[PATCH] tty: serial: cpm_uart: Fix behaviour for non existing GPIOs
devm_gpiod_get_index() doesn't return NULL but -ENOENT when the
requested GPIO doesn't exist, leading to the following messages:
[2.742468] gpiod_direction_input: invalid GPIO (errorpointer)
[2.748147] can't set direction for gpio #2: -2
[2.753081] gpiod_direction_input: invalid GPIO (errorpointer)
[2.758724] can't set direction for gpio #3: -2
[2.763666] gpiod_direction_output: invalid GPIO (errorpointer)
[2.769394] can't set direction for gpio #4: -2
[2.774341] gpiod_direction_input: invalid GPIO (errorpointer)
[2.779981] can't set direction for gpio #5: -2
[2.784545] ff000a20.serial: ttyCPM1 at MMIO 0xfff00a20 (irq = 39, base_baud
= 825) is a CPM UART
Use IS_ERR_OR_NULL() to properly check gpiod validity.
Fixes: 97cbaf2c829b ("tty: serial: cpm_uart: Convert to use GPIO descriptors")
Cc: sta...@vger.kernel.org
Cc: Linus Walleij
Signed-off-by: Christophe Leroy
---
drivers/tty/serial/cpm_uart/cpm_uart_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
index a04f74d2e854..3cbe24802296 100644
--- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c
+++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c
@@ -1217,7 +1217,7 @@ static int cpm_uart_init_port(struct device_node *np,
gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
- if (gpiod) {
+ if (!IS_ERR_OR_NULL(gpiod)) {
if (i == GPIO_RTS || i == GPIO_DTR)
ret = gpiod_direction_output(gpiod, 0);
else
--
2.25.0
Re: [PATCH v10 4/6] powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl()
Hi Ira and Dan,
Thanks for reviewing this patch. Have updated the patch based on your
feedback to upadate cmd_rc only when the nd_cmd was handled and return
'0' in that case.
Other errors in case the nd_cmd was unrecognized or invalid result in
error returned from this functions as you suggested.
~ Vaibhav
Dan Williams writes:
> On Fri, Jun 5, 2020 at 10:13 AM Ira Weiny wrote:
>>
>> On Fri, Jun 05, 2020 at 05:11:34AM +0530, Vaibhav Jain wrote:
>> > Since papr_scm_ndctl() can be called from outside papr_scm, its
>> > exposed to the possibility of receiving NULL as value of 'cmd_rc'
>> > argument. This patch updates papr_scm_ndctl() to protect against such
>> > possibility by assigning it pointer to a local variable in case cmd_rc
>> > == NULL.
>> >
>> > Finally the patch also updates the 'default' clause of the switch-case
>> > block removing a 'return' statement thereby ensuring that value of
>> > 'cmd_rc' is always logged when papr_scm_ndctl() returns.
>> >
>> > Cc: "Aneesh Kumar K . V"
>> > Cc: Dan Williams
>> > Cc: Michael Ellerman
>> > Cc: Ira Weiny
>> > Signed-off-by: Vaibhav Jain
>> > ---
>> > Changelog:
>> >
>> > v9..v10
>> > * New patch in the series
>>
>> Thanks for making this a separate patch it is easier to see what is going on
>> here.
>>
>> > ---
>> > arch/powerpc/platforms/pseries/papr_scm.c | 10 --
>> > 1 file changed, 8 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/arch/powerpc/platforms/pseries/papr_scm.c
>> > b/arch/powerpc/platforms/pseries/papr_scm.c
>> > index 0c091622b15e..6512fe6a2874 100644
>> > --- a/arch/powerpc/platforms/pseries/papr_scm.c
>> > +++ b/arch/powerpc/platforms/pseries/papr_scm.c
>> > @@ -355,11 +355,16 @@ static int papr_scm_ndctl(struct
>> > nvdimm_bus_descriptor *nd_desc,
>> > {
>> > struct nd_cmd_get_config_size *get_size_hdr;
>> > struct papr_scm_priv *p;
>> > + int rc;
>> >
>> > /* Only dimm-specific calls are supported atm */
>> > if (!nvdimm)
>> > return -EINVAL;
>> >
>> > + /* Use a local variable in case cmd_rc pointer is NULL */
>> > + if (!cmd_rc)
>> > + cmd_rc = &rc;
>> > +
>>
>> This protects you from the NULL. However...
>>
>> > p = nvdimm_provider_data(nvdimm);
>> >
>> > switch (cmd) {
>> > @@ -381,12 +386,13 @@ static int papr_scm_ndctl(struct
>> > nvdimm_bus_descriptor *nd_desc,
>> > break;
>> >
>> > default:
>> > - return -EINVAL;
>> > + dev_dbg(&p->pdev->dev, "Unknown command = %d\n", cmd);
>> > + *cmd_rc = -EINVAL;
>>
>> ... I think you are conflating rc and cmd_rc...
