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new scsi-generic abstraction, use SG_IO (Christoph Hellwig)

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Okay, I started looking into how to handle scsi-generic I/O in the
new world order.

I think the best is to use the SG_IO ioctl instead of the read/write
interface as that allows us to support scsi passthrough on disk/cdrom
devices, too.  See Hannes patch on the kvm list from August for an
example.

Now that we always do ioctls we don't need another abstraction than
bdrv_ioctl for the synchronous requests for now, and for asynchronous
requests I've added a aio_ioctl abstraction keeping it simple.

Long-term we might want to move the ops to a higher-level abstraction
and let the low-level code fill out the request header, but I'm lazy
enough to leave that to the people trying to support scsi-passthrough
on a non-Linux OS.

Tested lightly by issuing various sg_ commands from sg3-utils in a guest
to a host CDROM device.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6895 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aliguori 2009-03-28 17:28:41 +00:00
parent 64a7fde8e8
commit 221f715d90
7 changed files with 117 additions and 139 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
block-raw-posix.c
View File

@ -1209,6 +1209,26 @@ static int raw_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
return ioctl(s->fd, req, buf);
}
static BlockDriverAIOCB *raw_aio_ioctl(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque)
{
RawAIOCB *acb;
acb = raw_aio_setup(bs, 0, buf, 0, cb, opaque);
if (!acb)
return NULL;
acb->aiocb.aio_ioctl_cmd = req;
if (qemu_paio_ioctl(&acb->aiocb) < 0) {
raw_aio_remove(acb);
return NULL;
}
return &acb->common;
}
#elif defined(__FreeBSD__)
static int fd_open(BlockDriverState *bs)
@ -1349,34 +1369,15 @@ static int raw_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
{
return -ENOTSUP;
}
static BlockDriverAIOCB *raw_aio_ioctl(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque)
{
return -ENOTSUP;
}
#endif /* !linux && !FreeBSD */
static int raw_sg_send_command(BlockDriverState *bs, void *buf, int count)
{
return raw_pwrite(bs, -1, buf, count);
}
static int raw_sg_recv_response(BlockDriverState *bs, void *buf, int count)
{
return raw_pread(bs, -1, buf, count);
}
static BlockDriverAIOCB *raw_sg_aio_read(BlockDriverState *bs,
void *buf, int count,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return raw_aio_read(bs, 0, buf, -(int64_t)count, cb, opaque);
}
static BlockDriverAIOCB *raw_sg_aio_write(BlockDriverState *bs,
void *buf, int count,
BlockDriverCompletionFunc *cb,
void *opaque)
{
return raw_aio_write(bs, 0, buf, -(int64_t)count, cb, opaque);
}
BlockDriver bdrv_host_device = {
.format_name = "host_device",
.instance_size = sizeof(BDRVRawState),
@ -1402,8 +1403,5 @@ BlockDriver bdrv_host_device = {
.bdrv_set_locked = raw_set_locked,
/* generic scsi device */
.bdrv_ioctl = raw_ioctl,
.bdrv_sg_send_command = raw_sg_send_command,
.bdrv_sg_recv_response = raw_sg_recv_response,
.bdrv_sg_aio_read = raw_sg_aio_read,
.bdrv_sg_aio_write = raw_sg_aio_write,
.bdrv_aio_ioctl = raw_aio_ioctl,
};

25
block.c
View File

@ -1633,24 +1633,13 @@ int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
return -ENOTSUP;
}
int bdrv_sg_send_command(BlockDriverState *bs, void *buf, int count)
BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque)
{
return bs->drv->bdrv_sg_send_command(bs, buf, count);
}
BlockDriver *drv = bs->drv;
int bdrv_sg_recv_response(BlockDriverState *bs, void *buf, int count)
{
return bs->drv->bdrv_sg_recv_response(bs, buf, count);
}
BlockDriverAIOCB *bdrv_sg_aio_read(BlockDriverState *bs, void *buf, int count,
BlockDriverCompletionFunc *cb, void *opaque)
{
return bs->drv->bdrv_sg_aio_read(bs, buf, count, cb, opaque);
}
BlockDriverAIOCB *bdrv_sg_aio_write(BlockDriverState *bs, void *buf, int count,
BlockDriverCompletionFunc *cb, void *opaque)
{
return bs->drv->bdrv_sg_aio_write(bs, buf, count, cb, opaque);
if (drv && drv->bdrv_aio_ioctl)
return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
return NULL;
}

