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USB: f_fs: Allow epfile to be opened only once

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Due to USB cable disconnect, ADBD closes its epfiles and re-opens the same.
In normal operation the sequence is:
ffs_func_eps_disable() setting epfile->error to 1
ffs_epfile_release() setting epfile->error to 1
ffs_epfile_open() setting epfile->error to 0

In some cases when above sequeunce gets changed, epfile->error is set to 1.
Hence there is no data transfer happening on ep-IN endpoint. Fix this by
not allowing opening of epfiles until it has being successfully released.

Change-Id: I26b9ec1b6218d00cc0965ce3e71fcea49f9bf567
Signed-off-by: Mayank Rana <mrana@codeaurora.org>
This commit is contained in:
Mayank Rana 2015-07-31 15:55:31 -07:00 • committed by David Keitel
parent 86751cfb33
commit dbe778eee0
1 changed files with 16 additions and 0 deletions
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16
drivers/usb/gadget/function/f_fs.c
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@ -138,6 +138,7 @@ struct ffs_epfile {
unsigned char isoc; /* P: ffs->eps_lock */
unsigned char _pad;
atomic_t opened;
};
/* ffs_io_data structure ***************************************************/
@ -947,8 +948,19 @@ ffs_epfile_open(struct inode *inode, struct file *file)
if (WARN_ON(epfile->ffs->state != FFS_ACTIVE))
return -ENODEV;
smp_mb__before_atomic();
if (atomic_read(&epfile->opened)) {
pr_err("%s(): ep(%s) is already opened.\n",
__func__, epfile->name);
return -EBUSY;
}
smp_mb__before_atomic();
atomic_set(&epfile->opened, 1);
file->private_data = epfile;
ffs_data_opened(epfile->ffs);
smp_mb__before_atomic();
atomic_set(&epfile->error, 0);
return 0;
@ -1065,6 +1077,8 @@ ffs_epfile_release(struct inode *inode, struct file *file)
ENTER();
smp_mb__before_atomic();
atomic_set(&epfile->opened, 0);
atomic_set(&epfile->error, 1);
ffs_data_closed(epfile->ffs);
file->private_data = NULL;
@ -1662,6 +1676,7 @@ static int ffs_epfiles_create(struct ffs_data *ffs)
epfile->ffs = ffs;
mutex_init(&epfile->mutex);
init_waitqueue_head(&epfile->wait);
atomic_set(&epfile->opened, 0);
if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR)
sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]);
else
@ -1708,6 +1723,7 @@ static void ffs_func_eps_disable(struct ffs_function *func)
spin_lock_irqsave(&func->ffs->eps_lock, flags);
do {
smp_mb__before_atomic();
if (epfile)
atomic_set(&epfile->error, 1);