diff mbox series

[3/9] fs: explicitly check for CHECK_IOVEC_ONLY in rw_copy_check_uvector

Message ID 20200918124533.3487701-4-hch@lst.de
State Not Applicable
Delegated to: David Miller
Headers show
Series [1/9] kernel: add a PF_FORCE_COMPAT flag | expand

Commit Message

Christoph Hellwig Sept. 18, 2020, 12:45 p.m. UTC 
Explicitly check for the magic value insted of implicitly relying on
its number representation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/read_write.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Matthew Wilcox (Oracle) Sept. 18, 2020, 12:56 p.m. UTC | #1 
On Fri, Sep 18, 2020 at 02:45:27PM +0200, Christoph Hellwig wrote:
>  		}
> -		if (type >= 0
> -		    && unlikely(!access_ok(buf, len))) {
> +		if (type != CHECK_IOVEC_ONLY && unlikely(!access_ok(buf, len))) {

drop the unlikely() at the same time?  if it's really advantageous,
that should be embedded in the access_ok macro.
Johannes Thumshirn Sept. 18, 2020, 1:39 p.m. UTC | #2 
Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
diff mbox series

Patch

diff --git a/fs/read_write.c b/fs/read_write.c
index 5db58b8c78d0dd..f153116bc5399b 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -840,8 +840,7 @@  ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
 			ret = -EINVAL;
 			goto out;
 		}
-		if (type >= 0
-		    && unlikely(!access_ok(buf, len))) {
+		if (type != CHECK_IOVEC_ONLY && unlikely(!access_ok(buf, len))) {
 			ret = -EFAULT;
 			goto out;
 		}
@@ -911,7 +910,7 @@  ssize_t compat_rw_copy_check_uvector(int type,
 		}
 		if (len < 0)	/* size_t not fitting in compat_ssize_t .. */
 			goto out;
-		if (type >= 0 &&
+		if (type != CHECK_IOVEC_ONLY &&
 		    !access_ok(compat_ptr(buf), len)) {
 			ret = -EFAULT;
 			goto out;