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?
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;
}
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