tpm: Use container_of to locate the tpm_chip in tpm_open (58c09e21) · Commits · 戴 / test

misc_open sets the file->private_date to the misc_dev when calling open. We can use container_of to go from the misc_dev back to the tpm_chip. Future clean ups will move tpm_open into a new file and this change means we do not have to export the tpm_chip list. Signed-off-by:

Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Reviewed-by:

Joel Schopp <jschopp@linux.vnet.ibm.com> Reviewed-by:

Peter Huewe <peterhuewe@gmx.de> Acked-by:

Ashley Lai <adlai@linux.vnet.ibm.com> Signed-off-by:

Peter Huewe <peterhuewe@gmx.de>

drivers/char/tpm/tpm.c

+4 −17

Original line number	Diff line number	Diff line
		@@ -1170,38 +1170,25 @@ EXPORT_SYMBOL_GPL(wait_for_tpm_stat);
		*/
		int tpm_open(struct inode inode, struct file file)
		{
		int minor = iminor(inode);
		struct tpm_chip chip = NULL, pos;

		rcu_read_lock();
		list_for_each_entry_rcu(pos, &tpm_chip_list, list) {
		if (pos->vendor.miscdev.minor == minor) {
		chip = pos;
		get_device(chip->dev);
		break;
		}
		}
		rcu_read_unlock();

		if (!chip)
		return -ENODEV;
		struct miscdevice *misc = file->private_data;
		struct tpm_chip *chip = container_of(misc, struct tpm_chip,
		vendor.miscdev);

		if (test_and_set_bit(0, &chip->is_open)) {
		dev_dbg(chip->dev, "Another process owns this TPM\n");
		put_device(chip->dev);
		return -EBUSY;
		}

		chip->data_buffer = kzalloc(TPM_BUFSIZE, GFP_KERNEL);
		if (chip->data_buffer == NULL) {
		clear_bit(0, &chip->is_open);
		put_device(chip->dev);
		return -ENOMEM;
		}

		atomic_set(&chip->data_pending, 0);

		file->private_data = chip;
		get_device(chip->dev);
		return 0;
		}
		EXPORT_SYMBOL_GPL(tpm_open);

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