From: Juergen Gross <jgross@suse.com>
To: Olaf Hering <olaf@aepfle.de>, xen-devel@lists.xenproject.org
Cc: Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>
Subject: Re: [PATCH v20210601 04/38] tools: add readv_exact to libxenctrl
Date: Wed, 2 Jun 2021 08:30:08 +0200 [thread overview]
Message-ID: <23783088-dc59-abd1-c66c-5fcd314d1f5c@suse.com> (raw)
In-Reply-To: <20210601161118.18986-5-olaf@aepfle.de>
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On 01.06.21 18:10, Olaf Hering wrote:
> Read a batch of iovec's.
>
> In the common case of short reads, finish individual iov's with read_exact.
>
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> ---
> tools/libs/ctrl/xc_private.c | 55 +++++++++++++++++++++++++++++++++++-
> tools/libs/ctrl/xc_private.h | 1 +
> 2 files changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/tools/libs/ctrl/xc_private.c b/tools/libs/ctrl/xc_private.c
> index d94f846686..ea420b9ba8 100644
> --- a/tools/libs/ctrl/xc_private.c
> +++ b/tools/libs/ctrl/xc_private.c
> @@ -659,8 +659,23 @@ int write_exact(int fd, const void *data, size_t size)
>
> #if defined(__MINIOS__)
> /*
> - * MiniOS's libc doesn't know about writev(). Implement it as multiple
write()s.
> + * MiniOS's libc doesn't know about readv/writev().
> + * Implement it as multiple read/write()s.
> */
> +int readv_exact(int fd, const struct iovec *iov, int iovcnt)
> +{
> + int rc, i;
> +
> + for ( i = 0; i < iovcnt; ++i )
> + {
> + rc = read_exact(fd, iov[i].iov_base, iov[i].iov_len);
> + if ( rc )
> + return rc;
> + }
> +
> + return 0;
> +}
> +
> int writev_exact(int fd, const struct iovec *iov, int iovcnt)
> {
> int rc, i;
> @@ -675,6 +690,44 @@ int writev_exact(int fd, const struct iovec *iov, int iovcnt)
> return 0;
> }
> #else
> +int readv_exact(int fd, const struct iovec *iov, int iovcnt)
> +{
> + int rc = 0, idx = 0;
> + ssize_t len;
> +
> + while ( idx < iovcnt )
> + {
> + len = readv(fd, &iov[idx], min(iovcnt - idx, IOV_MAX));
> + if ( len == -1 && errno == EINTR )
> + continue;
> + if ( len <= 0 )
> + {
> + rc = -1;
Is EOF really an error?
> + goto out;
> + }
> + while ( len > 0 && idx < iovcnt )
> + {
> + if ( len >= iov[idx].iov_len )
> + {
> + len -= iov[idx].iov_len;
> + }
> + else
> + {
> + void *p = iov[idx].iov_base + len;
> + size_t l = iov[idx].iov_len - len;
> +
> + rc = read_exact(fd, p, l);
> + if ( rc )
> + goto out;
> + len = 0;
This will stop the loop, even if idx hasn't reached iovcnt.
