[Xen-changelog] [qemu-xen-3.4-testing] Fix DMA API when handling an immediate error from block layer (Avi Kivity)

[Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>]

commit 20976815da3884bd45b6775b9af0c650c9bc2d86
Author: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Date:   Wed Oct 7 15:49:32 2009 +0100

    Fix DMA API when handling an immediate error from block layer (Avi Kivity)
    
    The block layer may signal an immediate error on an asynchronous request
    by returning NULL.  The DMA API did not handle this correctly, returning
    an AIO request which would never complete (and which would crash if
    cancelled).
    
    Fix by detecting the failure and propagating it.
    
    Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
    Signed-off-by: Anthony Liguori <aliguori@xxxxxxxxxx>
    
    git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6893 
c046a42c-6fe2-441c-8c8c-71466251a162
    
    [ Backported from 6bbff9a0b495918309074ac60375be5f9dc868b3
      by Stefano Stabellini. ]
    
    Signed-off-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
    (cherry picked from commit b0c44fdfc7f9d1656d718aa2fecac4a81f941c8c)
---
 dma-helpers.c |   27 +++++++++++++++++++++------
 1 files changed, 21 insertions(+), 6 deletions(-)

diff --git a/dma-helpers.c b/dma-helpers.c
index a76c618..2a1621b 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -71,20 +71,26 @@ static void continue_after_map_failure(void *opaque)
     qemu_bh_schedule(dbs->bh);
 }
 
-static void dma_bdrv_cb(void *opaque, int ret)
+static void dma_bdrv_unmap(DMAAIOCB *dbs)
 {
-    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
-    target_phys_addr_t cur_addr, cur_len;
-    void *mem;
     int i;
 
-    dbs->acb = NULL;
-    dbs->sector_num += dbs->iov.size / 512;
     for (i = 0; i < dbs->iov.niov; ++i) {
         cpu_physical_memory_unmap(dbs->iov.iov[i].iov_base,
                                   dbs->iov.iov[i].iov_len, !dbs->is_write,
                                   dbs->iov.iov[i].iov_len);
     }
+}
+
+void dma_bdrv_cb(void *opaque, int ret)
+{
+    DMAAIOCB *dbs = (DMAAIOCB *)opaque;
+    target_phys_addr_t cur_addr, cur_len;
+    void *mem;
+
+    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) {
@@ -120,6 +126,11 @@ static void dma_bdrv_cb(void *opaque, int ret)
         dbs->acb = bdrv_aio_readv(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;
+    }
 }
 
 static BlockDriverAIOCB *dma_bdrv_io(
@@ -139,6 +150,10 @@ static 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;
+    }
 
 #ifdef __ia64__
     if (!is_write) {
--
generated by git-patchbot for /home/xen/git/qemu-xen-3.4-testing.git

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