| Message ID | 20230123191728.2928839-4-tjmercier@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Paul Moore |
| Headers | show |
| Series | Track exported dma-buffers with memcg | expand |
Hi Mercier",
Thank you for the patch! Yet something to improve:
[auto build test ERROR on 2241ab53cbb5cdb08a6b2d4688feb13971058f65]
url: https://github.com/intel-lab-lkp/linux/commits/T-J-Mercier/memcg-Track-exported-dma-buffers/20230124-032017
base: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
patch link: https://lore.kernel.org/r/20230123191728.2928839-4-tjmercier%40google.com
patch subject: [PATCH v2 3/4] binder: Add flags to relinquish ownership of fds
config: x86_64-randconfig-a016-20230123 (https://download.01.org/0day-ci/archive/20230125/202301251234.klClMpZF-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/41e80f59d1b70691eefc0490e7f1df800cead9f2
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review T-J-Mercier/memcg-Track-exported-dma-buffers/20230124-032017
git checkout 41e80f59d1b70691eefc0490e7f1df800cead9f2
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> ld.lld: error: undefined symbol: dma_buf_transfer_charge
>>> referenced by binder.c:2280 (drivers/android/binder.c:2280)
>>> drivers/android/binder.o:(binder_translate_fd) in archive vmlinux.a
On Mon, Jan 23, 2023 at 07:17:25PM +0000, T.J. Mercier wrote: > From: Hridya Valsaraju <hridya@google.com> > > This patch introduces flag BINDER_FD_FLAG_XFER_CHARGE that a process > sending an individual fd or fd array to another process over binder IPC > can set to relinquish ownership of the fd(s) being sent for memory > accounting purposes. If the flag is found to be set during the fd or fd > array translation and the fd is for a DMA-BUF, the buffer is uncharged > from the sender's cgroup and charged to the receiving process's cgroup > instead. > > It is up to the sending process to ensure that it closes the fds > regardless of whether the transfer failed or succeeded. > > Most graphics shared memory allocations in Android are done by the > graphics allocator HAL process. On requests from clients, the HAL > process allocates memory and sends the fds to the clients over binder > IPC. The graphics allocator HAL will not retain any references to the > buffers. When the HAL sets BINDER_FD_FLAG_XFER_CHARGE, binder will > transfer the charge for the buffer from the allocator process cgroup to > the client process cgroup. > > The pad [1] and pad_flags [2] fields of binder_fd_object and > binder_fda_array_object come from alignment with flat_binder_object and > have never been exposed for use from userspace. This new flags use > follows the pattern set by binder_buffer_object. > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/uapi/linux/android/binder.h?id=feba3900cabb8e7c87368faa28e7a6936809ba22 > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/uapi/linux/android/binder.h?id=5cdcf4c6a638591ec0e98c57404a19e7f9997567 > > Signed-off-by: Hridya Valsaraju <hridya@google.com> > Signed-off-by: T.J. Mercier <tjmercier@google.com> > --- > Documentation/admin-guide/cgroup-v2.rst | 3 ++- > drivers/android/binder.c | 25 +++++++++++++++++++++---- > include/uapi/linux/android/binder.h | 19 +++++++++++++++---- > 3 files changed, 38 insertions(+), 9 deletions(-) > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index 538ae22bc514..d225295932c0 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -1457,7 +1457,8 @@ PAGE_SIZE multiple when read back. > > dmabuf (npn) > Amount of memory used for exported DMA buffers allocated by the cgroup. > - Stays with the allocating cgroup regardless of how the buffer is shared. > + Stays with the allocating cgroup regardless of how the buffer is shared > + unless explicitly transferred. > > workingset_refault_anon > Number of refaults of previously evicted anonymous pages. > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index 880224ec6abb..5e707974793f 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -42,6 +42,7 @@ > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > +#include <linux/dma-buf.h> > #include <linux/fdtable.h> > #include <linux/file.h> > #include <linux/freezer.h> > @@ -2237,7 +2238,7 @@ static int binder_translate_handle(struct flat_binder_object *fp, > return ret; > } > > -static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > +static int binder_translate_fd(u32 fd, binder_size_t fd_offset, __u32 flags, > struct binder_transaction *t, > struct binder_thread *thread, > struct binder_transaction *in_reply_to) > @@ -2275,6 +2276,20 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > goto err_security; > } > > + if (IS_ENABLED(CONFIG_MEMCG) && (flags & BINDER_FD_FLAG_XFER_CHARGE)) { Do we need to test for MEMCG here? it seems this has been offloaded to dma_buf_transfer_charge()? > + ret = dma_buf_transfer_charge(file, target_proc->tsk); > + if (unlikely(ret == -EBADF)) { > + binder_user_error( > + "%d:%d got transaction with XFER_CHARGE for non-DMA-BUF fd, %d\n", > + proc->pid, thread->pid, fd); > + goto err_dmabuf; > + } else if (ret) { > + pr_warn("%d:%d Unable to transfer DMA-BUF fd charge to %d\n", > + proc->pid, thread->pid, target_proc->pid); > + goto err_xfer; > + } > + } > + > /* > * Add fixup record for this transaction. The allocation > * of the fd in the target needs to be done from a > @@ -2294,6 +2309,8 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > return ret; > > err_alloc: > +err_xfer: > +err_dmabuf: > err_security: > fput(file); > err_fget: > @@ -2604,7 +2621,7 @@ static int binder_translate_fd_array(struct list_head *pf_head, > > ret = copy_from_user(&fd, sender_ufda_base + sender_uoffset, sizeof(fd)); > if (!ret) > - ret = binder_translate_fd(fd, offset, t, thread, > + ret = binder_translate_fd(fd, offset, fda->flags, t, thread, > in_reply_to); > if (ret) > return ret > 0 ? -EINVAL : ret; > @@ -3383,8 +3400,8 @@ static void binder_transaction(struct binder_proc *proc, > struct binder_fd_object *fp = to_binder_fd_object(hdr); > binder_size_t fd_offset = object_offset + > (uintptr_t)&fp->fd - (uintptr_t)fp; > - int ret = binder_translate_fd(fp->fd, fd_offset, t, > - thread, in_reply_to); > + int ret = binder_translate_fd(fp->fd, fd_offset, fp->flags, > + t, thread, in_reply_to); > > fp->pad_binder = 0; > if (ret < 0 || > diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h > index e72e4de8f452..4b20dd1dccb1 100644 > --- a/include/uapi/linux/android/binder.h > +++ b/include/uapi/linux/android/binder.h > @@ -91,14 +91,14 @@ struct flat_binder_object { > /** > * struct binder_fd_object - describes a filedescriptor to be fixed up. > * @hdr: common header structure > - * @pad_flags: padding to remain compatible with old userspace code > + * @flags: One or more BINDER_FD_FLAG_* flags > * @pad_binder: padding to remain compatible with old userspace code > * @fd: file descriptor > * @cookie: opaque data, used by user-space > */ > struct binder_fd_object { > struct binder_object_header hdr; > - __u32 pad_flags; > + __u32 flags; > union { > binder_uintptr_t pad_binder; > __u32 fd; > @@ -107,6 +107,17 @@ struct binder_fd_object { > binder_uintptr_t cookie; > }; > > +enum { > + /** > + * @BINDER_FD_FLAG_XFER_CHARGE > + * > + * When set, the sender of a binder_fd_object wishes to relinquish ownership of the fd for > + * memory accounting purposes. If the fd is for a DMA-BUF, the buffer is uncharged from the > + * sender's cgroup and charged to the receiving process's cgroup instead. > + */ > + BINDER_FD_FLAG_XFER_CHARGE = 0x01, > +}; > + > /* struct binder_buffer_object - object describing a userspace buffer > * @hdr: common header structure > * @flags: one or more BINDER_BUFFER_* flags > @@ -141,7 +152,7 @@ enum { > > /* struct binder_fd_array_object - object describing an array of fds in a buffer > * @hdr: common header structure > - * @pad: padding to ensure correct alignment > + * @flags: One or more BINDER_FD_FLAG_* flags > * @num_fds: number of file descriptors in the buffer > * @parent: index in offset array to buffer holding the fd array > * @parent_offset: start offset of fd array in the buffer > @@ -162,7 +173,7 @@ enum { > */ > struct binder_fd_array_object { > struct binder_object_header hdr; > - __u32 pad; > + __u32 flags; > binder_size_t num_fds; > binder_size_t parent; > binder_size_t parent_offset; > -- > 2.39.0.246.g2a6d74b583-goog > Other than the previous question this looks good to me. Also, the error from the test robot seems to indicate a missing stub for dma_buf_transfer_charg() when !CONFIG_DMA_SHARED_BUFFER. However, this is likely to be fixed outside of this patch. Feel free to add this tag to the following round: Acked-by: Carlos Llamas <cmllamas@google.com> Thanks,
