}
}
+static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src)
+{
+ dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer);
+ dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer);
+ dst->opt_mem_alignment = MAX(dst->opt_mem_alignment,
+ src->opt_mem_alignment);
+ dst->min_mem_alignment = MAX(dst->min_mem_alignment,
+ src->min_mem_alignment);
+ dst->max_iov = MIN_NON_ZERO(dst->max_iov, src->max_iov);
+}
+
void bdrv_refresh_limits(BlockDriverState *bs, Error **errp)
{
BlockDriver *drv = bs->drv;
return;
}
+ /* Default alignment based on whether driver has byte interface */
+ bs->bl.request_alignment = drv->bdrv_co_preadv ? 1 : 512;
+
/* Take some limits from the children as a default */
if (bs->file) {
bdrv_refresh_limits(bs->file->bs, &local_err);
error_propagate(errp, local_err);
return;
}
- bs->bl.opt_transfer_length = bs->file->bs->bl.opt_transfer_length;
- bs->bl.max_transfer_length = bs->file->bs->bl.max_transfer_length;
- bs->bl.min_mem_alignment = bs->file->bs->bl.min_mem_alignment;
- bs->bl.opt_mem_alignment = bs->file->bs->bl.opt_mem_alignment;
- bs->bl.max_iov = bs->file->bs->bl.max_iov;
+ bdrv_merge_limits(&bs->bl, &bs->file->bs->bl);
} else {
bs->bl.min_mem_alignment = 512;
bs->bl.opt_mem_alignment = getpagesize();
error_propagate(errp, local_err);
return;
}
- bs->bl.opt_transfer_length =
- MAX(bs->bl.opt_transfer_length,
- bs->backing->bs->bl.opt_transfer_length);
- bs->bl.max_transfer_length =
- MIN_NON_ZERO(bs->bl.max_transfer_length,
- bs->backing->bs->bl.max_transfer_length);
- bs->bl.opt_mem_alignment =
- MAX(bs->bl.opt_mem_alignment,
- bs->backing->bs->bl.opt_mem_alignment);
- bs->bl.min_mem_alignment =
- MAX(bs->bl.min_mem_alignment,
- bs->backing->bs->bl.min_mem_alignment);
- bs->bl.max_iov =
- MIN(bs->bl.max_iov,
- bs->backing->bs->bl.max_iov);
+ bdrv_merge_limits(&bs->bl, &bs->backing->bs->bl);
}
/* Then let the driver override it */
ret = bdrv_get_info(bs, &bdi);
if (ret < 0 || bdi.cluster_size == 0) {
- return bs->request_alignment;
+ return bs->bl.request_alignment;
} else {
return bdi.cluster_size;
}
if (drv->bdrv_co_pwrite_zeroes &&
buffer_is_zero(bounce_buffer, iov.iov_len)) {
+ /* FIXME: Should we (perhaps conditionally) be setting
+ * BDRV_REQ_MAY_UNMAP, if it will allow for a sparser copy
+ * that still correctly reads as zero? */
ret = bdrv_co_do_pwrite_zeroes(bs, cluster_offset, cluster_bytes, 0);
} else {
/* This does not change the data on the disk, it is not necessary
assert((bytes & (align - 1)) == 0);
assert(!qiov || bytes == qiov->size);
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
- assert(!(flags & ~BDRV_REQ_MASK));
+
+ /* TODO: We would need a per-BDS .supported_read_flags and
+ * potential fallback support, if we ever implement any read flags
+ * to pass through to drivers. For now, there aren't any
+ * passthrough flags. */
+ assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ)));
/* Handle Copy on Read and associated serialisation */
if (flags & BDRV_REQ_COPY_ON_READ) {
}
max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
- if (bytes < max_bytes) {
+ if (bytes <= max_bytes) {
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
} else if (max_bytes > 0) {
QEMUIOVector local_qiov;
BlockDriver *drv = bs->drv;
BdrvTrackedRequest req;
- uint64_t align = bs->request_alignment;
+ uint64_t align = bs->bl.request_alignment;
uint8_t *head_buf = NULL;
uint8_t *tail_buf = NULL;
QEMUIOVector local_qiov;
return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
}
-#define MAX_WRITE_ZEROES_BOUNCE_BUFFER 32768
+/* Maximum buffer for write zeroes fallback, in bytes */
+#define MAX_WRITE_ZEROES_BOUNCE_BUFFER (32768 << BDRV_SECTOR_BITS)
static int coroutine_fn bdrv_co_do_pwrite_zeroes(BlockDriverState *bs,
int64_t offset, int count, BdrvRequestFlags flags)
int tail = 0;
int max_write_zeroes = MIN_NON_ZERO(bs->bl.max_pwrite_zeroes, INT_MAX);
- int alignment = MAX(bs->bl.pwrite_zeroes_alignment ?: 1,
- bs->request_alignment);
+ int alignment = MAX(bs->bl.pwrite_zeroes_alignment,
+ bs->bl.request_alignment);
assert(is_power_of_2(alignment));
head = offset & (alignment - 1);
if (ret == -ENOTSUP) {
/* Fall back to bounce buffer if write zeroes is unsupported */
- int max_xfer_len = MIN_NON_ZERO(bs->bl.max_transfer_length,
+ int max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
MAX_WRITE_ZEROES_BOUNCE_BUFFER);
BdrvRequestFlags write_flags = flags & ~BDRV_REQ_ZERO_WRITE;
write_flags &= ~BDRV_REQ_FUA;
need_flush = true;
}
- num = MIN(num, max_xfer_len << BDRV_SECTOR_BITS);
+ num = MIN(num, max_transfer);
iov.iov_len = num;
if (iov.iov_base == NULL) {
iov.iov_base = qemu_try_blockalign(bs, num);
/* Keep bounce buffer around if it is big enough for all
* all future requests.
