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Commit 8a2af064 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

ashmem: switch to ->read_iter 



And use the proper VFS helper for using the backing file.

Also make sure we hold ashmem_lock while updating f_pos to make sure that
it's not racy.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent cc4a41fe

drivers/staging/android/ashmem.c

+8 −21
Original line number Diff line number Diff line
@@ -294,19 +294,9 @@ static int ashmem_release(struct inode *ignored, struct file *file) 
	return 0;

}



/**

 * ashmem_read() - Reads a set of bytes from an Ashmem-enabled file

 * @file:	   The associated backing file.

 * @buf:	   The buffer of data being written to

 * @len:	   The number of bytes being read

 * @pos:	   The position of the first byte to read.

 *

 * Return: 0 if successful, or another return code if not.

 */

static ssize_t ashmem_read(struct file *file, char __user *buf,

			   size_t len, loff_t *pos)

static ssize_t ashmem_read_iter(struct kiocb *iocb, struct iov_iter *iter)

{

	struct ashmem_area *asma = file->private_data;

	struct ashmem_area *asma = iocb->ki_filp->private_data;

	int ret = 0;



	mutex_lock(&ashmem_mutex);
@@ -320,20 +310,17 @@ static ssize_t ashmem_read(struct file *file, char __user *buf, 
		goto out_unlock;

	}



	mutex_unlock(&ashmem_mutex);



	/*

	 * asma and asma->file are used outside the lock here.  We assume

	 * once asma->file is set it will never be changed, and will not

	 * be destroyed until all references to the file are dropped and

	 * ashmem_release is called.

	 */

	ret = __vfs_read(asma->file, buf, len, pos);

	if (ret >= 0)

		/** Update backing file pos, since f_ops->read() doesn't */

		asma->file->f_pos = *pos;

	return ret;



	mutex_unlock(&ashmem_mutex);

	ret = vfs_iter_read(asma->file, iter, &iocb->ki_pos, 0);

	mutex_lock(&ashmem_mutex);

	if (ret > 0)

		asma->file->f_pos = iocb->ki_pos;

out_unlock:

	mutex_unlock(&ashmem_mutex);

	return ret;
@@ -834,7 +821,7 @@ static const struct file_operations ashmem_fops = { 
	.owner = THIS_MODULE,

	.open = ashmem_open,

	.release = ashmem_release,

	.read = ashmem_read,

	.read_iter = ashmem_read_iter,

	.llseek = ashmem_llseek,

	.mmap = ashmem_mmap,

	.unlocked_ioctl = ashmem_ioctl,