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path: root/drivers/usb/gadget/function/f_fs.c
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Diffstat (limited to 'drivers/usb/gadget/function/f_fs.c')
-rw-r--r--drivers/usb/gadget/function/f_fs.c119
1 files changed, 99 insertions, 20 deletions
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 63314ede7ba6..af98b096af2f 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -31,6 +31,7 @@
#include <linux/aio.h>
#include <linux/mmu_context.h>
#include <linux/poll.h>
+#include <linux/eventfd.h>
#include "u_fs.h"
#include "u_f.h"
@@ -153,6 +154,8 @@ struct ffs_io_data {
struct usb_ep *ep;
struct usb_request *req;
+
+ struct ffs_data *ffs;
};
struct ffs_desc_helper {
@@ -390,17 +393,20 @@ done_spin:
return ret;
}
+/* Called with ffs->ev.waitq.lock and ffs->mutex held, both released on exit. */
static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
size_t n)
{
/*
- * We are holding ffs->ev.waitq.lock and ffs->mutex and we need
- * to release them.
+ * n cannot be bigger than ffs->ev.count, which cannot be bigger than
+ * size of ffs->ev.types array (which is four) so that's how much space
+ * we reserve.
*/
- struct usb_functionfs_event events[n];
+ struct usb_functionfs_event events[ARRAY_SIZE(ffs->ev.types)];
+ const size_t size = n * sizeof *events;
unsigned i = 0;
- memset(events, 0, sizeof events);
+ memset(events, 0, size);
do {
events[i].type = ffs->ev.types[i];
@@ -410,19 +416,15 @@ static ssize_t __ffs_ep0_read_events(struct ffs_data *ffs, char __user *buf,
}
} while (++i < n);
- if (n < ffs->ev.count) {
- ffs->ev.count -= n;
+ ffs->ev.count -= n;
+ if (ffs->ev.count)
memmove(ffs->ev.types, ffs->ev.types + n,
ffs->ev.count * sizeof *ffs->ev.types);
- } else {
- ffs->ev.count = 0;
- }
spin_unlock_irq(&ffs->ev.waitq.lock);
mutex_unlock(&ffs->mutex);
- return unlikely(__copy_to_user(buf, events, sizeof events))
- ? -EFAULT : sizeof events;
+ return unlikely(__copy_to_user(buf, events, size)) ? -EFAULT : size;
}
static ssize_t ffs_ep0_read(struct file *file, char __user *buf,
@@ -606,6 +608,8 @@ static unsigned int ffs_ep0_poll(struct file *file, poll_table *wait)
}
case FFS_CLOSING:
break;
+ case FFS_DEACTIVATED:
+ break;
}
mutex_unlock(&ffs->mutex);
@@ -673,6 +677,9 @@ static void ffs_user_copy_worker(struct work_struct *work)
aio_complete(io_data->kiocb, ret, ret);
+ if (io_data->ffs->ffs_eventfd && !io_data->kiocb->ki_eventfd)
+ eventfd_signal(io_data->ffs->ffs_eventfd, 1);
+
usb_ep_free_request(io_data->ep, io_data->req);
io_data->kiocb->private = NULL;
@@ -826,6 +833,7 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data)
io_data->buf = data;
io_data->ep = ep->ep;
io_data->req = req;
+ io_data->ffs = epfile->ffs;
req->context = io_data;
req->complete = ffs_epfile_async_io_complete;
@@ -1180,6 +1188,7 @@ struct ffs_sb_fill_data {
struct ffs_file_perms perms;