> + }
> + idx++;
> + }
> + }
> +out:
> + return rc;
> +}
> +
Juergen
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next prev parent reply other threads:[~2021-06-02 6:30 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 16:10 [PATCH v20210601 00/38] leftover from 2020 Olaf Hering
2021-06-01 16:10 ` [PATCH v20210601 01/38] tools: add API to work with sevaral bits at once Olaf Hering
2021-06-02 6:19 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 02/38] xl: fix description of migrate --debug Olaf Hering
2021-06-02 6:09 ` Juergen Gross
2021-06-02 10:43 ` Olaf Hering
2021-06-02 11:43 ` Juergen Gross
2021-06-02 12:32 ` [PATCH v20210602 " Olaf Hering
2021-06-02 13:48 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 03/38] tools: create libxensaverestore Olaf Hering
2021-06-01 16:10 ` [PATCH v20210601 04/38] tools: add readv_exact to libxenctrl Olaf Hering
2021-06-02 6:30 ` Juergen Gross [this message]
2021-06-02 10:57 ` Olaf Hering
2021-06-02 11:05 ` Olaf Hering
2021-06-02 11:41 ` Juergen Gross
2021-06-07 9:46 ` Olaf Hering
2021-06-07 11:31 ` Olaf Hering
2021-06-01 16:10 ` [PATCH v20210601 05/38] tools: add xc_is_known_page_type " Olaf Hering
2021-06-02 6:51 ` Juergen Gross
2021-06-02 11:10 ` Olaf Hering
2021-06-02 11:48 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 06/38] tools: use xc_is_known_page_type Olaf Hering
2021-06-02 6:53 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 07/38] tools: unify type checking for data pfns in migration stream Olaf Hering
2021-06-02 6:59 ` Juergen Gross
2021-06-02 11:21 ` Olaf Hering
2021-06-02 12:03 ` Juergen Gross
2021-06-07 10:12 ` Olaf Hering
2021-06-07 10:22 ` Juergen Gross
2021-06-18 12:25 ` Olaf Hering
2021-06-01 16:10 ` [PATCH v20210601 08/38] tools: show migration transfer rate in send_dirty_pages Olaf Hering
2021-06-02 7:10 ` Juergen Gross
2021-06-08 8:58 ` Olaf Hering
2021-06-08 10:07 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 09/38] tools/guest: prepare to allocate arrays once Olaf Hering
2021-06-02 7:29 ` Juergen Gross
2021-06-02 12:03 ` Olaf Hering
2021-06-02 12:09 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 10/38] tools/guest: save: move batch_pfns Olaf Hering
2021-06-02 7:31 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 11/38] tools/guest: save: move mfns array Olaf Hering
2021-06-02 7:32 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 12/38] tools/guest: save: move types array Olaf Hering
2021-06-02 7:32 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 13/38] tools/guest: save: move errors array Olaf Hering
2021-06-02 7:33 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 14/38] tools/guest: save: move iov array Olaf Hering
2021-06-02 7:34 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 15/38] tools/guest: save: move rec_pfns array Olaf Hering
2021-06-02 7:35 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 16/38] tools/guest: save: move guest_data array Olaf Hering
2021-06-02 7:39 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 17/38] tools/guest: save: move local_pages array Olaf Hering
2021-06-02 7:47 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 18/38] tools/guest: restore: move pfns array Olaf Hering
2021-06-02 7:55 ` Juergen Gross
2021-06-01 16:10 ` [PATCH v20210601 19/38] tools/guest: restore: move types array Olaf Hering
2021-06-02 7:56 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 20/38] tools/guest: restore: move mfns array Olaf Hering
2021-06-02 7:57 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 21/38] tools/guest: restore: move map_errs array Olaf Hering
2021-06-02 7:58 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 22/38] tools/guest: restore: move mfns array in populate_pfns Olaf Hering
2021-06-02 7:59 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 23/38] tools/guest: restore: move pfns " Olaf Hering
2021-06-02 7:59 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 24/38] tools/guest: restore: split record processing Olaf Hering
2021-06-02 9:57 ` Juergen Gross
2021-06-01 16:11 ` [PATCH v20210601 25/38] tools/guest: restore: split handle_page_data Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 26/38] tools/guest: restore: write data directly into guest Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 27/38] tools: recognize LIBXL_API_VERSION for 4.16 Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 28/38] tools: adjust libxl_domain_suspend to receive a struct props Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 29/38] tools: change struct precopy_stats to precopy_stats_t Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 30/38] tools: add callback to libxl for precopy_policy and precopy_stats_t Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 31/38] tools: add --max_iters to libxl_domain_suspend Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 32/38] tools: add --min_remaining " Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 33/38] tools: add --abort_if_busy " Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 34/38] tools: add API for expandable bitmaps Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 35/38] tools: use xg_sr_bitmap for populated_pfns Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 36/38] tools: use superpages during restore of HVM guest Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 37/38] tools: remove migration stream verify code Olaf Hering
2021-06-01 16:11 ` [PATCH v20210601 38/38] hotplug/Linux: fix starting of xenstored with restarting systemd Olaf Hering
2021-06-02 6:10 ` [PATCH v20210601 00/38] leftover from 2020 Juergen Gross
2021-06-02 6:54 ` Olaf Hering
2021-06-02 7:00 ` Juergen Gross
2021-06-02 12:07 ` Olaf Hering
2021-06-02 12:15 ` Juergen Gross
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