unsigned int rds_trans_stats_info_copy(struct rds_info_iterator *iter,
unsigned int avail)
{
struct rds_transport *trans;
unsigned int total = 0;
unsigned int part;
int i;
rds_info_iter_unmap(iter);
down_read(&rds_trans_sem);
for (i = 0; i < RDS_TRANS_COUNT; i++)
{
trans = transports[i];
if (!trans || !trans->stats_info_copy)
continue;
part = trans->stats_info_copy(iter, avail);
avail -= min(avail, part);
total += part;
}
up_read(&rds_trans_sem);
return total;
}
/*
* @optval points to the userspace buffer that the information snapshot
* will be copied into.
*
* @optlen on input is the size of the buffer in userspace. @optlen
* on output is the size of the requested snapshot in bytes.
*
* This function returns -errno if there is a failure, particularly -ENOSPC
* if the given userspace buffer was not large enough to fit the snapshot.
* On success it returns the positive number of bytes of each array element
* in the snapshot.
*/
int rds_info_getsockopt(struct socket *sock, int optname, char __user *optval,
int __user *optlen)
{
struct rds_info_iterator iter;
struct rds_info_lengths lens;
unsigned long nr_pages = 0;
unsigned long start;
unsigned long i;
rds_info_func func;
struct page **pages = NULL;
int ret;
int len;
int total;
if (get_user(len, optlen)) {
ret = -EFAULT;
goto out;
}
/* check for all kinds of wrapping and the like */
start = (unsigned long)optval;
if (len < 0 || len + PAGE_SIZE - 1 < len || start + len < start) {
ret = -EINVAL;
goto out;
}
/* a 0 len call is just trying to probe its length */
if (len == 0)
goto call_func;
nr_pages = (PAGE_ALIGN(start + len) - (start & PAGE_MASK))
>> PAGE_SHIFT;
pages = kmalloc(nr_pages * sizeof(struct page *), GFP_KERNEL);
if (pages == NULL) {
ret = -ENOMEM;
goto out;
}
ret = get_user_pages_fast(start, nr_pages, 1, pages);
if (ret != nr_pages) {
if (ret > 0)
nr_pages = ret;
else
nr_pages = 0;
ret = -EAGAIN; /* XXX ? */
goto out;
}
rdsdebug("len %d nr_pages %lu\n", len, nr_pages);
call_func:
func = rds_info_funcs[optname - RDS_INFO_FIRST];
if (func == NULL) {
ret = -ENOPROTOOPT;
goto out;
}
iter.pages = pages;
iter.addr = NULL;
iter.offset = start & (PAGE_SIZE - 1);
func(sock, len, &iter, &lens);
BUG_ON(lens.each == 0);
total = lens.nr * lens.each;
rds_info_iter_unmap(&iter);
if (total > len) {
len = total;
ret = -ENOSPC;
} else {
len = total;
ret = lens.each;
}
if (put_user(len, optlen))
ret = -EFAULT;
out:
for (i = 0; pages != NULL && i < nr_pages; i++)
put_page(pages[i]);
kfree(pages);
return ret;
}
