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block/io: use qemu_iovec_init_buf
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Use new qemu_iovec_init_buf() instead of
qemu_iovec_init_external( ... , 1), which simplifies the code.

While being here, use qemu_try_blockalign0 as well.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190218140926.333779-3-vsementsov@virtuozzo.com
Message-Id: <20190218140926.333779-3-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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@stefanhaRH
Vladimir Sementsov-Ogievskiy authored and stefanhaRH committed Feb 22, 2019
1 parent a1ca3ed commit 0d93ed0
Showing 1 changed file with 20 additions and 69 deletions.
89 changes: 20 additions & 69 deletions block/io.c
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Expand Up @@ -843,17 +843,13 @@ static int bdrv_prwv_co(BdrvChild *child, int64_t offset,
static int bdrv_rw_co(BdrvChild *child, int64_t sector_num, uint8_t *buf,
int nb_sectors, bool is_write, BdrvRequestFlags flags)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = (void *)buf,
.iov_len = nb_sectors * BDRV_SECTOR_SIZE,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf,
nb_sectors * BDRV_SECTOR_SIZE);

if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}

qemu_iovec_init_external(&qiov, &iov, 1);
return bdrv_prwv_co(child, sector_num << BDRV_SECTOR_BITS,
&qiov, is_write, flags);
}
Expand All @@ -880,13 +876,8 @@ int bdrv_write(BdrvChild *child, int64_t sector_num,
int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
int bytes, BdrvRequestFlags flags)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = NULL,
.iov_len = bytes,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, NULL, bytes);

qemu_iovec_init_external(&qiov, &iov, 1);
return bdrv_prwv_co(child, offset, &qiov, true,
BDRV_REQ_ZERO_WRITE | flags);
}
Expand Down Expand Up @@ -950,17 +941,12 @@ int bdrv_preadv(BdrvChild *child, int64_t offset, QEMUIOVector *qiov)

int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = (void *)buf,
.iov_len = bytes,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);

if (bytes < 0) {
return -EINVAL;
}

qemu_iovec_init_external(&qiov, &iov, 1);
return bdrv_preadv(child, offset, &qiov);
}

Expand All @@ -978,17 +964,12 @@ int bdrv_pwritev(BdrvChild *child, int64_t offset, QEMUIOVector *qiov)

int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = (void *) buf,
.iov_len = bytes,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);

if (bytes < 0) {
return -EINVAL;
}

qemu_iovec_init_external(&qiov, &iov, 1);
return bdrv_pwritev(child, offset, &qiov);
}

Expand Down Expand Up @@ -1165,7 +1146,6 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
void *bounce_buffer;

BlockDriver *drv = bs->drv;
struct iovec iov;
QEMUIOVector local_qiov;
int64_t cluster_offset;
int64_t cluster_bytes;
Expand Down Expand Up @@ -1230,9 +1210,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,

if (ret <= 0) {
/* Must copy-on-read; use the bounce buffer */
iov.iov_base = bounce_buffer;
iov.iov_len = pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
qemu_iovec_init_external(&local_qiov, &iov, 1);
pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);

ret = bdrv_driver_preadv(bs, cluster_offset, pnum,
&local_qiov, 0);
Expand Down Expand Up @@ -1477,7 +1456,7 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
{
BlockDriver *drv = bs->drv;
QEMUIOVector qiov;
struct iovec iov = {0};
void *buf = NULL;
int ret = 0;
bool need_flush = false;
int head = 0;
Expand Down Expand Up @@ -1547,25 +1526,23 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
need_flush = true;
}
num = MIN(num, max_transfer);
iov.iov_len = num;
if (iov.iov_base == NULL) {
iov.iov_base = qemu_try_blockalign(bs, num);
if (iov.iov_base == NULL) {
if (buf == NULL) {
buf = qemu_try_blockalign0(bs, num);
if (buf == NULL) {
ret = -ENOMEM;
goto fail;
}
memset(iov.iov_base, 0, num);
}
qemu_iovec_init_external(&qiov, &iov, 1);
qemu_iovec_init_buf(&qiov, buf, num);

ret = bdrv_driver_pwritev(bs, offset, num, &qiov, write_flags);

