relay: simplify relay_file_read() (a7c22421) · Commits · e / devices / android_kernel_oneplus_sm7250

kernel/relay.c

+20 −58

Original line number	Diff line number	Diff line
		@@ -1121,51 +1121,23 @@ static size_t relay_file_read_end_pos(struct rchan_buf *buf,
		return end_pos;
		}

		/*
		* subbuf_read_actor - read up to one subbuf's worth of data
		*/
		static int subbuf_read_actor(size_t read_start,
		struct rchan_buf *buf,
		size_t avail,
		read_descriptor_t *desc)
		{
		void *from;
		int ret = 0;

		from = buf->start + read_start;
		ret = avail;
		if (copy_to_user(desc->arg.buf, from, avail)) {
		desc->error = -EFAULT;
		ret = 0;
		}
		desc->arg.data += ret;
		desc->written += ret;
		desc->count -= ret;

		return ret;
		}

		typedef int (*subbuf_actor_t) (size_t read_start,
		struct rchan_buf *buf,
		size_t avail,
		read_descriptor_t *desc);

		/*
		* relay_file_read_subbufs - read count bytes, bridging subbuf boundaries
		*/
		static ssize_t relay_file_read_subbufs(struct file filp, loff_t ppos,
		subbuf_actor_t subbuf_actor,
		read_descriptor_t *desc)
		static ssize_t relay_file_read(struct file *filp,
		char __user *buffer,
		size_t count,
		loff_t *ppos)
		{
		struct rchan_buf *buf = filp->private_data;
		size_t read_start, avail;
		size_t written = 0;
		int ret;

		if (!desc->count)
		if (!count)
		return 0;

		inode_lock(file_inode(filp));
		do {
		void *from;

		if (!relay_file_read_avail(buf, *ppos))
		break;

		@@ -1174,32 +1146,22 @@ static ssize_t relay_file_read_subbufs(struct file filp, loff_t ppos,
		if (!avail)
		break;

		avail = min(desc->count, avail);
		ret = subbuf_actor(read_start, buf, avail, desc);
		if (desc->error < 0)
		avail = min(count, avail);
		from = buf->start + read_start;
		ret = avail;
		if (copy_to_user(buffer, from, avail))
		break;

		if (ret) {
		buffer += ret;
		written += ret;
		count -= ret;

		relay_file_read_consume(buf, read_start, ret);
		*ppos = relay_file_read_end_pos(buf, read_start, ret);
		}
		} while (desc->count && ret);
		} while (count);
		inode_unlock(file_inode(filp));

		return desc->written;
		}

		static ssize_t relay_file_read(struct file *filp,
		char __user *buffer,
		size_t count,
		loff_t *ppos)
		{
		read_descriptor_t desc;
		desc.written = 0;
		desc.count = count;
		desc.arg.buf = buffer;
		desc.error = 0;
		return relay_file_read_subbufs(filp, ppos, subbuf_read_actor, &desc);
		return written;
		}

		static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)