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From: James Simmons <jsimmons@infradead.org>
To: Andreas Dilger <adilger@whamcloud.com>,
	Oleg Drokin <green@whamcloud.com>, NeilBrown <neilb@suse.de>
Cc: Lustre Development List <lustre-devel@lists.lustre.org>
Subject: [lustre-devel] [PATCH 42/49] lustre: ptlrpc: don't use list_for_each_entry_safe unnecessarily.
Date: Thu, 15 Apr 2021 00:02:34 -0400	[thread overview]
Message-ID: <1618459361-17909-43-git-send-email-jsimmons@infradead.org> (raw)
In-Reply-To: <1618459361-17909-1-git-send-email-jsimmons@infradead.org>

From: NeilBrown <neilb@suse.de>

list_for_each_entry_safe() is only needed if the body of the
loop might change the list, or if it might drop a lock that would
otherwise prevent the list from being changed.

When the body does neither of these, list_for_each_entry() should be
preferred as it makes the behaviour of the loop more clear to readers.

In each of the cases changed there, the list cannot change while the
loop proceeds.

WC-bug-id: https://jira.whamcloud.com/browse/LU-6142
Lustre-commit: 5c89fa57cb2dfff6 ("LU-6142 lustre: ptlrpc: don't use list_for_each_entry_safe unnecessarily.")
Signed-off-by: NeilBrown <neilb@suse.de>
Reviewed-on: https://review.whamcloud.com/41939
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
---
 fs/lustre/ptlrpc/client.c  | 10 +++++-----
 fs/lustre/ptlrpc/import.c  | 14 +++++++-------
 fs/lustre/ptlrpc/ptlrpcd.c |  4 ++--
 fs/lustre/ptlrpc/recover.c | 14 +++++++-------
 4 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/fs/lustre/ptlrpc/client.c b/fs/lustre/ptlrpc/client.c
index 20c00ad..04e8fec 100644
--- a/fs/lustre/ptlrpc/client.c
+++ b/fs/lustre/ptlrpc/client.c
@@ -3060,7 +3060,7 @@ int ptlrpc_replay_req(struct ptlrpc_request *req)
  */
 void ptlrpc_abort_inflight(struct obd_import *imp)
 {
-	struct ptlrpc_request *req, *n;
+	struct ptlrpc_request *req;
 
 	/*
 	 * Make sure that no new requests get processed for this import.
@@ -3074,7 +3074,7 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
 	 * locked?  Also, how do we know if the requests on the list are
 	 * being freed at this time?
 	 */
-	list_for_each_entry_safe(req, n, &imp->imp_sending_list, rq_list) {
+	list_for_each_entry(req, &imp->imp_sending_list, rq_list) {
 		DEBUG_REQ(D_RPCTRACE, req, "inflight");
 
 		spin_lock(&req->rq_lock);
@@ -3086,7 +3086,7 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
 		spin_unlock(&req->rq_lock);
 	}
 
-	list_for_each_entry_safe(req, n, &imp->imp_delayed_list, rq_list) {
+	list_for_each_entry(req, &imp->imp_delayed_list, rq_list) {
 		DEBUG_REQ(D_RPCTRACE, req, "aborting waiting req");
 
 		spin_lock(&req->rq_lock);
@@ -3112,9 +3112,9 @@ void ptlrpc_abort_inflight(struct obd_import *imp)
  */
 void ptlrpc_abort_set(struct ptlrpc_request_set *set)
 {
-	struct ptlrpc_request *req, *tmp;
+	struct ptlrpc_request *req;
 
-	list_for_each_entry_safe(req, tmp, &set->set_requests, rq_set_chain) {
+	list_for_each_entry(req, &set->set_requests, rq_set_chain) {
 		spin_lock(&req->rq_lock);
 		if (req->rq_phase != RQ_PHASE_RPC) {
 			spin_unlock(&req->rq_lock);
diff --git a/fs/lustre/ptlrpc/import.c b/fs/lustre/ptlrpc/import.c
index 35c4f83..5e33ebc 100644
--- a/fs/lustre/ptlrpc/import.c
+++ b/fs/lustre/ptlrpc/import.c
@@ -271,11 +271,11 @@ void ptlrpc_deactivate_import(struct obd_import *imp)
 static time64_t ptlrpc_inflight_timeout(struct obd_import *imp)
 {
 	time64_t now = ktime_get_real_seconds();
-	struct ptlrpc_request *req, *n;
+	struct ptlrpc_request *req;
 	time64_t timeout = 0;
 