/* Keep bounce buffer around if it is big enough for all
* all future requests.
*/
if (num < max_transfer) {
qemu_vfree(iov.iov_base);
iov.iov_base = NULL;
qemu_vfree(buf);
buf = NULL;
}
}

Expand All @@ -1577,7 +1554,7 @@ static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
if (ret == 0 && need_flush) {
ret = bdrv_co_flush(bs);
}
qemu_vfree(iov.iov_base);
qemu_vfree(buf);
return ret;
}

Expand Down Expand Up @@ -1763,7 +1740,6 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
BlockDriverState *bs = child->bs;
uint8_t *buf = NULL;
QEMUIOVector local_qiov;
struct iovec iov;
uint64_t align = bs->bl.request_alignment;
unsigned int head_padding_bytes, tail_padding_bytes;
int ret = 0;
Expand All @@ -1775,11 +1751,7 @@ static int coroutine_fn bdrv_co_do_zero_pwritev(BdrvChild *child,
assert(flags & BDRV_REQ_ZERO_WRITE);
if (head_padding_bytes || tail_padding_bytes) {
buf = qemu_blockalign(bs, align);
iov = (struct iovec) {
.iov_base = buf,
.iov_len = align,
};
qemu_iovec_init_external(&local_qiov, &iov, 1);
qemu_iovec_init_buf(&local_qiov, buf, align);
}
if (head_padding_bytes) {
uint64_t zero_bytes = MIN(bytes, align - head_padding_bytes);
Expand Down Expand Up @@ -1885,17 +1857,12 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,

if (offset & (align - 1)) {
QEMUIOVector head_qiov;
struct iovec head_iov;

mark_request_serialising(&req, align);
wait_serialising_requests(&req);

head_buf = qemu_blockalign(bs, align);
head_iov = (struct iovec) {
.iov_base = head_buf,
.iov_len = align,
};
qemu_iovec_init_external(&head_qiov, &head_iov, 1);
qemu_iovec_init_buf(&head_qiov, head_buf, align);

bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
ret = bdrv_aligned_preadv(child, &req, offset & ~(align - 1), align,
Expand Down Expand Up @@ -1924,7 +1891,6 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,

if ((offset + bytes) & (align - 1)) {
QEMUIOVector tail_qiov;
struct iovec tail_iov;
size_t tail_bytes;
bool waited;

Expand All @@ -1933,11 +1899,7 @@ int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
assert(!waited || !use_local_qiov);

tail_buf = qemu_blockalign(bs, align);
tail_iov = (struct iovec) {
.iov_base = tail_buf,
.iov_len = align,
};
qemu_iovec_init_external(&tail_qiov, &tail_iov, 1);
qemu_iovec_init_buf(&tail_qiov, tail_buf, align);

bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
ret = bdrv_aligned_preadv(child, &req, (offset + bytes) & ~(align - 1),
Expand Down Expand Up @@ -2468,15 +2430,9 @@ bdrv_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
int64_t pos, int size)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = (void *) buf,
.iov_len = size,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
int ret;

qemu_iovec_init_external(&qiov, &iov, 1);

ret = bdrv_writev_vmstate(bs, &qiov, pos);
if (ret < 0) {
return ret;
Expand All @@ -2493,14 +2449,9 @@ int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
int64_t pos, int size)
{
QEMUIOVector qiov;
struct iovec iov = {
.iov_base = buf,
.iov_len = size,
};
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
int ret;

qemu_iovec_init_external(&qiov, &iov, 1);
ret = bdrv_readv_vmstate(bs, &qiov, pos);
if (ret < 0) {
return ret;
Expand Down

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