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From: Carlos Llamas <cmllamas@google.com>
To: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Arve Hjønnevåg" <arve@android.com>,
	"Todd Kjos" <tkjos@android.com>,
	"Martijn Coenen" <maco@android.com>,
	"Joel Fernandes" <joel@joelfernandes.org>,
	"Christian Brauner" <brauner@kernel.org>,
	"Carlos Llamas" <cmllamas@google.com>,
	"Suren Baghdasaryan" <surenb@google.com>
Cc: kernel-team@android.com,
	"Liam R . Howlett" <Liam.Howlett@oracle.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 4/7] binder: remove binder_alloc_set_vma()
Date: Mon, 29 Aug 2022 20:12:51 +0000	[thread overview]
Message-ID: <20220829201254.1814484-5-cmllamas@google.com> (raw)
In-Reply-To: <20220829201254.1814484-1-cmllamas@google.com>

The mmap_locked asserts here are not needed since this is only called
back from the mmap stack in ->mmap() and ->close() which always acquire
the lock first. Remove these asserts along with binder_alloc_set_vma()
altogether since it's trivial enough to be consumed by callers.

Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Carlos Llamas <cmllamas@google.com>
---
 drivers/android/binder_alloc.c | 25 ++-----------------------
 1 file changed, 2 insertions(+), 23 deletions(-)

diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c
index 749a4cd30a83..1c39cfce32fa 100644
--- a/drivers/android/binder_alloc.c
+++ b/drivers/android/binder_alloc.c
@@ -309,27 +309,6 @@ static int binder_update_page_range(struct binder_alloc *alloc, int allocate,
 	return vma ? -ENOMEM : -ESRCH;
 }
 
-
-static inline void binder_alloc_set_vma(struct binder_alloc *alloc,
-		struct vm_area_struct *vma)
-{
-	unsigned long vm_start = 0;
-
-	/*
-	 * Allow clearing the vma with holding just the read lock to allow
-	 * munmapping downgrade of the write lock before freeing and closing the
-	 * file using binder_alloc_vma_close().
-	 */
-	if (vma) {
-		vm_start = vma->vm_start;
-		mmap_assert_write_locked(alloc->mm);
-	} else {
-		mmap_assert_locked(alloc->mm);
-	}
-
-	alloc->vma_addr = vm_start;
-}
-
 static inline struct vm_area_struct *binder_alloc_get_vma(
 		struct binder_alloc *alloc)
 {
@@ -793,7 +772,7 @@ 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;
-	binder_alloc_set_vma(alloc, vma);
+	alloc->vma_addr = vma->vm_start;
 
 	return 0;
 
@@ -983,7 +962,7 @@ int binder_alloc_get_allocated_count(struct binder_alloc *alloc)
  */
 void binder_alloc_vma_close(struct binder_alloc *alloc)
 {
-	binder_alloc_set_vma(alloc, NULL);
+	alloc->vma_addr = 0;
 }
 
 /**
-- 
2.37.2.672.g94769d06f0-goog


  parent reply	other threads:[~2022-08-29 20:13 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29 20:12 [PATCH 0/7] fix null-ptr-deref in binder_alloc and others Carlos Llamas
2022-08-29 20:12 ` [PATCH 1/7] binder: fix alloc->vma_vm_mm null-ptr dereference Carlos Llamas
2022-08-29 20:34   ` Andrew Morton
2022-08-29 21:20     ` Carlos Llamas
2022-08-30 19:06   ` Liam Howlett
2022-08-30 19:40     ` Carlos Llamas
2022-08-30 20:30       ` Liam Howlett
2022-08-30 22:26   ` Todd Kjos
2022-08-29 20:12 ` [PATCH 2/7] binder: fix trivial kernel-doc typo Carlos Llamas
2022-08-30  7:53   ` Christian Brauner
2022-08-30 22:20   ` Todd Kjos
2022-08-29 20:12 ` [PATCH 3/7] binder: rename alloc->vma_vm_mm to alloc->mm Carlos Llamas
2022-08-30  7:56   ` Christian Brauner
2022-08-30 22:20   ` Todd Kjos
2022-08-29 20:12 ` Carlos Llamas [this message]
2022-08-30 18:57   ` [PATCH 4/7] binder: remove binder_alloc_set_vma() Liam Howlett
2022-08-30 21:08     ` Carlos Llamas
2022-08-29 20:12 ` [PATCH 5/7] binder: remove unused binder_alloc->buffer_free Carlos Llamas
2022-08-30  7:57   ` Christian Brauner
2022-08-30 22:21   ` Todd Kjos
2022-08-29 20:12 ` [PATCH 6/7] binder: fix binder_alloc kernel-doc warnings Carlos Llamas
2022-08-30  7:53   ` Christian Brauner
2022-08-30 22:22   ` Todd Kjos
2022-08-29 20:12 ` [PATCH 7/7] binderfs: remove unused INTSTRLEN macro Carlos Llamas
2022-08-30  7:53   ` Christian Brauner
2022-09-01 14:18 ` [PATCH 0/7] fix null-ptr-deref in binder_alloc and others Greg Kroah-Hartman

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