*/
- if (num < max_xfer_len << BDRV_SECTOR_BITS) {
+ if (num < max_transfer) {
qemu_vfree(iov.iov_base);
iov.iov_base = NULL;
}
*/
static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
- QEMUIOVector *qiov, int flags)
+ int64_t align, QEMUIOVector *qiov, int flags)
{
BlockDriver *drv = bs->drv;
bool waited;
int64_t start_sector = offset >> BDRV_SECTOR_BITS;
int64_t end_sector = DIV_ROUND_UP(offset + bytes, BDRV_SECTOR_SIZE);
+ assert(is_power_of_2(align));
+ assert((offset & (align - 1)) == 0);
+ assert((bytes & (align - 1)) == 0);
assert(!qiov || bytes == qiov->size);
assert((bs->open_flags & BDRV_O_NO_IO) == 0);
assert(!(flags & ~BDRV_REQ_MASK));
uint8_t *buf = NULL;
QEMUIOVector local_qiov;
struct iovec iov;
- uint64_t align = bs->request_alignment;
+ uint64_t align = bs->bl.request_alignment;
unsigned int head_padding_bytes, tail_padding_bytes;
int ret = 0;
memset(buf + head_padding_bytes, 0, zero_bytes);
ret = bdrv_aligned_pwritev(bs, req, offset & ~(align - 1), align,
- &local_qiov,
+ align, &local_qiov,
flags & ~BDRV_REQ_ZERO_WRITE);
if (ret < 0) {
goto fail;
if (bytes >= align) {
/* Write the aligned part in the middle. */
uint64_t aligned_bytes = bytes & ~(align - 1);
- ret = bdrv_aligned_pwritev(bs, req, offset, aligned_bytes,
+ ret = bdrv_aligned_pwritev(bs, req, offset, aligned_bytes, align,
NULL, flags);
if (ret < 0) {
goto fail;
bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
memset(buf, 0, bytes);
- ret = bdrv_aligned_pwritev(bs, req, offset, align,
+ ret = bdrv_aligned_pwritev(bs, req, offset, align, align,
&local_qiov, flags & ~BDRV_REQ_ZERO_WRITE);
}
fail:
BdrvRequestFlags flags)
{
BdrvTrackedRequest req;
- uint64_t align = bs->request_alignment;
+ uint64_t align = bs->bl.request_alignment;
uint8_t *head_buf = NULL;
uint8_t *tail_buf = NULL;
QEMUIOVector local_qiov;
bytes = ROUND_UP(bytes, align);
}
- ret = bdrv_aligned_pwritev(bs, &req, offset, bytes,
+ ret = bdrv_aligned_pwritev(bs, &req, offset, bytes, align,
use_local_qiov ? &local_qiov : qiov,
flags);
goto out;
}
- max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
+ max_discard = MIN_NON_ZERO(bs->bl.max_pdiscard >> BDRV_SECTOR_BITS,
+ BDRV_REQUEST_MAX_SECTORS);
while (nb_sectors > 0) {
int ret;
int num = nb_sectors;
+ int discard_alignment = bs->bl.pdiscard_alignment >> BDRV_SECTOR_BITS;
/* align request */
- if (bs->bl.discard_alignment &&
- num >= bs->bl.discard_alignment &&
- sector_num % bs->bl.discard_alignment) {
- if (num > bs->bl.discard_alignment) {
- num = bs->bl.discard_alignment;
+ if (discard_alignment &&
+ num >= discard_alignment &&
+ sector_num % discard_alignment) {
+ if (num > discard_alignment) {
+ num = discard_alignment;
}
- num -= sector_num % bs->bl.discard_alignment;
+ num -= sector_num % discard_alignment;
}
/* limit request size */
projects / qemu.git / blobdiff