11
block.h
View File

@ -102,12 +102,10 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
void bdrv_aio_cancel(BlockDriverAIOCB *acb);
/* sg packet commands */
int bdrv_sg_send_command(BlockDriverState *bs, void *buf, int count);
int bdrv_sg_recv_response(BlockDriverState *bs, void *buf, int count);
BlockDriverAIOCB *bdrv_sg_aio_read(BlockDriverState *bs, void *buf, int count,
BlockDriverCompletionFunc *cb, void *opaque);
BlockDriverAIOCB *bdrv_sg_aio_write(BlockDriverState *bs, void *buf, int count,
BlockDriverCompletionFunc *cb, void *opaque);
int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf);
BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque);
/* Ensure contents are flushed to disk. */
void bdrv_flush(BlockDriverState *bs);
@ -169,7 +167,6 @@ int bdrv_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
int bdrv_snapshot_list(BlockDriverState *bs,
QEMUSnapshotInfo **psn_info);
char *bdrv_snapshot_dump(char *buf, int buf_size, QEMUSnapshotInfo *sn);
int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf);
char *get_human_readable_size(char *buf, int buf_size, int64_t size);
int path_is_absolute(const char *path);

13
block_int.h
View File

@ -86,16 +86,9 @@ struct BlockDriver {
/* to control generic scsi devices */
int (*bdrv_ioctl)(BlockDriverState *bs, unsigned long int req, void *buf);
int (*bdrv_sg_send_command)(BlockDriverState *bs, void *buf, int count);
int (*bdrv_sg_recv_response)(BlockDriverState *bs, void *buf, int count);
BlockDriverAIOCB *(*bdrv_sg_aio_read)(BlockDriverState *bs,
void *buf, int count,
BlockDriverCompletionFunc *cb,
void *opaque);
BlockDriverAIOCB *(*bdrv_sg_aio_write)(BlockDriverState *bs,
void *buf, int count,
BlockDriverCompletionFunc *cb,
void *opaque);
BlockDriverAIOCB *(*bdrv_aio_ioctl)(BlockDriverState *bs,
unsigned long int req, void *buf,
BlockDriverCompletionFunc *cb, void *opaque);
AIOPool aio_pool;
struct BlockDriver *next;

42
hw/scsi-generic.c
View File

@ -201,8 +201,6 @@ static int execute_command(BlockDriverState *bdrv,
SCSIRequest *r, int direction,
BlockDriverCompletionFunc *complete)
{
int ret;
r->io_header.interface_id = 'S';
r->io_header.dxfer_direction = direction;
r->io_header.dxferp = r->buf;
@ -215,27 +213,7 @@ static int execute_command(BlockDriverState *bdrv,
r->io_header.usr_ptr = r;
r->io_header.flags |= SG_FLAG_DIRECT_IO;
ret = bdrv_sg_send_command(bdrv, &r->io_header, sizeof(r->io_header));
if (ret < 0) {
BADF("execute_command: write failed ! (%d)\n", errno);
return -1;
}
if (complete == NULL) {
int ret;
r->aiocb = NULL;
while ((ret = bdrv_sg_recv_response(bdrv, &r->io_header,
sizeof(r->io_header))) < 0 &&
ret == -EINTR)
;
if (ret < 0) {
BADF("execute_command: read failed !\n");
return -1;
}
return 0;
}
r->aiocb = bdrv_sg_aio_read(bdrv, (uint8_t*)&r->io_header,
sizeof(r->io_header), complete, r);
r->aiocb = bdrv_aio_ioctl(bdrv, SG_IO, &r->io_header, complete, r);
if (r->aiocb == NULL) {
BADF("execute_command: read failed !\n");
return -1;
@ -637,14 +615,7 @@ static int get_blocksize(BlockDriverState *bdrv)
io_header.sbp = sensebuf;
io_header.timeout = 6000; /* XXX */
ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
if (ret < 0)
return -1;
while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header))) < 0 &&
ret == -EINTR)
;
ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
if (ret < 0)
return -1;
@ -675,14 +646,7 @@ static int get_stream_blocksize(BlockDriverState *bdrv)
io_header.sbp = sensebuf;
io_header.timeout = 6000; /* XXX */
ret = bdrv_sg_send_command(bdrv, &io_header, sizeof(io_header));
if (ret < 0)
return -1;
while ((ret = bdrv_sg_recv_response(bdrv, &io_header, sizeof(io_header))) < 0 &&
ret == -EINTR)
;
ret = bdrv_ioctl(bdrv, SG_IO, &io_header);
if (ret < 0)
return -1;

