drivers: autoconvert trivial BKL users to private mutex

All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

These drivers do not seem to be under active
maintainance from my brief investigation. Apologies
to those maintainers that I have missed.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 14 insertions, 13 deletions

diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index 8a1b28a10ef..b3c756227e3 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -32,7 +32,7 @@
 #include <linux/mm.h>
 #include <linux/init.h>
 #include <linux/device.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 #include <linux/firmware.h>
 #include <linux/platform_device.h>
 #include <linux/uaccess.h>	/* For put_user and get_user */
@@ -94,6 +94,7 @@
 	} \
 }
 
+static DEFINE_MUTEX(dsp56k_mutex);
 static struct dsp56k_device {
 	unsigned long in_use;
 	long maxio, timeout;
@@ -330,9 +331,9 @@ static long dsp56k_ioctl(struct file *file, unsigned int cmd,
 			if (len > DSP56K_MAX_BINARY_LENGTH) {
 				return -EINVAL;
 			}
-			lock_kernel();
+			mutex_lock(&dsp56k_mutex);
 			r = dsp56k_upload(bin, len);
-			unlock_kernel();
+			mutex_unlock(&dsp56k_mutex);
 			if (r < 0) {
 				return r;
 			}
@@ -342,16 +343,16 @@ static long dsp56k_ioctl(struct file *file, unsigned int cmd,
 		case DSP56K_SET_TX_WSIZE:
 			if (arg > 4 || arg < 1)
 				return -EINVAL;
-			lock_kernel();
+			mutex_lock(&dsp56k_mutex);
 			dsp56k.tx_wsize = (int) arg;
-			unlock_kernel();
+			mutex_unlock(&dsp56k_mutex);
 			break;
 		case DSP56K_SET_RX_WSIZE:
 			if (arg > 4 || arg < 1)
 				return -EINVAL;
-			lock_kernel();
+			mutex_lock(&dsp56k_mutex);
 			dsp56k.rx_wsize = (int) arg;
-			unlock_kernel();
+			mutex_unlock(&dsp56k_mutex);
 			break;
 		case DSP56K_HOST_FLAGS:
 		{
@@ -363,7 +364,7 @@ static long dsp56k_ioctl(struct file *file, unsigned int cmd,
 			if(get_user(out, &hf->out) < 0)
 				return -EFAULT;
 
-			lock_kernel();
+			mutex_lock(&dsp56k_mutex);
 			if ((dir & 0x1) && (out & 0x1))
 				dsp56k_host_interface.icr |= DSP56K_ICR_HF0;
 			else if (dir & 0x1)
@@ -378,16 +379,16 @@ static long dsp56k_ioctl(struct file *file, unsigned int cmd,
 			if (dsp56k_host_interface.icr & DSP56K_ICR_HF1) status |= 0x2;
 			if (dsp56k_host_interface.isr & DSP56K_ISR_HF2) status |= 0x4;
 			if (dsp56k_host_interface.isr & DSP56K_ISR_HF3) status |= 0x8;
-			unlock_kernel();
+			mutex_unlock(&dsp56k_mutex);
 			return put_user(status, &hf->status);
 		}
 		case DSP56K_HOST_CMD:
 			if (arg > 31 || arg < 0)
 				return -EINVAL;
-			lock_kernel();
+			mutex_lock(&dsp56k_mutex);
 			dsp56k_host_interface.cvr = (u_char)((arg & DSP56K_CVR_HV_MASK) |
 							     DSP56K_CVR_HC);
-			unlock_kernel();
+			mutex_unlock(&dsp56k_mutex);
 			break;
 		default:
 			return -EINVAL;
@@ -427,7 +428,7 @@ static int dsp56k_open(struct inode *inode, struct file *file)
 	int dev = iminor(inode) & 0x0f;
 	int ret = 0;
 
-	lock_kernel();
+	mutex_lock(&dsp56k_mutex);
 	switch(dev)
 	{
 	case DSP56K_DEV_56001:
@@ -454,7 +455,7 @@ static int dsp56k_open(struct inode *inode, struct file *file)
 		ret = -ENODEV;
 	}
 out:
-	unlock_kernel();
+	mutex_unlock(&dsp56k_mutex);
 	return ret;
 }