Merge "platform: msm: spmi: Fix possible race condition in debugfs" (6ed191c5) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/platform/msm/spmi/spmi-dbgfs.c

+28 −9

Original line number	Diff line number	Diff line
		/* Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
		/* Copyright (c) 2012-2014, 2017, The Linux Foundation. All rights reserved.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 and
		@@ -69,6 +69,7 @@ struct spmi_trans {
		u32 addr; /* 20-bit address: SID + PID + Register offset */
		u32 offset; /* Offset of last read data */
		bool raw_data; /* Set to true for raw data dump */
		struct mutex spmi_dfs_lock; /* Prevent thread concurrency */
		struct spmi_controller *ctrl;
		struct spmi_log_buffer log; / log buffer */
		};
		@@ -168,6 +169,7 @@ static int spmi_dfs_open(struct spmi_ctrl_data ctrl_data, struct file file)
		trans->addr = ctrl_data->addr;
		trans->ctrl = ctrl_data->ctrl;
		trans->offset = trans->addr;
		mutex_init(&trans->spmi_dfs_lock);

		file->private_data = trans;
		return 0;
		@@ -197,6 +199,7 @@ static int spmi_dfs_close(struct inode inode, struct file file)

		if (trans && trans->log) {
		file->private_data = NULL;
		mutex_destroy(&trans->spmi_dfs_lock);
		kfree(trans->log);
		kfree(trans);
		}
		@@ -473,14 +476,21 @@ static ssize_t spmi_dfs_reg_write(struct file file, const char __user buf,
		int cnt = 0;
		u8 *values;
		size_t ret = 0;

		u32 offset;
		char *kbuf;
		struct spmi_trans *trans = file->private_data;
		u32 offset = trans->offset;

		mutex_lock(&trans->spmi_dfs_lock);

		trans = file->private_data;
		offset = trans->offset;

		/* Make a copy of the user data */
		char *kbuf = kmalloc(count + 1, GFP_KERNEL);
		if (!kbuf)
		return -ENOMEM;
		kbuf = kmalloc(count + 1, GFP_KERNEL);
		if (!kbuf) {
		ret = -ENOMEM;
		goto unlock_mutex;
		}

		ret = copy_from_user(kbuf, buf, count);
		if (ret == count) {
		@@ -517,6 +527,8 @@ static ssize_t spmi_dfs_reg_write(struct file file, const char __user buf,

		free_buf:
		kfree(kbuf);
		unlock_mutex:
		mutex_unlock(&trans->spmi_dfs_lock);
		return ret;
		}

		@@ -537,10 +549,13 @@ static ssize_t spmi_dfs_reg_read(struct file file, char __user buf,
		size_t ret;
		size_t len;

		mutex_lock(&trans->spmi_dfs_lock);
		/* Is the the log buffer empty */
		if (log->rpos >= log->wpos) {
		if (get_log_data(trans) <= 0)
		return 0;
		if (get_log_data(trans) <= 0) {
		len = 0;
		goto unlock_mutex;
		}
		}

		len = min(count, log->wpos - log->rpos);
		@@ -548,7 +563,8 @@ static ssize_t spmi_dfs_reg_read(struct file file, char __user buf,
		ret = copy_to_user(buf, &log->data[log->rpos], len);
		if (ret == len) {
		pr_err("error copy SPMI register values to user\n");
		return -EFAULT;
		len = -EFAULT;
		goto unlock_mutex;
		}

		/* 'ret' is the number of bytes not copied */
		@@ -556,6 +572,9 @@ static ssize_t spmi_dfs_reg_read(struct file file, char __user buf,

		*ppos += len;
		log->rpos += len;

		unlock_mutex:
		mutex_unlock(&trans->spmi_dfs_lock);
		return len;
		}