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Revert "binder: add lockless binder_alloc_(set|get)_vma()"

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This reverts commit 1cae0d5136.

It breaks the Android kernel abi, but will be brought in through a
different branch to ensure it ends up in the tree properly.

Bug: 161946584
Change-Id: Ie86172232c2dca2f30c1b100ead68a5599937380
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman
2023-06-15 12:08:58 +00:00
parent 4bbb48a4fe
commit d62b5b7db6
1 changed files with 15 additions and 7 deletions
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22
drivers/android/binder_alloc.c
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@@ -310,18 +310,29 @@ err_no_vma:
return vma ? -ENOMEM : -ESRCH;
}
static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
struct vm_area_struct *vma)
{
/* pairs with smp_load_acquire in binder_alloc_get_vma() */
smp_store_release(&alloc->vma, vma);
/*
* If we see alloc->vma is not NULL, buffer data structures set up
* completely. Look at smp_rmb side binder_alloc_get_vma.
*/
smp_wmb();
alloc->vma = vma;
}
static inline struct vm_area_struct *binder_alloc_get_vma(
struct binder_alloc *alloc)
{
/* pairs with smp_store_release in binder_alloc_set_vma() */
return smp_load_acquire(&alloc->vma);
struct vm_area_struct *vma = NULL;
if (alloc->vma) {
/* Look at description in binder_alloc_set_vma */
smp_rmb();
vma = alloc->vma;
}
return vma;
}
static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
@@ -384,7 +395,6 @@ static struct binder_buffer *binder_alloc_new_buf_locked(
size_t size, data_offsets_size;
int ret;
/* Check binder_alloc is fully initialized */
if (!binder_alloc_get_vma(alloc)) {
binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
"%d: binder_alloc_buf, no vma\n",
@@ -781,8 +791,6 @@ int binder_alloc_mmap_handler(struct binder_alloc *alloc,
buffer->free = 1;
binder_insert_free_buffer(alloc, buffer);
alloc->free_async_space = alloc->buffer_size / 2;
/* Signal binder_alloc is fully initialized */
binder_alloc_set_vma(alloc, vma);
return 0;