From da47c19e5c746829042933c8f945a71e2b62d6fc Mon Sep 17 00:00:00 2001
From: Yoshihisa Abe <yoshiabe@cs.cmu.edu>
Date: Mon, 25 Oct 2010 02:03:46 -0400
Subject: Coda: replace BKL with mutex

Replace the BKL with a mutex to protect the venus_comm structure which
binds the mountpoint with the character device and holds the upcall
queues.

Signed-off-by: Yoshihisa Abe <yoshiabe@cs.cmu.edu>
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/coda/upcall.c | 71 +++++++++++++++++++++++++++++++-------------------------
 1 file changed, 40 insertions(+), 31 deletions(-)

(limited to 'fs/coda/upcall.c')

diff --git a/fs/coda/upcall.c b/fs/coda/upcall.c
index 4c258cb5266d..c3563cab9758 100644
--- a/fs/coda/upcall.c
+++ b/fs/coda/upcall.c
@@ -27,7 +27,7 @@
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/slab.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <asm/uaccess.h>
 #include <linux/vmalloc.h>
 #include <linux/vfs.h>
@@ -607,7 +607,8 @@ static void coda_unblock_signals(sigset_t *old)
 				 (r)->uc_opcode != CODA_RELEASE) || \
 				(r)->uc_flags & CODA_REQ_READ))
 
-static inline void coda_waitfor_upcall(struct upc_req *req)
+static inline void coda_waitfor_upcall(struct venus_comm *vcp,
+				       struct upc_req *req)
 {
 	DECLARE_WAITQUEUE(wait, current);
 	unsigned long timeout = jiffies + coda_timeout * HZ;
@@ -640,10 +641,12 @@ static inline void coda_waitfor_upcall(struct upc_req *req)
 			break;
 		}
 
+		mutex_unlock(&vcp->vc_mutex);
 		if (blocked)
 			schedule_timeout(HZ);
 		else
 			schedule();
+		mutex_lock(&vcp->vc_mutex);
 	}
 	if (blocked)
 		coda_unblock_signals(&old);
@@ -671,7 +674,7 @@ static int coda_upcall(struct venus_comm *vcp,
 	struct upc_req *req = NULL, *sig_req;
 	int error;
 
-	lock_kernel();
+	mutex_lock(&vcp->vc_mutex);
 
 	if (!vcp->vc_inuse) {
 		printk(KERN_NOTICE "coda: Venus dead, not sending upcall\n");
@@ -711,7 +714,7 @@ static int coda_upcall(struct venus_comm *vcp,
 	 * ENODEV.  */
 
 	/* Go to sleep.  Wake up on signals only after the timeout. */
-	coda_waitfor_upcall(req);
+	coda_waitfor_upcall(vcp, req);
 
 	/* Op went through, interrupt or not... */
 	if (req->uc_flags & CODA_REQ_WRITE) {
@@ -765,7 +768,7 @@ static int coda_upcall(struct venus_comm *vcp,
 
 exit:
 	kfree(req);
-	unlock_kernel();
+	mutex_unlock(&vcp->vc_mutex);
 	return error;
 }
 
@@ -806,11 +809,11 @@ exit:
 int coda_downcall(struct venus_comm *vcp, int opcode, union outputArgs *out)
 {
 	struct inode *inode = NULL;
-	struct CodaFid *fid, *newfid;
+	struct CodaFid *fid = NULL, *newfid;
 	struct super_block *sb;
 
 	/* Handle invalidation requests. */
-	lock_kernel();
+	mutex_lock(&vcp->vc_mutex);
 	sb = vcp->vc_sb;
 	if (!sb || !sb->s_root)
 		goto unlock_out;
@@ -829,47 +832,53 @@ int coda_downcall(struct venus_comm *vcp, int opcode, union outputArgs *out)
 
 	case CODA_ZAPDIR:
 		fid = &out->coda_zapdir.CodaFid;
-		inode = coda_fid_to_inode(fid, sb);
-		if (inode) {
-			coda_flag_inode_children(inode, C_PURGE);
-			coda_flag_inode(inode, C_VATTR);
-		}
 		break;
 
 	case CODA_ZAPFILE:
 		fid = &out->coda_zapfile.CodaFid;
-		inode = coda_fid_to_inode(fid, sb);
-		if (inode)
-			coda_flag_inode(inode, C_VATTR);
 		break;
 
 	case CODA_PURGEFID:
 		fid = &out->coda_purgefid.CodaFid;
-		inode = coda_fid_to_inode(fid, sb);
-		if (inode) {
-			coda_flag_inode_children(inode, C_PURGE);
-
-			/* catch the dentries later if some are still busy */
-			coda_flag_inode(inode, C_PURGE);
-			d_prune_aliases(inode);
-
-		}
 		break;
 
 	case CODA_REPLACE:
 		fid = &out->coda_replace.OldFid;
-		newfid = &out->coda_replace.NewFid;
-		inode = coda_fid_to_inode(fid, sb);
-		if (inode)
-			coda_replace_fid(inode, fid, newfid);
 		break;
 	}
+	if (fid)
+		inode = coda_fid_to_inode(fid, sb);
 
 unlock_out:
-	unlock_kernel();
+	mutex_unlock(&vcp->vc_mutex);
+
+	if (!inode)
+		return 0;
+
+	switch (opcode) {
+	case CODA_ZAPDIR:
+		coda_flag_inode_children(inode, C_PURGE);
+		coda_flag_inode(inode, C_VATTR);
+		break;
+
+	case CODA_ZAPFILE:
+		coda_flag_inode(inode, C_VATTR);
+		break;
+
+	case CODA_PURGEFID:
+		coda_flag_inode_children(inode, C_PURGE);
 
-	if (inode)
-		iput(inode);
+		/* catch the dentries later if some are still busy */
+		coda_flag_inode(inode, C_PURGE);
+		d_prune_aliases(inode);
+		break;
+
+	case CODA_REPLACE:
+		newfid = &out->coda_replace.NewFid;
+		coda_replace_fid(inode, fid, newfid);
+		break;
+	}
+	iput(inode);
 	return 0;
 }
 
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