Re: [RFC net-next 04/13] net: page_pool: id the page pools

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/page_pool/types.h |  4 ++++
 net/core/Makefile             |  2 +-
 net/core/page_pool.c          | 21 +++++++++++++++-----
 net/core/page_pool_priv.h     |  9 +++++++++
 net/core/page_pool_user.c     | 36 +++++++++++++++++++++++++++++++++++
 5 files changed, 66 insertions(+), 6 deletions(-)
 create mode 100644 net/core/page_pool_priv.h
 create mode 100644 net/core/page_pool_user.c

diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 1ac7ce25fbd4..9fadf15dadfa 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h

@@ -189,6 +189,10 @@ struct page_pool {

        /* Slow/Control-path information follows */
        struct page_pool_params_slow slow;
+       /* User-facing fields, protected by page_pools_lock */
+       struct {
+               u32 id;
+       } user;
 };

 struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);

diff --git a/net/core/Makefile b/net/core/Makefile
index 731db2eaa610..4ae3d83f67d5 100644
--- a/net/core/Makefile
+++ b/net/core/Makefile

@@ -18,7 +18,7 @@ obj-y              += dev.o dev_addr_lists.o dst.o netevent.o \
 obj-$(CONFIG_NETDEV_ADDR_LIST_TEST) += dev_addr_lists_test.o

 obj-y += net-sysfs.o
-obj-$(CONFIG_PAGE_POOL) += page_pool.o
+obj-$(CONFIG_PAGE_POOL) += page_pool.o page_pool_user.o
 obj-$(CONFIG_PROC_FS) += net-procfs.o
 obj-$(CONFIG_NET_PKTGEN) += pktgen.o
 obj-$(CONFIG_NETPOLL) += netpoll.o

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 8e71e116224d..de199c356043 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c

@@ -23,6 +23,8 @@

 #include <trace/events/page_pool.h>

+#include "page_pool_priv.h"
+
 #define DEFER_TIME (msecs_to_jiffies(1000))
 #define DEFER_WARN_INTERVAL (60 * HZ)

@@ -264,13 +266,21 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
                return ERR_PTR(-ENOMEM);

        err = page_pool_init(pool, params);
-       if (err < 0) {
-               pr_warn("%s() gave up with errno %d\n", __func__, err);
-               kfree(pool);
-               return ERR_PTR(err);
-       }
+       if (err < 0)
+               goto err_free;
+
+       err = page_pool_list(pool);
+       if (err)
+               goto err_uninit;

        return pool;
+
+err_uninit:
+       page_pool_uninit(pool);
+err_free:
+       pr_warn("%s() gave up with errno %d\n", __func__, err);
+       kfree(pool);
+       return ERR_PTR(err);
 }
 EXPORT_SYMBOL(page_pool_create);

@@ -818,6 +828,7 @@ static void page_pool_free(struct page_pool *pool)
        if (pool->disconnect)
                pool->disconnect(pool);

+       page_pool_unlist(pool);
        page_pool_uninit(pool);
        kfree(pool);
 }

diff --git a/net/core/page_pool_priv.h b/net/core/page_pool_priv.h
new file mode 100644
index 000000000000..6c4e4aeed02a
--- /dev/null
+++ b/net/core/page_pool_priv.h

@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifndef __PAGE_POOL_PRIV_H
+#define __PAGE_POOL_PRIV_H
+
+int page_pool_list(struct page_pool *pool);
+void page_pool_unlist(struct page_pool *pool);
+
+#endif

diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
new file mode 100644
index 000000000000..af4ac38a2de1
--- /dev/null
+++ b/net/core/page_pool_user.c

@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/mutex.h>
+#include <linux/xarray.h>
+#include <net/page_pool/types.h>
+
+#include "page_pool_priv.h"
+
+static DEFINE_XARRAY_FLAGS(page_pools, XA_FLAGS_ALLOC1);
+static DEFINE_MUTEX(page_pools_lock);
+
+int page_pool_list(struct page_pool *pool)
+{
+       static u32 id_alloc_next;
+       int err;
+
+       mutex_lock(&page_pools_lock);
+       err = xa_alloc_cyclic(&page_pools, &pool->user.id, pool, xa_limit_32b,
+                             &id_alloc_next, GFP_KERNEL);
+       if (err < 0)
+               goto err_unlock;
+
+       mutex_unlock(&page_pools_lock);
+       return 0;
+
+err_unlock:
+       mutex_unlock(&page_pools_lock);
+       return err;
+}
+
+void page_pool_unlist(struct page_pool *pool)
+{
+       mutex_lock(&page_pools_lock);
+       xa_erase(&page_pools, pool->user.id);
+       mutex_unlock(&page_pools_lock);
+}
--

2.41.0