From: Matthew Wilcox <mawil...@microsoft.com>

Removes another user of radix_tree_preload().

Signed-off-by: Matthew Wilcox <mawil...@microsoft.com>
---
 fs/fscache/cookie.c     |   6 +-
 fs/fscache/internal.h   |   2 +-
 fs/fscache/object.c     |   2 +-
 fs/fscache/page.c       | 152 +++++++++++++++++++++---------------------------
 fs/fscache/stats.c      |   6 +-
 include/linux/fscache.h |   8 +--
 6 files changed, 76 insertions(+), 100 deletions(-)

diff --git a/fs/fscache/cookie.c b/fs/fscache/cookie.c
index e9054e0c1a49..6d45134d609e 100644
--- a/fs/fscache/cookie.c
+++ b/fs/fscache/cookie.c
@@ -109,9 +109,7 @@ struct fscache_cookie *__fscache_acquire_cookie(
        cookie->netfs_data      = netfs_data;
        cookie->flags           = (1 << FSCACHE_COOKIE_NO_DATA_YET);
 
-       /* radix tree insertion won't use the preallocation pool unless it's
-        * told it may not wait */
-       INIT_RADIX_TREE(&cookie->stores, GFP_NOFS & ~__GFP_DIRECT_RECLAIM);
+       xa_init(&cookie->stores);
 
        switch (cookie->def->type) {
        case FSCACHE_COOKIE_TYPE_INDEX:
@@ -608,7 +606,7 @@ void __fscache_relinquish_cookie(struct fscache_cookie 
*cookie, bool retire)
        /* Clear pointers back to the netfs */
        cookie->netfs_data      = NULL;
        cookie->def             = NULL;
-       BUG_ON(!radix_tree_empty(&cookie->stores));
+       BUG_ON(!xa_empty(&cookie->stores));
 
        if (cookie->parent) {
                ASSERTCMP(atomic_read(&cookie->parent->usage), >, 0);
diff --git a/fs/fscache/internal.h b/fs/fscache/internal.h
index 0ff4b49a0037..468d9bd7f8c3 100644
--- a/fs/fscache/internal.h
+++ b/fs/fscache/internal.h
@@ -200,7 +200,7 @@ extern atomic_t fscache_n_stores_oom;
 extern atomic_t fscache_n_store_ops;
 extern atomic_t fscache_n_store_calls;
 extern atomic_t fscache_n_store_pages;
-extern atomic_t fscache_n_store_radix_deletes;
+extern atomic_t fscache_n_store_xarray_deletes;
 extern atomic_t fscache_n_store_pages_over_limit;
 
 extern atomic_t fscache_n_store_vmscan_not_storing;
diff --git a/fs/fscache/object.c b/fs/fscache/object.c
index aa0e71f02c33..ed165736a358 100644
--- a/fs/fscache/object.c
+++ b/fs/fscache/object.c
@@ -956,7 +956,7 @@ static const struct fscache_state 
*_fscache_invalidate_object(struct fscache_obj
         * retire the object instead.
         */
        if (!fscache_use_cookie(object)) {
-               ASSERT(radix_tree_empty(&object->cookie->stores));
+               ASSERT(xa_empty(&object->cookie->stores));
                set_bit(FSCACHE_OBJECT_RETIRED, &object->flags);
                _leave(" [no cookie]");
                return transit_to(KILL_OBJECT);
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index 961029e04027..315e2745f822 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -22,13 +22,7 @@
  */
 bool __fscache_check_page_write(struct fscache_cookie *cookie, struct page 
*page)
 {
-       void *val;
-
-       rcu_read_lock();
-       val = radix_tree_lookup(&cookie->stores, page->index);
-       rcu_read_unlock();
-
-       return val != NULL;
+       return xa_load(&cookie->stores, page->index) != NULL;
 }
 EXPORT_SYMBOL(__fscache_check_page_write);
 
