Message-Id: <20170515090725.27055-7-dave@stgolabs.net>
Date:   Mon, 15 May 2017 02:07:25 -0700
From:   Davidlohr Bueso <dave@...olabs.net>
To:     mingo@...nel.org, peterz@...radead.org, akpm@...ux-foundation.org
Cc:     jack@...e.cz, kirill.shutemov@...ux.intel.com,
        ldufour@...ux.vnet.ibm.com, mhocko@...e.com,
        mgorman@...hsingularity.net, dave@...olabs.net,
        linux-kernel@...r.kernel.org, oleg.drokin@...el.com,
        andreas.dilger@...el.com, jsimmons@...radead.org,
        lustre-devel@...ts.lustre.org, Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH 6/6] staging/lustre: Use generic range rwlock

This replaces the in-house version, which is also derived
from Jan's interval tree implementation.

Cc: oleg.drokin@...el.com
Cc: andreas.dilger@...el.com
Cc: jsimmons@...radead.org
Cc: lustre-devel@...ts.lustre.org
Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
---
 drivers/staging/lustre/lustre/llite/Makefile       |   2 +-
 drivers/staging/lustre/lustre/llite/file.c         |  16 +-
 .../staging/lustre/lustre/llite/llite_internal.h   |   2 +-
 drivers/staging/lustre/lustre/llite/range_lock.c   | 239 ---------------------
 drivers/staging/lustre/lustre/llite/range_lock.h   |  82 -------
 5 files changed, 10 insertions(+), 331 deletions(-)
 delete mode 100644 drivers/staging/lustre/lustre/llite/range_lock.c
 delete mode 100644 drivers/staging/lustre/lustre/llite/range_lock.h

diff --git a/drivers/staging/lustre/lustre/llite/Makefile b/drivers/staging/lustre/lustre/llite/Makefile
index 322d4fa63f5d..922a901bc62c 100644
--- a/drivers/staging/lustre/lustre/llite/Makefile
+++ b/drivers/staging/lustre/lustre/llite/Makefile
@@ -1,6 +1,6 @@
 obj-$(CONFIG_LUSTRE_FS) += lustre.o
 lustre-y := dcache.o dir.o file.o llite_lib.o llite_nfs.o \
-	    rw.o rw26.o namei.o symlink.o llite_mmap.o range_lock.o \
+	    rw.o rw26.o namei.o symlink.o llite_mmap.o \
 	    xattr.o xattr_cache.o xattr_security.o \
 	    super25.o statahead.o glimpse.o lcommon_cl.o lcommon_misc.o \
 	    vvp_dev.o vvp_page.o vvp_lock.o vvp_io.o vvp_object.o \
diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
index 67c4b9cc6e75..bd020bdaf85d 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -1083,10 +1083,10 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
 		if (((iot == CIT_WRITE) ||
 		     (iot == CIT_READ && (file->f_flags & O_DIRECT))) &&
 		    !(vio->vui_fd->fd_flags & LL_FILE_GROUP_LOCKED)) {
-			CDEBUG(D_VFSTRACE, "Range lock [%llu, %llu]\n",
-			       range.rl_node.in_extent.start,
-			       range.rl_node.in_extent.end);
-			rc = range_lock(&lli->lli_write_tree, &range);
+			CDEBUG(D_VFSTRACE, "Range lock [%lu, %lu]\n",
+			       range.node.start,
+			       range.node.last);
+			rc = range_write_lock_interruptible(&lli->lli_write_tree, &range);
 			if (rc < 0)
 				goto out;
 
@@ -1096,10 +1096,10 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
 		rc = cl_io_loop(env, io);
 		ll_cl_remove(file, env);
 		if (range_locked) {
-			CDEBUG(D_VFSTRACE, "Range unlock [%llu, %llu]\n",
-			       range.rl_node.in_extent.start,
-			       range.rl_node.in_extent.end);
-			range_unlock(&lli->lli_write_tree, &range);
+			CDEBUG(D_VFSTRACE, "Range unlock [%lu, %lu]\n",
+			       range.node.start,
+			       range.node.last);
+			range_write_unlock(&lli->lli_write_tree, &range);
 		}
 	} else {
 		/* cl_io_rw_init() handled IO */
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index d2a0fabd8a69..58f0ec9fd03b 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -49,7 +49,7 @@
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>
 #include "vvp_internal.h"
-#include "range_lock.h"
+#include <linux/range_lock.h>
 
 #ifndef FMODE_EXEC
 #define FMODE_EXEC 0
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.c b/drivers/staging/lustre/lustre/llite/range_lock.c
deleted file mode 100644
index 161391b6fb36..000000000000
--- a/drivers/staging/lustre/lustre/llite/range_lock.c
+++ /dev/null
@@ -1,239 +0,0 @@
-/*
- * GPL HEADER START
- *
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License version 2 for more details (a copy is included
- * in the LICENSE file that accompanied this code).
