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i40iw: avoid potential uninitialized variable use 

gcc finds that the i40iw_make_cm_node() function in the recently added
i40iw driver uses an uninitilized variable as an index into an array
if CONFIG_IPV6 is disabled and the driver uses IPv6 mode:

drivers/infiniband/hw/i40iw/i40iw_cm.c: In function 'i40iw_make_cm_node':
drivers/infiniband/hw/i40iw/i40iw_cm.c:2206:52: error: 'arpindex' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  ether_addr_copy(cm_node->rem_mac, iwdev->arp_table[arpindex].mac_addr);

As far as I can tell, this code path can not be used because the ipv4
variable is always set with CONFIG_IPV6 is disabled, but it's better
to be sure and prevent the undefined behavior, as well as shut up
that warning in a proper way.

This adds an 'else' clause for the case we get the warning about,
causing the function to return an error in a controlled way.
To avoid adding extra mess with combined io()/#ifdef clauses,
I'm also converting the existing #ifdef into a more readable
if(IS_ENABLED()) check.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: f27b4746f3 ("i40iw: add connection management code")
Acked-by: Mustafa Ismail <Mustafa.ismail@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Arnd Bergmann 2016-03-23 11:34:36 +01:00 committed by Doug Ledford
parent 9967c70abc
commit 2fe7857176
1 changed files with 3 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/infiniband/hw/i40iw/i40iw_cm.c
View File

@ -1992,7 +1992,6 @@ static int i40iw_addr_resolve_neigh(struct i40iw_device *iwdev,
/** /**
* i40iw_get_dst_ipv6 * i40iw_get_dst_ipv6
*/ */
#if IS_ENABLED(CONFIG_IPV6)
static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr, static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr,
struct sockaddr_in6 *dst_addr) struct sockaddr_in6 *dst_addr)
{ {
@ -2008,7 +2007,6 @@ static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr,
dst = ip6_route_output(&init_net, NULL, &fl6); dst = ip6_route_output(&init_net, NULL, &fl6);
return dst; return dst;
} }
#endif
/** /**
* i40iw_addr_resolve_neigh_ipv6 - resolve neighbor ipv6 address * i40iw_addr_resolve_neigh_ipv6 - resolve neighbor ipv6 address
@ -2016,7 +2014,6 @@ static struct dst_entry *i40iw_get_dst_ipv6(struct sockaddr_in6 *src_addr,
* @dst_ip: remote ip address * @dst_ip: remote ip address
* @arpindex: if there is an arp entry * @arpindex: if there is an arp entry
*/ */
#if IS_ENABLED(CONFIG_IPV6)
static int i40iw_addr_resolve_neigh_ipv6(struct i40iw_device *iwdev, static int i40iw_addr_resolve_neigh_ipv6(struct i40iw_device *iwdev,
u32 *src, u32 *src,
u32 *dest, u32 *dest,
@ -2089,7 +2086,6 @@ static int i40iw_addr_resolve_neigh_ipv6(struct i40iw_device *iwdev,
dst_release(dst); dst_release(dst);
return rc; return rc;
} }
#endif
/** /**
* i40iw_ipv4_is_loopback - check if loopback * i40iw_ipv4_is_loopback - check if loopback
@ -2190,13 +2186,13 @@ static struct i40iw_cm_node *i40iw_make_cm_node(
cm_info->loc_addr[0], cm_info->loc_addr[0],
cm_info->rem_addr[0], cm_info->rem_addr[0],
oldarpindex); oldarpindex);
#if IS_ENABLED(CONFIG_IPV6) else if (IS_ENABLED(CONFIG_IPV6))
else
arpindex = i40iw_addr_resolve_neigh_ipv6(iwdev, arpindex = i40iw_addr_resolve_neigh_ipv6(iwdev,
cm_info->loc_addr, cm_info->loc_addr,
cm_info->rem_addr, cm_info->rem_addr,
oldarpindex); oldarpindex);
#endif else
arpindex = -EINVAL;
} }
if (arpindex < 0) { if (arpindex < 0) {
i40iw_pr_err("cm_node arpindex\n"); i40iw_pr_err("cm_node arpindex\n");