nbd: generalize usage of nbd_read

We generally do very similar things around nbd_read: error_prepend
specifying what we have tried to read, and be_to_cpu conversion of
integers.

So, it seems reasonable to move common things to helper functions,
which:
1. simplify code a bit
2. generalize nbd_read error descriptions, all starting with
   "Failed to read"
3. make it more difficult to forget to convert things from BE

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20190128165830.165170-1-vsementsov@virtuozzo.com>
[eblake: rename macro to DEF_NBD_READ_N and formatting tweaks;
checkpatch has false positive complaint]
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-01-28 19:58:30 +03:00 committed by Eric Blake
parent 0ae2d54645
commit e6798f06a6
5 changed files with 71 additions and 83 deletions

View file

@ -23,6 +23,7 @@
#include "qapi/qapi-types-block.h"
#include "io/channel-socket.h"
#include "crypto/tlscreds.h"
#include "qapi/error.h"
/* Handshake phase structs - this struct is passed on the wire */
@ -336,11 +337,38 @@ void nbd_server_start(SocketAddress *addr, const char *tls_creds,
* Reads @size bytes from @ioc. Returns 0 on success.
*/
static inline int nbd_read(QIOChannel *ioc, void *buffer, size_t size,
Error **errp)
const char *desc, Error **errp)
{
return qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
int ret = qio_channel_read_all(ioc, buffer, size, errp) < 0 ? -EIO : 0;
if (ret < 0) {
if (desc) {
error_prepend(errp, "Failed to read %s: ", desc);
}
return -1;
}
return 0;
}
#define DEF_NBD_READ_N(bits) \
static inline int nbd_read##bits(QIOChannel *ioc, \
uint##bits##_t *val, \
const char *desc, Error **errp) \
{ \
if (nbd_read(ioc, val, sizeof(*val), desc, errp) < 0) { \
return -1; \
} \
*val = be##bits##_to_cpu(*val); \
return 0; \
}
DEF_NBD_READ_N(16) /* Defines nbd_read16(). */
DEF_NBD_READ_N(32) /* Defines nbd_read32(). */
DEF_NBD_READ_N(64) /* Defines nbd_read64(). */
#undef DEF_NBD_READ_N
static inline bool nbd_reply_is_simple(NBDReply *reply)
{
return reply->magic == NBD_SIMPLE_REPLY_MAGIC;