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[PATCH] s390/zcrypt: optimize memory allocation in online_show()

yskelg@gmail.com posted 1 patch 1 year, 5 months ago 
drivers/s390/crypto/zcrypt_card.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
[PATCH] s390/zcrypt: optimize memory allocation in online_show()
Posted by yskelg@gmail.com 1 year, 5 months ago 
From: Yunseong Kim <yskelg@gmail.com>

Previously, when setting the online state for a card, the code would
allocate memory to store information about all attached queues,
regardless of whether their online state actually changed.
This patch improves efficiency by only allocating memory for the queues
that are truly affected by the online state change.

This allows for a more precise memory allocation (based on maxzqs) which
can reduce memory usage.

Signed-off-by: Yunseong Kim <yskelg@gmail.com>
---
 drivers/s390/crypto/zcrypt_card.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_card.c b/drivers/s390/crypto/zcrypt_card.c
index 050462d95222..2c80be3f2a00 100644
--- a/drivers/s390/crypto/zcrypt_card.c
+++ b/drivers/s390/crypto/zcrypt_card.c
@@ -88,9 +88,10 @@ static ssize_t online_store(struct device *dev,
 	 * the zqueue objects, we make sure they exist after lock release.
 	 */
 	list_for_each_entry(zq, &zc->zqueues, list)
-		maxzqs++;
+		if (!!zq->online != !!online)
+			maxzqs++;
 	if (maxzqs > 0)
-		zq_uelist = kcalloc(maxzqs + 1, sizeof(*zq_uelist), GFP_ATOMIC);
+		zq_uelist = kcalloc(maxzqs, sizeof(*zq_uelist), GFP_ATOMIC);
 	list_for_each_entry(zq, &zc->zqueues, list)
 		if (zcrypt_queue_force_online(zq, online))
 			if (zq_uelist) {
@@ -98,14 +99,11 @@ static ssize_t online_store(struct device *dev,
 				zq_uelist[i++] = zq;
 			}
 	spin_unlock(&zcrypt_list_lock);
-	if (zq_uelist) {
-		for (i = 0; zq_uelist[i]; i++) {
-			zq = zq_uelist[i];
-			ap_send_online_uevent(&zq->queue->ap_dev, online);
-			zcrypt_queue_put(zq);
-		}
-		kfree(zq_uelist);
+	while (i--) {
+		ap_send_online_uevent(&zq->queue->ap_dev, online);
+		zcrypt_queue_put(zq_uelist[i]);
 	}
+	kfree(zq_uelist);
 
 	return count;
 }
-- 
2.45.2
Re: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
Posted by Dan Carpenter 1 year, 5 months ago 
Hi,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/yskelg-gmail-com/s390-zcrypt-optimize-memory-allocation-in-online_show/20240626-071004
base:   https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features
patch link:    https://lore.kernel.org/r/20240623120147.35554-3-yskelg%40gmail.com
patch subject: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
config: s390-randconfig-r081-20240707 (https://download.01.org/0day-ci/archive/20240707/202407071714.4AUEoeUD-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 13.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202407071714.4AUEoeUD-lkp@intel.com/

smatch warnings:
drivers/s390/crypto/zcrypt_card.c:103 online_store() warn: iterator used outside loop: 'zq'

