Re: [PATCH] cxl/events: Use a common struct for DRAM and General Media events

From: Fabio M. De Francesco
Date: Fri May 17 2024 - 09:07:21 EST

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In reply to: Ira Weiny: "Re: [PATCH] cxl/events: Use a common struct for DRAM and General Media events"
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On Thursday, May 16, 2024 11:32:59 PM GMT+2 Ira Weiny wrote:
> Fabio M. De Francesco wrote:
> > Use cxl_event_media as a common structure to record information about DRAM
> > and General Media events because it simplifies handling the two events.
> >
> > Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Signed-off-by: Fabio M. De Francesco
> > <fabio.m.de.francesco@xxxxxxxxxxxxxxx>
> > ---
> >
> > drivers/cxl/core/mbox.c | 6 ++--
> > drivers/cxl/core/trace.h | 4 +--
> > include/linux/cxl-event.h | 70 +++++++++++++++---------------------
> > tools/testing/cxl/test/mem.c | 4 +--
> > 4 files changed, 36 insertions(+), 48 deletions(-)
>
> Other than saving 12 lines of code what are we saving with this change?
>
> The addition of media_common implies an additional event type which is not
> in the specification. (perhaps confusing future contributors?) And the
> code is more complex to follow. The decode of the phys_addr field is not
> simplified (which IIRC was the point of this idea.)
>
> I'm probably being dense but I just don't see the need for the
> struct_group complexity here.
>
> Ira

Ira,

I think you are right, there is no need for struct_group here and this code is
unnecessarily complex.

Anyway, for the next version, I'll use the simpler solution showed by Dan in
his comment on v2.