umode_t root_mode;
const char *dev_name;
+ bool no_disconnect;
struct ffs_data *ffs_data;
};
@@ -1250,6 +1259,12 @@ static int ffs_fs_parse_opts(struct ffs_sb_fill_data *data, char *opts)
/* Interpret option */
switch (eq - opts) {
+ case 13:
+ if (!memcmp(opts, "no_disconnect", 13))
+ data->no_disconnect = !!value;
+ else
+ goto invalid;
+ break;
case 5:
if (!memcmp(opts, "rmode", 5))
data->root_mode = (value & 0555) | S_IFDIR;
@@ -1314,6 +1329,7 @@ ffs_fs_mount(struct file_system_type *t, int flags,
.gid = GLOBAL_ROOT_GID,
},
.root_mode = S_IFDIR | 0500,
+ .no_disconnect = false,
};
struct dentry *rv;
int ret;
@@ -1330,6 +1346,7 @@ ffs_fs_mount(struct file_system_type *t, int flags,
if (unlikely(!ffs))
return ERR_PTR(-ENOMEM);
ffs->file_perms = data.perms;
+ ffs->no_disconnect = data.no_disconnect;
ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
if (unlikely(!ffs->dev_name)) {
@@ -1361,6 +1378,7 @@ ffs_fs_kill_sb(struct super_block *sb)
kill_litter_super(sb);
if (sb->s_fs_info) {
ffs_release_dev(sb->s_fs_info);
+ ffs_data_closed(sb->s_fs_info);
ffs_data_put(sb->s_fs_info);
}
}
@@ -1417,7 +1435,11 @@ static void ffs_data_opened(struct ffs_data *ffs)
ENTER();
atomic_inc(&ffs->ref);
- atomic_inc(&ffs->opened);
+ if (atomic_add_return(1, &ffs->opened) == 1 &&
+ ffs->state == FFS_DEACTIVATED) {
+ ffs->state = FFS_CLOSING;
+ ffs_data_reset(ffs);
+ }
}
static void ffs_data_put(struct ffs_data *ffs)
@@ -1439,6 +1461,21 @@ static void ffs_data_closed(struct ffs_data *ffs)
ENTER();
if (atomic_dec_and_test(&ffs->opened)) {
+ if (ffs->no_disconnect) {
+ ffs->state = FFS_DEACTIVATED;
+ if (ffs->epfiles) {
+ ffs_epfiles_destroy(ffs->epfiles,
+ ffs->eps_count);
+ ffs->epfiles = NULL;
+ }
+ if (ffs->setup_state == FFS_SETUP_PENDING)
+ __ffs_ep0_stall(ffs);
+ } else {
+ ffs->state = FFS_CLOSING;
+ ffs_data_reset(ffs);
+ }
+ }
+ if (atomic_read(&ffs->opened) < 0) {
ffs->state = FFS_CLOSING;
ffs_data_reset(ffs);
}
@@ -1480,6 +1517,9 @@ static void ffs_data_clear(struct ffs_data *ffs)
if (ffs->epfiles)
ffs_epfiles_destroy(ffs->epfiles, ffs->eps_count);
+ if (ffs->ffs_eventfd)
+ eventfd_ctx_put(ffs->ffs_eventfd);
+
kfree(ffs->raw_descs_data);
kfree(ffs->raw_strings);
kfree(ffs->stringtabs);
@@ -1581,10 +1621,10 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
mutex_init(&epfile->mutex);
init_waitqueue_head(&epfile->wait);
if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
- sprintf(epfiles->name, "ep%02x", ffs->eps_addrmap[i]);
+ sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
else
- sprintf(epfiles->name, "ep%u", i);
- epfile->dentry = ffs_sb_create_file(ffs->sb, epfiles->name,
+ sprintf(epfile->name, "ep%u", i);
+ epfile->dentry = ffs_sb_create_file(ffs->sb, epfile->name,
epfile,
&ffs_epfile_operations);
if (unlikely(!epfile->dentry)) {
@@ -1616,7 +1656,6 @@ static void ffs_epfiles_destroy(struct ffs_epfile *epfiles, unsigned count)
