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From: Alison Schofield <alison.schofield@intel.com>
To: Dave Jiang <dave.jiang@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>,
	nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org
Subject: Re: [ndctl PATCH v7 5/7] cxl/list: collect and parse media_error records
Date: Wed, 28 Feb 2024 18:45:09 -0800	[thread overview]
Message-ID: <Zd/vtfjCoLvjTT1q@aschofie-mobl2> (raw)
In-Reply-To: <b3f23b92-99f6-404e-aed2-19a8f5ceb43f@intel.com>

On Thu, Feb 08, 2024 at 09:50:27AM -0700, Dave Jiang wrote:
> 

Hi Dave,

Sorry I missed this in v8. Picking up for v9.  
See a question below -


snip
> 
> > +static const char *
> > +find_decoder_name(struct poison_ctx *ctx, const char *name, u64 addr)
> > +{
> > +	struct cxl_memdev *memdev = ctx->memdev;
> > +	struct cxl_memdev_mapping *mapping;
> > +	struct cxl_endpoint *endpoint;
> > +	struct cxl_decoder *decoder;
> > +	struct cxl_port *port;
> > +	u64 start, end;
> > +
> > +	if (memdev)
> > +		goto find_decoder;
> > +
> > +	cxl_mapping_foreach(ctx->region, mapping) {
> > +		decoder = cxl_mapping_get_decoder(mapping);
> > +		if (!decoder)
> > +			continue;
> > +
> > +		memdev = cxl_decoder_get_memdev(decoder);
> > +		if (strcmp(name, cxl_memdev_get_devname(memdev)) == 0)
> > +			break;
> > +
> > +		memdev = NULL;
> > +	}
> > +
> > +find_decoder:
> 
> Would it be cleaner to move this block into a helper function? Don't really care for goto blocks that are not error handling paths.

Done. Added a __find_memdev.

> 
> > +	if (!memdev)
> > +		return NULL;
> > +
> > +	endpoint = cxl_memdev_get_endpoint(memdev);
> > +	port = cxl_endpoint_get_port(endpoint);
> > +
> > +	cxl_decoder_foreach(port, decoder) {
> > +		start =  cxl_decoder_get_resource(decoder);
> > +		end = start + cxl_decoder_get_size(decoder) - 1;
> > +		if (start <= addr && addr <= end)
> > +			return cxl_decoder_get_devname(decoder);
> > +	}
> > +
> > +	return NULL;

And, with another look - cleaned up the above indented/hidden
successful return ;)


> > +}
> > +
> > +int poison_event_to_json(struct tep_event *event, struct tep_record *record,
> > +			 void *ctx)
> > +{
> > +	struct poison_ctx *p_ctx = (struct poison_ctx *)ctx;
> > +	struct json_object *jobj, *jp, *jpoison = p_ctx->jpoison;
> > +	unsigned long flags = p_ctx->flags;
> > +	bool overflow = false;
> > +	unsigned char *data;
> > +	const char *name;
> > +	int pflags;
> > +	char *str;
> > +
> > +	jp = json_object_new_object();
> > +	if (!jp)
> > +		return -ENOMEM;
> > +
> > +	/* Skip records not in this region when listing by region */
> > +	name = p_ctx->region ? cxl_region_get_devname(p_ctx->region) : NULL;
> > +	if (name)
> > +		str = cxl_get_field_string(event, record, "region");
> > +
> > +	if ((name) && (strcmp(name, str) != 0)) {
> > +		json_object_put(jp);
> > +		return 0;
> > +	}
> > +
> > +	/* Include endpoint decoder name with hpa, when present */
> > +	name = cxl_get_field_string(event, record, "memdev");
> > +	data = cxl_get_field_data(event, record, "hpa");
> > +	if (*(uint64_t *)data != ULLONG_MAX)
> > +		name = find_decoder_name(p_ctx, name, *(uint64_t *)data);
> > +	else
> > +		name = NULL;
> > +
> > +	if (name) {
> > +		jobj = json_object_new_string(name);
> > +		if (jobj)
> > +			json_object_object_add(jp, "decoder", jobj);
> > +
> > +		jobj = util_json_object_hex(*(uint64_t *)data, flags);
> > +		if (jobj)
> > +			json_object_object_add(jp, "hpa", jobj);
> > +	}
> > +
> > +	data = cxl_get_field_data(event, record, "dpa");
> > +	jobj = util_json_object_hex(*(uint64_t *)data, flags);
> > +	if (jobj)
> > +		json_object_object_add(jp, "dpa", jobj);
> > +
> > +	data = cxl_get_field_data(event, record, "dpa_length");
> > +	jobj = util_json_object_size(*(uint32_t *)data, flags);
> > +	if (jobj)
> > +		json_object_object_add(jp, "length", jobj);
> > +
> > +	str = cxl_get_field_string(event, record, "source");
> > +	switch (*(uint8_t *)str) {
> 
> This causes reading confusion when it looks like the code is retrieving a string and then compare as an integer. Should this be done through cxl_get_field_data()?
> 

Did a couple of things here -
reworked the helpers to give exactly what is needed here,
ie int, u64 or string. That gets rid of all the casting.
It also led to a bit more error checking on return value,
so bonus goodness.


