diff mbox series

[26/39] convert cachestat(2)

Message ID 20240730051625.14349-26-viro@kernel.org (mailing list archive)
State New
Headers show
Series [01/39] memcg_write_event_control(): fix a user-triggerable oops | expand

Commit Message

Al Viro July 30, 2024, 5:16 a.m. UTC 
From: Al Viro <viro@zeniv.linux.org.uk>

fdput() can be transposed with copy_to_user()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 mm/filemap.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

Comments

Christian Brauner Aug. 7, 2024, 10:39 a.m. UTC | #1 
On Tue, Jul 30, 2024 at 01:16:12AM GMT, viro@kernel.org wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> fdput() can be transposed with copy_to_user()
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---

Reviewed-by: Christian Brauner <brauner@kernel.org>
diff mbox series

Patch

diff --git a/mm/filemap.c b/mm/filemap.c
index 0b5cbd644fdd..9ef41935b0a7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -4387,31 +4387,25 @@  SYSCALL_DEFINE4(cachestat, unsigned int, fd,
 		struct cachestat_range __user *, cstat_range,
 		struct cachestat __user *, cstat, unsigned int, flags)
 {
-	struct fd f = fdget(fd);
+	CLASS(fd, f)(fd);
 	struct address_space *mapping;
 	struct cachestat_range csr;
 	struct cachestat cs;
 	pgoff_t first_index, last_index;
 
-	if (!fd_file(f))
+	if (fd_empty(f))
 		return -EBADF;
 
 	if (copy_from_user(&csr, cstat_range,
-			sizeof(struct cachestat_range))) {
-		fdput(f);
+			sizeof(struct cachestat_range)))
 		return -EFAULT;
-	}
 
 	/* hugetlbfs is not supported */
-	if (is_file_hugepages(fd_file(f))) {
-		fdput(f);
+	if (is_file_hugepages(fd_file(f)))
 		return -EOPNOTSUPP;
-	}
 
-	if (flags != 0) {
-		fdput(f);
+	if (flags != 0)
 		return -EINVAL;
-	}
 
 	first_index = csr.off >> PAGE_SHIFT;
 	last_index =
@@ -4419,7 +4413,6 @@  SYSCALL_DEFINE4(cachestat, unsigned int, fd,
 	memset(&cs, 0, sizeof(struct cachestat));
 	mapping = fd_file(f)->f_mapping;
 	filemap_cachestat(mapping, first_index, last_index, &cs);
-	fdput(f);
 
 	if (copy_to_user(cstat, &cs, sizeof(struct cachestat)))
 		return -EFAULT;