@@ -64,15 +58,15 @@ bool __fscache_maybe_release_page(struct fscache_cookie 
*cookie,
                                  struct page *page,
                                  gfp_t gfp)
 {
+       XA_STATE(xas, &cookie->stores, page->index);
        struct page *xpage;
-       void *val;
 
        _enter("%p,%p,%x", cookie, page, gfp);
 
 try_again:
        rcu_read_lock();
-       val = radix_tree_lookup(&cookie->stores, page->index);
-       if (!val) {
+       xpage = xas_load(&xas);
+       if (!xpage) {
                rcu_read_unlock();
                fscache_stat(&fscache_n_store_vmscan_not_storing);
                __fscache_uncache_page(cookie, page);
@@ -81,31 +75,32 @@ bool __fscache_maybe_release_page(struct fscache_cookie 
*cookie,
 
        /* see if the page is actually undergoing storage - if so we can't get
         * rid of it till the cache has finished with it */
-       if (radix_tree_tag_get(&cookie->stores, page->index,
-                              FSCACHE_COOKIE_STORING_TAG)) {
+       if (xas_get_tag(&xas, FSCACHE_COOKIE_STORING_TAG)) {
                rcu_read_unlock();
+               xas_retry(&xas, XA_RETRY_ENTRY);
                goto page_busy;
        }
 
        /* the page is pending storage, so we attempt to cancel the store and
         * discard the store request so that the page can be reclaimed */
-       spin_lock(&cookie->stores_lock);
+       xas_retry(&xas, XA_RETRY_ENTRY);
+       xas_lock(&xas);
        rcu_read_unlock();
 
-       if (radix_tree_tag_get(&cookie->stores, page->index,
-                              FSCACHE_COOKIE_STORING_TAG)) {
+       xpage = xas_load(&xas);
+       if (xas_get_tag(&xas, FSCACHE_COOKIE_STORING_TAG)) {
                /* the page started to undergo storage whilst we were looking,
                 * so now we can only wait or return */
                spin_unlock(&cookie->stores_lock);
                goto page_busy;
        }
 
-       xpage = radix_tree_delete(&cookie->stores, page->index);
+       xas_store(&xas, NULL);
        spin_unlock(&cookie->stores_lock);
 
        if (xpage) {
                fscache_stat(&fscache_n_store_vmscan_cancelled);
-               fscache_stat(&fscache_n_store_radix_deletes);
+               fscache_stat(&fscache_n_store_xarray_deletes);
                ASSERTCMP(xpage, ==, page);
        } else {
                fscache_stat(&fscache_n_store_vmscan_gone);
@@ -149,17 +144,19 @@ static void fscache_end_page_write(struct fscache_object 
*object,
        spin_lock(&object->lock);
        cookie = object->cookie;
        if (cookie) {
+               XA_STATE(xas, &cookie->stores, page->index);
                /* delete the page from the tree if it is now no longer
                 * pending */
-               spin_lock(&cookie->stores_lock);
-               radix_tree_tag_clear(&cookie->stores, page->index,
-                                    FSCACHE_COOKIE_STORING_TAG);
-               if (!radix_tree_tag_get(&cookie->stores, page->index,
-                                       FSCACHE_COOKIE_PENDING_TAG)) {
-                       fscache_stat(&fscache_n_store_radix_deletes);
-                       xpage = radix_tree_delete(&cookie->stores, page->index);
+               xas_lock(&xas);
+               xpage = xas_load(&xas);
+               xas_clear_tag(&xas, FSCACHE_COOKIE_STORING_TAG);
+               if (xas_get_tag(&xas, FSCACHE_COOKIE_PENDING_TAG)) {
+                       xpage = NULL;
+               } else {
+                       fscache_stat(&fscache_n_store_xarray_deletes);
+                       xas_store(&xas, NULL);
                }
-               spin_unlock(&cookie->stores_lock);
+               xas_unlock(&xas);
                wake_up_bit(&cookie->flags, 0);
        }
        spin_unlock(&object->lock);
@@ -765,13 +762,12 @@ static void fscache_release_write_op(struct 
fscache_operation *_op)
  */
 static void fscache_write_op(struct fscache_operation *_op)
 {
+       XA_STATE(xas, NULL, 0);
        struct fscache_storage *op =
                container_of(_op, struct fscache_storage, op);
        struct fscache_object *object = op->op.object;
        struct fscache_cookie *cookie;
        struct page *page;
-       unsigned n;
-       void *results[1];
        int ret;
 
