu, 21 Aug 2014 19:56:56 +0800 |
We are blocking the whole VM, which means that an irresponsive storage
backend will hang the whole guest. Let's switch to bdrv_aio_cancel_async
to improve this.
Signed-off-by: Fam Zheng <address@hidden>
---
hw/scsi/scsi-bus.c | 6 ++----
hw/scsi/scsi-disk.c | 41 ++++++++++-------------------------------
hw/scsi/scsi-generic.c | 21 ++++++---------------
3 files changed, 18 insertions(+), 50 deletions(-)
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index 6f4462b..59ec9f9 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -1615,7 +1615,6 @@ void scsi_req_continue(SCSIRequest *req)
{
if (req->io_canceled) {
trace_scsi_req_continue_canceled(req->dev->id, req->lun, req->tag);
- return;
}
trace_scsi_req_continue(req->dev->id, req->lun, req->tag);
if (req->cmd.mode == SCSI_XFER_TO_DEV) {
@@ -1633,7 +1632,6 @@ void scsi_req_data(SCSIRequest *req, int len)
uint8_t *buf;
if (req->io_canceled) {
trace_scsi_req_data_canceled(req->dev->id, req->lun, req->tag, len);
- return;
}
trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);
assert(req->cmd.mode != SCSI_XFER_NONE);
@@ -1721,7 +1719,7 @@ void scsi_req_complete(SCSIRequest *req, int status)
void scsi_req_cancel(SCSIRequest *req)
{
trace_scsi_req_cancel(req->dev->id, req->lun, req->tag);
- if (!req->enqueued) {
+ if (req->io_canceled) {
return;
}
scsi_req_ref(req);
@@ -1738,7 +1736,7 @@ void scsi_req_cancel(SCSIRequest *req)
void scsi_req_abort(SCSIRequest *req, int status)
{
- if (!req->enqueued) {
+ if (req->io_canceled) {
return;
}
scsi_req_ref(req);
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index d55521d..46b1e53 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -112,14 +112,9 @@ static void scsi_cancel_io(SCSIRequest *req)
DPRINTF("Cancel tag=0x%x\n", req->tag);
if (r->req.aiocb) {
- bdrv_aio_cancel(r->req.aiocb);
-
- /* This reference was left in by scsi_*_data. We take ownership of
- * it the moment scsi_req_cancel is called, independent of whether
- * bdrv_aio_cancel completes the request or not. */
- scsi_req_unref(&r->req);
+ assert(req->io_canceled);
+ bdrv_aio_cancel_async(r->req.aiocb);
}
- r->req.aiocb = NULL;
}
static uint32_t scsi_init_iovec(SCSIDiskReq *r, size_t size)
@@ -197,9 +192,7 @@ static void scsi_aio_complete(void *opaque, int ret)
scsi_req_complete(&r->req, GOOD);
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
static bool scsi_is_cmd_fua(SCSICommand *cmd)
@@ -245,9 +238,7 @@ static void scsi_write_do_fua(SCSIDiskReq *r)
scsi_req_complete(&r->req, GOOD);
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
static void scsi_dma_complete_noio(void *opaque, int ret)
@@ -279,9 +270,7 @@ static void scsi_dma_complete_noio(void *opaque, int ret)
}
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
static void scsi_dma_complete(void *opaque, int ret)
@@ -319,9 +308,7 @@ static void scsi_read_complete(void * opaque, int ret)
scsi_req_data(&r->req, r->qiov.size);
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
/* Actually issue a read to the block device. */
@@ -361,9 +348,7 @@ static void scsi_do_read(void *opaque, int ret)
}
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
/* Read more data from scsi device into buffer. */
@@ -478,9 +463,7 @@ static void scsi_write_complete(void * opaque, int ret)
}
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
static void scsi_write_data(SCSIRequest *req)
@@ -1577,9 +1560,7 @@ static void scsi_unmap_complete(void *opaque, int ret)
scsi_req_complete(&r->req, GOOD);
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
g_free(data);
}
@@ -1672,9 +1653,7 @@ static void scsi_write_same_complete(void *opaque, int
ret)
scsi_req_complete(&r->req, GOOD);
done:
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
qemu_vfree(data->iov.iov_base);
g_free(data);
}
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 0b2ff90..1c29ecb 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -132,27 +132,20 @@ static void scsi_command_complete(void *opaque, int ret)
DPRINTF("Command complete 0x%p tag=0x%x status=%d\n",
r, r->req.tag, status);
- scsi_req_complete(&r->req, status);
if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
+ scsi_req_complete(&r->req, status);
}
+ scsi_req_unref(&r->req);
}
/* Cancel a pending data transfer. */
static void scsi_cancel_io(SCSIRequest *req)
{
- SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
-
DPRINTF("Cancel tag=0x%x\n", req->tag);
- if (r->req.aiocb) {
- bdrv_aio_cancel(r->req.aiocb);
-
- /* This reference was left in by scsi_*_data. We take ownership of
- * it independent of whether bdrv_aio_cancel completes the request
- * or not. */
- scsi_req_unref(&r->req);
+ if (req->aiocb) {
+ req->io_canceled = true;
+ bdrv_aio_cancel_async(req->aiocb);
}
- r->req.aiocb = NULL;
}
static int execute_command(BlockDriverState *bdrv,
@@ -211,9 +204,7 @@ static void scsi_read_complete(void * opaque, int ret)
bdrv_set_guest_block_size(s->conf.bs, s->blocksize);
scsi_req_data(&r->req, len);
- if (!r->req.io_canceled) {
- scsi_req_unref(&r->req);
- }
+ scsi_req_unref(&r->req);
}
}
--
2.0.3
- Re: [Qemu-devel] [RFC PATCH 4/9] linux-aio: Implement .cancel_async, (continued)