kfree(epfiles);
}
-
static void ffs_func_eps_disable(struct ffs_function *func)
{
struct ffs_ep *ep = func->eps;
@@ -1629,10 +1668,12 @@ static void ffs_func_eps_disable(struct ffs_function *func)
/* pending requests get nuked */
if (likely(ep->ep))
usb_ep_disable(ep->ep);
- epfile->ep = NULL;
-
++ep;
- ++epfile;
+
+ if (epfile) {
+ epfile->ep = NULL;
+ ++epfile;
+ }
} while (--count);
spin_unlock_irqrestore(&func->ffs->eps_lock, flags);
}
@@ -2138,7 +2179,8 @@ static int __ffs_data_got_descs(struct ffs_data *ffs,
FUNCTIONFS_HAS_HS_DESC |
FUNCTIONFS_HAS_SS_DESC |
FUNCTIONFS_HAS_MS_OS_DESC |
- FUNCTIONFS_VIRTUAL_ADDR)) {
+ FUNCTIONFS_VIRTUAL_ADDR |
+ FUNCTIONFS_EVENTFD)) {
ret = -ENOSYS;
goto error;
}
@@ -2149,6 +2191,20 @@ static int __ffs_data_got_descs(struct ffs_data *ffs,
goto error;
}
+ if (flags & FUNCTIONFS_EVENTFD) {
+ if (len < 4)
+ goto error;
+ ffs->ffs_eventfd =
+ eventfd_ctx_fdget((int)get_unaligned_le32(data));
+ if (IS_ERR(ffs->ffs_eventfd)) {
+ ret = PTR_ERR(ffs->ffs_eventfd);
+ ffs->ffs_eventfd = NULL;
+ goto error;
+ }
+ data += 4;
+ len -= 4;
+ }
+
/* Read fs_count, hs_count and ss_count (if present) */
for (i = 0; i < 3; ++i) {
if (!(flags & (1 << i))) {
@@ -2377,6 +2433,13 @@ static void __ffs_event_add(struct ffs_data *ffs,
if (ffs->setup_state == FFS_SETUP_PENDING)
ffs->setup_state = FFS_SETUP_CANCELLED;
+ /*
+ * Logic of this function guarantees that there are at most four pending
+ * evens on ffs->ev.types queue. This is important because the queue
+ * has space for four elements only and __ffs_ep0_read_events function
+ * depends on that limit as well. If more event types are added, those
+ * limits have to be revisited or guaranteed to still hold.
+ */
switch (type) {
case FUNCTIONFS_RESUME:
rem_type2 = FUNCTIONFS_SUSPEND;
@@ -2416,6 +2479,8 @@ static void __ffs_event_add(struct ffs_data *ffs,
pr_vdebug("adding event %d\n", type);
ffs->ev.types[ffs->ev.count++] = type;
wake_up_locked(&ffs->ev.waitq);
+ if (ffs->ffs_eventfd)
+ eventfd_signal(ffs->ffs_eventfd, 1);
}
static void ffs_event_add(struct ffs_data *ffs,
@@ -2888,6 +2953,13 @@ static int ffs_func_bind(struct usb_configuration *c,
/* Other USB function hooks *************************************************/
+static void ffs_reset_work(struct work_struct *work)
+{
+ struct ffs_data *ffs = container_of(work,
+ struct ffs_data, reset_work);
+ ffs_data_reset(ffs);
+}
+
static int ffs_func_set_alt(struct usb_function *f,
unsigned interface, unsigned alt)
{
@@ -2904,6 +2976,13 @@ static int ffs_func_set_alt(struct usb_function *f,
if (ffs->func)
ffs_func_eps_disable(ffs->func);
+ if (ffs->state == FFS_DEACTIVATED) {
+ ffs->state = FFS_CLOSING;
+ INIT_WORK(&ffs->reset_work, ffs_reset_work);
+ schedule_work(&ffs->reset_work);
+ return -ENODEV;
+ }
+
if (ffs->state != FFS_ACTIVE)
return -ENODEV;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.