On Wed, Jan 25, 2023 at 9:30 AM Carlos Llamas <cmllamas@google.com> wrote: > > On Mon, Jan 23, 2023 at 07:17:25PM +0000, T.J. Mercier wrote: > > From: Hridya Valsaraju <hridya@google.com> > > > > This patch introduces flag BINDER_FD_FLAG_XFER_CHARGE that a process > > sending an individual fd or fd array to another process over binder IPC > > can set to relinquish ownership of the fd(s) being sent for memory > > accounting purposes. If the flag is found to be set during the fd or fd > > array translation and the fd is for a DMA-BUF, the buffer is uncharged > > from the sender's cgroup and charged to the receiving process's cgroup > > instead. > > > > It is up to the sending process to ensure that it closes the fds > > regardless of whether the transfer failed or succeeded. > > > > Most graphics shared memory allocations in Android are done by the > > graphics allocator HAL process. On requests from clients, the HAL > > process allocates memory and sends the fds to the clients over binder > > IPC. The graphics allocator HAL will not retain any references to the > > buffers. When the HAL sets BINDER_FD_FLAG_XFER_CHARGE, binder will > > transfer the charge for the buffer from the allocator process cgroup to > > the client process cgroup. > > > > The pad [1] and pad_flags [2] fields of binder_fd_object and > > binder_fda_array_object come from alignment with flat_binder_object and > > have never been exposed for use from userspace. This new flags use > > follows the pattern set by binder_buffer_object. > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/uapi/linux/android/binder.h?id=feba3900cabb8e7c87368faa28e7a6936809ba22 > > [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/include/uapi/linux/android/binder.h?id=5cdcf4c6a638591ec0e98c57404a19e7f9997567 > > > > Signed-off-by: Hridya Valsaraju <hridya@google.com> > > Signed-off-by: T.J. Mercier <tjmercier@google.com> > > --- > > Documentation/admin-guide/cgroup-v2.rst | 3 ++- > > drivers/android/binder.c | 25 +++++++++++++++++++++---- > > include/uapi/linux/android/binder.h | 19 +++++++++++++++---- > > 3 files changed, 38 insertions(+), 9 deletions(-) > > > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > > index 538ae22bc514..d225295932c0 100644 > > --- a/Documentation/admin-guide/cgroup-v2.rst > > +++ b/Documentation/admin-guide/cgroup-v2.rst > > @@ -1457,7 +1457,8 @@ PAGE_SIZE multiple when read back. > > > > dmabuf (npn) > > Amount of memory used for exported DMA buffers allocated by the cgroup. > > - Stays with the allocating cgroup regardless of how the buffer is shared. > > + Stays with the allocating cgroup regardless of how the buffer is shared > > + unless explicitly transferred. > > > > workingset_refault_anon > > Number of refaults of previously evicted anonymous pages. > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > > index 880224ec6abb..5e707974793f 100644 > > --- a/drivers/android/binder.c > > +++ b/drivers/android/binder.c > > @@ -42,6 +42,7 @@ > > > > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > > > > +#include <linux/dma-buf.h> > > #include <linux/fdtable.h> > > #include <linux/file.h> > > #include <linux/freezer.h> > > @@ -2237,7 +2238,7 @@ static int binder_translate_handle(struct flat_binder_object *fp, > > return ret; > > } > > > > -static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > > +static int binder_translate_fd(u32 fd, binder_size_t fd_offset, __u32 flags, > > struct binder_transaction *t, > > struct binder_thread *thread, > > struct binder_transaction *in_reply_to) > > @@ -2275,6 +2276,20 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > > goto err_security; > > } > > > > + if (IS_ENABLED(CONFIG_MEMCG) && (flags & BINDER_FD_FLAG_XFER_CHARGE)) { > > Do we need to test for MEMCG here? it seems this has been offloaded to > dma_buf_transfer_charge()? > Nope, that's a