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iser: fix posting of receive descriptors

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The old code is effectively always posting iser_conn->min_posted_rx
descriptors, since it is

   if (outstanding + iser_conn->min_posted_rx <= iser_conn->qp_max_recv_dtos) {
       if(iser_conn->qp_max_recv_dtos - outstanding > iser_conn->min_posted_rx)
           count = iser_conn->min_posted_rx;
       else
           count = iser_conn->qp_max_recv_dtos - outstanding;

which is equivalent to

    if(iser_conn->qp_max_recv_dtos - outstanding >= iser_conn->min_posted_rx)
        if(iser_conn->qp_max_recv_dtos - outstanding > iser_conn->min_posted_rx)
            count = iser_conn->min_posted_rx;
        else
            count = iser_conn->min_posted_rx;

So the "if" is redundant and the "min_posted_rx" is actually behaving more
like a _maximum_ number of posted descriptors in one iser_post_recvm.
Fix it with the (presumably) intended logic and remove a goto along
the way.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini
2018-10-01 13:35:14 +02:00
parent 346fb947cb
commit f0fcee72c4
1 changed files with 9 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
lib/iser.c
View File

@@ -1028,7 +1028,7 @@ iser_rcv_completion(struct iser_rx_desc *rx_desc,
struct iser_conn *iser_conn)
{
struct iscsi_in_pdu *in = NULL;
int outstanding, count = 0, err;
int empty, err;
struct iscsi_context *iscsi = iser_conn->cma_id->context;
in = iscsi_malloc(iscsi, sizeof(*in));
@@ -1096,23 +1096,17 @@ nop_target:
* for the posted rx bufs refcount to become zero handles everything */
iser_conn->post_recv_buf_count--;
if ((unsigned char *)rx_desc == iser_conn->login_resp_buf)
goto receive;
outstanding = iser_conn->post_recv_buf_count;
if (outstanding + iser_conn->min_posted_rx <= iser_conn->qp_max_recv_dtos) {
if(iser_conn->qp_max_recv_dtos - outstanding > iser_conn->min_posted_rx)
count = iser_conn->min_posted_rx;
else
count = iser_conn->qp_max_recv_dtos - outstanding;
err = iser_post_recvm(iser_conn, count);
if (err) {
err = -1;
goto error;
if ((unsigned char *)rx_desc != iser_conn->login_resp_buf) {
empty = iser_conn->qp_max_recv_dtos - iser_conn->post_recv_buf_count;
if (empty >= iser_conn->min_posted_rx) {
err = iser_post_recvm(iser_conn, empty);
if (err) {
err = -1;
goto error;
}
}
}
receive:
err = iscsi_process_pdu(iscsi, in);
error: