Em Sat, Dec 13, 2008 at 02:41:22PM +0100, Gerrit Renker escreveu:
> This adds auto-loading of CCIDs (when module loading is enabled)
> for the purpose of feature negotiation.
>
> The problem with loading the CCIDs at the end of feature negotiation is
> that this would happen in software interrupt context. Besides, if the host
> advertises CCIDs during negotiation, it should have them ready to use, in
> case an agreeing peer wants to use it for the connection.
>
> Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
> Signed-off-by: Ian McDonald <ian.mcdonald@xxxxxxxxxxx>
> ---
> net/dccp/ccid.h | 1 +
> net/dccp/ccid.c | 39 +++++++++++++++++++++++++++++----------
> net/dccp/feat.c | 5 +++++
> 3 files changed, 35 insertions(+), 10 deletions(-)
>
> --- a/net/dccp/ccid.h
> +++ b/net/dccp/ccid.h
> @@ -108,6 +108,7 @@ extern int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len);
> extern int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
> char __user *, int __user *);
>
> +extern int ccid_request_modules(u8 const *ccid_array, u8 array_len);
> extern struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx,
> gfp_t gfp);
>
> --- a/net/dccp/ccid.c
> +++ b/net/dccp/ccid.c
> @@ -196,22 +196,41 @@ int ccid_unregister(struct ccid_operations *ccid_ops)
>
> EXPORT_SYMBOL_GPL(ccid_unregister);
>
> +/**
> + * ccid_request_module - Pre-load CCID module for later use
> + * This should be called only from process context (e.g. during connection
> + * setup) and is necessary for later calls to ccid_new (typically in software
> + * interrupt), so that it has the modules available when they are needed.
> + */
> +static int ccid_request_module(u8 id)
> +{
> + if (!in_atomic()) {
Shouldn't the above be in a BUG_ON? It looks strange to simply refuse to
do that and return OK.
> + ccids_read_lock();
> + if (ccids[id] == NULL) {
> + ccids_read_unlock();
> + return request_module("net-dccp-ccid-%d", id);
> + }
> + ccids_read_unlock();
> + }
> + return 0;
> +}
> +
> +int ccid_request_modules(u8 const *ccid_array, u8 array_len)
> +{
> +#ifdef CONFIG_MODULES
> + while (array_len--)
> + if (ccid_request_module(ccid_array[array_len]))
> + return -1;
> +#endif
> + return 0;
> +}
> +
> struct ccid *ccid_new(unsigned char id, struct sock *sk, int rx, gfp_t gfp)
> {
> struct ccid_operations *ccid_ops;
> struct ccid *ccid = NULL;
>
> ccids_read_lock();
> -#ifdef CONFIG_MODULES
> - if (ccids[id] == NULL) {
> - /* We only try to load if in process context */
> - ccids_read_unlock();
> - if (gfp & GFP_ATOMIC)
> - goto out;
> - request_module("net-dccp-ccid-%d", id);
> - ccids_read_lock();
> - }
> -#endif
> ccid_ops = ccids[id];
> if (ccid_ops == NULL)
> goto out_unlock;
> --- a/net/dccp/feat.c
> +++ b/net/dccp/feat.c
> @@ -1163,6 +1163,11 @@ int dccp_feat_init(struct sock *sk)
> ccid_get_builtin_ccids(&rx.val, &rx.len))
> return -ENOBUFS;
>
> + /* Pre-load all CCID modules that are going to be advertised */
> + rc = -EUNATCH;
> + if (ccid_request_modules(tx.val, tx.len))
> + goto free_ccid_lists;
> +
> if (!dccp_feat_prefer(sysctl_dccp_feat_tx_ccid, tx.val, tx.len) ||
> !dccp_feat_prefer(sysctl_dccp_feat_rx_ccid, rx.val, rx.len))
> goto free_ccid_lists;
> --
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