From 0478b030fa2530cbbfc4d6432e8e39a16d06865b Mon Sep 17 00:00:00 2001 From: Nikolay Borisov Date: Thu, 29 Feb 2024 12:29:58 -0300 Subject: [PATCH] io: implement io_pwritev/preadv for QIOChannelFile MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The upcoming 'mapped-ram' feature will require qemu to write data to (and restore from) specific offsets of the migration file. Add a minimal implementation of pwritev/preadv and expose them via the io_pwritev and io_preadv interfaces. Signed-off-by: Nikolay Borisov Reviewed-by: "Daniel P. Berrangé" Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240229153017.2221-5-farosas@suse.de Signed-off-by: Peter Xu --- io/channel-file.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/io/channel-file.c b/io/channel-file.c index f91bf6db1c..a6ad7770c6 100644 --- a/io/channel-file.c +++ b/io/channel-file.c @@ -146,6 +146,58 @@ static ssize_t qio_channel_file_writev(QIOChannel *ioc, return ret; } +#ifdef CONFIG_PREADV +static ssize_t qio_channel_file_preadv(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp) +{ + QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc); + ssize_t ret; + + retry: + ret = preadv(fioc->fd, iov, niov, offset); + if (ret < 0) { + if (errno == EAGAIN) { + return QIO_CHANNEL_ERR_BLOCK; + } + if (errno == EINTR) { + goto retry; + } + + error_setg_errno(errp, errno, "Unable to read from file"); + return -1; + } + + return ret; +} + +static ssize_t qio_channel_file_pwritev(QIOChannel *ioc, + const struct iovec *iov, + size_t niov, + off_t offset, + Error **errp) +{ + QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc); + ssize_t ret; + + retry: + ret = pwritev(fioc->fd, iov, niov, offset); + if (ret <= 0) { + if (errno == EAGAIN) { + return QIO_CHANNEL_ERR_BLOCK; + } + if (errno == EINTR) { + goto retry; + } + error_setg_errno(errp, errno, "Unable to write to file"); + return -1; + } + return ret; +} +#endif /* CONFIG_PREADV */ + static int qio_channel_file_set_blocking(QIOChannel *ioc, bool enabled, Error **errp) @@ -231,6 +283,10 @@ static void qio_channel_file_class_init(ObjectClass *klass, ioc_klass->io_writev = qio_channel_file_writev; ioc_klass->io_readv = qio_channel_file_readv; ioc_klass->io_set_blocking = qio_channel_file_set_blocking; +#ifdef CONFIG_PREADV + ioc_klass->io_pwritev = qio_channel_file_pwritev; + ioc_klass->io_preadv = qio_channel_file_preadv; +#endif ioc_klass->io_seek = qio_channel_file_seek; ioc_klass->io_close = qio_channel_file_close; ioc_klass->io_create_watch = qio_channel_file_create_watch;