- *
- * You should have received a copy of the GNU General Public License
- * version 2 along with this program; If not, see
- * http://www.gnu.org/licenses/gpl-2.0.html
- *
- * GPL HEADER END
- */
-/*
- * Range lock is used to allow multiple threads writing a single shared
- * file given each thread is writing to a non-overlapping portion of the
- * file.
- *
- * Refer to the possible upstream kernel version of range lock by
- * Jan Kara <jack@...e.cz>: https://lkml.org/lkml/2013/1/31/480
- *
- * This file could later replaced by the upstream kernel version.
- */
-/*
- * Author: Prakash Surya <surya1@...l.gov>
- * Author: Bobi Jam <bobijam.xu@...el.com>
- */
-#include "range_lock.h"
-#include "../include/lustre/lustre_user.h"
-
-/**
- * Initialize a range lock tree
- *
- * \param tree [in]	an empty range lock tree
- *
- * Pre:  Caller should have allocated the range lock tree.
- * Post: The range lock tree is ready to function.
- */
-void range_lock_tree_init(struct range_lock_tree *tree)
-{
-	tree->rlt_root = NULL;
-	tree->rlt_sequence = 0;
-	spin_lock_init(&tree->rlt_lock);
-}
-
-/**
- * Initialize a range lock node
- *
- * \param lock  [in]	an empty range lock node
- * \param start [in]	start of the covering region
- * \param end   [in]	end of the covering region
- *
- * Pre:  Caller should have allocated the range lock node.
- * Post: The range lock node is meant to cover [start, end] region
- */
-int range_lock_init(struct range_lock *lock, __u64 start, __u64 end)
-{
-	int rc;
-
-	memset(&lock->rl_node, 0, sizeof(lock->rl_node));
-	if (end != LUSTRE_EOF)
-		end >>= PAGE_SHIFT;
-	rc = interval_set(&lock->rl_node, start >> PAGE_SHIFT, end);
-	if (rc)
-		return rc;
-
-	INIT_LIST_HEAD(&lock->rl_next_lock);
-	lock->rl_task = NULL;
-	lock->rl_lock_count = 0;
-	lock->rl_blocking_ranges = 0;
-	lock->rl_sequence = 0;
-	return rc;
-}
-
-static inline struct range_lock *next_lock(struct range_lock *lock)
-{
-	return list_entry(lock->rl_next_lock.next, typeof(*lock), rl_next_lock);
-}
-
-/**
- * Helper function of range_unlock()
- *
- * \param node [in]	a range lock found overlapped during interval node
- *			search
- * \param arg [in]	the range lock to be tested
- *
- * \retval INTERVAL_ITER_CONT	indicate to continue the search for next
- *				overlapping range node
- * \retval INTERVAL_ITER_STOP	indicate to stop the search
- */
-static enum interval_iter range_unlock_cb(struct interval_node *node, void *arg)
-{
-	struct range_lock *lock = arg;
-	struct range_lock *overlap = node2rangelock(node);
-	struct range_lock *iter;
-
-	list_for_each_entry(iter, &overlap->rl_next_lock, rl_next_lock) {
-		if (iter->rl_sequence > lock->rl_sequence) {
-			--iter->rl_blocking_ranges;
-			LASSERT(iter->rl_blocking_ranges > 0);
-		}
-	}
-	if (overlap->rl_sequence > lock->rl_sequence) {
-		--overlap->rl_blocking_ranges;
-		if (overlap->rl_blocking_ranges == 0)
-			wake_up_process(overlap->rl_task);
-	}
-	return INTERVAL_ITER_CONT;
-}
-
-/**
- * Unlock a range lock, wake up locks blocked by this lock.
