Patch "io_uring/unix: drop usage of io_uring socket" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    io_uring/unix: drop usage of io_uring socket

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     io_uring-unix-drop-usage-of-io_uring-socket.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 0e5ff5687c220803dab485b3f83c78564665f2f2
Author: Jens Axboe <axboe@xxxxxxxxx>
Date:   Wed Mar 13 18:33:48 2024 -0600

    io_uring/unix: drop usage of io_uring socket
    
    Commit a4104821ad651d8a0b374f0b2474c345bbb42f82 upstream.
    
    Since we no longer allow sending io_uring fds over SCM_RIGHTS, move to
    using io_is_uring_fops() to detect whether this is a io_uring fd or not.
    With that done, kill off io_uring_get_socket() as nobody calls it
    anymore.
    
    This is in preparation to yanking out the rest of the core related to
    unix gc with io_uring.
    
    Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 9de8961763b06..cd1858cc63206 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -381,19 +381,6 @@ static struct kmem_cache *req_cachep;
 
 static const struct file_operations io_uring_fops;
 
-struct sock *io_uring_get_socket(struct file *file)
-{
-#if defined(CONFIG_UNIX)
-	if (file->f_op == &io_uring_fops) {
-		struct io_ring_ctx *ctx = file->private_data;
-
-		return ctx->ring_sock->sk;
-	}
-#endif
-	return NULL;
-}
-EXPORT_SYMBOL(io_uring_get_socket);
-
 static void io_ring_ctx_ref_free(struct percpu_ref *ref)
 {
 	struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
@@ -3794,6 +3781,11 @@ static const struct file_operations io_uring_fops = {
 	.fasync		= io_uring_fasync,
 };
 
+bool io_is_uring_fops(struct file *file)
+{
+	return file->f_op == &io_uring_fops;
+}
+
 static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
 				  struct io_uring_params *p)
 {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e009b52ab6b0d..272f261894b17 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3614,11 +3614,11 @@ extern int generic_fadvise(struct file *file, loff_t offset, loff_t len,
 			   int advice);
 
 #if defined(CONFIG_IO_URING)
-extern struct sock *io_uring_get_socket(struct file *file);
+bool io_is_uring_fops(struct file *file);
 #else
-static inline struct sock *io_uring_get_socket(struct file *file)
+static inline bool io_is_uring_fops(struct file *file)
 {
-	return NULL;
+	return false;
 }
 #endif
 
diff --git a/net/core/scm.c b/net/core/scm.c
index 5525c14f33f1e..a442bf63cd480 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -105,7 +105,7 @@ static int scm_fp_copy(struct cmsghdr *cmsg, struct scm_fp_list **fplp)
 		if (fd < 0 || !(file = fget_raw(fd)))
 			return -EBADF;
 		/* don't allow io_uring files */
-		if (io_uring_get_socket(file)) {
+		if (io_is_uring_fops(file)) {
 			fput(file);
 			return -EINVAL;
 		}
diff --git a/net/unix/scm.c b/net/unix/scm.c
index e881a6e78af53..51b623de3be5f 100644
--- a/net/unix/scm.c
+++ b/net/unix/scm.c
@@ -33,10 +33,8 @@ struct sock *unix_get_socket(struct file *filp)
 		/* PF_UNIX ? */
 		if (s && sock->ops && sock->ops->family == PF_UNIX)
 			u_sock = s;
-	} else {
-		/* Could be an io_uring instance */
-		u_sock = io_uring_get_socket(filp);
 	}
+
 	return u_sock;
 }
 EXPORT_SYMBOL(unix_get_socket);