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authorAnthony Liguori <aliguori@us.ibm.com>2010-04-29 17:44:50 +0530
committerAnthony Liguori <aliguori@us.ibm.com>2010-05-03 12:17:38 -0500
commit1f5a89bf68193012df13dd3eb188783367e489d5 (patch)
tree4a28541d67772720a71b18d074c4ab3d465d0362 /hw/virtio-9p.c
parentbb9e3216bf32032a08a6f48799991f05203fa54b (diff)
virtio-9p: Add sg helper functions
Add scatter-gather helper functions. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Diffstat (limited to 'hw/virtio-9p.c')
-rw-r--r--hw/virtio-9p.c53
1 files changed, 53 insertions, 0 deletions
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index b37cdf2605..c31f48c36e 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -762,6 +762,56 @@ static int stat_to_v9stat(V9fsState *s, V9fsString *name,
return 0;
}
+static struct iovec *adjust_sg(struct iovec *sg, int len, int *iovcnt)
+{
+ while (len && *iovcnt) {
+ if (len < sg->iov_len) {
+ sg->iov_len -= len;
+ sg->iov_base += len;
+ len = 0;
+ } else {
+ len -= sg->iov_len;
+ sg++;
+ *iovcnt -= 1;
+ }
+ }
+
+ return sg;
+}
+
+static struct iovec *cap_sg(struct iovec *sg, int cap, int *cnt)
+{
+ int i;
+ int total = 0;
+
+ for (i = 0; i < *cnt; i++) {
+ if ((total + sg[i].iov_len) > cap) {
+ sg[i].iov_len -= ((total + sg[i].iov_len) - cap);
+ i++;
+ break;
+ }
+ total += sg[i].iov_len;
+ }
+
+ *cnt = i;
+
+ return sg;
+}
+
+static void print_sg(struct iovec *sg, int cnt)
+{
+ int i;
+
+ printf("sg[%d]: {", cnt);
+ for (i = 0; i < cnt; i++) {
+ if (i) {
+ printf(", ");
+ }
+ printf("(%p, %zd)", sg[i].iov_base, sg[i].iov_len);
+ }
+ printf("}\n");
+}
+
static void v9fs_dummy(V9fsState *s, V9fsPDU *pdu)
{
/* Note: The following have been added to prevent GCC from complaining
@@ -786,6 +836,9 @@ static void v9fs_dummy(V9fsState *s, V9fsPDU *pdu)
(void) donttouch_stat;
(void) v9fs_stat_free;
(void) stat_to_v9stat;
+ (void) adjust_sg;
+ (void) cap_sg;
+ (void) print_sg;
}
static void v9fs_version(V9fsState *s, V9fsPDU *pdu)