This removes quite some duplicated code.
v2 fixes a bug (uninitialized reply.error) and makes the loop more natural.
Signed-off-By: Michael Tokarev <m...@tls.msk.ru>
---
block/nbd.c | 95 +++++++++++++++++++---------------------------------------
1 files changed, 31 insertions(+), 64 deletions(-)
diff --git a/block/nbd.c b/block/nbd.c
index 161b299..a78e212 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -320,91 +320,58 @@ static int nbd_open(BlockDriverState *bs, const char*
filename, int flags)
return result;
}
-static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, QEMUIOVector *qiov,
- int offset)
-{
- BDRVNBDState *s = bs->opaque;
- struct nbd_request request;
- struct nbd_reply reply;
-
- request.type = NBD_CMD_READ;
- request.from = sector_num * 512;
- request.len = nb_sectors * 512;
-
- nbd_coroutine_start(s, &request);
- if (nbd_co_send_request(s, &request, NULL, 0) == -1) {
- reply.error = errno;
- } else {
- nbd_co_receive_reply(s, &request, &reply, qiov->iov, offset);
- }
- nbd_coroutine_end(s, &request);
- return -reply.error;
-
-}
+/* qemu-nbd has a limit of slightly less than 1M per request. Try to
+ * remain aligned to 4K. */
+#define NBD_MAX_SECTORS 2040
-static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num,
- int nb_sectors, QEMUIOVector *qiov,
- int offset)
+static int nbd_co_rwv(BlockDriverState *bs, int64_t sector_num,
+ int nb_sectors, QEMUIOVector *qiov, int iswrite)
{
BDRVNBDState *s = bs->opaque;
struct nbd_request request;
struct nbd_reply reply;
+ int offset = 0;
- request.type = NBD_CMD_WRITE;
- if (!bdrv_enable_write_cache(bs) && (s->nbdflags & NBD_FLAG_SEND_FUA)) {
+ request.type = iswrite ? NBD_CMD_WRITE : NBD_CMD_READ;
+ if (iswrite && !bdrv_enable_write_cache(bs) && (s->nbdflags &
NBD_FLAG_SEND_FUA)) {
request.type |= NBD_CMD_FLAG_FUA;
}
+ reply.error = 0;
+
+ /* we split the request into pieces of at most NBD_MAX_SECTORS size
+ * and process them in a loop... */
+ do {
+ request.from = sector_num * 512;
+ request.len = MIN(nb_sectors, NBD_MAX_SECTORS) * 512;
+
+ nbd_coroutine_start(s, &request);
+ if (nbd_co_send_request(s, &request, iswrite ? qiov->iov : NULL, 0) ==
-1) {
+ reply.error = errno;
+ } else {
+ nbd_co_receive_reply(s, &request, &reply, iswrite ? NULL :
qiov->iov, offset);
+ }
+ nbd_coroutine_end(s, &request);
- request.from = sector_num * 512;
- request.len = nb_sectors * 512;
+ offset += NBD_MAX_SECTORS * 512;
+ sector_num += NBD_MAX_SECTORS;
+ nb_sectors -= NBD_MAX_SECTORS;
+
+ /* ..till we hit an error or there's nothing more to process */
+ } while (reply.error == 0 && nb_sectors > 0);
- nbd_coroutine_start(s, &request);
- if (nbd_co_send_request(s, &request, qiov->iov, offset) == -1) {
- reply.error = errno;
- } else {
- nbd_co_receive_reply(s, &request, &reply, NULL, 0);
- }
- nbd_coroutine_end(s, &request);
return -reply.error;
}
-/* qemu-nbd has a limit of slightly less than 1M per request. Try to
- * remain aligned to 4K. */
-#define NBD_MAX_SECTORS 2040
-
static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
- int offset = 0;
- int ret;
- while (nb_sectors > NBD_MAX_SECTORS) {
- ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
- if (ret < 0) {
- return ret;
- }
- offset += NBD_MAX_SECTORS * 512;
- sector_num += NBD_MAX_SECTORS;
- nb_sectors -= NBD_MAX_SECTORS;
- }
- return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset);
+ return nbd_co_rwv(bs, sector_num, nb_sectors, qiov, 0);
}
static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num,
int nb_sectors, QEMUIOVector *qiov)
{
- int offset = 0;
- int ret;
- while (nb_sectors > NBD_MAX_SECTORS) {
- ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset);
- if (ret < 0) {
- return ret;
- }
- offset += NBD_MAX_SECTORS * 512;
- sector_num += NBD_MAX_SECTORS;
- nb_sectors -= NBD_MAX_SECTORS;
- }
- return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset);
+ return nbd_co_rwv(bs, sector_num, nb_sectors, qiov, 1);
}
static int nbd_co_flush(BlockDriverState *bs)
--
1.7.9