        _enter("{OP%x,%d}", op->op.debug_id, atomic_read(&op->op.usage));
@@ -804,29 +800,25 @@ static void fscache_write_op(struct fscache_operation 
*_op)
                return;
        }
 
-       spin_lock(&cookie->stores_lock);
+       xas.xa = &cookie->stores;
+       xas_lock(&xas);
 
        fscache_stat(&fscache_n_store_calls);
 
        /* find a page to store */
-       page = NULL;
-       n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0, 1,
-                                      FSCACHE_COOKIE_PENDING_TAG);
-       if (n != 1)
+       page = xas_find_tag(&xas, ULONG_MAX, FSCACHE_COOKIE_PENDING_TAG);
+       if (!page)
                goto superseded;
-       page = results[0];
-       _debug("gang %d [%lx]", n, page->index);
+       _debug("found %lx", page->index);
        if (page->index >= op->store_limit) {
                fscache_stat(&fscache_n_store_pages_over_limit);
                goto superseded;
        }
 
-       radix_tree_tag_set(&cookie->stores, page->index,
-                          FSCACHE_COOKIE_STORING_TAG);
-       radix_tree_tag_clear(&cookie->stores, page->index,
-                            FSCACHE_COOKIE_PENDING_TAG);
+       xas_set_tag(&xas, FSCACHE_COOKIE_STORING_TAG);
+       xas_clear_tag(&xas, FSCACHE_COOKIE_PENDING_TAG);
+       xas_unlock(&xas);
 
-       spin_unlock(&cookie->stores_lock);
        spin_unlock(&object->lock);
 
        fscache_stat(&fscache_n_store_pages);
@@ -848,7 +840,7 @@ static void fscache_write_op(struct fscache_operation *_op)
        /* this writer is going away and there aren't any more things to
         * write */
        _debug("cease");
-       spin_unlock(&cookie->stores_lock);
+       xas_unlock(&xas);
        clear_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags);
        spin_unlock(&object->lock);
        fscache_op_complete(&op->op, true);
@@ -860,32 +852,25 @@ static void fscache_write_op(struct fscache_operation 
*_op)
  */
 void fscache_invalidate_writes(struct fscache_cookie *cookie)
 {
+       XA_STATE(xas, &cookie->stores, 0);
+       unsigned int cleared = 0;
        struct page *page;
-       void *results[16];
-       int n, i;
 
        _enter("");
 
-       for (;;) {
-               spin_lock(&cookie->stores_lock);
-               n = radix_tree_gang_lookup_tag(&cookie->stores, results, 0,
-                                              ARRAY_SIZE(results),
-                                              FSCACHE_COOKIE_PENDING_TAG);
-               if (n == 0) {
-                       spin_unlock(&cookie->stores_lock);
-                       break;
-               }
-
-               for (i = n - 1; i >= 0; i--) {
-                       page = results[i];
-                       radix_tree_delete(&cookie->stores, page->index);
-               }
+       xas_lock(&xas);
+       xas_for_each_tag(&xas, page, ULONG_MAX, FSCACHE_COOKIE_PENDING_TAG) {
+               xas_store(&xas, NULL);
+               put_page(page);
+               if (++cleared % XA_CHECK_SCHED)
+                       continue;
 
-               spin_unlock(&cookie->stores_lock);
-
-               for (i = n - 1; i >= 0; i--)
-                       put_page(results[i]);
+               xas_pause(&xas);
+               xas_unlock(&xas);
+               cond_resched();
+               xas_lock(&xas);
        }
+       xas_unlock(&xas);
 
        wake_up_bit(&cookie->flags, 0);
 
