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Re: [PATCH] file-posix: split hdev_refresh_limits from raw_refresh_limit
From: |
Tom Yan |
Subject: |
Re: [PATCH] file-posix: split hdev_refresh_limits from raw_refresh_limits |
Date: |
Fri, 4 Sep 2020 08:01:26 +0800 |
Oops I forgot max_transfer needs to be in bytes (and BLKSECTGET in sg
has always been implemented wrongly). Will send a new version.
On Fri, 4 Sep 2020 at 06:37, Tom Yan <tom.ty89@gmail.com> wrote:
>
> sg_get_max_transfer_length() and sg_get_max_segments() have nothing
> to do with the sg driver or SG_IO at all. They can be and should be
> used on all host devices / cdroms (on Linux).
>
> Also use MIN_NON_ZERO instead when we clamp max_sectors against
> max_segments.
>
> Signed-off-by: Tom Yan <tom.ty89@gmail.com>
> ---
> block/file-posix.c | 39 ++++++++++++++++++++++-----------------
> 1 file changed, 22 insertions(+), 17 deletions(-)
>
> diff --git a/block/file-posix.c b/block/file-posix.c
> index 9a00d4190a..a38f43af4f 100644
> --- a/block/file-posix.c
> +++ b/block/file-posix.c
> @@ -1163,7 +1163,7 @@ static void raw_reopen_abort(BDRVReopenState *state)
> s->reopen_state = NULL;
> }
>
> -static int sg_get_max_transfer_length(int fd)
> +static int get_max_transfer_length(int fd)
> {
> #ifdef BLKSECTGET
> int max_bytes = 0;
> @@ -1178,7 +1178,7 @@ static int sg_get_max_transfer_length(int fd)
> #endif
> }
>
> -static int sg_get_max_segments(int fd)
> +static int get_max_segments(int fd)
> {
> #ifdef CONFIG_LINUX
> char buf[32];
> @@ -1233,23 +1233,28 @@ 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);
> +}
>
> - if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
> - bs->bl.max_transfer = pow2floor(ret);
> - }
> +static void hdev_refresh_limits(BlockDriverState *bs, Error **errp)
> +{
> + BDRVRawState *s = bs->opaque;
>
> - 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);
> - }
> + int ret = get_max_transfer_length(s->fd);
> +
> + if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) {
> + bs->bl.max_transfer = pow2floor(ret);
> }
>
> - 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);
> + 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_refresh_limits(bs, errp);
> }
>
> static int check_for_dasd(int fd)
> @@ -3604,7 +3609,7 @@ 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 +3733,7 @@ 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,
> --
> 2.28.0
>