[PATCH v3 17/28] convert cachestat(2)

Al Viro
2024-11-02T05:08:31Z

fdput() can be transposed with copy_to_user()

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

diff --git a/mm/filemap.c b/mm/filemap.c
index 36d22968be9a..5f2504428f3d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -4421,31 +4421,25 @@ 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 =
@@ -4453,7 +4447,6 @@ 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;
--
2.39.5