fixed up counting of mmaps by using struct file->private_data to keep

track of mmap count

diff --git a/comedi/comedi_fops.c b/comedi/comedi_fops.c
index 492567a43039869c05c9620ad5e93e48b32ca9f0..3357d75425c55345051c7dbff9f216c73614156e 100644 (file)
--- a/comedi/comedi_fops.c
+++ b/comedi/comedi_fops.c
@@ -177,7 +177,7 @@ static int do_bufconfig_ioctl(comedi_device *dev,void *arg)
                if(rsd->busy)
                        return -EBUSY;
 
-               if(rsd->subdev_flags & SDF_MMAPPED){
+               if(rsd->mmap_count){
                        DPRINTK("read subdevice is mmapped, cannot resize buffer\n");
                        return -EBUSY;
                }
@@ -194,7 +194,7 @@ static int do_bufconfig_ioctl(comedi_device *dev,void *arg)
                if(wsd->busy)
                        return -EBUSY;
 
-               if(wsd->subdev_flags & SDF_MMAPPED){
+               if(wsd->mmap_count){
                        DPRINTK("write subdevice is mmapped, cannot resize buffer\n");
                        return -EBUSY;
                }
@@ -1174,7 +1174,7 @@ static int do_lock_ioctl(comedi_device *dev,unsigned int arg,void * file)
 static int do_unlock_ioctl(comedi_device *dev,unsigned int arg,void * file)
 {
        comedi_subdevice *s;
-       
+
        if(arg>=dev->n_subdevices)
                return -EINVAL;
        s=dev->subdevices+arg;
@@ -1215,14 +1215,14 @@ static int do_cancel(comedi_device *dev,comedi_subdevice *s);
 static int do_cancel_ioctl(comedi_device *dev,unsigned int arg,void *file)
 {
        comedi_subdevice *s;
-       
+
        if(arg>=dev->n_subdevices)
                return -EINVAL;
        s=dev->subdevices+arg;
-       
+
        if(s->lock && s->lock!=file)
                return -EACCES;
-       
+
        if(!s->busy)
                return 0;
 
@@ -1244,6 +1244,11 @@ static int do_cancel(comedi_device *dev,comedi_subdevice *s)
        return ret;
 }
 
+struct comedi_file_private {
+       unsigned int read_mmap_count;
+       unsigned int write_mmap_count;
+};
+
 #ifdef LINUX_V22
 /*
    comedi_mmap_v22
@@ -1258,6 +1263,7 @@ static int comedi_mmap_v22(struct file * file, struct vm_area_struct *vma)
        comedi_device *dev=comedi_get_device_by_minor(minor);
        comedi_subdevice *s;
        int subdev;
+       struct comedi_file_private *cfp;
 
        if(vma->vm_flags & VM_WRITE){
                subdev=dev->write_subdev;
@@ -1274,14 +1280,19 @@ static int comedi_mmap_v22(struct file * file, struct vm_area_struct *vma)
                return -EINVAL;
        }
 
+       cfp = (struct comedi_file_private*) file->private_data;
+       if(subdev == dev->read_subdev)
+               cfp->read_mmap_count++;
+       else if(subdev == dev->write_subdev)
+               cfp->write_mmap_count++;
+
        rvmmap(s->prealloc_buf,s->prealloc_bufsz,vma);
 
        //vma->vm_file = file;
        //vma->vm_ops = &comedi_vm_ops;
        //file_atomic_inc(&file->f_count);
 
-       /* mark subdev as mapped */
-       s->subdev_flags |= SDF_MMAPPED;
+       s->mmap_count++;
 
        return 0;
 }
@@ -1587,6 +1598,7 @@ static int comedi_fop_open(struct inode *inode,struct file *file)
        comedi_device *dev;
        static int in_comedi_open=0;
        char mod[32];
+       struct comedi_file_private *cfp;
 
        if(minor>=COMEDI_NDEVICES)return -ENODEV;
 
@@ -1611,6 +1623,16 @@ static int comedi_fop_open(struct inode *inode,struct file *file)
 
 ok:
        MOD_INC_USE_COUNT;
+
+       cfp = kmalloc(sizeof(struct comedi_file_private), GFP_KERNEL);
+       if(cfp == NULL)
+       {
+               MOD_DEC_USE_COUNT;
+               return -ENOMEM;
+       }
+       memset(cfp, 0, sizeof(struct comedi_file_private));
+       file->private_data = cfp;
+
        if(dev->attached && dev->driver->module){
                __MOD_INC_USE_COUNT(dev->driver->module);
        }
@@ -1622,7 +1644,8 @@ ok:
 static int comedi_close_v22(struct inode *inode,struct file *file)
 {
        comedi_device *dev=comedi_get_device_by_minor(MINOR(inode->i_rdev));
-       comedi_subdevice *s;
+       comedi_subdevice *s=NULL;
+       struct comedi_file_private *cfp = (struct comedi_file_private*) file->private_data;
        int i;
 
        for(i=0;i<dev->n_subdevices;i++){
@@ -1642,7 +1665,19 @@ static int comedi_close_v22(struct inode *inode,struct file *file)
        }
 
        dev->use_count--;
-       
+
+       // decrement mmap_counts
+       if(cfp->read_mmap_count)
+       {
+               s = dev->subdevices + dev->read_subdev;
+               s->mmap_count -= cfp->read_mmap_count;
+       }
+       if(cfp->write_mmap_count)
+       {
+               s = dev->subdevices + dev->write_subdev;
+               s->mmap_count -= cfp->write_mmap_count;
+       }
+
        return 0;
 }
 

diff --git a/include/linux/comedi.h b/include/linux/comedi.h
index 7dff678c7ca043e7b2bb9020c03930f39d98b5cf..7a7db09e74b0cbeaefde53b57c60afa58223afa4 100644 (file)
--- a/include/linux/comedi.h
+++ b/include/linux/comedi.h
@@ -134,7 +134,6 @@ typedef unsigned short sampl_t;
 #define SDF_RUNNING    0x08000000      /* subdevice is acquiring data */
 #define SDF_LSAMPL     0x10000000      /* subdevice uses 32-bit samples */
 #define SDF_PACKED     0x20000000      /* subdevice can do packed DIO */
-#define SDF_MMAPPED    0x40000000      /* is currently mmap'ed */
 
 /* subdevice types */
 

diff --git a/include/linux/comedidev.h b/include/linux/comedidev.h
index 7f5cf390547dfd3efb4c56ea32e49508a02e7379..c50a46804bf9b061d2cb0fc4a56d97f6e603cf6a 100644 (file)
--- a/include/linux/comedidev.h
+++ b/include/linux/comedidev.h
@@ -70,6 +70,7 @@ struct comedi_subdevice_struct{
 
        void            *prealloc_buf;          /* pre-allocated buffer */
        unsigned int    prealloc_bufsz;         /* buffer size, in bytes */
+       unsigned int    mmap_count;     /* current number of mmaps of prealloc_buf */
 
        void *lock;
        void *busy;