 	spin_lock(&imp->imp_lock);
-	list_for_each_entry_safe(req, n, &imp->imp_sending_list, rq_list)
+	list_for_each_entry(req, &imp->imp_sending_list, rq_list)
 		timeout = max(ptlrpc_inflight_deadline(req, now), timeout);
 
 	spin_unlock(&imp->imp_lock);
@@ -290,7 +290,7 @@ static time64_t ptlrpc_inflight_timeout(struct obd_import *imp)
  */
 void ptlrpc_invalidate_import(struct obd_import *imp)
 {
-	struct ptlrpc_request *req, *n;
+	struct ptlrpc_request *req;
 	time64_t timeout;
 	int rc;
 
@@ -370,13 +370,13 @@ void ptlrpc_invalidate_import(struct obd_import *imp)
 				 */
 				rc = 0;
 			} else {
-				list_for_each_entry_safe(req, n,
-							 &imp->imp_sending_list, rq_list) {
+				list_for_each_entry(req, &imp->imp_sending_list,
+						    rq_list) {
 					DEBUG_REQ(D_ERROR, req,
 						  "still on sending list");
 				}
-				list_for_each_entry_safe(req, n,
-							 &imp->imp_delayed_list, rq_list) {
+				list_for_each_entry(req, &imp->imp_delayed_list,
+						    rq_list) {
 					DEBUG_REQ(D_ERROR, req,
 						  "still on delayed list");
 				}
diff --git a/fs/lustre/ptlrpc/ptlrpcd.c b/fs/lustre/ptlrpc/ptlrpcd.c
index b0b81cc..ef24b0e 100644
--- a/fs/lustre/ptlrpc/ptlrpcd.c
+++ b/fs/lustre/ptlrpc/ptlrpcd.c
@@ -200,12 +200,12 @@ void ptlrpcd_wake(struct ptlrpc_request *req)
 static int ptlrpcd_steal_rqset(struct ptlrpc_request_set *des,
 			       struct ptlrpc_request_set *src)
 {
-	struct ptlrpc_request *req, *tmp;
+	struct ptlrpc_request *req;
 	int rc = 0;
 
 	spin_lock(&src->set_new_req_lock);
 	if (likely(!list_empty(&src->set_new_requests))) {
-		list_for_each_entry_safe(req, tmp, &src->set_new_requests, rq_set_chain)
+		list_for_each_entry(req, &src->set_new_requests, rq_set_chain)
 			req->rq_set = des;
 
 		list_splice_init(&src->set_new_requests, &des->set_requests);
diff --git a/fs/lustre/ptlrpc/recover.c b/fs/lustre/ptlrpc/recover.c
index 09ea3b3..104af56 100644
--- a/fs/lustre/ptlrpc/recover.c
+++ b/fs/lustre/ptlrpc/recover.c
@@ -66,7 +66,7 @@ void ptlrpc_initiate_recovery(struct obd_import *imp)
 int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
 {
 	int rc = 0;
-	struct ptlrpc_request *req = NULL, *pos;
+	struct ptlrpc_request *req = NULL;
 	u64 last_transno;
 
 	*inflight = 0;
@@ -120,8 +120,8 @@ int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
 	if (!req) {
 		struct ptlrpc_request *tmp;
 
-		list_for_each_entry_safe(tmp, pos, &imp->imp_replay_list,
-					 rq_replay_list) {
+		list_for_each_entry(tmp, &imp->imp_replay_list,
+				    rq_replay_list) {
 			if (tmp->rq_transno > last_transno) {
 				req = tmp;
 				break;
@@ -172,7 +172,7 @@ int ptlrpc_replay_next(struct obd_import *imp, int *inflight)
  */
 int ptlrpc_resend(struct obd_import *imp)
 {
-	struct ptlrpc_request *req, *next;
+	struct ptlrpc_request *req;
 
 	/* As long as we're in recovery, nothing should be added to the sending
 	 * list, so we don't need to hold the lock during this iteration and
@@ -186,7 +186,7 @@ int ptlrpc_resend(struct obd_import *imp)
 		return -1;
 	}
 
