Re: [patch 3/6] sys_indirect RFC - sys_indirect core

On 6/29/07, Davide Libenzi <davidel@xxxxxxxxxxxxxxx> wrote:
+int indirect_set_context(struct fsa_context *ator,
+ const struct indirect_ctx __user * __user *ctxs,
+ unsigned int nctxs, struct indirect_op **first)
+{
+ unsigned int i;
+ int error;
+ u32 ctx;
+ const struct indirect_ctx __user *pctx;
+ struct indirect_op *new;
+
+ *first = NULL;
+ for (i = 0; i < nctxs; i++) {
+ if (get_user(pctx, &ctxs[i]) || get_user(ctx, &pctx->ctx))
+ return -EFAULT;
+ if (unlikely(ctx >= ARRAY_SIZE(inprocs) || !inprocs[ctx].set))
+ return -EINVAL;
+ error = (*inprocs[ctx].set)(ator, pctx, &new);
+ if (unlikely(error))
+ return error;
+ new->next = *first;
+ *first = new;
+ }

If you use one single struct as explained in my last mail all this
shouldn't be necessary. The sys_indirect syscall would simply points
current->ind_ctx to a kernel-copy of the struct. Then call the
syscall and on return clear current->ind_ctx.

In the affected syscalls we can then test whether current->ind_ctx is
NULL and if not, enable the extra functionality.

These callbacks etc seem to be far too expensive and complicated.
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