[PATCH 16/18] fs_context: de-obfuscate control flow in fscontext_read()

From: Eric Biggers
Date: Sun Jul 08 2018 - 17:06:18 EST


From: Eric Biggers <ebiggers@xxxxxxxxxx>

Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/fsopen.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/fsopen.c b/fs/fsopen.c
index 1fbd8b0ca194b..dd38f6b65aace 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -161,20 +161,18 @@ static ssize_t fscontext_read(struct file *file,
if (ret < 0)
return ret;

- ret = -ENODATA;
- if (log->head != log->tail) {
- index = log->tail & (logsize - 1);
- p = log->buffer[index];
- need_free = log->need_free & (1 << index);
- log->buffer[index] = NULL;
- log->need_free &= ~(1 << index);
- log->tail++;
- ret = 0;
+ if (log->head == log->tail) {
+ mutex_unlock(&fc->uapi_mutex);
+ return -ENODATA;
}

+ index = log->tail & (logsize - 1);
+ p = log->buffer[index];
+ need_free = log->need_free & (1 << index);
+ log->buffer[index] = NULL;
+ log->need_free &= ~(1 << index);
+ log->tail++;
mutex_unlock(&fc->uapi_mutex);
- if (ret < 0)
- return ret;

ret = -EMSGSIZE;
n = strlen(p);
--
2.18.0