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authorKevin Wolf <kwolf@redhat.com>2014-07-09 19:17:30 +0200
committerKevin Wolf <kwolf@redhat.com>2014-07-14 12:03:21 +0200
commit58f423fbd5f7f435e8dc56dfa565b043d20d1e1b (patch)
tree7d9178c0b85596d3ea4b2565ce1054e8213ce423
parent80504dcaa11097b99842312014f5954a54fe1826 (diff)
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dma-helpers: Fix too long qiov
If the size of the scatter/gather list isn't a multiple of 512, the number of sectors for the block layer request is rounded down, resulting in a qiov that doesn't match the request length. Truncate the qiov to the new length of the request. This fixes the IDE qtest case /x86_64/ide/bmdma/short_prdt. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
-rw-r--r--dma-helpers.c4
-rw-r--r--include/qemu-common.h1
-rw-r--r--util/iov.c13
3 files changed, 18 insertions, 0 deletions
diff --git a/dma-helpers.c b/dma-helpers.c
index 53cbe92..499b52b 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -170,6 +170,10 @@ static void dma_bdrv_cb(void *opaque, int ret)
return;
}
+ if (dbs->iov.size & ~BDRV_SECTOR_MASK) {
+ qemu_iovec_discard_back(&dbs->iov, dbs->iov.size & ~BDRV_SECTOR_MASK);
+ }
+
dbs->acb = dbs->io_func(dbs->bs, dbs->sector_num, &dbs->iov,
dbs->iov.size / 512, dma_bdrv_cb, dbs);
assert(dbs->acb);
diff --git a/include/qemu-common.h b/include/qemu-common.h
index ae76197..6ef8282 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -329,6 +329,7 @@ size_t qemu_iovec_memset(QEMUIOVector *qiov, size_t offset,
int fillc, size_t bytes);
ssize_t qemu_iovec_compare(QEMUIOVector *a, QEMUIOVector *b);
void qemu_iovec_clone(QEMUIOVector *dest, const QEMUIOVector *src, void *buf);
+void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes);
bool buffer_is_zero(const void *buf, size_t len);
diff --git a/util/iov.c b/util/iov.c
index 2b4f46d..24566c8 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -550,3 +550,16 @@ size_t iov_discard_back(struct iovec *iov, unsigned int *iov_cnt,
return total;
}
+
+void qemu_iovec_discard_back(QEMUIOVector *qiov, size_t bytes)
+{
+ size_t total;
+ unsigned int niov = qiov->niov;
+
+ assert(qiov->size >= bytes);
+ total = iov_discard_back(qiov->iov, &niov, bytes);
+ assert(total == bytes);
+
+ qiov->niov = niov;
+ qiov->size -= bytes;
+}