> > +	case CXL_POISON_SOURCE_UNKNOWN:
> > +		jobj = json_object_new_string("Unknown");
> > +		break;
> > +	case CXL_POISON_SOURCE_EXTERNAL:
> > +		jobj = json_object_new_string("External");
> > +		break;
> > +	case CXL_POISON_SOURCE_INTERNAL:
> > +		jobj = json_object_new_string("Internal");
> > +		break;
> > +	case CXL_POISON_SOURCE_INJECTED:
> > +		jobj = json_object_new_string("Injected");
> > +		break;
> > +	case CXL_POISON_SOURCE_VENDOR:
> > +		jobj = json_object_new_string("Vendor");
> > +		break;
> > +	default:
> > +		jobj = json_object_new_string("Reserved");
> > +	}
> > +	if (jobj)
> > +		json_object_object_add(jp, "source", jobj);
> > +
> > +	str = cxl_get_field_string(event, record, "flags");
> > +	pflags = *(uint8_t *)str;
> 
> Same as above comment here

Gone. All the values that can be held in "int" are fetched
using a cxl_get_field_int().

snip
> > +static struct json_object *
> > +util_cxl_poison_events_to_json(struct tracefs_instance *inst,
> > +			       struct poison_ctx *p_ctx)
> > +{
> > +	struct event_ctx ectx = {
> > +		.event_name = "cxl_poison",
> > +		.event_pid = getpid(),
> > +		.system = "cxl",
> > +		.private_ctx = p_ctx,
> > +		.parse_event = poison_event_to_json,
> > +	};
> > +	int rc = 0;
> > +
> > +	p_ctx->jpoison = json_object_new_array();
> > +	if (!p_ctx->jpoison)
> > +		return NULL;
> > +
> > +	rc = cxl_parse_events(inst, &ectx);
> > +	if (rc < 0) {
> > +		fprintf(stderr, "Failed to parse events: %d\n", rc);
> > +		json_object_put(p_ctx->jpoison);
> > +		return NULL;
> 
> Maybe a goto err here and the next error path may now be warranted?
> > +	}
> > +
> > +	if (json_object_array_length(p_ctx->jpoison) == 0) {
> > +		json_object_put(p_ctx->jpoison);
> > +		return NULL;
> > +	}
> > +
> > +	return p_ctx->jpoison;
> > +}

Not sure what you suggest here. I can combine the err cases like
this:

if ((rc < 0) || json_object_array_length(p_ctx->jpoison) == 0) {
	fprintf(stderr, "Failed to parse events: %d\n", rc);
	json_object_put(p_ctx->jpoison);
	return NULL;
}

Or (and) something else?


  reply	other threads:[~2024-02-29  2:45 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-08  1:01 [ndctl PATCH v7 0/7] Support poison list retrieval alison.schofield
2024-02-08  1:01 ` [ndctl PATCH v7 1/7] libcxl: add interfaces for GET_POISON_LIST mailbox commands alison.schofield
2024-02-08  1:01 ` [ndctl PATCH v7 2/7] cxl: add an optional pid check to event parsing alison.schofield
2024-02-08  1:01 ` [ndctl PATCH v7 3/7] cxl/event_trace: add a private context for private parsers alison.schofield
2024-02-08  1:01 ` [ndctl PATCH v7 4/7] cxl/event_trace: add helpers get_field_[string|data]() alison.schofield
2024-02-08  1:01 ` [ndctl PATCH v7 5/7] cxl/list: collect and parse media_error records alison.schofield
2024-02-08 16:50   ` Dave Jiang
2024-02-29  2:45     ` Alison Schofield [this message]
2024-02-08  1:01 ` [ndctl PATCH v7 6/7] cxl/list: add --media-errors option to cxl list alison.schofield
2024-02-08 16:51   ` Dave Jiang
2024-02-08  1:01 ` [ndctl PATCH v7 7/7] cxl/test: add cxl-poison.sh unit test alison.schofield
2024-02-08 18:18   ` Dave Jiang
2024-02-22  8:04   ` Verma, Vishal L

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