Author: kib
Date: Mon Dec 10 05:14:04 2012
New Revision: 244076
URL: http://svnweb.freebsd.org/changeset/base/244076
Log:
Do not ignore zero address, possibly returned by the vm_map_find()
call. The function indicates a failure by the TRUE return value. To
be extra safe, assert that the return value from the following
vm_map_insert() indicates success.
Fix style issues in the nearby lines, reformulate the comment.
Reviewed by: alc (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/sys/kern/vfs_bio.c
Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c Mon Dec 10 03:11:19 2012 (r244075)
+++ head/sys/kern/vfs_bio.c Mon Dec 10 05:14:04 2012 (r244076)
@@ -2107,15 +2107,16 @@ restart:
if (maxsize != bp->b_kvasize) {
vm_offset_t addr = 0;
+ int rv;
bfreekva(bp);
vm_map_lock(buffer_map);
if (vm_map_findspace(buffer_map,
- vm_map_min(buffer_map), maxsize, &addr)) {
+ vm_map_min(buffer_map), maxsize, &addr)) {
/*
- * Uh oh. Buffer map is to fragmented. We
- * must defragment the map.
+ * Buffer map is too fragmented.
+ * We must defragment the map.
*/
atomic_add_int(&bufdefragcnt, 1);
vm_map_unlock(buffer_map);
@@ -2124,22 +2125,21 @@ restart:
brelse(bp);
goto restart;
}
- if (addr) {
- vm_map_insert(buffer_map, NULL, 0,
- addr, addr + maxsize,
- VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
-
- bp->b_kvabase = (caddr_t) addr;
- bp->b_kvasize = maxsize;
- atomic_add_long(&bufspace, bp->b_kvasize);
- atomic_add_int(&bufreusecnt, 1);
- }
+ rv = vm_map_insert(buffer_map, NULL, 0, addr,
+ addr + maxsize, VM_PROT_ALL, VM_PROT_ALL,
+ MAP_NOFAULT);
+ KASSERT(rv == KERN_SUCCESS,
+ ("vm_map_insert(buffer_map) rv %d", rv));
vm_map_unlock(buffer_map);
+ bp->b_kvabase = (caddr_t)addr;
+ bp->b_kvasize = maxsize;
+ atomic_add_long(&bufspace, bp->b_kvasize);
+ atomic_add_int(&bufreusecnt, 1);
}
bp->b_saveaddr = bp->b_kvabase;
bp->b_data = bp->b_saveaddr;
}
- return(bp);
+ return (bp);
}
/*
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