From 1a52a73d68632fda840fd88a8377c4e791bfff20 Mon Sep 17 00:00:00 2001
From: Poul-Henning Kamp <phk@FreeBSD.org>
Date: Thu, 23 Sep 2004 14:45:04 +0000
Subject: [PATCH] Eliminate DEV_STRATEGY() macro: call dev_strategy() directly.

Make dev_strategy() handle errors and departing devices properly.
---
 sys/fs/specfs/spec_vnops.c | 20 ++------------------
 sys/kern/kern_physio.c     |  2 +-
 sys/kern/vfs_aio.c         |  2 +-
 sys/kern/vfs_bio.c         | 15 ++++++++++++---
 sys/sys/conf.h             |  2 --
 5 files changed, 16 insertions(+), 25 deletions(-)

diff --git a/sys/fs/specfs/spec_vnops.c b/sys/fs/specfs/spec_vnops.c
index f1f8075c5e27..1d4a12a343af 100644
--- a/sys/fs/specfs/spec_vnops.c
+++ b/sys/fs/specfs/spec_vnops.c
@@ -476,7 +476,6 @@ static int
 spec_xstrategy(struct vnode *vp, struct buf *bp)
 {
 	struct mount *mp;
-	struct cdevsw *dsw;
 	struct thread *td = curthread;
 	
 	KASSERT(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE,
@@ -508,23 +507,8 @@ spec_xstrategy(struct vnode *vp, struct buf *bp)
 				mp->mnt_stat.f_syncreads++;
 		}
 	}
-	dsw = devsw(bp->b_dev);
-	if (dsw == NULL) {
-		bp->b_error = ENXIO;
-		bp->b_ioflags |= BIO_ERROR;
-		bufdone(bp);
-		return (0);
-	}
-	KASSERT(dsw->d_strategy != NULL,
-	   ("No strategy on dev %s responsible for buffer %p\n",
-	   devtoname(bp->b_dev), bp));
-	
-	if (!(dsw->d_flags & D_NEEDGIANT)) {
-		/* XXX: notyet DROP_GIANT(); */
-		DEV_STRATEGY(bp);
-		/* XXX: notyet PICKUP_GIANT(); */
-	} else
-		DEV_STRATEGY(bp);
+
+	dev_strategy(bp);	
 		
 	return (0);
 }
diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c
index 803995c0380b..a6d47e1fbbe0 100644
--- a/sys/kern/kern_physio.c
+++ b/sys/kern/kern_physio.c
@@ -95,7 +95,7 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
 					goto doerror;
 				}
 
-			DEV_STRATEGY(bp);
+			dev_strategy(bp);
 			if (uio->uio_rw == UIO_READ)
 				bwait(bp, PRIBIO, "physrd");
 			else
diff --git a/sys/kern/vfs_aio.c b/sys/kern/vfs_aio.c
index 21bc1019b228..b72e3c3bd324 100644
--- a/sys/kern/vfs_aio.c
+++ b/sys/kern/vfs_aio.c
@@ -1144,7 +1144,7 @@ aio_qphysio(struct proc *p, struct aiocblist *aiocbe)
 	splx(s);
 
 	/* Perform transfer. */
-	DEV_STRATEGY(bp);
+	dev_strategy(bp);
 
 	notify = 0;
 	s = splbio();
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index b2e73b96e210..853803c540dc 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -3105,14 +3105,23 @@ dev_strategy(struct buf *bp)
 	bp->b_io.bio_done = bufdonebio;
 	bp->b_io.bio_caller2 = bp;
 	dev = bp->b_io.bio_dev;
-	csw = devsw(dev);
 	KASSERT(dev->si_refcount > 0,
 	    ("dev_strategy on un-referenced struct cdev *(%s)",
 	    devtoname(dev)));
 	dev_lock();
-	dev->si_threadcount++;
+	csw = devsw(dev);
+	if (csw != NULL)
+		dev->si_threadcount++;
 	dev_unlock();
-	(*devsw(bp->b_io.bio_dev)->d_strategy)(&bp->b_io);
+	if (csw == NULL) {
+		bp->b_error = ENXIO;
+		bp->b_ioflags = BIO_ERROR;
+		mtx_lock(&Giant);	/* XXX: too defensive ? */
+		bufdone(bp);
+		mtx_unlock(&Giant);	/* XXX: too defensive ? */
+		return;
+	}
+	(*csw->d_strategy)(&bp->b_io);
 	dev_lock();
 	dev->si_threadcount--;
 	dev_unlock();
diff --git a/sys/sys/conf.h b/sys/sys/conf.h
index c714019c1e10..eed4b4b9d293 100644
--- a/sys/sys/conf.h
+++ b/sys/sys/conf.h
@@ -160,8 +160,6 @@ typedef int dumper_t(
 	off_t offset,		/* Byte-offset to write at. */
 	size_t length);		/* Number of bytes to dump. */
 
-#define DEV_STRATEGY(bp) dev_strategy(bp)
-
 #endif /* _KERNEL */
 
 /*