[NDCTL PATCH] ndctl: cxl: Remove dependency for attributes derived from IDENTIFY command

[NDCTL PATCH] ndctl: cxl: Remove dependency for attributes derived from IDENTIFY command

[Dave Jiang]

A memdev may optionally not host a mailbox and therefore not able to execute
the IDENTIFY command. Currently the kernel emits empty strings for some of
the attributes instead of making them invisible in order to keep backward
compatibility for CXL CLI. Remove dependency of CXL CLI on the existance of
these attributes and only expose them if they exist. Without the dependency
the kernel will be able to make the non-existant attributes invisible.

Link: https://lore.kernel.org/all/20230606121534.00003870@Huawei.com/
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 cxl/lib/libcxl.c | 48 ++++++++++++++++++++++++++----------------------
 cxl/memdev.c     | 15 ++++++++++-----
 2 files changed, 36 insertions(+), 27 deletions(-)

diff --git a/cxl/lib/libcxl.c b/cxl/lib/libcxl.c
index 1537a33d370e..f807ec4ed4e6 100644
--- a/cxl/lib/libcxl.c
+++ b/cxl/lib/libcxl.c
@@ -1251,28 +1251,30 @@ static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)
 	memdev->minor = minor(st.st_rdev);
 
 	sprintf(path, "%s/pmem/size", cxlmem_base);
-	if (sysfs_read_attr(ctx, path, buf) < 0)
-		goto err_read;
-	memdev->pmem_size = strtoull(buf, NULL, 0);
+	if (sysfs_read_attr(ctx, path, buf) == 0)
+		memdev->pmem_size = strtoull(buf, NULL, 0);
 
 	sprintf(path, "%s/ram/size", cxlmem_base);
-	if (sysfs_read_attr(ctx, path, buf) < 0)
-		goto err_read;
-	memdev->ram_size = strtoull(buf, NULL, 0);
+	if (sysfs_read_attr(ctx, path, buf) == 0)
+		memdev->ram_size = strtoull(buf, NULL, 0);
 
 	sprintf(path, "%s/payload_max", cxlmem_base);
-	if (sysfs_read_attr(ctx, path, buf) < 0)
-		goto err_read;
-	memdev->payload_max = strtoull(buf, NULL, 0);
-	if (memdev->payload_max < 0)
-		goto err_read;
+	if (sysfs_read_attr(ctx, path, buf) == 0) {
+		memdev->payload_max = strtoull(buf, NULL, 0);
+		if (memdev->payload_max < 0)
+			goto err_read;
+	} else {
+		memdev->payload_max = -1;
+	}
 
 	sprintf(path, "%s/label_storage_size", cxlmem_base);
-	if (sysfs_read_attr(ctx, path, buf) < 0)
-		goto err_read;
-	memdev->lsa_size = strtoull(buf, NULL, 0);
-	if (memdev->lsa_size == ULLONG_MAX)
-		goto err_read;
+	if (sysfs_read_attr(ctx, path, buf) == 0) {
+		memdev->lsa_size = strtoull(buf, NULL, 0);
+		if (memdev->lsa_size == ULLONG_MAX)
+			goto err_read;
+	} else {
+		memdev->lsa_size = ULLONG_MAX;
+	}
 
 	sprintf(path, "%s/serial", cxlmem_base);
 	if (sysfs_read_attr(ctx, path, buf) < 0)
@@ -1299,12 +1301,11 @@ static void *add_cxl_memdev(void *parent, int id, const char *cxlmem_base)
 	host[0] = '\0';
 
 	sprintf(path, "%s/firmware_version", cxlmem_base);
-	if (sysfs_read_attr(ctx, path, buf) < 0)
-		goto err_read;
-
-	memdev->firmware_version = strdup(buf);
-	if (!memdev->firmware_version)
-		goto err_read;
+	if (sysfs_read_attr(ctx, path, buf) == 0) {
+		memdev->firmware_version = strdup(buf);
+		if (!memdev->firmware_version)
+			goto err_read;
+	}
 
 	memdev->dev_buf = calloc(1, strlen(cxlmem_base) + 50);
 	if (!memdev->dev_buf)
@@ -4543,6 +4544,9 @@ static int lsa_op(struct cxl_memdev *memdev, int op, void *buf,
 	if (length == 0)
 		return 0;
 
+	if (memdev->payload_max < 0)
+		return -EINVAL;
+
 	label_iter_max = memdev->payload_max - sizeof(struct cxl_cmd_set_lsa);
 	while (remaining) {
 		cur_len = min((size_t)label_iter_max, remaining);
diff --git a/cxl/memdev.c b/cxl/memdev.c
index 81f07991da06..feab7ea76e78 100644
--- a/cxl/memdev.c
+++ b/cxl/memdev.c
@@ -473,10 +473,13 @@ static int action_zero(struct cxl_memdev *memdev, struct action_context *actx)
 	size_t size;
 	int rc;
 
-	if (param.len)
+	if (param.len) {
 		size = param.len;
-	else
+	} else {
 		size = cxl_memdev_get_label_size(memdev);
+		if (size == ULLONG_MAX)
+			return -EINVAL;
+	}
 
 	if (cxl_memdev_nvdimm_bridge_active(memdev)) {
 		log_err(&ml,
@@ -547,11 +550,13 @@ static int action_read(struct cxl_memdev *memdev, struct action_context *actx)
 	char *buf;
 	int rc;
 