vim +/zq +103 drivers/s390/crypto/zcrypt_card.c

ac2b96f351d7d2 Harald Freudenberger 2018-08-17   60  static ssize_t online_store(struct device *dev,
e28d2af43614eb Ingo Tuchscherer     2016-08-25   61  			    struct device_attribute *attr,
e28d2af43614eb Ingo Tuchscherer     2016-08-25   62  			    const char *buf, size_t count)
e28d2af43614eb Ingo Tuchscherer     2016-08-25   63  {
b5adbbf896d837 Julian Wiedmann      2021-06-07   64  	struct zcrypt_card *zc = dev_get_drvdata(dev);
4f2fcccdb547b0 Harald Freudenberger 2020-07-02   65  	struct ap_card *ac = to_ap_card(dev);
e28d2af43614eb Ingo Tuchscherer     2016-08-25   66  	struct zcrypt_queue *zq;
df6f508c68dbc6 Harald Freudenberger 2021-04-13   67  	int online, id, i = 0, maxzqs = 0;
df6f508c68dbc6 Harald Freudenberger 2021-04-13   68  	struct zcrypt_queue **zq_uelist = NULL;
e28d2af43614eb Ingo Tuchscherer     2016-08-25   69  
e28d2af43614eb Ingo Tuchscherer     2016-08-25   70  	if (sscanf(buf, "%d\n", &online) != 1 || online < 0 || online > 1)
e28d2af43614eb Ingo Tuchscherer     2016-08-25   71  		return -EINVAL;
e28d2af43614eb Ingo Tuchscherer     2016-08-25   72  
cfaef6516e9ac6 Ingo Franzki         2023-10-26   73  	if (online && (!ac->config || ac->chkstop))
4f2fcccdb547b0 Harald Freudenberger 2020-07-02   74  		return -ENODEV;
4f2fcccdb547b0 Harald Freudenberger 2020-07-02   75  
e28d2af43614eb Ingo Tuchscherer     2016-08-25   76  	zc->online = online;
e28d2af43614eb Ingo Tuchscherer     2016-08-25   77  	id = zc->card->id;
cccd85bfb7bf67 Harald Freudenberger 2016-11-24   78  
3f74eb5f78198a Harald Freudenberger 2021-10-15   79  	ZCRYPT_DBF_INFO("%s card=%02x online=%d\n", __func__, id, online);
cccd85bfb7bf67 Harald Freudenberger 2016-11-24   80  
df6f508c68dbc6 Harald Freudenberger 2021-04-13   81  	ap_send_online_uevent(&ac->ap_dev, online);
df6f508c68dbc6 Harald Freudenberger 2021-04-13   82  
e28d2af43614eb Ingo Tuchscherer     2016-08-25   83  	spin_lock(&zcrypt_list_lock);
df6f508c68dbc6 Harald Freudenberger 2021-04-13   84  	/*
df6f508c68dbc6 Harald Freudenberger 2021-04-13   85  	 * As we are in atomic context here, directly sending uevents
df6f508c68dbc6 Harald Freudenberger 2021-04-13   86  	 * does not work. So collect the zqueues in a dynamic array
df6f508c68dbc6 Harald Freudenberger 2021-04-13   87  	 * and process them after zcrypt_list_lock release. As we get/put
df6f508c68dbc6 Harald Freudenberger 2021-04-13   88  	 * the zqueue objects, we make sure they exist after lock release.
df6f508c68dbc6 Harald Freudenberger 2021-04-13   89  	 */
df6f508c68dbc6 Harald Freudenberger 2021-04-13   90  	list_for_each_entry(zq, &zc->zqueues, list)
2ff6be56a27c2d Yunseong Kim         2024-06-23   91  		if (!!zq->online != !!online)
df6f508c68dbc6 Harald Freudenberger 2021-04-13   92  			maxzqs++;
df6f508c68dbc6 Harald Freudenberger 2021-04-13   93  	if (maxzqs > 0)
2ff6be56a27c2d Yunseong Kim         2024-06-23   94  		zq_uelist = kcalloc(maxzqs, sizeof(*zq_uelist), GFP_ATOMIC);
e28d2af43614eb Ingo Tuchscherer     2016-08-25   95  	list_for_each_entry(zq, &zc->zqueues, list)
df6f508c68dbc6 Harald Freudenberger 2021-04-13   96  		if (zcrypt_queue_force_online(zq, online))
df6f508c68dbc6 Harald Freudenberger 2021-04-13   97  			if (zq_uelist) {
df6f508c68dbc6 Harald Freudenberger 2021-04-13   98  				zcrypt_queue_get(zq);
df6f508c68dbc6 Harald Freudenberger 2021-04-13   99  				zq_uelist[i++] = zq;
df6f508c68dbc6 Harald Freudenberger 2021-04-13  100  			}
e28d2af43614eb Ingo Tuchscherer     2016-08-25  101  	spin_unlock(&zcrypt_list_lock);
2ff6be56a27c2d Yunseong Kim         2024-06-23  102  	while (i--) {
df6f508c68dbc6 Harald Freudenberger 2021-04-13 @103  		ap_send_online_uevent(&zq->queue->ap_dev, online);
                                                                                       ^^
zq is an invalid pointer here.  It's an offset off the list head.
There used to be a "zq = zq_uelist[i];" before this function call but
the patch deleted it.

