[PATCH v1 0/5] Convert svcrdma stats to per-CPU counters

[PATCH v1 0/5] Convert svcrdma stats to per-CPU counters

[Chuck Lever]

These follow on Amir's patches that did the same for the generic
NFSD stats. See:

https://lore.kernel.org/linux-nfs/20210106075236.4184-2-amir73il@gmail.com/T/

---

Chuck Lever (5):
      svcrdma: Refactor svc_rdma_init() and svc_rdma_clean_up()
      svcrdma: Convert rdma_stat_recv to a per-CPU counter
      svcrdma: Convert rdma_stat_sq_starve to a per-CPU counter
      svcrdma: Restore read and write stats
      svcrdma: Deprecate stat variables that are no longer used


 include/linux/sunrpc/svc_rdma.h         |  14 +-
 net/sunrpc/xprtrdma/svc_rdma.c          | 164 ++++++++++++++----------
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |   3 +-
 net/sunrpc/xprtrdma/svc_rdma_rw.c       |   3 +
 net/sunrpc/xprtrdma/svc_rdma_sendto.c   |   2 +-
 5 files changed, 108 insertions(+), 78 deletions(-)

--
Chuck Lever

[PATCH v1 1/5] svcrdma: Refactor svc_rdma_init() and svc_rdma_clean_up()

[Chuck Lever]

Setting up the proc variables is about to get more complicated.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprtrdma/svc_rdma.c |   30 +++++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index 526da5d4710b..1fc1d5cbeb9b 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -224,27 +224,43 @@ static struct ctl_table svcrdma_root_table[] = {
 	{ },
 };
 
+static void svc_rdma_proc_cleanup(void)
+{
+	if (!svcrdma_table_header)
+		return;
+	unregister_sysctl_table(svcrdma_table_header);
+	svcrdma_table_header = NULL;
+}
+
+static int svc_rdma_proc_init(void)
+{
+	if (svcrdma_table_header)
+		return 0;
+
+	svcrdma_table_header = register_sysctl_table(svcrdma_root_table);
+	return 0;
+}
+
 void svc_rdma_cleanup(void)
 {
 	dprintk("SVCRDMA Module Removed, deregister RPC RDMA transport\n");
-	if (svcrdma_table_header) {
-		unregister_sysctl_table(svcrdma_table_header);
-		svcrdma_table_header = NULL;
-	}
 	svc_unreg_xprt_class(&svc_rdma_class);
+	svc_rdma_proc_cleanup();
 }
 
 int svc_rdma_init(void)
 {
+	int rc;
+
 	dprintk("SVCRDMA Module Init, register RPC RDMA transport\n");
 	dprintk("\tsvcrdma_ord      : %d\n", svcrdma_ord);
 	dprintk("\tmax_requests     : %u\n", svcrdma_max_requests);
 	dprintk("\tmax_bc_requests  : %u\n", svcrdma_max_bc_requests);
 	dprintk("\tmax_inline       : %d\n", svcrdma_max_req_size);
 
-	if (!svcrdma_table_header)
-		svcrdma_table_header =
-			register_sysctl_table(svcrdma_root_table);
+	rc = svc_rdma_proc_init();
+	if (rc)
+		return rc;
 
 	/* Register RDMA with the SVC transport switch */
 	svc_reg_xprt_class(&svc_rdma_class);

[PATCH v1 2/5] svcrdma: Convert rdma_stat_recv to a per-CPU counter

[Chuck Lever]

Receives are frequent events. Avoid the overhead of a memory bus
lock cycle for counting a value that is hardly every used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h         |    3 +-
 net/sunrpc/xprtrdma/svc_rdma.c          |   55 +++++++++++++++++++++++++++++--
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |    3 +-
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 294b56e61522..ff32c59a27e7 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -49,6 +49,7 @@
 #include <linux/sunrpc/rpc_rdma_cid.h>
 #include <linux/sunrpc/svc_rdma_pcl.h>
 
+#include <linux/percpu_counter.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/rdma_cm.h>
 
@@ -65,7 +66,7 @@ extern unsigned int svcrdma_max_requests;
 extern unsigned int svcrdma_max_bc_requests;
 extern unsigned int svcrdma_max_req_size;
 
