diff options
| author | Tejun Heo <tj@kernel.org> | 2013-10-01 17:42:03 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-10-05 17:27:40 -0700 |
| commit | 91270162bf8a86bee756da7e931591d9953cb5a8 (patch) | |
| tree | 086f17394395fdaadd0ddbc3761a3115c9c032c2 | |
| parent | 13c589d5b0ac654d9da7e490a2dd548e6b86b4a5 (diff) | |
| download | linux-91270162bf8a86bee756da7e931591d9953cb5a8.tar.bz2 | |
sysfs: skip bin_buffer->buffer while reading
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 <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/sysfs/bin.c | 21 |
1 files changed, 8 insertions, 13 deletions
diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c index d49e6ca3345b..d2142c0648eb 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; } |