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authorJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2017-11-05 13:16:26 +0200
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2018-01-08 12:58:36 +0200
commitaad887f6641145fec2a801da2ce4ed36cf99c6a5 (patch)
tree80d2e496024240dbe3ee26cb43b955696a312013 /drivers/char/tpm/tpm-chip.c
parent58cc1e4faf10a73c4302825ffd37a47d410fc1b5 (diff)
tpm: use struct tpm_chip for tpm_chip_find_get()
Device number (the character device index) is not a stable identifier for a TPM chip. That is the reason why every call site passes TPM_ANY_NUM to tpm_chip_find_get(). This commit changes the API in a way that instead a struct tpm_chip instance is given and NULL means the default chip. In addition, this commit refines the documentation to be up to date with the implementation. Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> (@chip_num -> @chip part) Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Reviewed-by: Jason Gunthorpe <jgg@ziepe.ca> Tested-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Diffstat (limited to 'drivers/char/tpm/tpm-chip.c')
-rw-r--r--drivers/char/tpm/tpm-chip.c24
1 files changed, 14 insertions, 10 deletions
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index a114e8f7fb90..bab9c14e040c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -81,21 +81,26 @@ void tpm_put_ops(struct tpm_chip *chip)
EXPORT_SYMBOL_GPL(tpm_put_ops);
/**
- * tpm_chip_find_get() - return tpm_chip for a given chip number
- * @chip_num: id to find
+ * tpm_chip_find_get() - find and reserve a TPM chip
+ * @chip: a &struct tpm_chip instance, %NULL for the default chip
*
- * The return'd chip has been tpm_try_get_ops'd and must be released via
- * tpm_put_ops
+ * Finds a TPM chip and reserves its class device and operations. The chip must
+ * be released with tpm_chip_put_ops() after use.
+ *
+ * Return:
+ * A reserved &struct tpm_chip instance.
+ * %NULL if a chip is not found.
+ * %NULL if the chip is not available.
*/
-struct tpm_chip *tpm_chip_find_get(int chip_num)
+struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
{
- struct tpm_chip *chip, *res = NULL;
+ struct tpm_chip *res = NULL;
+ int chip_num = 0;
int chip_prev;
mutex_lock(&idr_lock);
- if (chip_num == TPM_ANY_NUM) {
- chip_num = 0;
+ if (!chip) {
do {
chip_prev = chip_num;
chip = idr_get_next(&dev_nums_idr, &chip_num);
@@ -105,8 +110,7 @@ struct tpm_chip *tpm_chip_find_get(int chip_num)
}
} while (chip_prev != chip_num);
} else {
- chip = idr_find(&dev_nums_idr, chip_num);
- if (chip && !tpm_try_get_ops(chip))
+ if (!tpm_try_get_ops(chip))
res = chip;
}

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