After b31ca3f5dfc ("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: Tejun Heo <[email protected]>
---
fs/sysfs/bin.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c
index d49e6ca..d2142c0 100644
--- a/fs/sysfs/bin.c
+++ b/fs/sysfs/bin.c
@@ -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, buf, offs, count);
+ mutex_unlock(&bb->mutex);
- count = fill_read(file, bb->buffer, offs, count);
- if (count < 0) {
- mutex_unlock(&bb->mutex);
+ if (count < 0)
goto out_free;
- }
-
- memcpy(temp, bb->buffer, count);
- mutex_unlock(&bb->mutex);
-
- 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;
}
--
1.8.3.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