-extern atomic_t rdma_stat_recv;
+extern struct percpu_counter svcrdma_stat_recv;
 extern atomic_t rdma_stat_read;
 extern atomic_t rdma_stat_write;
 extern atomic_t rdma_stat_sq_starve;
diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index 1fc1d5cbeb9b..3e5e622bad81 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -63,7 +63,7 @@ unsigned int svcrdma_max_req_size = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int min_max_inline = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH;
 
-atomic_t rdma_stat_recv;
+struct percpu_counter svcrdma_stat_recv;
 atomic_t rdma_stat_read;
 atomic_t rdma_stat_write;
 atomic_t rdma_stat_sq_starve;
@@ -110,6 +110,42 @@ static int read_reset_stat(struct ctl_table *table, int write,
 	return 0;
 }
 
+enum {
+	SVCRDMA_COUNTER_BUFSIZ	= sizeof(unsigned long long),
+};
+
+static int svcrdma_counter_handler(struct ctl_table *table, int write,
+				   void *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct percpu_counter *stat = (struct percpu_counter *)table->data;
+	char tmp[SVCRDMA_COUNTER_BUFSIZ + 1];
+	int len;
+
+	if (write) {
+		percpu_counter_set(stat, 0);
+		return 0;
+	}
+
+	len = snprintf(tmp, SVCRDMA_COUNTER_BUFSIZ, "%lld\n",
+		       percpu_counter_sum_positive(stat));
+	if (len >= SVCRDMA_COUNTER_BUFSIZ)
+		return -EFAULT;
+	len = strlen(tmp);
+	if (*ppos > len) {
+		*lenp = 0;
+		return 0;
+	}
+	len -= *ppos;
+	if (len > *lenp)
+		len = *lenp;
+	if (len)
+		memcpy(buffer, tmp, len);
+	*lenp = len;
+	*ppos += len;
+
+	return 0;
+}
+
 static struct ctl_table_header *svcrdma_table_header;
 static struct ctl_table svcrdma_parm_table[] = {
 	{
@@ -149,10 +185,10 @@ static struct ctl_table svcrdma_parm_table[] = {
 	},
 	{
 		.procname	= "rdma_stat_recv",
-		.data		= &rdma_stat_recv,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_recv,
+		.maxlen		= SVCRDMA_COUNTER_BUFSIZ,
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= svcrdma_counter_handler,
 	},
 	{
 		.procname	= "rdma_stat_write",
@@ -230,15 +266,26 @@ static void svc_rdma_proc_cleanup(void)
 		return;
 	unregister_sysctl_table(svcrdma_table_header);
 	svcrdma_table_header = NULL;
+
+	percpu_counter_destroy(&svcrdma_stat_recv);
 }
 
 static int svc_rdma_proc_init(void)
 {
+	int rc;
+
 	if (svcrdma_table_header)
 		return 0;
 
+	rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL);
+	if (rc)
+		goto out_err;
+
 	svcrdma_table_header = register_sysctl_table(svcrdma_root_table);
 	return 0;
+
+out_err:
+	return rc;
 }
 
 void svc_rdma_cleanup(void)
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index cbdb71247755..7d14a74df716 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -845,8 +845,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 	}
 	list_del(&ctxt->rc_list);
 	spin_unlock(&rdma_xprt->sc_rq_dto_lock);
-
-	atomic_inc(&rdma_stat_recv);
+	percpu_counter_inc(&svcrdma_stat_recv);
 
 	svc_rdma_build_arg_xdr(rqstp, ctxt);
 

[PATCH v1 3/5] svcrdma: Convert rdma_stat_sq_starve to a per-CPU counter

[Chuck Lever]

