[PATCH 04/12] bpf: use __anon_inode_getfd

Christoph Hellwig
2020-05-08T15:38:20Z

get_unused_fd_flags + anon_inode_getfile. Also switch the
bpf_link_new_file calling conventions to match __anon_inode_getfd.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/bpf.h | 2 +-
kernel/bpf/cgroup.c | 6 +++---
kernel/bpf/syscall.c | 31 +++++++++----------------------
3 files changed, 13 insertions(+), 26 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index fd2b2322412d7..539649fe8b885 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1103,7 +1103,7 @@ void bpf_link_cleanup(struct bpf_link *link, struct file *link_file,
void bpf_link_inc(struct bpf_link *link);
void bpf_link_put(struct bpf_link *link);
int bpf_link_new_fd(struct bpf_link *link);
-struct file *bpf_link_new_file(struct bpf_link *link, int *reserved_fd);
+int bpf_link_new_file(struct bpf_link *link, struct file **link_file);
struct bpf_link *bpf_link_get_from_fd(u32 ufd);

int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index cb305e71e7deb..8605287adcd9e 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -836,10 +836,10 @@ int cgroup_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
link->cgroup = cgrp;
link->type = attr->link_create.attach_type;

- link_file = bpf_link_new_file(&link->link, &link_fd);
- if (IS_ERR(link_file)) {
+ link_fd = bpf_link_new_file(&link->link, &link_file);
+ if (link_fd < 0) {
kfree(link);
- err = PTR_ERR(link_file);
+ err = link_fd;
goto out_put_cgroup;
}

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 64783da342020..cb2364e17423c 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2307,23 +2307,10 @@ int bpf_link_new_fd(struct bpf_link *link)
* complicated and expensive operations and should be delayed until all the fd
* reservation and anon_inode creation succeeds.
*/
-struct file *bpf_link_new_file(struct bpf_link *link, int *reserved_fd)
+int bpf_link_new_file(struct bpf_link *link, struct file **file)
{
- struct file *file;
- int fd;
-
- fd = get_unused_fd_flags(O_CLOEXEC);
- if (fd < 0)
- return ERR_PTR(fd);
-
- file = anon_inode_getfile("bpf_link", &bpf_link_fops, link, O_CLOEXEC);
- if (IS_ERR(file)) {
- put_unused_fd(fd);
- return file;
- }
-
- *reserved_fd = fd;
- return file;
+ return __anon_inode_getfd("bpf_link", &bpf_link_fops, link, O_CLOEXEC,
+ file);
}

struct bpf_link *bpf_link_get_from_fd(u32 ufd)
@@ -2406,10 +2393,10 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog)
}
bpf_link_init(&link->link, &bpf_tracing_link_lops, prog);

- link_file = bpf_link_new_file(&link->link, &link_fd);
- if (IS_ERR(link_file)) {
+ link_fd = bpf_link_new_file(&link->link, &link_file);
+ if (link_fd < 0) {
kfree(link);
- err = PTR_ERR(link_file);
+ err = link_fd;
goto out_put_prog;
}

@@ -2520,10 +2507,10 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
bpf_link_init(&link->link, &bpf_raw_tp_lops, prog);
link->btp = btp;

- link_file = bpf_link_new_file(&link->link, &link_fd);
- if (IS_ERR(link_file)) {
+ link_fd = bpf_link_new_file(&link->link, &link_file);
+ if (link_fd < 0) {
kfree(link);
- err = PTR_ERR(link_file);
+ err = link_fd;
goto out_put_btp;
}

--
2.26.2