@@ -925,9 +910,11 @@ int __fscache_write_page(struct fscache_cookie *cookie,
                         struct page *page,
                         gfp_t gfp)
 {
+       XA_STATE(xas, &cookie->stores, page->index);
        struct fscache_storage *op;
        struct fscache_object *object;
        bool wake_cookie = false;
+       struct page *xpage;
        int ret;
 
        _enter("%p,%x,", cookie, (u32) page->flags);
@@ -952,10 +939,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
                (1 << FSCACHE_OP_WAITING) |
                (1 << FSCACHE_OP_UNUSE_COOKIE);
 
-       ret = radix_tree_maybe_preload(gfp & ~__GFP_HIGHMEM);
-       if (ret < 0)
-               goto nomem_free;
-
+retry:
        ret = -ENOBUFS;
        spin_lock(&cookie->lock);
 
@@ -967,23 +951,19 @@ int __fscache_write_page(struct fscache_cookie *cookie,
        if (test_bit(FSCACHE_IOERROR, &object->cache->flags))
                goto nobufs;
 
-       /* add the page to the pending-storage radix tree on the backing
-        * object */
+       /* add the page to the pending-storage xarray on the backing object */
        spin_lock(&object->lock);
-       spin_lock(&cookie->stores_lock);
+       xas_lock(&xas);
 
        _debug("store limit %llx", (unsigned long long) object->store_limit);
 
-       ret = radix_tree_insert(&cookie->stores, page->index, page);
-       if (ret < 0) {
-               if (ret == -EEXIST)
-                       goto already_queued;
-               _debug("insert failed %d", ret);
+       xpage = xas_create(&xas);
+       if (xpage)
+               goto already_queued;
+       if (xas_error(&xas))
                goto nobufs_unlock_obj;
-       }
-
-       radix_tree_tag_set(&cookie->stores, page->index,
-                          FSCACHE_COOKIE_PENDING_TAG);
+       xas_store(&xas, page);
+       xas_set_tag(&xas, FSCACHE_COOKIE_PENDING_TAG);
        get_page(page);
 
        /* we only want one writer at a time, but we do need to queue new
@@ -991,7 +971,7 @@ int __fscache_write_page(struct fscache_cookie *cookie,
        if (test_and_set_bit(FSCACHE_OBJECT_PENDING_WRITE, &object->flags))
                goto already_pending;
 
-       spin_unlock(&cookie->stores_lock);
+       xas_unlock(&xas);
        spin_unlock(&object->lock);
 
        op->op.debug_id = atomic_inc_return(&fscache_op_debug_id);
@@ -1002,7 +982,6 @@ int __fscache_write_page(struct fscache_cookie *cookie,
                goto submit_failed;
 
        spin_unlock(&cookie->lock);
-       radix_tree_preload_end();
        fscache_stat(&fscache_n_store_ops);
        fscache_stat(&fscache_n_stores_ok);
 
@@ -1014,30 +993,31 @@ int __fscache_write_page(struct fscache_cookie *cookie,
 already_queued:
        fscache_stat(&fscache_n_stores_again);
 already_pending:
-       spin_unlock(&cookie->stores_lock);
+       xas_unlock(&xas);
        spin_unlock(&object->lock);
        spin_unlock(&cookie->lock);
-       radix_tree_preload_end();
        fscache_put_operation(&op->op);
        fscache_stat(&fscache_n_stores_ok);
        _leave(" = 0");
        return 0;
 
 submit_failed:
-       spin_lock(&cookie->stores_lock);
-       radix_tree_delete(&cookie->stores, page->index);
-       spin_unlock(&cookie->stores_lock);
+       xa_erase(&cookie->stores, page->index);
        wake_cookie = __fscache_unuse_cookie(cookie);
        put_page(page);
        ret = -ENOBUFS;
        goto nobufs;
 