>>
>> > }
>> >
>> > dev_dbg(&p->pdev->dev, "returned with cmd_rc = %d\n", *cmd_rc);
>> >
>> > - return 0;
>> > + return *cmd_rc;
>>
>> ... this changes the behavior of the current commands. Now if the underlying
>> papr_scm_meta_[get|set]() fails you return that failure as rc rather than 0.
>>
>> Is that ok?
>
> The expectation is that rc is "did the command get sent to the device,
> or did it fail for 'transport' reasons". The role of cmd_rc is to
> translate the specific status response of the command into a common
> error code. The expectations are:
>
> rc < 0: Error code, Linux terminated the ioctl before talking to hardware
>
> rc == 0: Linux successfully submitted the command to hardware, cmd_rc
> is valid for command specific response
>
> rc > 0: Linux successfully submitted the command, but detected that
> only a subset of the data was accepted for "write"-style commands, or
> that only subset of data was returned for "read"-style commands. I.e.
> short-write / short-read semantics. cmd_rc is valid in this case and
> its up to userspace to determine if a short transfer is an error or
> not.
>
>> Also 'logging cmd_rc' in the invalid cmd case does not seem quite right
>> unless
>> you really want rc to be cmd_rc.
>>
>> The architecture is designed to separate errors which occur in the kernel vs
>> errors in the firmware/dimm. Are they always the same? The current code
>> differentiates them.
>
> Yeah, they're distinct, transport vs end-point / command-specific
> status returns.
--
Cheers
~ Vaibhav
Re: [PATCH v10 6/6] powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
Ira Weiny writes:
> On Fri, Jun 05, 2020 at 05:11:36AM +0530, Vaibhav Jain wrote:
>> This patch implements support for PDSM request 'PAPR_PDSM_HEALTH'
>> that returns a newly introduced 'struct nd_papr_pdsm_health' instance
>> containing dimm health information back to user space in response to
>> ND_CMD_CALL. This functionality is implemented in newly introduced
>> papr_pdsm_health() that queries the nvdimm health information and
>> then copies this information to the package payload whose layout is
>> defined by 'struct nd_papr_pdsm_health'.
>>
>> Cc: "Aneesh Kumar K . V"
>> Cc: Dan Williams
>> Cc: Michael Ellerman
>> Cc: Ira Weiny
>> Signed-off-by: Vaibhav Jain
>> ---
>> Changelog:
>>
>> v9..v10:
>> * Removed code in papr_pdsm_health that performed validation on pdsm
>> payload version and corrosponding struct and defines used for
>> validation of payload version.
>> * Dropped usage of struct papr_pdsm_health in 'struct
>> papr_scm_priv'. Instead papr_psdm_health() now uses
>> 'papr_scm_priv.health_bitmap' to populate the pdsm payload.
>> * Above change also fixes the problem where this patch was removing
>> the code that was previously introduced in this patch-series.
>> [ Ira ]
>> * Introduced a new def ND_PDSM_ENVELOPE_HDR_SIZE that indicates the
>> space allocated to 'struct nd_pdsm_cmd_pkg' fields except 'struct
>> nd_cmd_pkg'. This def is useful in validating payload sizes.
>> * Reworked papr_pdsm_health() to enforce a specific payload size for
>> 'PAPR_PDSM_HEALTH' pdsm request.
>>
>> Resend:
>> * Added ack from Aneesh.
>>
>> v8..v9:
>> * s/PAPR_SCM_PDSM_HEALTH/PAPR_PDSM_HEALTH/g [ Dan , Aneesh ]
>> * s/PAPR_SCM_PSDM_DIMM_*/PAPR_PDSM_DIMM_*/g
>> * Renamed papr_scm_get_health() to papr_psdm_health()
>> * Updated patch description to replace papr-scm dimm with nvdimm.
>>
>> v7..v8:
>> * None
>>
>> Resend:
>> * None
>>
>> v6..v7:
>> * Updated flags_show() to use seq_buf_printf(). [Mpe]
>> * Updated papr_scm_get_health() to use newly introduced
>> __drc_pmem_query_health() bypassing the cache [Mpe].
