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>

4 files changed, 70 insertions, 50 deletions

diff --git a/fs/coda/inode.c b/fs/coda/inode.c
index b7fa3e3d772f..7993b96ca348 100644
--- a/fs/coda/inode.c
+++ b/fs/coda/inode.c
@@ -15,7 +15,7 @@
 #include <linux/stat.h>
 #include <linux/errno.h>
 #include <linux/unistd.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/spinlock.h>
 #include <linux/file.h>
 #include <linux/vfs.h>
@@ -145,7 +145,7 @@ static int get_device_index(struct coda_mount_data *data)
 static int coda_fill_super(struct super_block *sb, void *data, int silent)
 {
         struct inode *root = NULL;
-        struct venus_comm *vc = NULL;
+        struct venus_comm *vc;
         struct CodaFid fid;
         int error;
         int idx;
@@ -159,7 +159,7 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
         printk(KERN_INFO "coda_read_super: device index: %i\n", idx);
 
         vc = &coda_comms[idx];
-        lock_kernel();
+        mutex_lock(&vc->vc_mutex);
 
         if (!vc->vc_inuse) {
                 printk("coda_read_super: No pseudo device\n");
@@ -178,7 +178,7 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent)
                 goto unlock_out;
 
         vc->vc_sb = sb;
-        unlock_kernel();
+        mutex_unlock(&vc->vc_mutex);
 
         sb->s_fs_info = vc;
         sb->s_flags |= MS_NOATIME;
@@ -217,20 +217,23 @@ error:
         if (root)
                 iput(root);
 
-        lock_kernel();
+        mutex_lock(&vc->vc_mutex);
         bdi_destroy(&vc->bdi);
         vc->vc_sb = NULL;
         sb->s_fs_info = NULL;
 unlock_out:
-        unlock_kernel();
+        mutex_unlock(&vc->vc_mutex);
         return error;
 }
 
 static void coda_put_super(struct super_block *sb)
 {
-        bdi_destroy(&coda_vcp(sb)->bdi);
-        coda_vcp(sb)->vc_sb = NULL;
+        struct venus_comm *vcp = coda_vcp(sb);
+        mutex_lock(&vcp->vc_mutex);
+        bdi_destroy(&vcp->bdi);
+        vcp->vc_sb = NULL;
         sb->s_fs_info = NULL;
+        mutex_unlock(&vcp->vc_mutex);
 
         printk("Coda: Bye bye.\n");
 }
diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c
index 9a9248e632c6..62647a8595e4 100644
--- a/fs/coda/psdev.c
+++ b/fs/coda/psdev.c
@@ -35,7 +35,7 @@
 #include <linux/poll.h>
 #include <linux/init.h>
 #include <linux/list.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/device.h>
 #include <asm/io.h>
 #include <asm/system.h>
@@ -67,8 +67,10 @@ static unsigned int coda_psdev_poll(struct file *file, poll_table * wait)
         unsigned int mask = POLLOUT | POLLWRNORM;
 
         poll_wait(file, &vcp->vc_waitq, wait);
+        mutex_lock(&vcp->vc_mutex);
         if (!list_empty(&vcp->vc_pending))
                 mask |= POLLIN | POLLRDNORM;
+        mutex_unlock(&vcp->vc_mutex);
 
         return mask;
 }
@@ -143,7 +145,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
         }
         
         /* Look for the message on the processing queue. */
-        lock_kernel();
+        mutex_lock(&vcp->vc_mutex);
         list_for_each(lh, &vcp->vc_processing) {
                 tmp = list_entry(lh, struct upc_req , uc_chain);
                 if (tmp->uc_unique == hdr.unique) {
@@ -152,7 +154,7 @@ static ssize_t coda_psdev_write(struct file *file, const char __user *buf,
                         break;
                 }
         }
-        unlock_kernel();
+        mutex_unlock(&vcp->vc_mutex);
 
         if (!req) {
                 printk("psdev_write: msg (%d, %d) not found\n", 
@@ -207,7 +209,7 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf,
         if (nbytes == 0)
                 return 0;
 
-        lock_kernel();
+        mutex_lock(&vcp->vc_mutex);
 
         add_wait_queue(&vcp->vc_waitq, &wait);
         set_current_state(TASK_INTERRUPTIBLE);
@@ -221,7 +223,9 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf,
                         retval = -ERESTARTSYS;
                         break;
                 }
+                mutex_unlock(&vcp->vc_mutex);
                 schedule();
+                mutex_lock(&vcp->vc_mutex);
         }
 
         set_current_state(TASK_RUNNING);
@@ -254,7 +258,7 @@ static ssize_t coda_psdev_read(struct file * file, char __user * buf,
         CODA_FREE(req->uc_data, sizeof(struct coda_in_hdr));
         kfree(req);
 out:
-        unlock_kernel();
+        mutex_unlock(&vcp->vc_mutex);
         return (count ? count : retval);
 }
 
@@ -267,10 +271,10 @@ static int coda_psdev_open(struct inode * inode, struct file * file)
         if (idx < 0 || idx >= MAX_CODADEVS)
                 return -ENODEV;
 
-        lock_kernel();
-
         err = -EBUSY;
         vcp = &coda_comms[idx];
+        mutex_lock(&vcp->vc_mutex);
+
         if (!vcp->vc_inuse) {
                 vcp->vc_inuse++;
 
@@ -284,7 +288,7 @@ static int coda_psdev_open(struct inode * inode, struct file * file)
                 err = 0;
         }
 
-        unlock_kernel();
+        mutex_unlock(&vcp->vc_mutex);
         return err;
 }
 
@@ -299,7 +303,7 @@ static int coda_psdev_release(struct inode * inode, struct file * file)
                 return -1;
         }
 
-        lock_kernel();
+        mutex_lock(&vcp->vc_mutex);
 
         /* Wakeup clients so they can return. */
         list_for_each_entry_safe(req, tmp, &vcp->vc_pending, uc_chain) {
@@ -324,7 +328,7 @@ static int coda_psdev_release(struct inode * inode, struct file * file)
 
         file->private_data = NULL;
         vcp->vc_inuse--;
-        unlock_kernel();
+        mutex_unlock(&vcp->vc_mutex);
         return 0;
 }
 
@@ -353,9 +357,11 @@ static int init_coda_psdev(void)
                 err = PTR_ERR(coda_psdev_class);
                 goto out_chrdev;
         }               
-        for (i = 0; i < MAX_CODADEVS; i++)
+        for (i = 0; i < MAX_CODADEVS; i++) {
+                mutex_init(&(&coda_comms[i])->vc_mutex);
                 device_create(coda_psdev_class, NULL,
                               MKDEV(CODA_PSDEV_MAJOR, i), NULL, "cfs%d", i);
+        }
         coda_sysctl_init();
         goto out;
 
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;
 }
 
diff --git a/include/linux/coda_psdev.h b/include/linux/coda_psdev.h
index 1e60c5a41a5b..72f2d2f0af91 100644
--- a/include/linux/coda_psdev.h
+++ b/include/linux/coda_psdev.h
@@ -8,6 +8,7 @@
 
 #ifdef __KERNEL__
 #include <linux/backing-dev.h>
+#include <linux/mutex.h>
 
 struct kstatfs;
 
@@ -20,6 +21,7 @@ struct venus_comm {
         int                 vc_inuse;
         struct super_block *vc_sb;
         struct backing_dev_info bdi;
+        struct mutex        vc_mutex;
 };