It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com --- block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); }
+/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) { - unsigned int i, first = 1; - ssize_t ret = 0; - - for_each_cpu(i, hctx->cpumask) { - if (first) - ret += sprintf(ret + page, "%u", i); - else - ret += sprintf(ret + page, ", %u", i); - - first = 0; + unsigned int cpu = cpumask_first(hctx->cpumask); + ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu); + int last_len = len; + + while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) { + int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len, + ", %u", cpu); + if (cur_len >= PAGE_SIZE - 1 - len) { + len -= last_len; + len += snprintf(page + len, PAGE_SIZE - 1 - len, + "..."); + break; + } + len += cur_len; + last_len = cur_len; }
- ret += sprintf(ret + page, "\n"); - return ret; + len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n"); + return len; }
static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
thanks,
greg k-h
On Thu, Aug 15, 2019 at 02:24:19PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
It is /sys/block/$DEV/mq/$N/cpu_list, all CPUs in this hctx($N) will be shown via sysfs buffer. The buffer size is one PAGE, how can it hold when there are too many CPUs(close to 1K)?
Thanks, Ming
On Thu, Aug 15, 2019 at 08:29:10PM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 02:24:19PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
It is /sys/block/$DEV/mq/$N/cpu_list, all CPUs in this hctx($N) will be shown via sysfs buffer. The buffer size is one PAGE, how can it hold when there are too many CPUs(close to 1K)?
Looks like I only see 1 cpu listed on my machines in those files, what am I doing wrong?
Also, I don't see cpu_list in any of the documentation files, so I have no idea what you are trying to have this file show.
And again, "one value per file" is the sysfs rule. "all cpus in the system" is not "one value" :)
thanks,
greg k-h
On Thu, Aug 15, 2019 at 02:35:35PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:29:10PM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 02:24:19PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
It is /sys/block/$DEV/mq/$N/cpu_list, all CPUs in this hctx($N) will be shown via sysfs buffer. The buffer size is one PAGE, how can it hold when there are too many CPUs(close to 1K)?
Looks like I only see 1 cpu listed on my machines in those files, what am I doing wrong?
It depends on machine. The issue is reported on one machine with 896 CPU cores, when 4K buffer can only hold 841 cores.
Also, I don't see cpu_list in any of the documentation files, so I have no idea what you are trying to have this file show.
And again, "one value per file" is the sysfs rule. "all cpus in the system" is not "one value" :)
I agree, and this file shouldn't be there, given each CPU will have one kobject dir under the hctx dir.
We may kill the 'cpu_list' attribute, is there anyone who objects?
Thanks, Ming
On Thu, Aug 15, 2019 at 08:43:22PM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 02:35:35PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:29:10PM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 02:24:19PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
It is /sys/block/$DEV/mq/$N/cpu_list, all CPUs in this hctx($N) will be shown via sysfs buffer. The buffer size is one PAGE, how can it hold when there are too many CPUs(close to 1K)?
Looks like I only see 1 cpu listed on my machines in those files, what am I doing wrong?
It depends on machine. The issue is reported on one machine with 896 CPU cores, when 4K buffer can only hold 841 cores.
Also, I don't see cpu_list in any of the documentation files, so I have no idea what you are trying to have this file show.
And again, "one value per file" is the sysfs rule. "all cpus in the system" is not "one value" :)
I agree, and this file shouldn't be there, given each CPU will have one kobject dir under the hctx dir.
We may kill the 'cpu_list' attribute, is there anyone who objects?
Given that it was never documented, perhaps no one actually uses it :)
greg k-h
Hi Ming,
In the customer case, the cpu_list file was not needed. It was just part of a SAP Hana script to collect all the block device data (similar to sosreport). So they were just dumping everything, and it picks up the mq-related files.
I know with IRQs, we have bitmaps/mask, and can represent the list such as "0-27", without listing every CPU. I'm sure there's lots of options to address this, and getting rid of the cpu_list is one of them.
Best Regards,
Mark Ray HPE Global Solutions Engineering mark.ray@hpe.com
-----Original Message----- From: Ming Lei [mailto:ming.lei@redhat.com] Sent: Thursday, August 15, 2019 9:43 PM To: Greg KH gregkh@linuxfoundation.org Cc: Jens Axboe axboe@kernel.dk; linux-block@vger.kernel.org; stable@vger.kernel.org; Ray, Mark C (Global Solutions Engineering (GSE)) mark.ray@hpe.com Subject: Re: [PATCH] blk-mq: avoid sysfs buffer overflow by too many CPU cores
On Thu, Aug 15, 2019 at 02:35:35PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:29:10PM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 02:24:19PM +0200, Greg KH wrote:
On Thu, Aug 15, 2019 at 08:15:18PM +0800, Ming Lei wrote:
It is reported that sysfs buffer overflow can be triggered in case of too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs in one hctx.
So use snprintf for avoiding the potential buffer overflow.
