Module Name: src
Committed By: riastradh
Date: Tue Feb 15 22:51:03 UTC 2022
Modified Files:
src/sys/external/bsd/drm2/linux: linux_dma_resv.c
Log Message:
drm: Use KM_SLEEP to allocate reservation fence arrays.
Except as a fast path in an RCU reader.
The array sizes appear to be reasonably small and not trivially
controlled by userland, from what I can tell, so if my impression is
accurate, it is reasonable to sleep for allocation here.
To generate a diff of this commit:
cvs rdiff -u -r1.21 -r1.22 src/sys/external/bsd/drm2/linux/linux_dma_resv.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/linux/linux_dma_resv.c
diff -u src/sys/external/bsd/drm2/linux/linux_dma_resv.c:1.21 src/sys/external/bsd/drm2/linux/linux_dma_resv.c:1.22
--- src/sys/external/bsd/drm2/linux/linux_dma_resv.c:1.21 Sun Dec 19 12:36:02 2021
+++ src/sys/external/bsd/drm2/linux/linux_dma_resv.c Tue Feb 15 22:51:03 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: linux_dma_resv.c,v 1.21 2021/12/19 12:36:02 riastradh Exp $ */
+/* $NetBSD: linux_dma_resv.c,v 1.22 2022/02/15 22:51:03 riastradh Exp $ */
/*-
* Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_dma_resv.c,v 1.21 2021/12/19 12:36:02 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_dma_resv.c,v 1.22 2022/02/15 22:51:03 riastradh Exp $");
#include <sys/param.h>
#include <sys/poll.h>
@@ -56,6 +56,17 @@ objlist_tryalloc(uint32_t n)
return list;
}
+static struct dma_resv_list *
+objlist_alloc(uint32_t n)
+{
+ struct dma_resv_list *list;
+
+ list = kmem_alloc(offsetof(typeof(*list), shared[n]), KM_SLEEP);
+ list->shared_max = n;
+
+ return list;
+}
+
static void
objlist_free(struct dma_resv_list *list)
{
@@ -346,9 +357,7 @@ dma_resv_reserve_shared(struct dma_resv
/* Try to double its capacity. */
nalloc = n > UINT32_MAX/2 ? UINT32_MAX : 2*n;
- prealloc = objlist_tryalloc(nalloc);
- if (prealloc == NULL)
- return -ENOMEM;
+ prealloc = objlist_alloc(nalloc);
/* Swap the new preallocated list and free the old one. */
objlist_free(robj->robj_prealloc);
@@ -356,9 +365,8 @@ dma_resv_reserve_shared(struct dma_resv
} else {
/* Start with some spare. */
nalloc = n > UINT32_MAX/2 ? UINT32_MAX : MAX(2*n, 4);
- prealloc = objlist_tryalloc(nalloc);
- if (prealloc == NULL)
- return -ENOMEM;
+ prealloc = objlist_alloc(nalloc);
+
/* Save the new preallocated list. */
robj->robj_prealloc = prealloc;
}
@@ -689,8 +697,10 @@ dma_resv_add_shared_fence(struct dma_res
prealloc->shared_count = shared_count;
/* If we didn't find one, add it at the end. */
- if (replace == NULL)
+ if (replace == NULL) {
+ KASSERT(prealloc->shared_count < prealloc->shared_max);
prealloc->shared[prealloc->shared_count++] = fence;
+ }
/*
* Now ready to replace the list. Begin an update.
@@ -919,11 +929,20 @@ top: KASSERT(fence == NULL);
if (!dma_resv_get_shared_reader(src_robj, &src_list, &shared_count,
&read_ticket))
goto restart;
- if (src_list != NULL) {
- /* Allocate a new list. */
- dst_list = objlist_tryalloc(shared_count);
+ if (src_list) {
+ /* Allocate a new list, if necessary. */
if (dst_list == NULL)
- return -ENOMEM;
+ dst_list = objlist_tryalloc(shared_count);
+ if (dst_list == NULL || dst_list->shared_max < shared_count) {
+ rcu_read_unlock();
+ if (dst_list) {
+ objlist_free(dst_list);
+ dst_list = NULL;
+ }
+ dst_list = objlist_alloc(shared_count);
+ dst_list->shared_count = 0; /* paranoia */
+ goto top;
+ }
/* Copy over all fences that are not yet signalled. */
dst_list->shared_count = 0;
@@ -1005,8 +1024,7 @@ restart:
dma_fence_put(dst_list->shared[i]);
dst_list->shared[i] = NULL; /* paranoia */
}
- objlist_free(dst_list);
- dst_list = NULL;
+ /* reuse dst_list allocation for the next attempt */
}
goto top;
}
