FAILED: patch "[PATCH] usb: gadget: f_fs: Initialize epfile->in early to fix" failed to apply to 6.18-stable tree

The patch below does not apply to the 6.18-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x 82cfd4739011bdc7e87b5d585703427e89ddfaa5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026071415-tragedy-purely-e8df@gregkh' --subject-prefix 'PATCH 6.18.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 82cfd4739011bdc7e87b5d585703427e89ddfaa5 Mon Sep 17 00:00:00 2001
From: Neill Kapron <[email protected]>
Date: Fri, 19 Jun 2026 04:06:03 +0000
Subject: [PATCH] usb: gadget: f_fs: Initialize epfile->in early to fix
endpoint direction checks

When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions.

By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files.

index 745c44d251f7..d9b95fb830df 100644
@@ -2367,6 +2367,7 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
 			sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
 		else
 			sprintf(epfile->name, "ep%u", i);
+		epfile->in = (ffs->eps_addrmap[i] & USB_ENDPOINT_DIR_MASK) ? 1 : 0;
 		err = ffs_sb_create_file(ffs->sb, epfile->name,
 					 epfile, &ffs_epfile_operations);
 		if (err) {

@@ -2456,7 +2457,6 @@ static int ffs_func_eps_enable(struct ffs_function *func)
 		ret = usb_ep_enable(ep->ep);
 		if (!ret) {
 			epfile->ep = ep;
-			epfile->in = usb_endpoint_dir_in(ep->ep->desc);
 			epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
 		} else {
 			break;

When parsing endpoint descriptors, ffs_data_got_descs() generates the eps_addrmap which contains the endpoint direction. However, epfile->in was previously only populated in ffs_func_eps_enable() which executes upon USB host connection. As a result, early userspace ioctls like FUNCTIONFS_DMABUF_ATTACH that run before the host connects would see epfile->in as 0, leading to incorrect DMA directions.

By moving the initialization to ffs_epfiles_create(), epfile->in is accurate before userspace opens the endpoint files.

---
 drivers/usb/gadget/function/f_fs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 737d60b26e02..1a1fa04a9e34 100644
@@ -2353,6 +2353,7 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
 			sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
 		else
 			sprintf(epfile->name, "ep%u", i);
+		epfile->in = (ffs->eps_addrmap[i] & USB_ENDPOINT_DIR_MASK) ? 1 : 0;
 		epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
 						 epfile,
 						 &ffs_epfile_operations);

@@ -2439,7 +2440,6 @@ static int ffs_func_eps_enable(struct ffs_function *func)
 		ret = usb_ep_enable(ep->ep);
 		if (!ret) {
 			epfile->ep = ep;
-			epfile->in = usb_endpoint_dir_in(ep->ep->desc);
 			epfile->isoc = usb_endpoint_xfer_isoc(ep->ep->desc);
 		} else {
 			break;

2.55.0.141.g00534a21ce-goog