- *
- * \param tree [in]	range lock tree
- * \param lock [in]	range lock to be deleted
- *
- * If this lock has been granted, relase it; if not, just delete it from
- * the tree or the same region lock list. Wake up those locks only blocked
- * by this lock through range_unlock_cb().
- */
-void range_unlock(struct range_lock_tree *tree, struct range_lock *lock)
-{
-	spin_lock(&tree->rlt_lock);
-	if (!list_empty(&lock->rl_next_lock)) {
-		struct range_lock *next;
-
-		if (interval_is_intree(&lock->rl_node)) { /* first lock */
-			/* Insert the next same range lock into the tree */
-			next = next_lock(lock);
-			next->rl_lock_count = lock->rl_lock_count - 1;
-			interval_erase(&lock->rl_node, &tree->rlt_root);
-			interval_insert(&next->rl_node, &tree->rlt_root);
-		} else {
-			/* find the first lock in tree */
-			list_for_each_entry(next, &lock->rl_next_lock,
-					    rl_next_lock) {
-				if (!interval_is_intree(&next->rl_node))
-					continue;
-
-				LASSERT(next->rl_lock_count > 0);
-				next->rl_lock_count--;
-				break;
-			}
-		}
-		list_del_init(&lock->rl_next_lock);
-	} else {
-		LASSERT(interval_is_intree(&lock->rl_node));
-		interval_erase(&lock->rl_node, &tree->rlt_root);
-	}
-
-	interval_search(tree->rlt_root, &lock->rl_node.in_extent,
-			range_unlock_cb, lock);
-	spin_unlock(&tree->rlt_lock);
-}
-
-/**
- * Helper function of range_lock()
- *
- * \param node [in]	a range lock found overlapped during interval node
- *			search
- * \param arg [in]	the range lock to be tested
- *
- * \retval INTERVAL_ITER_CONT	indicate to continue the search for next
- *				overlapping range node
- * \retval INTERVAL_ITER_STOP	indicate to stop the search
- */
-static enum interval_iter range_lock_cb(struct interval_node *node, void *arg)
-{
-	struct range_lock *lock = arg;
-	struct range_lock *overlap = node2rangelock(node);
-
-	lock->rl_blocking_ranges += overlap->rl_lock_count + 1;
-	return INTERVAL_ITER_CONT;
-}
-
-/**
- * Lock a region
- *
- * \param tree [in]	range lock tree
- * \param lock [in]	range lock node containing the region span
- *
- * \retval 0	get the range lock
- * \retval <0	error code while not getting the range lock
- *
- * If there exists overlapping range lock, the new lock will wait and
- * retry, if later it find that it is not the chosen one to wake up,
- * it wait again.
- */
-int range_lock(struct range_lock_tree *tree, struct range_lock *lock)
-{
-	struct interval_node *node;
-	int rc = 0;
-
-	spin_lock(&tree->rlt_lock);
-	/*
-	 * We need to check for all conflicting intervals
-	 * already in the tree.
