[PATCH 05/15] tpm: Use container_of to locate the tpm_chip in tpm_open

From: Peter Huewe
Date: Tue Oct 22 2013 - 13:54:40 EST


From: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Joel Schopp <jschopp@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Peter Huewe <peterhuewe@xxxxxx>
Acked-by: Ashley Lai <adlai@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Huewe <peterhuewe@xxxxxx>
---
drivers/char/tpm/tpm.c | 21 ++++-----------------
1 files changed, 4 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 71eb8c7..c3ab508 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -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);
--
1.7.5.4

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