Module Name: src
Committed By: mlelstv
Date: Tue Mar 26 09:33:58 UTC 2019
Modified Files:
src/sys/kern: kern_physio.c
Log Message:
physio can issue multiple concurrent I/O requests for scatter/gather and
split requests, concurrent requests are limited to use multiple-of-DEV_BSIZE
offsets.
Restrict this to D_DISK devices.
For other devices fix uio accounting to allow arbitrary offsets again.
To generate a diff of this commit:
cvs rdiff -u -r1.93 -r1.94 src/sys/kern/kern_physio.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_physio.c
diff -u src/sys/kern/kern_physio.c:1.93 src/sys/kern/kern_physio.c:1.94
--- src/sys/kern/kern_physio.c:1.93 Tue Apr 21 10:54:52 2015
+++ src/sys/kern/kern_physio.c Tue Mar 26 09:33:58 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_physio.c,v 1.93 2015/04/21 10:54:52 pooka Exp $ */
+/* $NetBSD: kern_physio.c,v 1.94 2019/03/26 09:33:58 mlelstv Exp $ */
/*-
* Copyright (c) 1982, 1986, 1990, 1993
@@ -71,10 +71,11 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_physio.c,v 1.93 2015/04/21 10:54:52 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_physio.c,v 1.94 2019/03/26 09:33:58 mlelstv Exp $");
#include <sys/param.h>
#include <sys/systm.h>
+#include <sys/conf.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/once.h>
@@ -100,6 +101,7 @@ struct physio_stat {
int ps_error;
int ps_failed;
off_t ps_endoffset;
+ size_t ps_resid;
buf_t *ps_orig_bp;
kmutex_t ps_lock;
kcondvar_t ps_cv;
@@ -152,6 +154,8 @@ physio_done(struct work *wk, void *dummy
ps->ps_error = bp->b_error;
}
ps->ps_failed++;
+
+ ps->ps_resid += todo - done;
} else {
KASSERT(bp->b_error == 0);
}
@@ -220,6 +224,7 @@ physio(void (*strategy)(struct buf *), s
struct buf *bp = NULL;
struct physio_stat *ps;
int concurrency = physio_concurrency - 1;
+ int isdisk;
error = RUN_ONCE(&physio_initialized, physio_init);
if (__predict_false(error != 0)) {
@@ -237,9 +242,15 @@ physio(void (*strategy)(struct buf *), s
/* ps->ps_failed = 0; */
ps->ps_orig_bp = obp;
ps->ps_endoffset = -1;
+ ps->ps_resid = 0;
mutex_init(&ps->ps_lock, MUTEX_DEFAULT, IPL_NONE);
cv_init(&ps->ps_cv, "physio");
+ /* Allow concurrent I/O only for disks */
+ isdisk = cdev_type(dev) == D_DISK;
+ if (!isdisk)
+ concurrency = 0;
+
/* Make sure we have a buffer, creating one if necessary. */
if (obp != NULL) {
mutex_enter(&bufcache_lock);
@@ -291,11 +302,30 @@ physio(void (*strategy)(struct buf *), s
/* Set up the buffer for a maximum-sized transfer. */
bp->b_blkno = btodb(uio->uio_offset);
- if (dbtob(bp->b_blkno) != uio->uio_offset) {
- error = EINVAL;
- goto done;
+ if (isdisk) {
+ /*
+ * For disks, check that offsets are at least block
+ * aligned, the block addresses are used to track
+ * errors of finished requests.
+ */
+ if (dbtob(bp->b_blkno) != uio->uio_offset) {
+ error = EINVAL;
+ goto done;
+ }
+ /*
+ * Split request into MAXPHYS chunks
+ */
+ bp->b_bcount = MIN(MAXPHYS, iovp->iov_len);
+ } else {
+ /*
+ * Verify that buffer can handle size
+ */
+ if (iovp->iov_len > MAXBSIZE) {
+ error = EINVAL;
+ goto done;
+ }
+ bp->b_bcount = iovp->iov_len;
}
- bp->b_bcount = MIN(MAXPHYS, iovp->iov_len);
bp->b_data = iovp->iov_base;
/*
@@ -364,16 +394,25 @@ done_locked:
physio_wait(ps, 0);
mutex_exit(&ps->ps_lock);
- if (ps->ps_failed != 0) {
- off_t delta;
+ KASSERT(ps->ps_failed || ps->ps_endoffset == -1);
- delta = uio->uio_offset - ps->ps_endoffset;
- KASSERT(delta > 0);
- uio->uio_resid += delta;
- /* uio->uio_offset = ps->ps_endoffset; */
+ /*
+ * Compute residual, for disks adjust for the
+ * lowest numbered block that returned an error.
+ */
+ if (isdisk) {
+ if (ps->ps_failed != 0) {
+ off_t delta;
+
+ delta = uio->uio_offset - ps->ps_endoffset;
+ KASSERT(delta > 0);
+ uio->uio_resid += delta;
+ /* uio->uio_offset = ps->ps_endoffset; */
+ }
} else {
- KASSERT(ps->ps_endoffset == -1);
+ uio->uio_resid += ps->ps_resid;
}
+
if (bp != NULL && bp != obp) {
putiobuf(bp);
}
