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 */
+#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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