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qemu-nbd: add client pointer to NBDRequest 

By attaching a client to an NBDRequest, we can avoid passing around the
socket descriptor and data buffer.

Also, we can now manage the reference count for the client in
nbd_request_get/put request instead of having to do it ourselved in
nbd_read.  This simplifies things when coroutines are used.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2011-10-07 16:47:56 +02:00
parent 1743b51586
commit 72deddc5e6
1 changed files with 27 additions and 21 deletions
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48
nbd.c
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@ -589,6 +589,7 @@ typedef struct NBDRequest NBDRequest;
struct NBDRequest {
QSIMPLEQ_ENTRY(NBDRequest) entry;
NBDClient *client;
uint8_t *data;
};
@ -631,9 +632,11 @@ static void nbd_client_close(NBDClient *client)
nbd_client_put(client);
}
static NBDRequest *nbd_request_get(NBDExport *exp)
static NBDRequest *nbd_request_get(NBDClient *client)
{
NBDRequest *req;
NBDExport *exp = client->exp;
if (QSIMPLEQ_EMPTY(&exp->requests)) {
req = g_malloc0(sizeof(NBDRequest));
req->data = qemu_blockalign(exp->bs, NBD_BUFFER_SIZE);
@ -641,12 +644,16 @@ static NBDRequest *nbd_request_get(NBDExport *exp)
req = QSIMPLEQ_FIRST(&exp->requests);
QSIMPLEQ_REMOVE_HEAD(&exp->requests, entry);
}
nbd_client_get(client);
req->client = client;
return req;
}
static void nbd_request_put(NBDExport *exp, NBDRequest *req)
static void nbd_request_put(NBDRequest *req)
{
QSIMPLEQ_INSERT_HEAD(&exp->requests, req, entry);
NBDClient *client = req->client;
QSIMPLEQ_INSERT_HEAD(&client->exp->requests, req, entry);
nbd_client_put(client);
}
NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset,
@ -674,9 +681,11 @@ void nbd_export_close(NBDExport *exp)
g_free(exp);
}
static int nbd_do_send_reply(int csock, struct nbd_reply *reply,
uint8_t *data, int len)
static int nbd_do_send_reply(NBDRequest *req, struct nbd_reply *reply,
int len)
{
NBDClient *client = req->client;
int csock = client->sock;
int rc, ret;
if (!len) {
@ -688,7 +697,7 @@ static int nbd_do_send_reply(int csock, struct nbd_reply *reply,
socket_set_cork(csock, 1);
rc = nbd_send_reply(csock, reply);
if (rc != -1) {
ret = write_sync(csock, data, len);
ret = write_sync(csock, req->data, len);
if (ret != len) {
errno = EIO;
rc = -1;
@ -702,9 +711,10 @@ static int nbd_do_send_reply(int csock, struct nbd_reply *reply,
return rc;
}
static int nbd_do_receive_request(int csock, struct nbd_request *request,
uint8_t *data)
static int nbd_do_receive_request(NBDRequest *req, struct nbd_request *request)
{
NBDClient *client = req->client;
int csock = client->sock;
int rc;
if (nbd_receive_request(csock, request) == -1) {
@ -731,7 +741,7 @@ static int nbd_do_receive_request(int csock, struct nbd_request *request,
if ((request->type & NBD_CMD_MASK_COMMAND) == NBD_CMD_WRITE) {
TRACE("Reading %u byte(s)", request->len);
if (read_sync(csock, data, request->len) != request->len) {
if (read_sync(csock, req->data, request->len) != request->len) {
LOG("reading from socket failed");
rc = -EIO;
goto out;
@ -745,9 +755,8 @@ out:
static int nbd_trip(NBDClient *client)
{
NBDRequest *req = nbd_request_get(client);
NBDExport *exp = client->exp;
NBDRequest *req = nbd_request_get(exp);
int csock = client->sock;
struct nbd_request request;
struct nbd_reply reply;
int rc = -1;
@ -755,7 +764,7 @@ static int nbd_trip(NBDClient *client)
TRACE("Reading request.");
ret = nbd_do_receive_request(csock, &request, req->data);
ret = nbd_do_receive_request(req, &request);
if (ret == -EIO) {
goto out;
}
@ -790,7 +799,7 @@ static int nbd_trip(NBDClient *client)
}
TRACE("Read %u byte(s)", request.len);
if (nbd_do_send_reply(csock, &reply, req->data, request.len) < 0)
if (nbd_do_send_reply(req, &reply, request.len) < 0)
goto out;
break;
case NBD_CMD_WRITE:
@ -821,7 +830,7 @@ static int nbd_trip(NBDClient *client)
}
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
if (nbd_do_send_reply(req, &reply, 0) < 0)
goto out;
break;
case NBD_CMD_DISC:
@ -837,7 +846,7 @@ static int nbd_trip(NBDClient *client)
reply.error = -ret;
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
if (nbd_do_send_reply(req, &reply, 0) < 0)
goto out;
break;
case NBD_CMD_TRIM:
@ -848,7 +857,7 @@ static int nbd_trip(NBDClient *client)
LOG("discard failed");
reply.error = -ret;
}
if (nbd_do_send_reply(csock, &reply, NULL, 0) < 0)
if (nbd_do_send_reply(req, &reply, 0) < 0)
goto out;
break;
default:
@ -856,7 +865,7 @@ static int nbd_trip(NBDClient *client)
invalid_request:
reply.error = -EINVAL;
error_reply:
if (nbd_do_send_reply(csock, &reply, NULL, 0) == -1)
if (nbd_do_send_reply(req, &reply, 0) == -1)
goto out;
break;
}
@ -865,7 +874,7 @@ static int nbd_trip(NBDClient *client)
rc = 0;
out:
nbd_request_put(exp, req);
nbd_request_put(req);
return rc;
}
@ -873,12 +882,9 @@ static void nbd_read(void *opaque)
{
NBDClient *client = opaque;
nbd_client_get(client);
if (nbd_trip(client) != 0) {
nbd_client_close(client);
}
nbd_client_put(client);
}
NBDClient *nbd_client_new(NBDExport *exp, int csock,