Author: kib
Date: Wed Mar 27 11:34:27 2013
New Revision: 248792
URL: http://svnweb.freebsd.org/changeset/base/248792
Log:
Add dev_strategy_csw() function, which is similar to dev_strategy()
but assumes that a thread reference was already obtained on the passed
device. Use the function from physio(), to avoid two extra dev_mtx
lock and unlock. Note that physio() is always used as the cdevsw
method, or is called from a cdevsw method, and the caller already owns
the reference.
dev_strategy() is left to keep KPI intact, but now it is implemented
as a wrapper around dev_strategy_csw().
Do some style cleanup in physio().
Requested and reviewed by: kan (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/kern/kern_physio.c
head/sys/kern/vfs_bio.c
head/sys/sys/conf.h
Modified: head/sys/kern/kern_physio.c
==============================================================================
--- head/sys/kern/kern_physio.c Wed Mar 27 11:31:39 2013 (r248791)
+++ head/sys/kern/kern_physio.c Wed Mar 27 11:34:27 2013 (r248792)
@@ -34,11 +34,11 @@ __FBSDID("$FreeBSD$");
int
physio(struct cdev *dev, struct uio *uio, int ioflag)
{
- int i;
- int error;
+ struct buf *bp;
+ struct cdevsw *csw;
caddr_t sa;
u_int iolen;
- struct buf *bp;
+ int error, i, mapped;
/* Keep the process UPAGES from being swapped. XXX: why ? */
PHOLD(curproc);
@@ -91,11 +91,8 @@ physio(struct cdev *dev, struct uio *uio
bp->b_blkno = btodb(bp->b_offset);
+ csw = dev->si_devsw;
if (uio->uio_segflg == UIO_USERSPACE) {
- struct cdevsw *csw;
- int mapped;
-
- csw = dev->si_devsw;
if (csw != NULL &&
(csw->d_flags & D_UNMAPPED_IO) != 0)
mapped = 0;
@@ -107,7 +104,7 @@ physio(struct cdev *dev, struct uio *uio
}
}
- dev_strategy(dev, bp);
+ dev_strategy_csw(dev, csw, bp);
if (uio->uio_rw == UIO_READ)
bwait(bp, PRIBIO, "physrd");
else
Modified: head/sys/kern/vfs_bio.c
==============================================================================
--- head/sys/kern/vfs_bio.c Wed Mar 27 11:31:39 2013 (r248791)
+++ head/sys/kern/vfs_bio.c Wed Mar 27 11:34:27 2013 (r248792)
@@ -3687,11 +3687,34 @@ void
dev_strategy(struct cdev *dev, struct buf *bp)
{
struct cdevsw *csw;
- struct bio *bip;
int ref;
- if ((!bp->b_iocmd) || (bp->b_iocmd & (bp->b_iocmd - 1)))
- panic("b_iocmd botch");
+ KASSERT(dev->si_refcount > 0,
+ ("dev_strategy on un-referenced struct cdev *(%s) %p",
+ devtoname(dev), dev));
+
+ csw = dev_refthread(dev, &ref);
+ dev_strategy_csw(dev, csw, bp);
+ dev_relthread(dev, ref);
+}
+
+void
+dev_strategy_csw(struct cdev *dev, struct cdevsw *csw, struct buf *bp)
+{
+ struct bio *bip;
+
+ KASSERT(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE,
+ ("b_iocmd botch"));
+ KASSERT(((dev->si_flags & SI_ETERNAL) != 0 && csw != NULL) ||
+ dev->si_threadcount > 0,
+ ("dev_strategy_csw threadcount cdev *(%s) %p", devtoname(dev),
+ dev));
+ if (csw == NULL) {
+ bp->b_error = ENXIO;
+ bp->b_ioflags = BIO_ERROR;
+ bufdone(bp);
+ return;
+ }
for (;;) {
bip = g_new_bio();
if (bip != NULL)
@@ -3707,19 +3730,7 @@ dev_strategy(struct cdev *dev, struct bu
bip->bio_done = bufdonebio;
bip->bio_caller2 = bp;
bip->bio_dev = dev;
- KASSERT(dev->si_refcount > 0,
- ("dev_strategy on un-referenced struct cdev *(%s)",
- devtoname(dev)));
- csw = dev_refthread(dev, &ref);
- if (csw == NULL) {
- g_destroy_bio(bip);
- bp->b_error = ENXIO;
- bp->b_ioflags = BIO_ERROR;
- bufdone(bp);
- return;
- }
(*csw->d_strategy)(bip);
- dev_relthread(dev, ref);
}
/*
Modified: head/sys/sys/conf.h
==============================================================================
--- head/sys/sys/conf.h Wed Mar 27 11:31:39 2013 (r248791)
+++ head/sys/sys/conf.h Wed Mar 27 11:34:27 2013 (r248792)
@@ -255,6 +255,7 @@ void dev_ref(struct cdev *dev);
void dev_refl(struct cdev *dev);
void dev_rel(struct cdev *dev);
void dev_strategy(struct cdev *dev, struct buf *bp);
+void dev_strategy_csw(struct cdev *dev, struct cdevsw *csw, struct buf *bp);
struct cdev *make_dev(struct cdevsw *_devsw, int _unit, uid_t _uid, gid_t _gid,
int _perms, const char *_fmt, ...) __printflike(6, 7);
struct cdev *make_dev_cred(struct cdevsw *_devsw, int _unit,
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