2ff6be56a27c2d Yunseong Kim         2024-06-23  104  		zcrypt_queue_put(zq_uelist[i]);
df6f508c68dbc6 Harald Freudenberger 2021-04-13  105  	}
df6f508c68dbc6 Harald Freudenberger 2021-04-13  106  	kfree(zq_uelist);
df6f508c68dbc6 Harald Freudenberger 2021-04-13  107  
e28d2af43614eb Ingo Tuchscherer     2016-08-25  108  	return count;
e28d2af43614eb Ingo Tuchscherer     2016-08-25  109  }

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
Posted by Yunseong Kim 1 year, 5 months ago 
Hi Dan,

On 7/9/24 12:55 오전, Dan Carpenter wrote:
> Hi,
> 
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/yskelg-gmail-com/s390-zcrypt-optimize-memory-allocation-in-online_show/20240626-071004
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git features
> patch link:    https://lore.kernel.org/r/20240623120147.35554-3-yskelg%40gmail.com
> patch subject: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
> config: s390-randconfig-r081-20240707 (https://download.01.org/0day-ci/archive/20240707/202407071714.4AUEoeUD-lkp@intel.com/config)
> compiler: s390-linux-gcc (GCC) 13.2.0
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202407071714.4AUEoeUD-lkp@intel.com/
> 
> smatch warnings:
> drivers/s390/crypto/zcrypt_card.c:103 online_store() warn: iterator used outside loop: 'zq'
> 
> vim +/zq +103 drivers/s390/crypto/zcrypt_card.c

Thank you for the review. I decided not to work on my patch anymore
after the review because my patch was problematic and not useful.

> df6f508c68dbc6 Harald Freudenberger 2021-04-13   90  	list_for_each_entry(zq, &zc->zqueues, list)
> 2ff6be56a27c2d Yunseong Kim         2024-06-23   91  		if (!!zq->online != !!online)
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   92  			maxzqs++;
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   93  	if (maxzqs > 0)
> 2ff6be56a27c2d Yunseong Kim         2024-06-23   94  		zq_uelist = kcalloc(maxzqs, sizeof(*zq_uelist), GFP_ATOMIC);
> e28d2af43614eb Ingo Tuchscherer     2016-08-25   95  	list_for_each_entry(zq, &zc->zqueues, list)
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   96  		if (zcrypt_queue_force_online(zq, online))
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   97  			if (zq_uelist) {
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   98  				zcrypt_queue_get(zq);
> df6f508c68dbc6 Harald Freudenberger 2021-04-13   99  				zq_uelist[i++] = zq;
> df6f508c68dbc6 Harald Freudenberger 2021-04-13  100  			}
> e28d2af43614eb Ingo Tuchscherer     2016-08-25  101  	spin_unlock(&zcrypt_list_lock);
> 2ff6be56a27c2d Yunseong Kim         2024-06-23  102  	while (i--) {
> df6f508c68dbc6 Harald Freudenberger 2021-04-13 @103  		ap_send_online_uevent(&zq->queue->ap_dev, online);
>                                                                                        ^^
> zq is an invalid pointer here.  It's an offset off the list head.
> There used to be a "zq = zq_uelist[i];" before this function call but
> the patch deleted it.

My patch doesn't mean much to me at this point, but if it needed to be
fixed, I think it should have been.

> 2ff6be56a27c2d Yunseong Kim         2024-06-23  104  		zcrypt_queue_put(zq_uelist[i]);
> df6f508c68dbc6 Harald Freudenberger 2021-04-13  105  	}
> df6f508c68dbc6 Harald Freudenberger 2021-04-13  106  	kfree(zq_uelist);
> df6f508c68dbc6 Harald Freudenberger 2021-04-13  107  
> e28d2af43614eb Ingo Tuchscherer     2016-08-25  108  	return count;
> e28d2af43614eb Ingo Tuchscherer     2016-08-25  109  }


I've been doing some Linux kernel research on the IBM Cloud s390x VPC
and running syzkaller and Linux kernel tests tools to send out useful
patches. :)


Warm regards,

Yunseong kim
Re: [PATCH] s390/zcrypt: optimize memory allocation in online_show()
Posted by Markus Elfring 1 year, 5 months ago 
…
> This patch improves efficiency by only allocating memory for the queues
…

* Please improve the change description with imperative wordings.
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.10-rc4#n94

* Would you like to add any tags (like “Fixes” or “Cc”) accordingly?


Regards,
Markus

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