>>
>> v5..v6:
>> * Added attribute '__packed' to 'struct nd_papr_pdsm_health_v1' to
>> gaurd against possibility of different compilers adding different
>> paddings to the struct [ Dan Williams ]
>>
>> * Updated 'struct nd_papr_pdsm_health_v1' to use __u8 instead of
>> 'bool' and also updated drc_pmem_query_health() to take this into
>> account. [ Dan Williams ]
>>
>> v4..v5:
>> * None
>>
>> v3..v4:
>> * Call the DSM_PAPR_SCM_HEALTH service function from
>> papr_scm_service_dsm() instead of papr_scm_ndctl(). [Aneesh]
>>
>> v2..v3:
>> * Updated struct nd_papr_scm_dimm_health_stat_v1 to use '__xx' types
>> as its exported to the userspace [Aneesh]
>> * Changed the constants DSM_PAPR_SCM_DIMM_XX indicating dimm health
>> from enum to #defines [Aneesh]
>>
>> v1..v2:
>> * New patch in the series
>> ---
>> arch/powerpc/include/uapi/asm/papr_pdsm.h | 33 +++
>> arch/powerpc/platforms/pseries/papr_scm.c | 70 +++
>> 2 files changed, 103 insertions(+)
>>
>> diff --git a/arch/powerpc/include/uapi/asm/papr_pdsm.h
>> b/arch/powerpc/include/uapi/asm/papr_pdsm.h
>> index 8b1a4f8fa316..c4c990ede5d4 100644
>> --- a/arch/powerpc/include/uapi/asm/papr_pdsm.h
>> +++ b/arch/powerpc/include/uapi/asm/papr_pdsm.h
>> @@ -71,12 +71,17 @@ struct nd_pdsm_cmd_pkg {
>> __u8 payload[]; /* In/Out: Sub-cmd data buffer */
>> } __packed;
>>
>> +/* Calculate size used by the pdsm header fields minus 'struct nd_cmd_pkg'
>> */
>> +#define ND_PDSM_ENVELOPE_HDR_SIZE \
>> +(sizeof(struct nd_pdsm_cmd_pkg) - sizeof(struct nd_cmd_pkg))
>> +
[ ]
>
> This is kind of a weird name for this.
>
> Isn't this just the ND PDSM header size? What is 'envelope' mean
> here?
Was referring to 'nd_cmd_pkg' envelop here. But yes removing 'ENVELOPE'
should make it more concise. Have already done this in v11 of this patch.
>
>> /*
>> * Methods to be embedded in ND_CMD_CALL request. These are sent to the
>> kernel
>> * via 'nd_pdsm_cmd_pkg.hdr.nd_command' member of the ioctl struct
>> */
>> enum papr_pdsm {
>> PAPR_PDSM_MIN = 0x0,
>> +PAPR_PDSM_HEALTH,
>> PAPR_PDSM_MAX,
>> };
>>
>> @@ -95,4 +100,32 @@ static inline void *pdsm_cmd_to_payload(struct
>> nd_pdsm_cmd_pkg *pcmd)
>> return (void *)(pcmd->payload);
>> }
>>
>> +/* Various nvdimm health indicators */
>> +#define PAPR_PDSM_DIMM_HEALTHY 0
>> +#define PAPR_PDSM_DIMM_UNHEALTHY 1
>> +#define PAPR_PDSM_DIMM_CRITICAL 2
>> +#define PAPR_PDSM_DIMM_FATAL 3
>> +
>> +/*
>> + * Struct exchanged between kernel & ndctl in for PAPR_PDSM_HEALTH
>> + * Various flags indicate the health status of the dimm.
>> + *
>> + * dimm_unarmed : Dimm not armed. So contents wont persist.
>> + * dimm_bad_shutdown: Previous shutdown did not persist contents.
>> + * dimm_bad_restore : Contents from previous shutdown werent restored.
>> + * dimm_scrubb
Re: [PATCH v10 6/6] powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
On Sat, Jun 06, 2020 at 06:04:11PM +0530, Vaibhav Jain wrote:
> >> + /* update health struct with various flags derived from health bitmap */
> >> + health = (struct nd_papr_pdsm_health) {
> >> + .dimm_unarmed = p->health_bitmap & PAPR_PMEM_UNARMED_MASK,
> >> + .dimm_bad_shutdown = p->health_bitmap &
> >> PAPR_PMEM_BAD_SHUTDOWN_MASK,
> >> + .dimm_bad_restore = p->health_bitmap &
> >> PAPR_PMEM_BAD_RESTORE_MASK,
> >> + .dimm_encrypted = p->health_bitmap & PAPR_PMEM_ENCRYPTED,
> >> + .dimm_locked = p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >> + .dimm_scrubbed = p->health_bitmap &
> >> PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >
> > Are you sure these work? These are not assignments to a bool so I don't
> > think
> > gcc will do what you want here.
> Yeah, somehow this slipped by and didnt show up in my tests. I checked
> the assembly dump and seems GCC was silently skipping initializing these
> fields without making any noise.
It's not "skipping" that, it initialises the field to 0, just like your
code said it should :-)
If you think GCC should warn for this, please open a PR? It is *normal*
for bit-fields to be truncated from what is assigned to it, but maybe we
could warn for it in the 1-bit case (we currently don't seem to, even
when the bit-field type is _Bool).
Thanks,
Segher
