@@ -1178,7 +1178,23 @@ static int sg_get_max_transfer_length(int fd)
#endif
}
-static int sg_get_max_segments(int fd)
+static int get_max_transfer_length(int fd)
+{
+#if defined(BLKSECTGET) && defined(BLKSSZGET)
+ int sect = 0;
+ int ssz = 0;
+
+ if (ioctl(fd, BLKSECTGET, §) == 0 && ioctl(fd, BLKSSZGET, &ssz)) {
+ return sect * ssz;
+ } else {
+ return -errno;
+ }
+#else
+ return -ENOSYS;
+#endif
+}
+
+static int get_max_segments(int fd)
{
#ifdef CONFIG_LINUX
char buf[32];
@@ -1233,23 +1249,31 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
{
BDRVRawState *s = bs->opaque;
- if (bs->sg) {
- int ret = sg_get_max_transfer_length(s->fd);
+ raw_probe_alignment(bs, s->fd, errp);
+ bs->bl.min_mem_alignment = s->buf_align;
+ bs->bl.opt_mem_alignment = MAX(s->buf_align, qemu_real_host_page_size);
+}
+
+static void hdev_refresh_limits(BlockDriverState *bs, Error **errp)
+{
+ BDRVRawState *s = bs->opaque;
+
+ /* BLKSECTGET has always been implemented wrongly in the sg driver
+ and BLKSSZGET has never been supported by it*/
+ int ret = bs->sg ? sg_get_max_transfer_length(s->fd) :
+ get_max_transfer_length(s->fd);
- if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
- bs->bl.max_transfer = pow2floor(ret);
- }
+ if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
+ bs->bl.max_transfer = pow2floor(ret);
+ }
- ret = sg_get_max_segments(s->fd);
- if (ret > 0) {
- bs->bl.max_transfer = MIN(bs->bl.max_transfer,
- ret * qemu_real_host_page_size);
- }
+ ret = get_max_segments(s->fd);
+ if (ret > 0) {
+ bs->bl.max_transfer = MIN_NON_ZERO(bs->bl.max_transfer,
+ ret * qemu_real_host_page_size);
}
- raw_probe_alignment(bs, s->fd, errp);
- bs->bl.min_mem_alignment = s->buf_align;
- bs->bl.opt_mem_alignment = MAX(s->buf_align, qemu_real_host_page_size);
+ raw_refresh_limits(bs, errp);
}
static int check_for_dasd(int fd)
@@ -3604,7 +3628,7 @@ static BlockDriver bdrv_host_device = {
.bdrv_co_pdiscard = hdev_co_pdiscard,
.bdrv_co_copy_range_from = raw_co_copy_range_from,
.bdrv_co_copy_range_to = raw_co_copy_range_to,
- .bdrv_refresh_limits = raw_refresh_limits,
+ .bdrv_refresh_limits = hdev_refresh_limits,
.bdrv_io_plug = raw_aio_plug,
.bdrv_io_unplug = raw_aio_unplug,
.bdrv_attach_aio_context = raw_aio_attach_aio_context,
@@ -3728,7 +3752,7 @@ static BlockDriver bdrv_host_cdrom = {
.bdrv_co_preadv = raw_co_preadv,
.bdrv_co_pwritev = raw_co_pwritev,
.bdrv_co_flush_to_disk = raw_co_flush_to_disk,
- .bdrv_refresh_limits = raw_refresh_limits,
+ .bdrv_refresh_limits = hdev_refresh_limits,
.bdrv_io_plug = raw_aio_plug,
.bdrv_io_unplug = raw_aio_unplug,
.bdrv_attach_aio_context = raw_aio_attach_aio_context,
We can and should get max transfer length and max segments for all host devices / cdroms (on Linux). Also use MIN_NON_ZERO instead when we clamp max transfer length against max segments. Signed-off-by: Tom Yan <tom.ty89@gmail.com> --- v2: fix get_max_transfer_length for non-sg devices; also add/fix sg_get_max_segments for sg devices block/file-posix.c | 56 +++++++++++++++++++++++++++++++++------------- 1 file changed, 40 insertions(+), 16 deletions(-)