On Tuesday 01 April 2008, Nathan Lynch wrote:
> Nathan Lynch wrote:
> >
> > One could argue that the real problem is using the proc_dir_entry's
> > reference count to enforce exclusive open.
>
>
> I think this is better... the way these files are used is lame, but
> this should preserve the existing behavior. I haven't yet tested
> this, can you?
I did and it works for me...
>
>
> diff --git a/arch/powerpc/kernel/rtas_flash.c
> b/arch/powerpc/kernel/rtas_flash.c
> index f227659..00bc308 100644
> --- a/arch/powerpc/kernel/rtas_flash.c
> +++ b/arch/powerpc/kernel/rtas_flash.c
> @@ -139,7 +139,7 @@ struct rtas_validate_flash_t
> unsigned int update_results; /* Update results token */
> };
>
> -static DEFINE_SPINLOCK(flash_file_open_lock);
> +static atomic_t open_count = ATOMIC_INIT(0);
> static struct proc_dir_entry *firmware_flash_pde;
> static struct proc_dir_entry *firmware_update_pde;
> static struct proc_dir_entry *validate_pde;
> @@ -216,7 +216,7 @@ static int rtas_flash_release(struct inode *inode, struct
> file *file)
> uf->flist = NULL;
> }
>
> - atomic_dec(&dp->count);
> + atomic_dec(&open_count);
> return 0;
> }
>
> @@ -352,26 +352,17 @@ static ssize_t rtas_flash_write(struct file *file,
> const char __user *buffer,
>
> static int rtas_excl_open(struct inode *inode, struct file *file)
> {
> - struct proc_dir_entry *dp = PDE(inode);
> -
> - /* Enforce exclusive open with use count of PDE */
> - spin_lock(&flash_file_open_lock);
> - if (atomic_read(&dp->count) > 1) {
> - spin_unlock(&flash_file_open_lock);
> + if (atomic_inc_return(&open_count) > 1) {
> + atomic_dec(&open_count);
> return -EBUSY;
> }
>
> - atomic_inc(&dp->count);
> - spin_unlock(&flash_file_open_lock);
> -
> return 0;
> }
>
> static int rtas_excl_release(struct inode *inode, struct file *file)
> {
> - struct proc_dir_entry *dp = PDE(inode);
> -
> - atomic_dec(&dp->count);
> + atomic_dec(&open_count);
>
> return 0;
> }
> @@ -580,7 +571,7 @@ static int validate_flash_release(struct inode *inode,
> struct file *file)
> }
>
> /* The matching atomic_inc was in rtas_excl_open() */
> - atomic_dec(&dp->count);
> + atomic_dec(&open_count);
>
> return 0;
> }
>
Gruß,
Jens
IBM Deutschland Entwicklung GmbH
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