video1394: remove BKL contention

video1394 does not need to take the BKL. The data structures shared between
file_operations and interrupts are already protected through context-specific
spinlocks.

The only other danger is video1394_release() being called during another
operation, however this cannot happen because release is only ever invoked
when the last thread has closed the fd.

Signed-off-by: Daniel Drake <ddrake@brontes3d.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 6 insertions, 24 deletions

diff --git a/drivers/ieee1394/video1394.c b/drivers/ieee1394/video1394.c
index 776b6618e80e..77f58bc83135 100644
--- a/drivers/ieee1394/video1394.c
+++ b/drivers/ieee1394/video1394.c
@@ -714,8 +714,8 @@ static inline unsigned video1394_buffer_state(struct dma_iso_ctx *d,
         return ret;
 }
 
-static int __video1394_ioctl(struct file *file,
-                             unsigned int cmd, unsigned long arg)
+static long video1394_ioctl(struct file *file,
+                            unsigned int cmd, unsigned long arg)
 {
         struct file_ctx *ctx = (struct file_ctx *)file->private_data;
         struct ti_ohci *ohci = ctx->ohci;
@@ -1158,15 +1158,6 @@ static int __video1394_ioctl(struct file *file,
         }
 }
 
-static long video1394_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
-        int err;
-        lock_kernel();
-        err = __video1394_ioctl(file, cmd, arg);
-        unlock_kernel();
-        return err;
-}
-
 /*
  *      This maps the vmalloced and reserved buffer to user space.
  *
@@ -1179,17 +1170,14 @@ static long video1394_ioctl(struct file *file, unsigned int cmd, unsigned long a
 static int video1394_mmap(struct file *file, struct vm_area_struct *vma)
 {
         struct file_ctx *ctx = (struct file_ctx *)file->private_data;
-        int res = -EINVAL;
 
-        lock_kernel();
         if (ctx->current_ctx == NULL) {
                 PRINT(KERN_ERR, ctx->ohci->host->id,
                                 "Current iso context not set");
-        } else
-                res = dma_region_mmap(&ctx->current_ctx->dma, file, vma);
-        unlock_kernel();
+                return -EINVAL;
+        }
 
-        return res;
+        return dma_region_mmap(&ctx->current_ctx->dma, file, vma);
 }
 
 static unsigned int video1394_poll(struct file *file, poll_table *pt)
@@ -1200,14 +1188,12 @@ static unsigned int video1394_poll(struct file *file, poll_table *pt)
         struct dma_iso_ctx *d;
         int i;
 
-        lock_kernel();
         ctx = file->private_data;
         d = ctx->current_ctx;
         if (d == NULL) {
                 PRINT(KERN_ERR, ctx->ohci->host->id,
                                 "Current iso context not set");
-                mask = POLLERR;
-                goto done;
+                return POLLERR;
         }
 
         poll_wait(file, &d->waitq, pt);
@@ -1220,8 +1206,6 @@ static unsigned int video1394_poll(struct file *file, poll_table *pt)
                 }
         }
         spin_unlock_irqrestore(&d->lock, flags);
-done:
-        unlock_kernel();
 
         return mask;
 }
@@ -1257,7 +1241,6 @@ static int video1394_release(struct inode *inode, struct file *file)
         struct list_head *lh, *next;
         u64 mask;
 
-        lock_kernel();
         list_for_each_safe(lh, next, &ctx->context_list) {
                 struct dma_iso_ctx *d;
                 d = list_entry(lh, struct dma_iso_ctx, link);
@@ -1278,7 +1261,6 @@ static int video1394_release(struct inode *inode, struct file *file)
         kfree(ctx);
         file->private_data = NULL;
 
-        unlock_kernel();
         return 0;
 }