Commit ef503a84 authored by Peter Lieven's avatar Peter Lieven Committed by Jeff Cody
Browse files

block/nfs: try to avoid the bounce buffer in pwritev 



if the passed qiov contains exactly one iov we can
pass the buffer directly.

Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Message-id: 1487349541-10201-3-git-send-email-pl@kamp.de
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
parent 69785a22

block/nfs.c

+16 −7
Original line number Diff line number Diff line
@@ -302,20 +302,27 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset, 
    NFSClient *client = bs->opaque;

    NFSRPC task;

    char *buf = NULL;

    bool my_buffer = false;



    nfs_co_init_task(bs, &task);



    if (iov->niov != 1) {

        buf = g_try_malloc(bytes);

        if (bytes && buf == NULL) {

            return -ENOMEM;

        }



        qemu_iovec_to_buf(iov, 0, buf, bytes);

        my_buffer = true;

    } else {

        buf = iov->iov[0].iov_base;

    }



    if (nfs_pwrite_async(client->context, client->fh,

                         offset, bytes, buf,

                         nfs_co_generic_cb, &task) != 0) {

        if (my_buffer) {

            g_free(buf);

        }

        return -ENOMEM;

    }
@@ -324,7 +331,9 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset, 
        qemu_coroutine_yield();

    }



    if (my_buffer) {

        g_free(buf);

    }



    if (task.ret != bytes) {

        return task.ret < 0 ? task.ret : -EIO;