100
posix-aio-compat.c
View File

@ -11,6 +11,7 @@
*
*/
#include <sys/ioctl.h>
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
@ -75,6 +76,47 @@ static void thread_create(pthread_t *thread, pthread_attr_t *attr,
if (ret) die2(ret, "pthread_create");
}
static size_t handle_aiocb_readwrite(struct qemu_paiocb *aiocb)
{
size_t offset = 0;
ssize_t len;
while (offset < aiocb->aio_nbytes) {
if (aiocb->aio_type == QEMU_PAIO_WRITE)
len = pwrite(aiocb->aio_fildes,
(const char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
else
len = pread(aiocb->aio_fildes,
(char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
if (len == -1 && errno == EINTR)
continue;
else if (len == -1) {
offset = -errno;
break;
} else if (len == 0)
break;
offset += len;
}
return offset;
}
static size_t handle_aiocb_ioctl(struct qemu_paiocb *aiocb)
{
int ret;
ret = ioctl(aiocb->aio_fildes, aiocb->aio_ioctl_cmd, aiocb->aio_buf);
if (ret == -1)
return -errno;
return ret;
}
static void *aio_thread(void *unused)
{
pid_t pid;
@ -88,8 +130,7 @@ static void *aio_thread(void *unused)
while (1) {
struct qemu_paiocb *aiocb;
size_t offset;
int ret = 0;
size_t ret = 0;
qemu_timeval tv;
struct timespec ts;
@ -109,40 +150,26 @@ static void *aio_thread(void *unused)
aiocb = TAILQ_FIRST(&request_list);
TAILQ_REMOVE(&request_list, aiocb, node);
offset = 0;
aiocb->active = 1;
idle_threads--;
mutex_unlock(&lock);
while (offset < aiocb->aio_nbytes) {
ssize_t len;
if (aiocb->is_write)
len = pwrite(aiocb->aio_fildes,
(const char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
else
len = pread(aiocb->aio_fildes,
(char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
if (len == -1 && errno == EINTR)
continue;
else if (len == -1) {
offset = -errno;
break;
} else if (len == 0)
break;
offset += len;
}
switch (aiocb->aio_type) {
case QEMU_PAIO_READ:
case QEMU_PAIO_WRITE:
ret = handle_aiocb_readwrite(aiocb);
break;
case QEMU_PAIO_IOCTL:
ret = handle_aiocb_ioctl(aiocb);
break;
default:
fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type);
ret = -EINVAL;
break;
}
mutex_lock(&lock);
aiocb->ret = offset;
aiocb->ret = ret;
idle_threads++;
mutex_unlock(&lock);
@ -178,9 +205,9 @@ int qemu_paio_init(struct qemu_paioinit *aioinit)
return 0;
}
static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write)
static int qemu_paio_submit(struct qemu_paiocb *aiocb, int type)
{
aiocb->is_write = is_write;
aiocb->aio_type = type;
aiocb->ret = -EINPROGRESS;
aiocb->active = 0;
mutex_lock(&lock);
@ -195,12 +222,17 @@ static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write)
int qemu_paio_read(struct qemu_paiocb *aiocb)
{
return qemu_paio_submit(aiocb, 0);
return qemu_paio_submit(aiocb, QEMU_PAIO_READ);
}
int qemu_paio_write(struct qemu_paiocb *aiocb)
{
return qemu_paio_submit(aiocb, 1);
return qemu_paio_submit(aiocb, QEMU_PAIO_WRITE);
}
int qemu_paio_ioctl(struct qemu_paiocb *aiocb)
{
return qemu_paio_submit(aiocb, QEMU_PAIO_IOCTL);
}
ssize_t qemu_paio_return(struct qemu_paiocb *aiocb)

7
posix-aio-compat.h
View File

@ -29,12 +29,16 @@ struct qemu_paiocb
int aio_fildes;
void *aio_buf;
size_t aio_nbytes;
#define aio_ioctl_cmd aio_nbytes /* for QEMU_PAIO_IOCTL */
int ev_signo;
off_t aio_offset;
/* private */
TAILQ_ENTRY(qemu_paiocb) node;
int is_write;
int aio_type;
#define QEMU_PAIO_READ 0x01
#define QEMU_PAIO_WRITE 0x02
#define QEMU_PAIO_IOCTL 0x03
ssize_t ret;
int active;
};
@ -49,6 +53,7 @@ struct qemu_paioinit
int qemu_paio_init(struct qemu_paioinit *aioinit);
int qemu_paio_read(struct qemu_paiocb *aiocb);
int qemu_paio_write(struct qemu_paiocb *aiocb);
int qemu_paio_ioctl(struct qemu_paiocb *aiocb);
int qemu_paio_error(struct qemu_paiocb *aiocb);
ssize_t qemu_paio_return(struct qemu_paiocb *aiocb);
int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb);