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genfs_getpages: if number of pages requested is >16,

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use malloc/free for array of pointers to vm_page.
otherwise, use on-stack array as used to.
this change fixes assertion failure when nfsd gets a big read request
that isn't aligned with filesystem block.
discussed on tech-kern.
This commit is contained in:
yamt 2003-06-15 16:14:46 +00:00
parent 9f376c42d4
commit 424a10b9cc
1 changed files with 27 additions and 6 deletions
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33
sys/miscfs/genfs/genfs_vnops.c
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@ -1,4 +1,4 @@
/* $NetBSD: genfs_vnops.c,v 1.76 2003/04/23 00:55:19 tls Exp $ */
/* $NetBSD: genfs_vnops.c,v 1.77 2003/06/15 16:14:46 yamt Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1993
@ -35,7 +35,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: genfs_vnops.c,v 1.76 2003/04/23 00:55:19 tls Exp $");
__KERNEL_RCSID(0, "$NetBSD: genfs_vnops.c,v 1.77 2003/06/15 16:14:46 yamt Exp $");
#include "opt_nfsserver.h"
@ -479,7 +479,8 @@ genfs_getpages(void *v)
struct vnode *devvp;
struct genfs_node *gp = VTOG(vp);
struct uvm_object *uobj = &vp->v_uobj;
struct vm_page *pg, *pgs[MAX_READ_AHEAD];
struct vm_page *pg, **pgs, *pgs_onstack[MAX_READ_AHEAD];
int pgs_size;
struct ucred *cred = curproc->p_ucred; /* XXXUBC curlwp */
boolean_t async = (flags & PGO_SYNCIO) == 0;
boolean_t write = (ap->a_access_type & VM_PROT_WRITE) != 0;
@ -563,15 +564,27 @@ genfs_getpages(void *v)
endoffset = MIN(endoffset, round_page(memeof));
ridx = (origoffset - startoffset) >> PAGE_SHIFT;
memset(pgs, 0, sizeof(pgs));
pgs_size = sizeof(struct vm_page *) *
((endoffset - startoffset) >> PAGE_SHIFT);
if (pgs_size > sizeof(pgs_onstack)) {
pgs = malloc(pgs_size, M_DEVBUF, M_NOWAIT | M_ZERO);
} else {
pgs = pgs_onstack;
memset(pgs, 0, pgs_size);
}
if (pgs == NULL) {
simple_unlock(&uobj->vmobjlock);
return (ENOMEM);
}
UVMHIST_LOG(ubchist, "ridx %d npages %d startoff %ld endoff %ld",
ridx, npages, startoffset, endoffset);
KASSERT(&pgs[ridx + npages] <= &pgs[MAX_READ_AHEAD]);
if (uvn_findpages(uobj, origoffset, &npages, &pgs[ridx],
async ? UFP_NOWAIT : UFP_ALL) != orignpages) {
KASSERT(async != 0);
genfs_rel_pages(&pgs[ridx], orignpages);
simple_unlock(&uobj->vmobjlock);
if (pgs != pgs_onstack)
free(pgs, M_DEVBUF);
return (EBUSY);
}
@ -626,7 +639,7 @@ genfs_getpages(void *v)
*/
genfs_rel_pages(&pgs[ridx], orignpages);
memset(pgs, 0, sizeof(pgs));
memset(pgs, 0, pgs_size);
UVMHIST_LOG(ubchist, "reset npages start 0x%x end 0x%x",
startoffset, endoffset, 0,0);
@ -636,6 +649,8 @@ genfs_getpages(void *v)
KASSERT(async != 0);
genfs_rel_pages(pgs, npages);
simple_unlock(&uobj->vmobjlock);
if (pgs != pgs_onstack)
free(pgs, M_DEVBUF);
return (EBUSY);
}
}
@ -831,6 +846,8 @@ loopdone:
if (async) {
UVMHIST_LOG(ubchist, "returning 0 (async)",0,0,0,0);
lockmgr(&gp->g_glock, LK_RELEASE, NULL);
if (pgs != pgs_onstack)
free(pgs, M_DEVBUF);
return (0);
}
if (bp != NULL) {
@ -920,6 +937,8 @@ raout:
uvm_unlock_pageq();
simple_unlock(&uobj->vmobjlock);
UVMHIST_LOG(ubchist, "returning error %d", error,0,0,0);
if (pgs != pgs_onstack)
free(pgs, M_DEVBUF);
return (error);
}
@ -965,6 +984,8 @@ out:
memcpy(ap->a_m, &pgs[ridx],
orignpages * sizeof(struct vm_page *));
}
if (pgs != pgs_onstack)
free(pgs, M_DEVBUF);
return (0);
}