Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 91270162 authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman
Browse files

sysfs: skip bin_buffer->buffer while reading 



After b31ca3f5 ("sysfs: fix deadlock"), bin read() first writes
data to bb->buffer and bounces it to a transient kernel buffer which
is then copied out to userland.  The double bouncing doesn't add
anything.  Let's just use the transient buffer directly.

While at it, rename @temp to @buf for clarity.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 13c589d5

fs/sysfs/bin.c

+8 −13
Original line number Diff line number Diff line
@@ -72,7 +72,7 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) 
	int size = file_inode(file)->i_size;

	loff_t offs = *off;

	int count = min_t(size_t, bytes, PAGE_SIZE);

	char *temp;

	char *buf;



	if (!bytes)

		return 0;
@@ -84,23 +84,18 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) 
			count = size - offs;

	}



	temp = kmalloc(count, GFP_KERNEL);

	if (!temp)

	buf = kmalloc(count, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	mutex_lock(&bb->mutex);



	count = fill_read(file, bb->buffer, offs, count);

	if (count < 0) {

	count = fill_read(file, buf, offs, count);

	mutex_unlock(&bb->mutex);

		goto out_free;

	}



	memcpy(temp, bb->buffer, count);



	mutex_unlock(&bb->mutex);

	if (count < 0)

		goto out_free;



	if (copy_to_user(userbuf, temp, count)) {

	if (copy_to_user(userbuf, buf, count)) {

		count = -EFAULT;

		goto out_free;

	}
@@ -110,7 +105,7 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) 
	*off = offs + count;



 out_free:

	kfree(temp);

	kfree(buf);

	return count;

}