duplicate check now. Will remove. > > + ret = dma_buf_transfer_charge(file, target_proc->tsk); > > + if (unlikely(ret == -EBADF)) { > > + binder_user_error( > > + "%d:%d got transaction with XFER_CHARGE for non-DMA-BUF fd, %d\n", > > + proc->pid, thread->pid, fd); > > + goto err_dmabuf; > > + } else if (ret) { > > + pr_warn("%d:%d Unable to transfer DMA-BUF fd charge to %d\n", > > + proc->pid, thread->pid, target_proc->pid); > > + goto err_xfer; > > + } > > + } > > + > > /* > > * Add fixup record for this transaction. The allocation > > * of the fd in the target needs to be done from a > > @@ -2294,6 +2309,8 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, > > return ret; > > > > err_alloc: > > +err_xfer: > > +err_dmabuf: > > err_security: > > fput(file); > > err_fget: > > @@ -2604,7 +2621,7 @@ static int binder_translate_fd_array(struct list_head *pf_head, > > > > ret = copy_from_user(&fd, sender_ufda_base + sender_uoffset, sizeof(fd)); > > if (!ret) > > - ret = binder_translate_fd(fd, offset, t, thread, > > + ret = binder_translate_fd(fd, offset, fda->flags, t, thread, > > in_reply_to); > > if (ret) > > return ret > 0 ? -EINVAL : ret; > > @@ -3383,8 +3400,8 @@ static void binder_transaction(struct binder_proc *proc, > > struct binder_fd_object *fp = to_binder_fd_object(hdr); > > binder_size_t fd_offset = object_offset + > > (uintptr_t)&fp->fd - (uintptr_t)fp; > > - int ret = binder_translate_fd(fp->fd, fd_offset, t, > > - thread, in_reply_to); > > + int ret = binder_translate_fd(fp->fd, fd_offset, fp->flags, > > + t, thread, in_reply_to); > > > > fp->pad_binder = 0; > > if (ret < 0 || > > diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h > > index e72e4de8f452..4b20dd1dccb1 100644 > > --- a/include/uapi/linux/android/binder.h > > +++ b/include/uapi/linux/android/binder.h > > @@ -91,14 +91,14 @@ struct flat_binder_object { > > /** > > * struct binder_fd_object - describes a filedescriptor to be fixed up. > > * @hdr: common header structure > > - * @pad_flags: padding to remain compatible with old userspace code > > + * @flags: One or more BINDER_FD_FLAG_* flags > > * @pad_binder: padding to remain compatible with old userspace code > > * @fd: file descriptor > > * @cookie: opaque data, used by user-space > > */ > > struct binder_fd_object { > > struct binder_object_header hdr; > > - __u32 pad_flags; > > + __u32 flags; > > union { > > binder_uintptr_t pad_binder; > > __u32 fd; > > @@ -107,6 +107,17 @@ struct binder_fd_object { > > binder_uintptr_t cookie; > > }; > > > > +enum { > > + /** > > + * @BINDER_FD_FLAG_XFER_CHARGE > > + * > > + * When set, the sender of a binder_fd_object wishes to relinquish ownership of the fd for > > + * memory accounting purposes. If the fd is for a DMA-BUF, the buffer is uncharged from the > > + * sender's cgroup and charged to the receiving process's cgroup instead. > > + */ > > + BINDER_FD_FLAG_XFER_CHARGE = 0x01, > > +}; > > + > > /* struct binder_buffer_object - object describing a userspace buffer > > * @hdr: common header structure > > * @flags: one or more BINDER_BUFFER_* flags > > @@ -141,7 +152,7 @@ enum { > > > > /* struct binder_fd_array_object - object describing an array of fds in a buffer > > * @hdr: common header structure > > - * @pad: padding to ensure correct alignment > > + * @flags: One or more BINDER_FD_FLAG_* flags > > * @num_fds: number of file descriptors in the buffer > > * @parent: index in offset array to buffer holding the fd array > > * @parent_offset: start offset of fd array in the buffer > > @@ -162,7 +173,7 @@ enum { > > */ > > struct binder_fd_array_object { > > struct binder_object_header hdr; > > - __u32 pad; > > + __u32 flags; > > binder_size_t num_fds; > > binder_size_t parent; > > binder_size_t parent_offset; > > -- > > 2.39.0.246.g2a6d74b583-goog > > > > Other than the previous question this looks good to me. Also, the error > from the test robot seems to indicate a missing stub for > dma_buf_transfer_charg() when !CONFIG_DMA_SHARED_BUFFER. However, this > is likely to be fixed outside of this patch. Feel free to add this tag > to the following round: > > Acked-by: Carlos Llamas <cmllamas@google.com> > > Thanks, Got it, thanks!
