On 07/30/2012 10:59 AM, Sage Weil wrote:
> This function's calling convention is very limiting. In particular,
> we can't return any error other than ENOMEM (and only implicitly),
> which is a problem (see next patch).
>
> Instead, return an normal 0 or error code, and make the skip a pointer
> output parameter. Drop the useless in_hdr argument (we have the con
> pointer).
>
> Signed-off-by: Sage Weil <sage@xxxxxxxxxxx>
I think this is a good change. I have a few minor nits below
but it looks good.
Reviewed-by: Alex Elder <elder@xxxxxxxxxxx>
> ---
> net/ceph/messenger.c | 56 ++++++++++++++++++++++++++++----------------------
> 1 file changed, 31 insertions(+), 25 deletions(-)
>
> diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
> index c3b628c..5177af0 100644
> --- a/net/ceph/messenger.c
> +++ b/net/ceph/messenger.c
. . .
> @@ -2715,43 +2714,50 @@ static int ceph_alloc_middle(struct ceph_connection *con, struct ceph_msg *msg)
> * connection, and save the result in con->in_msg. Uses the
> * connection's private alloc_msg op if available.
> *
> - * Returns true if the message should be skipped, false otherwise.
> - * If true is returned (skip message), con->in_msg will be NULL.
> - * If false is returned, con->in_msg will contain a pointer to the
> - * newly-allocated message, or NULL in case of memory exhaustion.
> + * Returns 0 on success, or a negative error code.
> + *
> + * On success, *skip may be set to 1:
> + * - the next message should be skipped and ignored.
> + * - con->in_msg == NULL.
I'm pretty sure you mean that con->in_msg will be null if *skip
is 1, but it isn't crystal clear the way it's written here.
> + * or *skip may be 0:
> + * - con->in_msg is non-zero.
Use "non-null" since it's a pointer, or "a valid message pointer".
> + * On error (ENOMEM, EAGAIN, ...),
> + * - con->in_msg == NULL
> */
> -static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
> - struct ceph_msg_header *hdr)
> +static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip)
> {
Getting rid of the hdr argument here was a good idea anyway, since
only &con->in_hdr is ever used.
> + struct ceph_msg_header *hdr = &con->in_hdr;
> int type = le16_to_cpu(hdr->type);
> int front_len = le32_to_cpu(hdr->front_len);
> int middle_len = le32_to_cpu(hdr->middle_len);
> - int ret;
> + int ret = 0;
>
> BUG_ON(con->in_msg != NULL);
>
> if (con->ops->alloc_msg) {
> - int skip = 0;
> -
> mutex_unlock(&con->mutex);
> - con->in_msg = con->ops->alloc_msg(con, hdr, &skip);
> + con->in_msg = con->ops->alloc_msg(con, hdr, skip);
> mutex_lock(&con->mutex);
> if (con->in_msg) {
> con->in_msg->con = con->ops->get(con);
> BUG_ON(con->in_msg->con == NULL);
> }
> - if (skip)
> + if (*skip) {
> con->in_msg = NULL;
> -
> - if (!con->in_msg)
> - return skip != 0;
> + return 0;
> + }
> + if (!con->in_msg) {
> + con->error_msg =
> + "error allocating memory for incoming message";
> + return -ENOMEM;
> + }
> }
> if (!con->in_msg) {
> con->in_msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
> if (!con->in_msg) {
> pr_err("unable to allocate msg type %d len %d\n",
> type, front_len);
> - return false;
> + return -ENOMEM;
> }
> con->in_msg->con = con->ops->get(con);
> BUG_ON(con->in_msg->con == NULL);
> @@ -2767,7 +2773,7 @@ static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
> }
> }
>
> - return false;
> + return ret;
I believe ret will always be 0 here, and if you agree, this
should just be more direct about it:
return 0;
> }
>
>
>
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