release mtx before pool_get() in __xa_alloc()/__xa_store() when

PR_WAITOK is used to not sleep with mtx held

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index b9bd039..004a7bd 100644 (file)
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: drm_linux.c,v 1.88 2022/01/20 06:33:03 jsg Exp $      */
+/*     $OpenBSD: drm_linux.c,v 1.89 2022/01/21 23:49:36 jsg Exp $      */
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -936,11 +936,17 @@ int
 __xa_alloc(struct xarray *xa, u32 *id, void *entry, int limit, gfp_t gfp)
 {
        struct xarray_entry *xid;
-       int flags = (gfp & GFP_NOWAIT) ? PR_NOWAIT : PR_WAITOK;
        int start = (xa->xa_flags & XA_FLAGS_ALLOC1) ? 1 : 0;
        int begin;
 
-       xid = pool_get(&xa_pool, flags);
+       if (gfp & GFP_NOWAIT) {
+               xid = pool_get(&xa_pool, PR_NOWAIT);
+       } else {
+               mtx_leave(&xa->xa_lock);
+               xid = pool_get(&xa_pool, PR_WAITOK);
+               mtx_enter(&xa->xa_lock);
+       }
+
        if (xid == NULL)
                return -ENOMEM;
 
@@ -997,7 +1003,6 @@ __xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
 {
        struct xarray_entry find, *res;
        void *prev;
-       int flags = (gfp & GFP_NOWAIT) ? PR_NOWAIT : PR_WAITOK;
 
        if (entry == NULL)
                return __xa_erase(xa, index);
@@ -1013,7 +1018,13 @@ __xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
        }
 
        /* index not found, add new */
-       res = pool_get(&xa_pool, flags);
+       if (gfp & GFP_NOWAIT) {
+               res = pool_get(&xa_pool, PR_NOWAIT);
+       } else {
+               mtx_leave(&xa->xa_lock);
+               res = pool_get(&xa_pool, PR_WAITOK);
+               mtx_enter(&xa->xa_lock);
+       }
        if (res == NULL)
                return XA_ERROR(-ENOMEM);
        res->id = index;