net/mlx5: fix uaccess beyond "count" in debugfs read/write handlers

[sfrench/cifs-2.6.git] / drivers / net / ethernet / mellanox / mlx5 / core / debugfs.c

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c b/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
index 413080a312a7fdba0d159559032d09eeea173460..90fabd612b6cd84f1420afa151cc6c3b0103acfb 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/debugfs.c
@@ -150,22 +150,13 @@ static ssize_t average_read(struct file *filp, char __user *buf, size_t count,
        int ret;
        char tbuf[22];
 
-       if (*pos)
-               return 0;
-
        stats = filp->private_data;
        spin_lock_irq(&stats->lock);
        if (stats->n)
                field = div64_u64(stats->sum, stats->n);
        spin_unlock_irq(&stats->lock);
        ret = snprintf(tbuf, sizeof(tbuf), "%llu\n", field);
-       if (ret > 0) {
-               if (copy_to_user(buf, tbuf, ret))
-                       return -EFAULT;
-       }
-
-       *pos += ret;
-       return ret;
+       return simple_read_from_buffer(buf, count, pos, tbuf, ret);
 }
 
 static ssize_t average_write(struct file *filp, const char __user *buf,
@@ -442,9 +433,6 @@ static ssize_t dbg_read(struct file *filp, char __user *buf, size_t count,
        u64 field;
        int ret;
 
-       if (*pos)
-               return 0;
-
        desc = filp->private_data;
        d = (void *)(desc - desc->i) - sizeof(*d);
        switch (d->type) {
@@ -470,13 +458,7 @@ static ssize_t dbg_read(struct file *filp, char __user *buf, size_t count,
        else
                ret = snprintf(tbuf, sizeof(tbuf), "0x%llx\n", field);
 
-       if (ret > 0) {
-               if (copy_to_user(buf, tbuf, ret))
-                       return -EFAULT;
-       }
-
-       *pos += ret;
-       return ret;
+       return simple_read_from_buffer(buf, count, pos, tbuf, ret);
 }
 
 static const struct file_operations fops = {