[{"id":3677292,"web_url":"http://patchwork.ozlabs.org/comment/3677292/","msgid":"<87eckhzgf5.fsf@suse.de>","list_archive_url":null,"date":"2026-04-14T15:54:06","subject":"Re: [PATCH v3 2/4] io/channel: introduce qio_channel_pwrite{v,\n }_all()","submitter":{"id":85343,"url":"http://patchwork.ozlabs.org/api/people/85343/","name":"Fabiano Rosas","email":"farosas@suse.de"},"content":"Junjie Cao writes:\n\n> Add positioned write helpers that retry on short writes, matching\n> the pread_all family from the previous patch.\n>\n> qio_channel_pwritev_all() -- retry loop; returns 0 on success,\n> -1 on error.\n> qio_channel_pwrite_all() -- single-buffer convenience wrapper.\n>\n> Signed-off-by: Junjie Cao \n> ---\n> include/io/channel.h | 41 +++++++++++++++++++++++++++++++++++++\n> io/channel.c | 48 ++++++++++++++++++++++++++++++++++++++++++++\n> 2 files changed, 89 insertions(+)\n>\n> diff --git a/include/io/channel.h b/include/io/channel.h\n> index 47af409ede..287d10cd6f 100644\n> --- a/include/io/channel.h\n> +++ b/include/io/channel.h\n> @@ -598,6 +598,47 @@ ssize_t qio_channel_pwritev(QIOChannel *ioc, const struct iovec *iov,\n> ssize_t qio_channel_pwrite(QIOChannel *ioc, void *buf, size_t buflen,\n> off_t offset, Error **errp);\n> \n> +/**\n> + * qio_channel_pwritev_all:\n> + * @ioc: the channel object\n> + * @iov: the array of memory regions to write data from\n> + * @niov: the length of the @iov array\n> + * @offset: the starting offset in the channel to write to\n> + * @errp: pointer to a NULL-initialized error object\n> + *\n> + * Writes @iov, possibly blocking or (if the channel is non-blocking)\n> + * yielding from the current coroutine multiple times until the entire\n> + * content is written. Otherwise behaves as qio_channel_pwritev().\n> + *\n> + * Returns: 0 if all bytes were written, or -1 on error\n> + */\n> +int coroutine_mixed_fn qio_channel_pwritev_all(QIOChannel *ioc,\n> + const struct iovec *iov,\n> + size_t niov,\n> + off_t offset,\n> + Error **errp);\n> +\n> +/**\n> + * qio_channel_pwrite_all:\n> + * @ioc: the channel object\n> + * @buf: the memory region to write data from\n> + * @buflen: the number of bytes to write from @buf\n> + * @offset: the starting offset in the channel to write to\n> + * @errp: pointer to a NULL-initialized error object\n> + *\n> + * Writes @buflen bytes from @buf, possibly blocking or (if the\n> + * channel is non-blocking) yielding from the current coroutine\n> + * multiple times until the entire content is written. Otherwise\n> + * behaves as qio_channel_pwrite().\n> + *\n> + * Returns: 0 if all bytes were written, or -1 on error\n> + */\n> +int coroutine_mixed_fn qio_channel_pwrite_all(QIOChannel *ioc,\n> + const void *buf,\n> + size_t buflen,\n> + off_t offset,\n> + Error **errp);\n> +\n> /**\n> * qio_channel_preadv\n> * @ioc: the channel object\n> diff --git a/io/channel.c b/io/channel.c\n> index 52c1abfcbc..2853dadb68 100644\n> --- a/io/channel.c\n> +++ b/io/channel.c\n> @@ -478,6 +478,54 @@ ssize_t qio_channel_pwrite(QIOChannel *ioc, void *buf, size_t buflen,\n> return qio_channel_pwritev(ioc, &iov, 1, offset, errp);\n> }\n> \n> +int coroutine_mixed_fn qio_channel_pwritev_all(QIOChannel *ioc,\n> + const struct iovec *iov,\n> + size_t niov,\n> + off_t offset,\n> + Error **errp)\n> +{\n> + int ret = -1;\n> + struct iovec *local_iov = g_new(struct iovec, niov);\n> + struct iovec *local_iov_head = local_iov;\n> + unsigned int nlocal_iov = niov;\n> +\n> + nlocal_iov = iov_copy(local_iov, nlocal_iov,\n> + iov, niov,\n> + 0, iov_size(iov, niov));\n> +\n> + while (nlocal_iov > 0) {\n> + ssize_t len;\n> +\n> + len = qio_channel_pwritev(ioc, local_iov, nlocal_iov, offset, errp);\n> +\n> + if (len == QIO_CHANNEL_ERR_BLOCK) {\n> + qio_channel_wait_cond(ioc, G_IO_OUT);\n> + continue;\n> + }\n> + if (len < 0) {\n> + goto cleanup;\n> + }\n> +\n> + offset += len;\n> + iov_discard_front(&local_iov, &nlocal_iov, len);\n> + }\n> +\n> + ret = 0;\n> + cleanup:\n> + g_free(local_iov_head);\n> + return ret;\n> +}\n> +\n> +int coroutine_mixed_fn qio_channel_pwrite_all(QIOChannel *ioc,\n> + const void *buf,\n> + size_t buflen,\n> + off_t offset,\n> + Error **errp)\n> +{\n> + struct iovec iov = { .iov_base = (char *)buf, .iov_len = buflen };\n> + return qio_channel_pwritev_all(ioc, &iov, 1, offset, errp);\n> +}\n> +\n> ssize_t qio_channel_preadv(QIOChannel *ioc, const struct iovec *iov,\n> size_t niov, off_t offset, Error **errp)\n> {\n\nReviewed-by: Fabiano Rosas ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256\n header.s=susede2_rsa header.b=zK0brRpg;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=Xz+Iyeoa;\n\tdkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de\n header.a=rsa-sha256 header.s=susede2_rsa header.b=zK0brRpg;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=Xz+Iyeoa;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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