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genfs_do_directio: acquire the lock of page owner for now and fix PR/45177. 

Will be revisited to avoid locking dance and be more efficient, e.g. we can
use unmanaged-mapping by allocating with colouring in mind.
This commit is contained in:
rmind 2011-08-31 22:16:54 +00:00
parent e14f406cd9
commit 8c8246dce6
1 changed files with 33 additions and 8 deletions
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41
sys/miscfs/genfs/genfs_io.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: genfs_io.c,v 1.49 2011/06/12 03:35:58 rmind Exp $ */
/* $NetBSD: genfs_io.c,v 1.50 2011/08/31 22:16:54 rmind Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1993
@ -31,7 +31,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.49 2011/06/12 03:35:58 rmind Exp $");
__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.50 2011/08/31 22:16:54 rmind Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -1748,6 +1748,8 @@ genfs_do_directio(struct vmspace *vs, vaddr_t uva, size_t len, struct vnode *vp,
int error, rv, poff, koff;
const int pgoflags = PGO_CLEANIT | PGO_SYNCIO | PGO_JOURNALLOCKED |
(rw == UIO_WRITE ? PGO_FREE : 0);
struct vm_page *pg;
kmutex_t *slock;
/*
* For writes, verify that this range of the file already has fully
@ -1804,13 +1806,22 @@ genfs_do_directio(struct vmspace *vs, vaddr_t uva, size_t len, struct vnode *vp,
kva = uvm_km_alloc(kernel_map, klen, 0,
UVM_KMF_VAONLY | UVM_KMF_WAITVA);
puva = trunc_page(uva);
mutex_enter(vp->v_interlock);
for (poff = 0; poff < klen; poff += PAGE_SIZE) {
rv = pmap_extract(upm, puva + poff, &pa);
KASSERT(rv);
pg = PHYS_TO_VM_PAGE(pa);
retry1: /* XXX: Rework to not use managed-mappings.. */
mutex_enter(&uvm_pageqlock);
slock = uvmpd_trylockowner(pg);
mutex_exit(&uvm_pageqlock);
if (slock == NULL) {
kpause("gendiolk", false, 1, slock);
goto retry1;
}
pmap_enter(kpm, kva + poff, pa, prot, prot | PMAP_WIRED);
mutex_exit(slock);
}
mutex_exit(vp->v_interlock);
pmap_update(kpm);
/*
@ -1825,9 +1836,24 @@ genfs_do_directio(struct vmspace *vs, vaddr_t uva, size_t len, struct vnode *vp,
* Tear down the kernel mapping.
*/
mutex_enter(vp->v_interlock);
pmap_remove(kpm, kva, kva + klen);
mutex_exit(vp->v_interlock);
for (koff = 0; koff < klen; koff += PAGE_SIZE) {
vaddr_t sva = kva + koff;
rv = pmap_extract(kpm, sva, &pa);
KASSERT(rv);
pg = PHYS_TO_VM_PAGE(pa);
retry2: /* XXX: Rework to not use managed-mappings.. */
mutex_enter(&uvm_pageqlock);
slock = uvmpd_trylockowner(pg);
mutex_exit(&uvm_pageqlock);
if (slock == NULL) {
kpause("gendiolk", false, 1, slock);
goto retry2;
}
pmap_remove(kpm, sva, sva + PAGE_SIZE);
mutex_exit(slock);
}
pmap_update(kpm);
uvm_km_free(kernel_map, kva, klen, UVM_KMF_VAONLY);
@ -1838,4 +1864,3 @@ genfs_do_directio(struct vmspace *vs, vaddr_t uva, size_t len, struct vnode *vp,
uvm_vsunlock(vs, (void *)uva, len);
return error;
}