bpf: Convert btf_idr to XArray

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 5fcc7a17eb5a4d538ffef61335481a262bc23720..e62b35f209fa5d70719069429312c21ccdb7ec2d 100644 (file)
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -12,8 +12,8 @@
 #include <linux/file.h>
 #include <linux/uaccess.h>
 #include <linux/kernel.h>
-#include <linux/idr.h>
 #include <linux/sort.h>
+#include <linux/xarray.h>
 #include <linux/bpf_verifier.h>
 #include <linux/btf.h>
 
@@ -195,8 +195,8 @@
             i < btf_type_vlen(struct_type);                                    \
             i++, member++)
 
-static DEFINE_IDR(btf_idr);
-static DEFINE_SPINLOCK(btf_idr_lock);
+static DEFINE_XARRAY_FLAGS(btf_xa, XA_FLAGS_ALLOC1 | XA_FLAGS_LOCK_BH);
+static u32 btf_next_id;
 
 struct btf {
        void *data;
@@ -860,20 +860,8 @@ static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
 
 static int btf_alloc_id(struct btf *btf)
 {
-       int id;
-
-       idr_preload(GFP_KERNEL);
-       spin_lock_bh(&btf_idr_lock);
-       id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
-       if (id > 0)
-               btf->id = id;
-       spin_unlock_bh(&btf_idr_lock);
-       idr_preload_end();
-
-       if (WARN_ON_ONCE(!id))
-               return -ENOSPC;
-
-       return id > 0 ? 0 : id;
+       return xa_alloc_cyclic_bh(&btf_xa, &btf->id, btf, xa_limit_31b,
+                       &btf_next_id, GFP_KERNEL);
 }
 
 static void btf_free_id(struct btf *btf)
@@ -889,9 +877,9 @@ static void btf_free_id(struct btf *btf)
         * we need to use the _irqsave() version instead
         * of the _bh() version.
         */
-       spin_lock_irqsave(&btf_idr_lock, flags);
-       idr_remove(&btf_idr, btf->id);
-       spin_unlock_irqrestore(&btf_idr_lock, flags);
+       xa_lock_irqsave(&btf_xa, flags);
+       __xa_erase(&btf_xa, btf->id);
+       xa_unlock_irqrestore(&btf_xa, flags);
 }
 
 static void btf_free(struct btf *btf)
@@ -3404,7 +3392,7 @@ int btf_new_fd(const union bpf_attr *attr)
                return PTR_ERR(btf);
 
        ret = btf_alloc_id(btf);
-       if (ret) {
+       if (ret < 0) {
                btf_free(btf);
                return ret;
        }
@@ -3481,13 +3469,13 @@ int btf_get_fd_by_id(u32 id)
        int fd;
 
        rcu_read_lock();
-       btf = idr_find(&btf_idr, id);
-       if (!btf || !refcount_inc_not_zero(&btf->refcnt))
-               btf = ERR_PTR(-ENOENT);
+       btf = xa_load(&btf_xa, id);
+       if (btf && !refcount_inc_not_zero(&btf->refcnt))
+               btf = NULL;
        rcu_read_unlock();
 
-       if (IS_ERR(btf))
-               return PTR_ERR(btf);
+       if (!btf)
+               return -ENOENT;
 
        fd = __btf_new_fd(btf);
        if (fd < 0)