io_uring: define and set show_fdinfo only if procfs is enabled

mainline inclusion
from mainline-5.6-rc4
commit bebdb65e
category: feature
bugzilla: https://bugzilla.openeuler.org/show_bug.cgi?id=27
CVE: NA
---------------------------

Follow the pattern used with other *_show_fdinfo functions and only
define and use io_uring_show_fdinfo and its helper functions if
CONFIG_PROC_FS is set.

Fixes: 87ce955b ("io_uring: add ->show_fdinfo() for the io_uring file descriptor")
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: Nyangerkun <yangerkun@huawei.com>
Reviewed-by: Nzhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

fs/io_uring.c

@@ -6576,6 +6576,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 	return submitted ? submitted : ret;
 }
 
+#ifdef CONFIG_PROC_FS
 static int io_uring_show_cred(int id, void *p, void *data)
 {
 	const struct cred *cred = p;
@@ -6649,6 +6650,7 @@ static void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
 		percpu_ref_put(&ctx->refs);
 	}
 }
+#endif
 
 static const struct file_operations io_uring_fops = {
 	.release	= io_uring_release,
@@ -6660,7 +6662,9 @@ static const struct file_operations io_uring_fops = {
 #endif
 	.poll		= io_uring_poll,
 	.fasync		= io_uring_fasync,
+#ifdef CONFIG_PROC_FS
 	.show_fdinfo	= io_uring_show_fdinfo,
+#endif
 };
 
 static int io_allocate_scq_urings(struct io_ring_ctx *ctx,