Avoid the overhead of a memory bus lock cycle for counting a value
that is hardly every used.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h       |    2 +-
 net/sunrpc/xprtrdma/svc_rdma.c        |   13 +++++++++----
 net/sunrpc/xprtrdma/svc_rdma_rw.c     |    1 +
 net/sunrpc/xprtrdma/svc_rdma_sendto.c |    2 +-
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index ff32c59a27e7..c06b16ccf83e 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -69,7 +69,7 @@ extern unsigned int svcrdma_max_req_size;
 extern struct percpu_counter svcrdma_stat_recv;
 extern atomic_t rdma_stat_read;
 extern atomic_t rdma_stat_write;
-extern atomic_t rdma_stat_sq_starve;
+extern struct percpu_counter svcrdma_stat_sq_starve;
 extern atomic_t rdma_stat_rq_starve;
 extern atomic_t rdma_stat_rq_poll;
 extern atomic_t rdma_stat_rq_prod;
diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index 3e5e622bad81..ee768d4c3c90 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -66,7 +66,7 @@ static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH;
 struct percpu_counter svcrdma_stat_recv;
 atomic_t rdma_stat_read;
 atomic_t rdma_stat_write;
-atomic_t rdma_stat_sq_starve;
+struct percpu_counter svcrdma_stat_sq_starve;
 atomic_t rdma_stat_rq_starve;
 atomic_t rdma_stat_rq_poll;
 atomic_t rdma_stat_rq_prod;
@@ -199,10 +199,10 @@ static struct ctl_table svcrdma_parm_table[] = {
 	},
 	{
 		.procname	= "rdma_stat_sq_starve",
-		.data		= &rdma_stat_sq_starve,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_sq_starve,
+		.maxlen		= SVCRDMA_COUNTER_BUFSIZ,
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= svcrdma_counter_handler,
 	},
 	{
 		.procname	= "rdma_stat_rq_starve",
@@ -267,6 +267,7 @@ static void svc_rdma_proc_cleanup(void)
 	unregister_sysctl_table(svcrdma_table_header);
 	svcrdma_table_header = NULL;
 
+	percpu_counter_destroy(&svcrdma_stat_sq_starve);
 	percpu_counter_destroy(&svcrdma_stat_recv);
 }
 
@@ -278,6 +279,9 @@ static int svc_rdma_proc_init(void)
 		return 0;
 
 	rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL);
+	if (rc)
+		goto out_err;
+	rc = percpu_counter_init(&svcrdma_stat_sq_starve, 0, GFP_KERNEL);
 	if (rc)
 		goto out_err;
 
@@ -285,6 +289,7 @@ static int svc_rdma_proc_init(void)
 	return 0;
 
 out_err:
+	percpu_counter_destroy(&svcrdma_stat_recv);
 	return rc;
 }
 
diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 0b63e1321d74..d7d98b2df00b 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -364,6 +364,7 @@ static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc)
 			return 0;
 		}
 
+		percpu_counter_inc(&svcrdma_stat_sq_starve);
 		trace_svcrdma_sq_full(rdma);
 		atomic_add(cc->cc_sqecount, &rdma->sc_sq_avail);
 		wait_event(rdma->sc_send_wait,
diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 68af79d4f04f..52c759a8543e 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -317,7 +317,7 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt)
 	/* If the SQ is full, wait until an SQ entry is available */
 	while (1) {
 		if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) {
-			atomic_inc(&rdma_stat_sq_starve);
+			percpu_counter_inc(&svcrdma_stat_sq_starve);
 			trace_svcrdma_sq_full(rdma);
 			atomic_inc(&rdma->sc_sq_avail);
 			wait_event(rdma->sc_send_wait,

[PATCH v1 4/5] svcrdma: Restore read and write stats

[Chuck Lever]

Now that we have an efficient mechanism to update these two stats,
let's start maintaining them again.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h   |    4 ++--
 net/sunrpc/xprtrdma/svc_rdma.c    |   26 ++++++++++++++++++--------
 net/sunrpc/xprtrdma/svc_rdma_rw.c |    2 ++
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index c06b16ccf83e..c882816cba8e 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -66,10 +66,10 @@ extern unsigned int svcrdma_max_requests;
 extern unsigned int svcrdma_max_bc_requests;
 extern unsigned int svcrdma_max_req_size;
 
