pan/kmod: Make default allocator thread-safe

Allocations targeting a pan_kmod_dev can happen concurrently, so we
need the pan_kmod_dev allocator to be thread-safe.

ralloc() is not thread-safe, and we don't really need a hierarchical
allocator in this context anyway, so let's just switch to calloc/free
instead.

Fixes: d95ec56f8c68 ("panfrost: Abstract kernel driver operations")
Reported-by: Eric Smith <eric.smith@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Tested-by: Eric Smith <eric.smith@collabora.com>
Reviewed-by: Eric Smith <eric.smith@collabora.com>
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28926>
(cherry picked from commit 4c74d1473054ca3cc609bae6e31028063bd531bf)

2 files changed, 10 insertions, 33 deletions

diff --git a/.pick_status.json b/.pick_status.json
index 0230b1b5b8f..f78ffc427c0 100644
--- a/.pick_status.json
+++ b/.pick_status.json
@@ -54,7 +54,7 @@
         "description": "pan/kmod: Make default allocator thread-safe",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "d95ec56f8c6884e0ae975b683fe7249fab9e740d",
         "notes": null
diff --git a/src/panfrost/lib/kmod/pan_kmod.c b/src/panfrost/lib/kmod/pan_kmod.c
index 395bc378f31..b6b43a5cf3b 100644
--- a/src/panfrost/lib/kmod/pan_kmod.c
+++ b/src/panfrost/lib/kmod/pan_kmod.c
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <xf86drm.h>
 
+#include "util/u_memory.h"
 #include "util/macros.h"
 #include "pan_kmod.h"
 
@@ -26,28 +27,19 @@ static void *
 default_zalloc(const struct pan_kmod_allocator *allocator, size_t size,
                UNUSED bool transient)
 {
-   return rzalloc_size(allocator, size);
+   return os_calloc(1, size);
 }
 
 static void
 default_free(const struct pan_kmod_allocator *allocator, void *data)
 {
-   return ralloc_free(data);
+   os_free(data);
 }
 
-static const struct pan_kmod_allocator *
-create_default_allocator(void)
-{
-   struct pan_kmod_allocator *allocator =
-      rzalloc(NULL, struct pan_kmod_allocator);
-
-   if (allocator) {
-      allocator->zalloc = default_zalloc;
-      allocator->free = default_free;
-   }
-
-   return allocator;
-}
+static const struct pan_kmod_allocator default_allocator = {
+   .zalloc = default_zalloc,
+   .free = default_free,
+};
 
 struct pan_kmod_dev *
 pan_kmod_dev_create(int fd, uint32_t flags,
@@ -59,28 +51,18 @@ pan_kmod_dev_create(int fd, uint32_t flags,
    if (!version)
       return NULL;
 
-   if (!allocator) {
-      allocator = create_default_allocator();
-      if (!allocator)
-         goto out_free_version;
-   }
+   if (!allocator)
+      allocator = &default_allocator;
 
    for (unsigned i = 0; i < ARRAY_SIZE(drivers); i++) {
       if (!strcmp(drivers[i].name, version->name)) {
          const struct pan_kmod_ops *ops = drivers[i].ops;
 
          dev = ops->dev_create(fd, flags, version, allocator);
-         if (dev)
-            goto out_free_version;
-
          break;
       }
    }
 
-   if (allocator->zalloc == default_zalloc)
-      ralloc_free((void *)allocator);
-
-out_free_version:
    drmFreeVersion(version);
    return dev;
 }
@@ -88,12 +70,7 @@ out_free_version:
 void
 pan_kmod_dev_destroy(struct pan_kmod_dev *dev)
 {
-   const struct pan_kmod_allocator *allocator = dev->allocator;
-
    dev->ops->dev_destroy(dev);
-
-   if (allocator->zalloc == default_zalloc)
-      ralloc_free((void *)allocator);
 }
 
 struct pan_kmod_bo *