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kernel/linux-rt-4.4.41/drivers/block/drbd/drbd_nla.c 1.38 KB
5113f6f70   김현기   kernel add
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  #include <linux/kernel.h>
  #include <net/netlink.h>
  #include <linux/drbd_genl_api.h>
  #include "drbd_nla.h"
  
  static int drbd_nla_check_mandatory(int maxtype, struct nlattr *nla)
  {
  	struct nlattr *head = nla_data(nla);
  	int len = nla_len(nla);
  	int rem;
  
  	/*
  	 * validate_nla (called from nla_parse_nested) ignores attributes
  	 * beyond maxtype, and does not understand the DRBD_GENLA_F_MANDATORY flag.
  	 * In order to have it validate attributes with the DRBD_GENLA_F_MANDATORY
  	 * flag set also, check and remove that flag before calling
  	 * nla_parse_nested.
  	 */
  
  	nla_for_each_attr(nla, head, len, rem) {
  		if (nla->nla_type & DRBD_GENLA_F_MANDATORY) {
  			nla->nla_type &= ~DRBD_GENLA_F_MANDATORY;
  			if (nla_type(nla) > maxtype)
  				return -EOPNOTSUPP;
  		}
  	}
  	return 0;
  }
  
  int drbd_nla_parse_nested(struct nlattr *tb[], int maxtype, struct nlattr *nla,
  			  const struct nla_policy *policy)
  {
  	int err;
  
  	err = drbd_nla_check_mandatory(maxtype, nla);
  	if (!err)
  		err = nla_parse_nested(tb, maxtype, nla, policy);
  
  	return err;
  }
  
  struct nlattr *drbd_nla_find_nested(int maxtype, struct nlattr *nla, int attrtype)
  {
  	int err;
  	/*
  	 * If any nested attribute has the DRBD_GENLA_F_MANDATORY flag set and
  	 * we don't know about that attribute, reject all the nested
  	 * attributes.
  	 */
  	err = drbd_nla_check_mandatory(maxtype, nla);
  	if (err)
  		return ERR_PTR(err);
  	return nla_find_nested(nla, attrtype);
  }