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staging: lustre: lnet: Fix recent breakage from list_for_each conversion 

Commit 8e55b6fd06 ("staging: lustre: lnet: replace list_for_each
with list_for_each_entry") was intended to be an idempotent change,
but actually broke the behavior of ksocknal_add_peer() causing mounts to fail.
The fact that it caused an existing "route2 = NULL;" to become
redundant could have been a clue.  The fact that the loop body
set the new loop variable to NULL might also have been a clue

The original code relied on "route2" being NULL if nothing was found.
The new code would always set route2 to a non-NULL value if the list
was empty, and would likely crash if the list was not empty.

Restore correct functionality by using code-flow rather the value of
"route2" to determine whether to use on old route, or to add a new one.

Fixes: 8e55b6fd06 ("staging: lustre: lnet: replace list_for_each with list_for_each_entry")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
NeilBrown 2017-12-14 15:43:43 +11:00 committed by Greg Kroah-Hartman
parent 1291a0d504
commit a93639090a
1 changed files with 10 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
drivers/staging/lustre/lnet/klnds/socklnd/socklnd.c
View File

@ -487,21 +487,18 @@ ksocknal_add_peer(struct lnet_ni *ni, struct lnet_process_id id, __u32 ipaddr,
ksocknal_nid2peerlist(id.nid));
}
route2 = NULL;
list_for_each_entry(route2, &peer->ksnp_routes, ksnr_list) {
if (route2->ksnr_ipaddr == ipaddr)
break;
route2 = NULL;
if (route2->ksnr_ipaddr == ipaddr) {
/* Route already exists, use the old one */
ksocknal_route_decref(route);
route2->ksnr_share_count++;
goto out;
}
}
if (!route2) {
ksocknal_add_route_locked(peer, route);
route->ksnr_share_count++;
} else {
ksocknal_route_decref(route);
route2->ksnr_share_count++;
}
/* Route doesn't already exist, add the new one */
ksocknal_add_route_locked(peer, route);
route->ksnr_share_count++;
out:
write_unlock_bh(&ksocknal_data.ksnd_global_lock);
return 0;