Potentially unfinished fixes to uvm_share() in uvm_map.c

[Chris Waddey]

There was a diff a while back (4 Dec 2019) that fixed a bad offset
calculation in this function, but it seems to me that it made a couple
other lines of code incorrect as a result. The diff below tweaks the
lines so that they have their original intent (based on looking at the
diff from when the function was introduced on 5 Jun 2016).

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 9ee15eaab94..6507fa66f65 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -3567,7 +3567,7 @@ uvm_share(struct vm_map *dstmap, vaddr_t dstaddr, 
vm_prot_t prot,
                /* hole in address space, bail out */
                if (psrc_entry != NULL && psrc_entry->end != src_entry->start)
                        break;
-               if (src_entry->start >= srcaddr + sz)
+               if (src_entry->start >= srcaddr + n)
                        break;
 
                if (UVM_ET_ISSUBMAP(src_entry))
@@ -3603,7 +3603,7 @@ uvm_share(struct vm_map *dstmap, vaddr_t dstaddr, 
vm_prot_t prot,
                n -= len;
                dstva += len;
                srcaddr += len;
-               unmap_end = dstva + len;
+               unmap_end = dstva;
                if (n == 0)
                        goto exit_unlock;
        }