+extern struct percpu_counter svcrdma_stat_read;
 extern struct percpu_counter svcrdma_stat_recv;
-extern atomic_t rdma_stat_read;
-extern atomic_t rdma_stat_write;
 extern struct percpu_counter svcrdma_stat_sq_starve;
+extern struct percpu_counter svcrdma_stat_write;
 extern atomic_t rdma_stat_rq_starve;
 extern atomic_t rdma_stat_rq_poll;
 extern atomic_t rdma_stat_rq_prod;
diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index ee768d4c3c90..c8336df7a142 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -63,10 +63,10 @@ unsigned int svcrdma_max_req_size = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int min_max_inline = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH;
 
+struct percpu_counter svcrdma_stat_read;
 struct percpu_counter svcrdma_stat_recv;
-atomic_t rdma_stat_read;
-atomic_t rdma_stat_write;
 struct percpu_counter svcrdma_stat_sq_starve;
+struct percpu_counter svcrdma_stat_write;
 atomic_t rdma_stat_rq_starve;
 atomic_t rdma_stat_rq_poll;
 atomic_t rdma_stat_rq_prod;
@@ -178,10 +178,10 @@ static struct ctl_table svcrdma_parm_table[] = {
 
 	{
 		.procname	= "rdma_stat_read",
-		.data		= &rdma_stat_read,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_read,
+		.maxlen		= SVCRDMA_COUNTER_BUFSIZ,
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= svcrdma_counter_handler,
 	},
 	{
 		.procname	= "rdma_stat_recv",
@@ -192,10 +192,10 @@ static struct ctl_table svcrdma_parm_table[] = {
 	},
 	{
 		.procname	= "rdma_stat_write",
-		.data		= &rdma_stat_write,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_write,
+		.maxlen		= SVCRDMA_COUNTER_BUFSIZ,
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= svcrdma_counter_handler,
 	},
 	{
 		.procname	= "rdma_stat_sq_starve",
@@ -267,8 +267,10 @@ static void svc_rdma_proc_cleanup(void)
 	unregister_sysctl_table(svcrdma_table_header);
 	svcrdma_table_header = NULL;
 
+	percpu_counter_destroy(&svcrdma_stat_write);
 	percpu_counter_destroy(&svcrdma_stat_sq_starve);
 	percpu_counter_destroy(&svcrdma_stat_recv);
+	percpu_counter_destroy(&svcrdma_stat_read);
 }
 
 static int svc_rdma_proc_init(void)
@@ -278,10 +280,16 @@ static int svc_rdma_proc_init(void)
 	if (svcrdma_table_header)
 		return 0;
 
+	rc = percpu_counter_init(&svcrdma_stat_read, 0, GFP_KERNEL);
+	if (rc)
+		goto out_err;
 	rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL);
 	if (rc)
 		goto out_err;
 	rc = percpu_counter_init(&svcrdma_stat_sq_starve, 0, GFP_KERNEL);
+	if (rc)
+		goto out_err;
+	rc = percpu_counter_init(&svcrdma_stat_write, 0, GFP_KERNEL);
 	if (rc)
 		goto out_err;
 
@@ -289,7 +297,9 @@ static int svc_rdma_proc_init(void)
 	return 0;
 
 out_err:
+	percpu_counter_destroy(&svcrdma_stat_sq_starve);
 	percpu_counter_destroy(&svcrdma_stat_recv);
+	percpu_counter_destroy(&svcrdma_stat_read);
 	return rc;
 }
 
diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index d7d98b2df00b..693d139a8633 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -469,6 +469,7 @@ svc_rdma_build_writes(struct svc_rdma_write_info *info,
 					   DMA_TO_DEVICE);
 		if (ret < 0)
 			return -EIO;
+		percpu_counter_inc(&svcrdma_stat_write);
 
 		list_add(&ctxt->rw_list, &cc->cc_rwctxts);
 		cc->cc_sqecount += ret;
@@ -719,6 +720,7 @@ static int svc_rdma_build_read_segment(struct svc_rdma_read_info *info,
 				   segment->rs_handle, DMA_FROM_DEVICE);
 	if (ret < 0)
 		return -EIO;
+	percpu_counter_inc(&svcrdma_stat_read);
 
 	list_add(&ctxt->rw_list, &cc->cc_rwctxts);
 	cc->cc_sqecount += ret;

[PATCH v1 5/5] svcrdma: Deprecate stat variables that are no longer used

[Chuck Lever]