Thanks,

Fabio

>
> > diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> > index 2626f3fff201..ad4d7b0f7f4d 100644
> > --- a/drivers/cxl/core/mbox.c
> > +++ b/drivers/cxl/core/mbox.c
> > @@ -875,16 +875,16 @@ void cxl_event_trace_record(const struct cxl_memdev
> > *cxlmd,>
> > guard(rwsem_read)(&cxl_region_rwsem);
> > guard(rwsem_read)(&cxl_dpa_rwsem);
> >
> > - dpa = le64_to_cpu(evt->common.phys_addr) &
CXL_DPA_MASK;
> > + dpa = le64_to_cpu(evt->media_common.phys_addr) &
CXL_DPA_MASK;
> >
> > cxlr = cxl_dpa_to_region(cxlmd, dpa);
> > if (cxlr)
> >
> > hpa = cxl_trace_hpa(cxlr, cxlmd, dpa);
> >
> > if (event_type == CXL_CPER_EVENT_GEN_MEDIA)
> >
> > trace_cxl_general_media(cxlmd, type, cxlr,
hpa,
> >
> > - &evt-
>gen_media);
> > + &evt-
>media_general);
> >
> > else if (event_type == CXL_CPER_EVENT_DRAM)
> >
> > - trace_cxl_dram(cxlmd, type, cxlr, hpa, &evt-
>dram);
> > + trace_cxl_dram(cxlmd, type, cxlr, hpa, &evt-
>media_dram);
> >
> > }
> >
> > }
> > EXPORT_SYMBOL_NS_GPL(cxl_event_trace_record, CXL);
> >
> > diff --git a/drivers/cxl/core/trace.h b/drivers/cxl/core/trace.h
> > index 07a0394b1d99..2c7293761bb2 100644
> > --- a/drivers/cxl/core/trace.h
> > +++ b/drivers/cxl/core/trace.h
> > @@ -316,7 +316,7 @@ TRACE_EVENT(cxl_generic_event,
> >
> > TRACE_EVENT(cxl_general_media,
> >
> > TP_PROTO(const struct cxl_memdev *cxlmd, enum cxl_event_log_type
log,
> >
> > - struct cxl_region *cxlr, u64 hpa, struct
cxl_event_gen_media *rec),
> > + struct cxl_region *cxlr, u64 hpa, struct
cxl_event_media *rec),
> >
> > TP_ARGS(cxlmd, log, cxlr, hpa, rec),
> >
> > @@ -413,7 +413,7 @@ TRACE_EVENT(cxl_general_media,
> >
> > TRACE_EVENT(cxl_dram,
> >
> > TP_PROTO(const struct cxl_memdev *cxlmd, enum cxl_event_log_type
log,
> >
> > - struct cxl_region *cxlr, u64 hpa, struct
cxl_event_dram *rec),
> > + struct cxl_region *cxlr, u64 hpa, struct
cxl_event_media *rec),
> >
> > TP_ARGS(cxlmd, log, cxlr, hpa, rec),
> >
> > diff --git a/include/linux/cxl-event.h b/include/linux/cxl-event.h
> > index 60b25020281f..e417556cc120 100644
> > --- a/include/linux/cxl-event.h
> > +++ b/include/linux/cxl-event.h
> > @@ -32,41 +32,38 @@ struct cxl_event_generic {
> >
> > * CXL rev 3.0 Section 8.2.9.2.1.1; Table 8-43
> > */
> >
> > #define CXL_EVENT_GEN_MED_COMP_ID_SIZE 0x10
> >
> > -struct cxl_event_gen_media {
> > - struct cxl_event_record_hdr hdr;
> > - __le64 phys_addr;
> > - u8 descriptor;
> > - u8 type;
> > - u8 transaction_type;
> > - u8 validity_flags[2];
> > - u8 channel;
> > - u8 rank;
> > - u8 device[3];
> > - u8 component_id[CXL_EVENT_GEN_MED_COMP_ID_SIZE];
> > - u8 reserved[46];
> > -} __packed;
> > -
> >
> > /*
> >
> > * DRAM Event Record - DER
> > * CXL rev 3.0 section 8.2.9.2.1.2; Table 3-44
> > */
> >
> > #define CXL_EVENT_DER_CORRECTION_MASK_SIZE 0x20
> >
> > -struct cxl_event_dram {
> > +struct cxl_event_media {
> >
> > struct cxl_event_record_hdr hdr;
> >
> > - __le64 phys_addr;
> > - u8 descriptor;
> > - u8 type;
> > - u8 transaction_type;
> > - u8 validity_flags[2];
> > - u8 channel;
> > - u8 rank;
> > - u8 nibble_mask[3];
> > - u8 bank_group;
> > - u8 bank;
> > - u8 row[3];
> > - u8 column[2];
> > - u8 correction_mask[CXL_EVENT_DER_CORRECTION_MASK_SIZE];
> > - u8 reserved[0x17];
> > + struct_group_tagged(cxl_event_media_hdr, media_hdr,
> > + __le64 phys_addr;
> > + u8 descriptor;
> > + u8 type;
> > + u8 transaction_type;
> > + u8 validity_flags[2];
> > + u8 channel;
> > + u8 rank;
> > + );
> > + union {
> > + struct_group(general,
> > + u8 device[3];
> > + u8
component_id[CXL_EVENT_GEN_MED_COMP_ID_SIZE];
> > + u8 gen_reserved[46];
> > + );
> > + struct_group(dram,
> > + u8 nibble_mask[3];
> > + u8 bank_group;
> > + u8 bank;
> > + u8 row[3];
> > + u8 column[2];
> > + u8
correction_mask[CXL_EVENT_DER_CORRECTION_MASK_SIZE];
> > + u8 dram_reserved[0x17];
> > + );
> > + };
> >
> > } __packed;
> >
> > /*
> >
> > @@ -95,21 +92,12 @@ struct cxl_event_mem_module {
> >
> > u8 reserved[0x3d];
> >
> > } __packed;
> >
> > -/*
> > - * General Media or DRAM Event Common Fields
> > - * - provides common access to phys_addr
> > - */
> > -struct cxl_event_common {
> > - struct cxl_event_record_hdr hdr;
> > - __le64 phys_addr;
> > -} __packed;
> > -
> >
> > union cxl_event {
> >
> > struct cxl_event_generic generic;
> >
> > - struct cxl_event_gen_media gen_media;
> > - struct cxl_event_dram dram;
> > + struct cxl_event_media media_general;
> > + struct cxl_event_media media_dram;
> >
> > struct cxl_event_mem_module mem_module;
> >
> > - struct cxl_event_common common;
> > + struct cxl_event_media media_common;
> >
> > } __packed;
> >
> > /*
> >
> > diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
> > index 6584443144de..0a8fd145c391 100644
> > --- a/tools/testing/cxl/test/mem.c
> > +++ b/tools/testing/cxl/test/mem.c
> > @@ -378,7 +378,7 @@ struct cxl_event_record_raw hardware_replace = {
> >
> > struct cxl_test_gen_media {
> >
> > uuid_t id;
> >
> > - struct cxl_event_gen_media rec;
> > + struct cxl_event_media rec;
> >
> > } __packed;
> >
> > struct cxl_test_gen_media gen_media = {
> >
> > @@ -402,7 +402,7 @@ struct cxl_test_gen_media gen_media = {
> >
> > struct cxl_test_dram {
> >
> > uuid_t id;
> >
> > - struct cxl_event_dram rec;
> > + struct cxl_event_media rec;
> >
> > } __packed;
> >
> > struct cxl_test_dram dram = {

Next message: Richard Fitzgerald: "Re: [PATCH 04/11] regmap: kunit: Run sparse cache tests at non-zero register addresses"
Previous message: Alvin Šipraga: "[PATCH 08/13] clk: add AD24xx clock driver"
In reply to: Ira Weiny: "Re: [PATCH] cxl/events: Use a common struct for DRAM and General Media events"
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