| Message ID | 20180622164613.1609313-3-stefanb@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jun 22, 2018 at 12:46:11PM -0400, Stefan Berger wrote: > Implement tpm_chip_find() for other subsystems to find a TPM chip and > get a reference to that chip. > > Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> > drivers/char/tpm/tpm-chip.c | 27 +++++++++++++++++++++++++++ > include/linux/tpm.h | 5 +++++ > 2 files changed, 32 insertions(+) > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > index 4e83695af068..2520555b1e17 100644 > +++ b/drivers/char/tpm/tpm-chip.c > @@ -81,6 +81,33 @@ void tpm_put_ops(struct tpm_chip *chip) > EXPORT_SYMBOL_GPL(tpm_put_ops); > > /** > + * tpm_chip_find() - find a TPM chip and get a reference to it > + */ > +struct tpm_chip *tpm_chip_find(void) I feel like this should be called 'tpm_default_chip()' > +{ > + struct tpm_chip *chip, *res = NULL; > + int chip_num = 0; > + int chip_prev; > + > + mutex_lock(&idr_lock); > + > + do { > + chip_prev = chip_num; > + chip = idr_get_next(&dev_nums_idr, &chip_num); > + if (chip) { > + get_device(&chip->dev); > + res = chip; > + break; > + } > + } while (chip_prev != chip_num); > + > + mutex_unlock(&idr_lock); And what was tpm_chip_find_get should just call this function.. Jason
On 06/22/2018 04:43 PM, Jason Gunthorpe wrote: > On Fri, Jun 22, 2018 at 12:46:11PM -0400, Stefan Berger wrote: >> Implement tpm_chip_find() for other subsystems to find a TPM chip and >> get a reference to that chip. >> >> Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> >> drivers/char/tpm/tpm-chip.c | 27 +++++++++++++++++++++++++++ >> include/linux/tpm.h | 5 +++++ >> 2 files changed, 32 insertions(+) >> >> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c >> index 4e83695af068..2520555b1e17 100644 >> +++ b/drivers/char/tpm/tpm-chip.c >> @@ -81,6 +81,33 @@ void tpm_put_ops(struct tpm_chip *chip) >> EXPORT_SYMBOL_GPL(tpm_put_ops); >> >> /** >> + * tpm_chip_find() - find a TPM chip and get a reference to it >> + */ >> +struct tpm_chip *tpm_chip_find(void) > I feel like this should be called 'tpm_default_chip()' > >> +{ >> + struct tpm_chip *chip, *res = NULL; >> + int chip_num = 0; >> + int chip_prev; >> + >> + mutex_lock(&idr_lock); >> + >> + do { >> + chip_prev = chip_num; >> + chip = idr_get_next(&dev_nums_idr, &chip_num); >> + if (chip) { >> + get_device(&chip->dev); >> + res = chip; >> + break; >> + } >> + } while (chip_prev != chip_num); >> + >> + mutex_unlock(&idr_lock); > And what was tpm_chip_find_get should just call this function.. And then after that each time tpm_get_ops() ? > > Jason >
On Fri, Jun 22, 2018 at 04:45:47PM -0400, Stefan Berger wrote: > On 06/22/2018 04:43 PM, Jason Gunthorpe wrote: > >On Fri, Jun 22, 2018 at 12:46:11PM -0400, Stefan Berger wrote: > >>Implement tpm_chip_find() for other subsystems to find a TPM chip and > >>get a reference to that chip. > >> > >>Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> > >> drivers/char/tpm/tpm-chip.c | 27 +++++++++++++++++++++++++++ > >> include/linux/tpm.h | 5 +++++ > >> 2 files changed, 32 insertions(+) > >> > >>diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > >>index 4e83695af068..2520555b1e17 100644 > >>+++ b/drivers/char/tpm/tpm-chip.c > >>@@ -81,6 +81,33 @@ void tpm_put_ops(struct tpm_chip *chip) > >> EXPORT_SYMBOL_GPL(tpm_put_ops); > >> /** > >>+ * tpm_chip_find() - find a TPM chip and get a reference to it > >>+ */ > >>+struct tpm_chip *tpm_chip_find(void) > >I feel like this should be called 'tpm_default_chip()' > > > >>+{ > >>+ struct tpm_chip *chip, *res = NULL; > >>+ int chip_num = 0; > >>+ int chip_prev; > >>+ > >>+ mutex_lock(&idr_lock); > >>+ > >>+ do { > >>+ chip_prev = chip_num; > >>+ chip = idr_get_next(&dev_nums_idr, &chip_num); > >>+ if (chip) { > >>+ get_device(&chip->dev); > >>+ res = chip; > >>+ break; > >>+ } > >>+ } while (chip_prev != chip_num); > >>+ > >>+ mutex_unlock(&idr_lock); > >And what was tpm_chip_find_get should just call this function.. > And then after that each time tpm_get_ops() ? It is best to keep the tpm_chip_find_get/tpm_put_ops for internal use as it also manages the kref lifetime of chip in a subtle way, it relies on the ops lock not the kref to keep the memory valid when it has a NULL parameter.. Something like this: struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip) { int rc; if (chip) { if (!tpm_try_get_ops(chip)) return NULL; return chip; } chip = tpm_default_chip(); rc = tpm_try_get_ops(chip)); put_device(&chip->dev); if (rc) return NULL; return chip; } Jason
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 4e83695af068..2520555b1e17 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -81,6 +81,33 @@ void tpm_put_ops(struct tpm_chip *chip) EXPORT_SYMBOL_GPL(tpm_put_ops); /** + * tpm_chip_find() - find a TPM chip and get a reference to it + */ +struct tpm_chip *tpm_chip_find(void) +{ + struct tpm_chip *chip, *res = NULL; + int chip_num = 0; + int chip_prev; + + mutex_lock(&idr_lock); + + do { + chip_prev = chip_num; + chip = idr_get_next(&dev_nums_idr, &chip_num); + if (chip) { + get_device(&chip->dev); + res = chip; + break; + } + } while (chip_prev != chip_num); + + mutex_unlock(&idr_lock); + + return res; +} +EXPORT_SYMBOL_GPL(tpm_chip_find); + +/** * tpm_get_ops() - find and reserve a TPM chip * @chip: a &struct tpm_chip instance, %NULL for the default chip * diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 06639fb6ab85..a9c65f5670b6 100644 --- a/include/linux/tpm.h +++ b/include/linux/tpm.h @@ -61,6 +61,7 @@ extern int tpm_seal_trusted(struct tpm_chip *chip, extern int tpm_unseal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload, struct trusted_key_options *options); +extern struct tpm_chip *tpm_chip_find(void); #else static inline int tpm_is_tpm2(struct tpm_chip *chip) { @@ -96,5 +97,9 @@ static inline int tpm_unseal_trusted(struct tpm_chip *chip, { return -ENODEV; } +static inline struct tpm_chip *tpm_chip_find(void) +{ + return NULL; +} #endif #endif
Implement tpm_chip_find() for other subsystems to find a TPM chip and get a reference to that chip. Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com> --- drivers/char/tpm/tpm-chip.c | 27 +++++++++++++++++++++++++++ include/linux/tpm.h | 5 +++++ 2 files changed, 32 insertions(+)