On Sun, May 7, 2017 at 12:59 AM, David Butterfield <dab21774@xxxxxxxxx> wrote:
> This change may need adjustment for local style conventions;
> but it's what I did in my copy to use the rbd iovec functions
> instead of copying through a bounce_buffer. Note all the extra
> conditional checks are done at compile-time.
>
> Signed-off-by: David Butterfield <dab21774@xxxxxxxxx>
> ---
> rbd.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++-------------------
> 1 file changed, 49 insertions(+), 19 deletions(-)
>
> diff --git a/rbd.c b/rbd.c
> index c8019b5..1b80d14 100644
> --- a/rbd.c
> +++ b/rbd.c
> @@ -37,6 +37,17 @@
>
> #include <rbd/librbd.h>
>
> +/* Use gcc -DCONFIG_TCMU_NO_IOV=0 to enable use of RBD iovec calls */
> +/* Use gcc -DCONFIG_TCMU_NO_IOV=1 to disable use of RBD iovec calls */
Why not just re-use LIBRBD_SUPPORTS_IOVEC which is defined in librbd.h
in order to switch between iov vs bounce buffer mode?
> +#ifndef CONFIG_TCMU_NO_IOV
> +#define CONFIG_TCMU_NO_IOV true /* default for now is to assume older library */
> +#endif
> +
> +#if CONFIG_TCMU_NO_IOV
> +#define rbd_aio_readv(image, iov, iov_cnt, offset, completion) -EIO
> +#define rbd_aio_writev(image, iov, iov_cnt, offset, completion) -EIO
> +#endif
> +
> enum {
> TCMU_RBD_OPENING,
> TCMU_RBD_OPENED,
> @@ -516,15 +527,18 @@ static void rbd_finish_aio_read(rbd_completion_t completion,
> } else if (ret < 0) {
> tcmu_r = tcmu_set_sense_data(tcmulib_cmd->sense_buf,
> MEDIUM_ERROR, ASC_READ_ERROR, NULL);
> - } else {
> + } else if (CONFIG_TCMU_NO_IOV) {
> tcmu_r = SAM_STAT_GOOD;
> tcmu_memcpy_into_iovec(iovec, iov_cnt,
> aio_cb->bounce_buffer, aio_cb->length);
> - }
> + } else
> + tcmu_r = SAM_STAT_GOOD;
>
> tcmulib_cmd->done(dev, tcmulib_cmd, tcmu_r);
>
> - free(aio_cb->bounce_buffer);
> + if (CONFIG_TCMU_NO_IOV)
> + free(aio_cb->bounce_buffer);
> +
> free(aio_cb);
> }
>
> @@ -547,10 +561,12 @@ static int tcmu_rbd_read(struct tcmu_device *dev, struct tcmulib_cmd *cmd,
> aio_cb->length = length;
> aio_cb->tcmulib_cmd = cmd;
>
> - aio_cb->bounce_buffer = malloc(length);
> - if (!aio_cb->bounce_buffer) {
> - tcmu_dev_err(dev, "Could not allocate bounce buffer.\n");
> - goto out_free_aio_cb;
> + if (CONFIG_TCMU_NO_IOV) {
> + aio_cb->bounce_buffer = malloc(length);
> + if (!aio_cb->bounce_buffer) {
> + tcmu_dev_err(dev, "Could not allocate bounce buffer.\n");
> + goto out_free_aio_cb;
> + }
> }
>
> ret = rbd_aio_create_completion
> @@ -559,8 +575,12 @@ static int tcmu_rbd_read(struct tcmu_device *dev, struct tcmulib_cmd *cmd,
> goto out_free_bounce_buffer;
> }
>
> - ret = rbd_aio_read(state->image, offset, length, aio_cb->bounce_buffer,
> - completion);
> + if (CONFIG_TCMU_NO_IOV)
> + ret = rbd_aio_read(state->image, offset, length,
> + aio_cb->bounce_buffer, completion);
> + else
> + ret = rbd_aio_readv(state->image, iov, iov_cnt, offset, completion);
> +
> if (ret < 0) {
> goto out_remove_tracked_aio;
> }
> @@ -570,7 +590,8 @@ static int tcmu_rbd_read(struct tcmu_device *dev, struct tcmulib_cmd *cmd,
> out_remove_tracked_aio:
> rbd_aio_release(completion);
> out_free_bounce_buffer:
> - free(aio_cb->bounce_buffer);
> + if (CONFIG_TCMU_NO_IOV)
> + free(aio_cb->bounce_buffer);
> out_free_aio_cb:
> free(aio_cb);
> out:
> @@ -628,22 +649,27 @@ static int tcmu_rbd_write(struct tcmu_device *dev, struct tcmulib_cmd *cmd,
> aio_cb->length = length;
> aio_cb->tcmulib_cmd = cmd;
>
> - aio_cb->bounce_buffer = malloc(length);
> - if (!aio_cb->bounce_buffer) {
> - tcmu_dev_err(dev, "Failed to allocate bounce buffer.\n");
> - goto out_free_aio_cb;
> + if (CONFIG_TCMU_NO_IOV) {
> + aio_cb->bounce_buffer = malloc(length);
> + if (!aio_cb->bounce_buffer) {
> + tcmu_dev_err(dev, "Failed to allocate bounce buffer.\n");
> + goto out_free_aio_cb;
> + }
> + tcmu_memcpy_from_iovec(aio_cb->bounce_buffer, length, iov, iov_cnt);
> }
>
> - tcmu_memcpy_from_iovec(aio_cb->bounce_buffer, length, iov, iov_cnt);
> -
> ret = rbd_aio_create_completion
> (aio_cb, (rbd_callback_t) rbd_finish_aio_generic, &completion);
> if (ret < 0) {
> goto out_free_bounce_buffer;
> }
>
> - ret = rbd_aio_write(state->image, offset,
> - length, aio_cb->bounce_buffer, completion);
> + if (CONFIG_TCMU_NO_IOV)
> + ret = rbd_aio_write(state->image, offset,
> + length, aio_cb->bounce_buffer, completion);
> + else
> + ret = rbd_aio_writev(state->image, iov, iov_cnt, offset, completion);
> +
> if (ret < 0) {
> goto out_remove_tracked_aio;
> }
> @@ -653,7 +679,8 @@ static int tcmu_rbd_write(struct tcmu_device *dev, struct tcmulib_cmd *cmd,
> out_remove_tracked_aio:
> rbd_aio_release(completion);
> out_free_bounce_buffer:
> - free(aio_cb->bounce_buffer);
> + if (CONFIG_TCMU_NO_IOV)
> + free(aio_cb->bounce_buffer);
> out_free_aio_cb:
> free(aio_cb);
> out:
> @@ -733,5 +760,8 @@ struct tcmur_handler tcmu_rbd_handler = {
>
> int handler_init(void)
> {
> + if (!CONFIG_TCMU_NO_IOV)
> + tcmu_info("tcmu/rbd using iovec calls");
> +
> return tcmur_register_handler(&tcmu_rbd_handler);
> }
> --
> 2.12.2.575.gb14f27f
>
> --
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