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[Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation |
Date: |
Wed, 7 Sep 2011 17:21:00 +0200 |
This fixes various problems with completion/cancellation:
* If DMA encounters a bounce buffer conflict, and the DMA operation is
canceled before the bottom half fires, bad things happen.
* memory is not unmapped after cancellation, again causing problems
when doing DMA to I/O areas
* cancellation could leak the iovec
and probably more that I've missed. The patch fixes them by sharing
the cleanup code between completion and cancellation. The dma_bdrv_cb
now returns a boolean completed/not completed flag, and the wrapper
dma_continue takes care of tasks to do upon completion.
Most of these are basically impossible in practice, but it is better
to be tidy...
Signed-off-by: Paolo Bonzini <address@hidden>
---
dma-helpers.c | 37 ++++++++++++++++++++++++-------------
1 files changed, 24 insertions(+), 13 deletions(-)
diff --git a/dma-helpers.c b/dma-helpers.c
index ca97e14..cc8c4e3 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -58,7 +58,7 @@ static void reschedule_dma(void *opaque)
qemu_bh_delete(dbs->bh);
dbs->bh = NULL;
- dma_bdrv_cb(opaque, 0);
+ dma_bdrv_cb(dbs, 0);
}
static void continue_after_map_failure(void *opaque)
@@ -78,6 +78,21 @@ static void dma_bdrv_unmap(DMAAIOCB *dbs)
dbs->iov.iov[i].iov_len, !dbs->to_dev,
dbs->iov.iov[i].iov_len);
}
+ qemu_iovec_reset(&dbs->iov);
+}
+
+static void dma_complete(DMAAIOCB *dbs, int ret)
+{
+ dma_bdrv_unmap(dbs);
+ if (dbs->common.cb) {
+ dbs->common.cb(dbs->common.opaque, ret);
+ }
+ qemu_iovec_destroy(&dbs->iov);
+ if (dbs->bh) {
+ qemu_bh_delete(dbs->bh);
+ dbs->bh = NULL;
+ }
+ qemu_aio_release(dbs);
}
static void dma_bdrv_cb(void *opaque, int ret)
@@ -89,12 +104,9 @@ static void dma_bdrv_cb(void *opaque, int ret)
dbs->acb = NULL;
dbs->sector_num += dbs->iov.size / 512;
dma_bdrv_unmap(dbs);
- qemu_iovec_reset(&dbs->iov);
if (dbs->sg_cur_index == dbs->sg->nsg || ret < 0) {
- dbs->common.cb(dbs->common.opaque, ret);
- qemu_iovec_destroy(&dbs->iov);
- qemu_aio_release(dbs);
+ dma_complete(dbs, ret);
return;
}
@@ -120,9 +132,8 @@ static void dma_bdrv_cb(void *opaque, int ret)
dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs);
if (!dbs->acb) {
- dma_bdrv_unmap(dbs);
- qemu_iovec_destroy(&dbs->iov);
- return;
+ dbs->common.cb = NULL;
+ dma_complete(dbs, -ENOMEM);
}
}
@@ -131,8 +142,12 @@ static void dma_aio_cancel(BlockDriverAIOCB *acb)
DMAAIOCB *dbs = container_of(acb, DMAAIOCB, common);
if (dbs->acb) {
- bdrv_aio_cancel(dbs->acb);
+ BlockDriverAIOCB *acb = dbs->acb;
+ dbs->acb = NULL;
+ bdrv_aio_cancel(acb);
}
+ dbs->common.cb = NULL;
+ dma_complete(dbs, 0);
}
static AIOPool dma_aio_pool = {
@@ -158,10 +173,6 @@ BlockDriverAIOCB *dma_bdrv_io(
dbs->bh = NULL;
qemu_iovec_init(&dbs->iov, sg->nsg);
dma_bdrv_cb(dbs, 0);
- if (!dbs->acb) {
- qemu_aio_release(dbs);
- return NULL;
- }
return &dbs->common;
}
--
1.7.6
- [Qemu-devel] [PATCH 0/5] block: preparatory patches for scatter/gather support, Paolo Bonzini, 2011/09/07
- [Qemu-devel] [PATCH 4/5] scsi-disk: commonize iovec creation between reads and writes, Paolo Bonzini, 2011/09/07
- [Qemu-devel] [PATCH 5/5] scsi-disk: lazily allocate bounce buffer, Paolo Bonzini, 2011/09/07
- [Qemu-devel] [PATCH 2/5] dma-helpers: allow including from target-independent code, Paolo Bonzini, 2011/09/07
- [Qemu-devel] [PATCH 1/5] dma-helpers: rename is_write to to_dev, Paolo Bonzini, 2011/09/07
- [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Kevin Wolf, 2011/09/09
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Paolo Bonzini, 2011/09/09
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Kevin Wolf, 2011/09/09
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Paolo Bonzini, 2011/09/09
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Kevin Wolf, 2011/09/09
- Re: [Qemu-devel] [PATCH 3/5] dma-helpers: rewrite completion/cancellation, Paolo Bonzini, 2011/09/09