 nobufs_unlock_obj:
-       spin_unlock(&cookie->stores_lock);
+       xas_unlock(&xas);
        spin_unlock(&object->lock);
+       spin_unlock(&cookie->lock);
+       if (xas_nomem(&xas, gfp))
+               goto retry;
+       goto nobufs2;
 nobufs:
        spin_unlock(&cookie->lock);
-       radix_tree_preload_end();
+nobufs2:
        fscache_put_operation(&op->op);
        if (wake_cookie)
                __fscache_wake_unused_cookie(cookie);
@@ -1045,8 +1025,6 @@ int __fscache_write_page(struct fscache_cookie *cookie,
        _leave(" = -ENOBUFS");
        return -ENOBUFS;
 
-nomem_free:
-       fscache_put_operation(&op->op);
 nomem:
        fscache_stat(&fscache_n_stores_oom);
        _leave(" = -ENOMEM");
diff --git a/fs/fscache/stats.c b/fs/fscache/stats.c
index 7ac6e839b065..9c012b4229cd 100644
--- a/fs/fscache/stats.c
+++ b/fs/fscache/stats.c
@@ -63,7 +63,7 @@ atomic_t fscache_n_stores_oom;
 atomic_t fscache_n_store_ops;
 atomic_t fscache_n_store_calls;
 atomic_t fscache_n_store_pages;
-atomic_t fscache_n_store_radix_deletes;
+atomic_t fscache_n_store_xarray_deletes;
 atomic_t fscache_n_store_pages_over_limit;
 
 atomic_t fscache_n_store_vmscan_not_storing;
@@ -232,11 +232,11 @@ static int fscache_stats_show(struct seq_file *m, void *v)
                   atomic_read(&fscache_n_stores_again),
                   atomic_read(&fscache_n_stores_nobufs),
                   atomic_read(&fscache_n_stores_oom));
-       seq_printf(m, "Stores : ops=%u run=%u pgs=%u rxd=%u olm=%u\n",
+       seq_printf(m, "Stores : ops=%u run=%u pgs=%u xar=%u olm=%u\n",
                   atomic_read(&fscache_n_store_ops),
                   atomic_read(&fscache_n_store_calls),
                   atomic_read(&fscache_n_store_pages),
-                  atomic_read(&fscache_n_store_radix_deletes),
+                  atomic_read(&fscache_n_store_xarray_deletes),
                   atomic_read(&fscache_n_store_pages_over_limit));
 
        seq_printf(m, "VmScan : nos=%u gon=%u bsy=%u can=%u wt=%u\n",
diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index e7cc90aeac3d..9a3b83b295a3 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -22,7 +22,7 @@
 #include <linux/list.h>
 #include <linux/pagemap.h>
 #include <linux/pagevec.h>
-#include <linux/radix-tree.h>
+#include <linux/xarray.h>
 
 #if defined(CONFIG_FSCACHE) || defined(CONFIG_FSCACHE_MODULE)
 #define fscache_available() (1)
@@ -175,9 +175,9 @@ struct fscache_cookie {
        const struct fscache_cookie_def *def;           /* definition */
        struct fscache_cookie           *parent;        /* parent of this entry 
*/
        void                            *netfs_data;    /* back pointer to 
netfs */
-       struct radix_tree_root          stores;         /* pages to be stored 
on this cookie */
-#define FSCACHE_COOKIE_PENDING_TAG     0               /* pages tag: pending 
write to cache */
-#define FSCACHE_COOKIE_STORING_TAG     1               /* pages tag: writing 
to cache */
+       struct xarray                   stores;         /* pages to be stored 
on this cookie */
+#define FSCACHE_COOKIE_PENDING_TAG     XA_TAG_0        /* pages tag: pending 
write to cache */
+#define FSCACHE_COOKIE_STORING_TAG     XA_TAG_1        /* pages tag: writing 
to cache */
 
        unsigned long                   flags;
 #define FSCACHE_COOKIE_LOOKING_UP      0       /* T if non-index cookie being 
looked up still */
-- 
2.15.1

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