-	list_for_each_entry_safe(req, next, &imp->imp_sending_list, rq_list) {
+	list_for_each_entry(req, &imp->imp_sending_list, rq_list) {
 		LASSERTF((long)req > PAGE_SIZE && req != LP_POISON,
 			 "req %p bad\n", req);
 		LASSERTF(req->rq_type != LI_POISON, "req %p freed\n", req);
@@ -211,10 +211,10 @@ int ptlrpc_resend(struct obd_import *imp)
  */
 void ptlrpc_wake_delayed(struct obd_import *imp)
 {
-	struct ptlrpc_request *req, *pos;
+	struct ptlrpc_request *req;
 
 	spin_lock(&imp->imp_lock);
-	list_for_each_entry_safe(req, pos, &imp->imp_delayed_list, rq_list) {
+	list_for_each_entry(req, &imp->imp_delayed_list, rq_list) {
 		DEBUG_REQ(D_HA, req, "waking (set %p):", req->rq_set);
 		ptlrpc_client_wake_req(req);
 	}
-- 
1.8.3.1

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  parent reply	other threads:[~2021-04-15  4:04 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15  4:01 [lustre-devel] [PATCH 00/49] lustre: sync to OpenSFS as of March 30 2021 James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 01/49] lnet: libcfs: Fix for unconfigured arch_stackwalk James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 02/49] lustre: lmv: iput() can safely be passed NULL James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 03/49] lustre: llite: mark extended attr and inode flags James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 04/49] lnet: lnet_notify sets route aliveness incorrectly James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 05/49] lnet: Prevent discovery on peer marked deletion James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 06/49] lnet: Prevent discovery on deleted peer James Simmons
2021-04-15  4:01 ` [lustre-devel] [PATCH 07/49] lnet: Transfer disc src NID when merging peers James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 08/49] lnet: Lookup lpni after discovery James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 09/49] lustre: llite: update and fix module loading bug in mounting code James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 10/49] lnet: socklnd: change various ints to bool James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 11/49] lnet: Correct asymmetric route detection James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 12/49] lustre: fixup ldlm_pool and lu_object shrinker failure cases James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 13/49] lustre: log: Add ending newline for some messages James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 14/49] lustre: use with_imp_locked() more broadly James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 15/49] lnet: o2iblnd: change some ints to bool James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 16/49] lustre: lmv: striped directory as subdirectory mount James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 17/49] lustre: llite: create file_operations registration function James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 18/49] lustre: osc: fix performance regression in osc_extent_merge() James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 19/49] lustre: mds: add enums for MDS_ATTR flags James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 20/49] lustre: uapi: remove OBD_IOC_LOV_GET_CONFIG James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 21/49] lustre: sec: fix migrate for encrypted dir James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 22/49] lnet: libcfs: restore LNET_DUMP_ON_PANIC functionality James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 23/49] lustre: ptlrpc: fix ASSERTION on scp_rqbd_posted James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 24/49] lustre: ldlm: not freed req on enqueue James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 25/49] lnet: uapi: move userland only nidstr.h handling James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 26/49] lnet: libcfs: don't depend on sysctl support for debugfs James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 27/49] lustre: ptlrpc: Add a binary heap implementation James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 28/49] lustre: ptlrpc: Implement NRS Delay Policy James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 29/49] lustre: ptlrpc: rename cfs_binheap to simply binheap James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 30/49] lustre: ptlrpc: mark some functions as static James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 31/49] lustre: use tgt_pool for lov layer James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 32/49] lustre: quota: make used for pool correct James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 33/49] lustre: quota: call rhashtable_lookup near params decl James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 34/49] lustre: lov: cancel layout lock on replay deadlock James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 35/49] lustre: obdclass: Protect cl_env_percpu[] James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 36/49] lnet: libcfs: discard cfs_trace_console_buffers[] James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 37/49] lnet: libcfs: discard cfs_trace_copyin_string() James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 38/49] lustre: lmv: don't use lqr_alloc spinlock in lmv James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 39/49] lustre: lov: fault page update cp_lov_index James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 40/49] lustre: update version to 2.14.51 James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 41/49] lustre: llite: mirror extend/copy keeps sparseness James Simmons
2021-04-15  4:02 ` James Simmons [this message]
2021-04-15  4:02 ` [lustre-devel] [PATCH 43/49] lnet: Age peer NI out of recovery James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 44/49] lnet: Only recover known good peer NIs James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 45/49] lnet: Recover peer NI w/exponential backoff interval James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 46/49] lustre: lov: return valid stripe_count/size for PFL files James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 47/49] lnet: convert lpni_refcount to a kref James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 48/49] lustre: lmv: handle default stripe_count=-1 properly James Simmons
2021-04-15  4:02 ` [lustre-devel] [PATCH 49/49] lnet: libcfs: discard cfs_array_alloc() James Simmons

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