Clean up. We are not permitted to remove old proc files. Instead,
convert these variables to stubs that are only ever allowed to be
zero.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/sunrpc/svc_rdma.h |    5 --
 net/sunrpc/xprtrdma/svc_rdma.c  |   84 +++++++++++++--------------------------
 2 files changed, 27 insertions(+), 62 deletions(-)

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index c882816cba8e..1e76ed688044 100644
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -70,11 +70,6 @@ extern struct percpu_counter svcrdma_stat_read;
 extern struct percpu_counter svcrdma_stat_recv;
 extern struct percpu_counter svcrdma_stat_sq_starve;
 extern struct percpu_counter svcrdma_stat_write;
-extern atomic_t rdma_stat_rq_starve;
-extern atomic_t rdma_stat_rq_poll;
-extern atomic_t rdma_stat_rq_prod;
-extern atomic_t rdma_stat_sq_poll;
-extern atomic_t rdma_stat_sq_prod;
 
 struct svcxprt_rdma {
 	struct svc_xprt      sc_xprt;		/* SVC transport structure */
diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index c8336df7a142..5bc20e9d09cd 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -62,53 +62,13 @@ static unsigned int max_max_requests = 16384;
 unsigned int svcrdma_max_req_size = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int min_max_inline = RPCRDMA_DEF_INLINE_THRESH;
 static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH;
+static unsigned int svcrdma_stat_unused;
+static unsigned int zero;
 
 struct percpu_counter svcrdma_stat_read;
 struct percpu_counter svcrdma_stat_recv;
 struct percpu_counter svcrdma_stat_sq_starve;
 struct percpu_counter svcrdma_stat_write;
-atomic_t rdma_stat_rq_starve;
-atomic_t rdma_stat_rq_poll;
-atomic_t rdma_stat_rq_prod;
-atomic_t rdma_stat_sq_poll;
-atomic_t rdma_stat_sq_prod;
-
-/*
- * This function implements reading and resetting an atomic_t stat
- * variable through read/write to a proc file. Any write to the file
- * resets the associated statistic to zero. Any read returns it's
- * current value.
- */
-static int read_reset_stat(struct ctl_table *table, int write,
-			   void *buffer, size_t *lenp, loff_t *ppos)
-{
-	atomic_t *stat = (atomic_t *)table->data;
-
-	if (!stat)
-		return -EINVAL;
-
-	if (write)
-		atomic_set(stat, 0);
-	else {
-		char str_buf[32];
-		int len = snprintf(str_buf, 32, "%d\n", atomic_read(stat));
-		if (len >= 32)
-			return -EFAULT;
-		len = strlen(str_buf);
-		if (*ppos > len) {
-			*lenp = 0;
-			return 0;
-		}
-		len -= *ppos;
-		if (len > *lenp)
-			len = *lenp;
-		if (len)
-			memcpy(buffer, str_buf, len);
-		*lenp = len;
-		*ppos += len;
-	}
-	return 0;
-}
 
 enum {
 	SVCRDMA_COUNTER_BUFSIZ	= sizeof(unsigned long long),
@@ -206,38 +166,48 @@ static struct ctl_table svcrdma_parm_table[] = {
 	},
 	{
 		.procname	= "rdma_stat_rq_starve",
-		.data		= &rdma_stat_rq_starve,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_unused,
+		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &zero,
 	},
 	{
 		.procname	= "rdma_stat_rq_poll",
-		.data		= &rdma_stat_rq_poll,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_unused,
+		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &zero,
 	},
 	{
 		.procname	= "rdma_stat_rq_prod",
-		.data		= &rdma_stat_rq_prod,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_unused,
+		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &zero,
 	},
 	{
 		.procname	= "rdma_stat_sq_poll",
-		.data		= &rdma_stat_sq_poll,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_unused,
+		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &zero,
 	},
 	{
 		.procname	= "rdma_stat_sq_prod",
-		.data		= &rdma_stat_sq_prod,
-		.maxlen		= sizeof(atomic_t),
+		.data		= &svcrdma_stat_unused,
+		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
-		.proc_handler	= read_reset_stat,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &zero,
 	},
 	{ },
 };