[PATCH 26/39] convert cachestat(2)

viro
2024-07-30T05:15:11Z

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(-)

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;
--
2.39.2