-	if (param.len)
+	if (param.len) {
 		size = param.len;
-	else
+	} else {
 		size = cxl_memdev_get_label_size(memdev);
-
+		if (size == ULLONG_MAX)
+			return -EINVAL;
+	}
 	buf = calloc(1, size);
 	if (!buf)
 		return -ENOMEM;
-- 
2.43.0

RE: [NDCTL PATCH] ndctl: cxl: Remove dependency for attributes derived from IDENTIFY command

[Wonjae Lee]

On Fri, Feb 09, 2024 at 02:39:17PM -0700, Dave Jiang wrote:
> A memdev may optionally not host a mailbox and therefore not able to execute
> the IDENTIFY command. Currently the kernel emits empty strings for some of
> the attributes instead of making them invisible in order to keep backward
> compatibility for CXL CLI. Remove dependency of CXL CLI on the existance of
> these attributes and only expose them if they exist. Without the dependency
> the kernel will be able to make the non-existant attributes invisible.
>
> Link: https://lore.kernel.org/all/20230606121534.00003870@Huawei.com/
> Suggested-by: Dan Williams <dan.j.williams@intel.com>
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  cxl/lib/libcxl.c | 48 ++++++++++++++++++++++++++----------------------
>  cxl/memdev.c     | 15 ++++++++++-----
>  2 files changed, 36 insertions(+), 27 deletions(-)
>

[snip]

> diff --git a/cxl/memdev.c b/cxl/memdev.c
> index 81f07991da06..feab7ea76e78 100644
> --- a/cxl/memdev.c
> +++ b/cxl/memdev.c
> @@ -473,10 +473,13 @@ static int action_zero(struct cxl_memdev *memdev, struct action_context *actx)
>   size_t size;
>   int rc;
>
> - if (param.len)
> + if (param.len) {
>       size = param.len;
> - else
> + } else {
>       size = cxl_memdev_get_label_size(memdev);
> +     if (size == ULLONG_MAX)
> +         return -EINVAL;
> + }

Hello,

Doesn't action_write() also need to check the return value of
cxl_memdev_get_label_size() like below?

diff --git a/cxl/memdev.c b/cxl/memdev.c
index feab7ea..de46edc 100644
--- a/cxl/memdev.c
+++ b/cxl/memdev.c
@@ -511,6 +511,8 @@ static int action_write(struct cxl_memdev *memdev, struct action_context *actx)

        if (!size) {
                size_t label_size = cxl_memdev_get_label_size(memdev);
+               if (label_size == ULLONG_MAX)
+                       return -EINVAL;

                fseek(actx->f_in, 0L, SEEK_END);
                size = ftell(actx->f_in);

Thanks,
Wonjae

Re: [NDCTL PATCH] ndctl: cxl: Remove dependency for attributes derived from IDENTIFY command

[Dave Jiang]

On 2/14/24 1:00 AM, Wonjae Lee wrote:
> On Fri, Feb 09, 2024 at 02:39:17PM -0700, Dave Jiang wrote:
>> A memdev may optionally not host a mailbox and therefore not able to execute
>> the IDENTIFY command. Currently the kernel emits empty strings for some of
>> the attributes instead of making them invisible in order to keep backward
>> compatibility for CXL CLI. Remove dependency of CXL CLI on the existance of
>> these attributes and only expose them if they exist. Without the dependency
>> the kernel will be able to make the non-existant attributes invisible.
>>
>> Link: https://lore.kernel.org/all/20230606121534.00003870@Huawei.com/
>> Suggested-by: Dan Williams <dan.j.williams@intel.com>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>> ---
>>  cxl/lib/libcxl.c | 48 ++++++++++++++++++++++++++----------------------
>>  cxl/memdev.c     | 15 ++++++++++-----
>>  2 files changed, 36 insertions(+), 27 deletions(-)
>>
> 
> [snip]
> 
>> diff --git a/cxl/memdev.c b/cxl/memdev.c
>> index 81f07991da06..feab7ea76e78 100644
>> --- a/cxl/memdev.c
>> +++ b/cxl/memdev.c
>> @@ -473,10 +473,13 @@ static int action_zero(struct cxl_memdev *memdev, struct action_context *actx)
>>   size_t size;
>>   int rc;
>>
>> - if (param.len)
>> + if (param.len) {
>>       size = param.len;
>> - else
>> + } else {
>>       size = cxl_memdev_get_label_size(memdev);
>> +     if (size == ULLONG_MAX)
>> +         return -EINVAL;
>> + }
> 
> Hello,
> 
> Doesn't action_write() also need to check the return value of
> cxl_memdev_get_label_size() like below?

Yes. I missed that one. Thank you!
> 
> diff --git a/cxl/memdev.c b/cxl/memdev.c
> index feab7ea..de46edc 100644
> --- a/cxl/memdev.c
> +++ b/cxl/memdev.c
> @@ -511,6 +511,8 @@ static int action_write(struct cxl_memdev *memdev, struct action_context *actx)
> 
>         if (!size) {
>                 size_t label_size = cxl_memdev_get_label_size(memdev);
> +               if (label_size == ULLONG_MAX)
> +                       return -EINVAL;
> 
>                 fseek(actx->f_in, 0L, SEEK_END);
>                 size = ftell(actx->f_in);
> 
> Thanks,
> Wonjae