-	 */
-	interval_search(tree->rlt_root, &lock->rl_node.in_extent,
-			range_lock_cb, lock);
-	/*
-	 * Insert to the tree if I am unique, otherwise I've been linked to
-	 * the rl_next_lock of another lock which has the same range as mine
-	 * in range_lock_cb().
-	 */
-	node = interval_insert(&lock->rl_node, &tree->rlt_root);
-	if (node) {
-		struct range_lock *tmp = node2rangelock(node);
-
-		list_add_tail(&lock->rl_next_lock, &tmp->rl_next_lock);
-		tmp->rl_lock_count++;
-	}
-	lock->rl_sequence = ++tree->rlt_sequence;
-
-	while (lock->rl_blocking_ranges > 0) {
-		lock->rl_task = current;
-		__set_current_state(TASK_INTERRUPTIBLE);
-		spin_unlock(&tree->rlt_lock);
-		schedule();
-
-		if (signal_pending(current)) {
-			range_unlock(tree, lock);
-			rc = -EINTR;
-			goto out;
-		}
-		spin_lock(&tree->rlt_lock);
-	}
-	spin_unlock(&tree->rlt_lock);
-out:
-	return rc;
-}
diff --git a/drivers/staging/lustre/lustre/llite/range_lock.h b/drivers/staging/lustre/lustre/llite/range_lock.h
deleted file mode 100644
index 779091ccec4e..000000000000
--- a/drivers/staging/lustre/lustre/llite/range_lock.h
+++ /dev/null
@@ -1,82 +0,0 @@
-/*
- * GPL HEADER START
- *
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * General Public License version 2 for more details (a copy is included
- * in the LICENSE file that accompanied this code).
- *
- * You should have received a copy of the GNU General Public License
- * version 2 along with this program; If not, see
- * http://www.gnu.org/licenses/gpl-2.0.html
- *
- * GPL HEADER END
- */
-/*
- * Range lock is used to allow multiple threads writing a single shared
- * file given each thread is writing to a non-overlapping portion of the
- * file.
- *
- * Refer to the possible upstream kernel version of range lock by
- * Jan Kara <jack@...e.cz>: https://lkml.org/lkml/2013/1/31/480
- *
- * This file could later replaced by the upstream kernel version.
- */
-/*
- * Author: Prakash Surya <surya1@...l.gov>
- * Author: Bobi Jam <bobijam.xu@...el.com>
- */
-#ifndef _RANGE_LOCK_H
-#define _RANGE_LOCK_H
-
-#include "../../include/linux/libcfs/libcfs.h"
-#include "../include/interval_tree.h"
-
-struct range_lock {
-	struct interval_node	rl_node;
-	/**
-	 * Process to enqueue this lock.
-	 */
-	struct task_struct	*rl_task;
-	/**
-	 * List of locks with the same range.
-	 */
-	struct list_head	rl_next_lock;
-	/**
-	 * Number of locks in the list rl_next_lock
-	 */
-	unsigned int		rl_lock_count;
-	/**
-	 * Number of ranges which are blocking acquisition of the lock
-	 */
-	unsigned int		rl_blocking_ranges;
-	/**
-	 * Sequence number of range lock. This number is used to get to know
-	 * the order the locks are queued; this is required for range_cancel().
-	 */
-	__u64			rl_sequence;
-};
-
-static inline struct range_lock *node2rangelock(const struct interval_node *n)
-{
-	return container_of(n, struct range_lock, rl_node);
-}
-
-struct range_lock_tree {
-	struct interval_node	*rlt_root;
-	spinlock_t		 rlt_lock;	/* protect range lock tree */
-	__u64			 rlt_sequence;
-};
-
-void range_lock_tree_init(struct range_lock_tree *tree);
-int range_lock_init(struct range_lock *lock, __u64 start, __u64 end);
-int  range_lock(struct range_lock_tree *tree, struct range_lock *lock);
-void range_unlock(struct range_lock_tree *tree, struct range_lock *lock);
-#endif
-- 
2.12.0

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