binder: keep vma addresses type as unsigned long

The vma addresses in binder are currently stored as void __user *. This
requires casting back and forth between the mm/ api which uses unsigned
long. Since we also do internal arithmetic on these addresses we end up
having to cast them _again_ to an integer type.

Lets stop all the unnecessary casting which kills code readability and
store the virtual addresses as the native unsigned long from mm/. Note
that this approach is preferred over uintptr_t as Linus explains in [1].

Opportunistically add a few cosmetic touchups.

Link: https://lore.kernel.org/all/CAHk-=wj2OHy-5e+srG1fy+ZU00TmZ1NFp6kFLbVLMXHe7A1d-g@mail.gmail.com/ [1]
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20231201172212.1813387-10-cmllamas@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 10 insertions, 11 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 71a40a4c546f..437d1097b118 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2077,9 +2077,8 @@ static void binder_transaction_buffer_release(struct binder_proc *proc,
 			 * Convert the address to an offset relative to
 			 * the base of the transaction buffer.
 			 */
-			fda_offset =
-			    (parent->buffer - (uintptr_t)buffer->user_data) +
-			    fda->parent_offset;
+			fda_offset = parent->buffer - buffer->user_data +
+				fda->parent_offset;
 			for (fd_index = 0; fd_index < fda->num_fds;
 			     fd_index++) {
 				u32 fd;
@@ -2597,7 +2596,7 @@ static int binder_translate_fd_array(struct list_head *pf_head,
 	 * Convert the address to an offset relative to
 	 * the base of the transaction buffer.
 	 */
-	fda_offset = (parent->buffer - (uintptr_t)t->buffer->user_data) +
+	fda_offset = parent->buffer - t->buffer->user_data +
 		fda->parent_offset;
 	sender_ufda_base = (void __user *)(uintptr_t)sender_uparent->buffer +
 				fda->parent_offset;
@@ -2672,8 +2671,9 @@ static int binder_fixup_parent(struct list_head *pf_head,
 				  proc->pid, thread->pid);
 		return -EINVAL;
 	}
-	buffer_offset = bp->parent_offset +
-			(uintptr_t)parent->buffer - (uintptr_t)b->user_data;
+
+	buffer_offset = bp->parent_offset + parent->buffer - b->user_data;
+
 	return binder_add_fixup(pf_head, buffer_offset, bp->buffer, 0);
 }
 
@@ -3250,7 +3250,7 @@ static void binder_transaction(struct binder_proc *proc,
 				    ALIGN(extra_buffers_size, sizeof(void *)) -
 				    ALIGN(secctx_sz, sizeof(u64));
 
-		t->security_ctx = (uintptr_t)t->buffer->user_data + buf_offset;
+		t->security_ctx = t->buffer->user_data + buf_offset;
 		err = binder_alloc_copy_to_buffer(&target_proc->alloc,
 						  t->buffer, buf_offset,
 						  secctx, secctx_sz);
@@ -3527,8 +3527,7 @@ static void binder_transaction(struct binder_proc *proc,
 				goto err_translate_failed;
 			}
 			/* Fixup buffer pointer to target proc address space */
-			bp->buffer = (uintptr_t)
-				t->buffer->user_data + sg_buf_offset;
+			bp->buffer = t->buffer->user_data + sg_buf_offset;
 			sg_buf_offset += ALIGN(bp->length, sizeof(u64));
 
 			num_valid = (buffer_offset - off_start_offset) /
@@ -4698,7 +4697,7 @@ retry:
 		}
 		trd->data_size = t->buffer->data_size;
 		trd->offsets_size = t->buffer->offsets_size;
-		trd->data.ptr.buffer = (uintptr_t)t->buffer->user_data;
+		trd->data.ptr.buffer = t->buffer->user_data;
 		trd->data.ptr.offsets = trd->data.ptr.buffer +
 					ALIGN(t->buffer->data_size,
 					    sizeof(void *));
@@ -5981,7 +5980,7 @@ static void print_binder_transaction_ilocked(struct seq_file *m,
 	}
 	if (buffer->target_node)
 		seq_printf(m, " node %d", buffer->target_node->debug_id);
-	seq_printf(m, " size %zd:%zd data %pK\n",
+	seq_printf(m, " size %zd:%zd data %lx\n",
 		   buffer->data_size, buffer->offsets_size,
 		   buffer->user_data);
 }