Cc: stable@vger.kernel.org Cc: Mark Ray mark.ray@hpe.com Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei ming.lei@redhat.com
block/blk-mq-sysfs.c | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c index d6e1a9bd7131..e75f41a98415 100644 --- a/block/blk-mq-sysfs.c +++ b/block/blk-mq-sysfs.c @@ -164,22 +164,28 @@ static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx, return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags); } +/* avoid overflow by too many CPU cores */ static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page) {
- unsigned int i, first = 1;
- ssize_t ret = 0;
- for_each_cpu(i, hctx->cpumask) {
if (first)ret += sprintf(ret + page, "%u", i);elseret += sprintf(ret + page, ", %u", i);first = 0;
- unsigned int cpu = cpumask_first(hctx->cpumask);
- ssize_t len = snprintf(page, PAGE_SIZE - 1, "%u", cpu);
- int last_len = len;
- while ((cpu = cpumask_next(cpu, hctx->cpumask)) < nr_cpu_ids) {
int cur_len = snprintf(page + len, PAGE_SIZE - 1 - len,", %u", cpu);if (cur_len >= PAGE_SIZE - 1 - len) {len -= last_len;len += snprintf(page + len, PAGE_SIZE - 1 - len,"...");break;}len += cur_len;last_len = cur_len;
- ret += sprintf(ret + page, "\n");
- return ret;
- len += snprintf(page + len, PAGE_SIZE - 1 - len, "\n");
- return len;
}
What????
sysfs is "one value per file". You should NEVER have to care about the size of the sysfs buffer. If you do, you are doing something wrong.
What excatly are you trying to show in this sysfs file? I can't seem to find the Documenatation/ABI/ entry for it, am I just missing it because I don't know the filename for it?
It is /sys/block/$DEV/mq/$N/cpu_list, all CPUs in this hctx($N) will be shown via sysfs buffer. The buffer size is one PAGE, how can it hold when there are too many CPUs(close to 1K)?
Looks like I only see 1 cpu listed on my machines in those files, what am I doing wrong?
It depends on machine. The issue is reported on one machine with 896 CPU cores, when 4K buffer can only hold 841 cores.
Also, I don't see cpu_list in any of the documentation files, so I have no idea what you are trying to have this file show.
And again, "one value per file" is the sysfs rule. "all cpus in the system" is not "one value" :)
I agree, and this file shouldn't be there, given each CPU will have one kobject dir under the hctx dir.
We may kill the 'cpu_list' attribute, is there anyone who objects?
Thanks, Ming
On Thu, Aug 15, 2019 at 11:10:35PM +0000, Ray, Mark C (Global Solutions Engineering (GSE)) wrote:
Hi Ming,
In the customer case, the cpu_list file was not needed. It was just part of a SAP Hana script to collect all the block device data (similar to sosreport). So they were just dumping everything, and it picks up the mq-related files.
I know with IRQs, we have bitmaps/mask, and can represent the list such as "0-27", without listing every CPU. I'm sure there's lots of options to address this, and getting rid of the cpu_list is one of them.
Indeed, same with several attributes under /sys/devices/system/cpu/, actually we can use cpumap_print_to_pagebuf() to print the CPUs.
Thanks, Ming
On Fri, Aug 16, 2019 at 10:49:35AM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 11:10:35PM +0000, Ray, Mark C (Global Solutions Engineering (GSE)) wrote:
Hi Ming,
In the customer case, the cpu_list file was not needed. It was just part of a SAP Hana script to collect all the block device data (similar to sosreport). So they were just dumping everything, and it picks up the mq-related files.
I know with IRQs, we have bitmaps/mask, and can represent the list such as "0-27", without listing every CPU. I'm sure there's lots of options to address this, and getting rid of the cpu_list is one of them.
Indeed, same with several attributes under /sys/devices/system/cpu/, actually we can use cpumap_print_to_pagebuf() to print the CPUs.
And that is changing the format of the file, which means it is obvious no one is using it, so just please delete the thing.
thanks,
greg k-h
On 8/16/19 1:12 AM, Greg KH wrote:
On Fri, Aug 16, 2019 at 10:49:35AM +0800, Ming Lei wrote:
On Thu, Aug 15, 2019 at 11:10:35PM +0000, Ray, Mark C (Global Solutions Engineering (GSE)) wrote:
Hi Ming,
In the customer case, the cpu_list file was not needed. It was just part of a SAP Hana script to collect all the block device data (similar to sosreport). So they were just dumping everything, and it picks up the mq-related files.
I know with IRQs, we have bitmaps/mask, and can represent the list such as "0-27", without listing every CPU. I'm sure there's lots of options to address this, and getting rid of the cpu_list is one of them.
Indeed, same with several attributes under /sys/devices/system/cpu/, actually we can use cpumap_print_to_pagebuf() to print the CPUs.
And that is changing the format of the file, which means it is obvious no one is using it, so just please delete the thing.
IFF that patch was valid, then yes, it follows that you could delete it. But that's not a given.
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Jens Axboe -
Ming Lei -
Ray, Mark C (Global Solutions Engineering (GSE))