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 538ae22bc514..d225295932c0 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1457,7 +1457,8 @@ PAGE_SIZE multiple when read back. dmabuf (npn) Amount of memory used for exported DMA buffers allocated by the cgroup. - Stays with the allocating cgroup regardless of how the buffer is shared. + Stays with the allocating cgroup regardless of how the buffer is shared + unless explicitly transferred. workingset_refault_anon Number of refaults of previously evicted anonymous pages. diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 880224ec6abb..5e707974793f 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -42,6 +42,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/dma-buf.h> #include <linux/fdtable.h> #include <linux/file.h> #include <linux/freezer.h> @@ -2237,7 +2238,7 @@ static int binder_translate_handle(struct flat_binder_object *fp, return ret; } -static int binder_translate_fd(u32 fd, binder_size_t fd_offset, +static int binder_translate_fd(u32 fd, binder_size_t fd_offset, __u32 flags, struct binder_transaction *t, struct binder_thread *thread, struct binder_transaction *in_reply_to) @@ -2275,6 +2276,20 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, goto err_security; } + if (IS_ENABLED(CONFIG_MEMCG) && (flags & BINDER_FD_FLAG_XFER_CHARGE)) { + ret = dma_buf_transfer_charge(file, target_proc->tsk); + if (unlikely(ret == -EBADF)) { + binder_user_error( + "%d:%d got transaction with XFER_CHARGE for non-DMA-BUF fd, %d\n", + proc->pid, thread->pid, fd); + goto err_dmabuf; + } else if (ret) { + pr_warn("%d:%d Unable to transfer DMA-BUF fd charge to %d\n", + proc->pid, thread->pid, target_proc->pid); + goto err_xfer; + } + } + /* * Add fixup record for this transaction. The allocation * of the fd in the target needs to be done from a @@ -2294,6 +2309,8 @@ static int binder_translate_fd(u32 fd, binder_size_t fd_offset, return ret; err_alloc: +err_xfer: +err_dmabuf: err_security: fput(file); err_fget: @@ -2604,7 +2621,7 @@ static int binder_translate_fd_array(struct list_head *pf_head, ret = copy_from_user(&fd, sender_ufda_base + sender_uoffset, sizeof(fd)); if (!ret) - ret = binder_translate_fd(fd, offset, t, thread, + ret = binder_translate_fd(fd, offset, fda->flags, t, thread, in_reply_to); if (ret) return ret > 0 ? -EINVAL : ret; @@ -3383,8 +3400,8 @@ static void binder_transaction(struct binder_proc *proc, struct binder_fd_object *fp = to_binder_fd_object(hdr); binder_size_t fd_offset = object_offset + (uintptr_t)&fp->fd - (uintptr_t)fp; - int ret = binder_translate_fd(fp->fd, fd_offset, t, - thread, in_reply_to); + int ret = binder_translate_fd(fp->fd, fd_offset, fp->flags, + t, thread, in_reply_to); fp->pad_binder = 0; if (ret < 0 || diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h index e72e4de8f452..4b20dd1dccb1 100644 --- a/include/uapi/linux/android/binder.h +++ b/include/uapi/linux/android/binder.h @@ -91,14 +91,14 @@ struct flat_binder_object { /** * struct binder_fd_object - describes a filedescriptor to be fixed up. * @hdr: common header structure - * @pad_flags: padding to remain compatible with old userspace code + * @flags: One or more BINDER_FD_FLAG_* flags * @pad_binder: padding to remain compatible with old userspace code * @fd: file descriptor * @cookie: opaque data, used by user-space */ struct binder_fd_object { struct binder_object_header hdr; - __u32 pad_flags; + __u32 flags; union { binder_uintptr_t pad_binder; __u32 fd; @@ -107,6 +107,17 @@ struct binder_fd_object { binder_uintptr_t cookie; }; +enum { + /** + * @BINDER_FD_FLAG_XFER_CHARGE + * + * When set, the sender of a binder_fd_object wishes to relinquish ownership of the fd for + * memory accounting purposes. If the fd is for a DMA-BUF, the buffer is uncharged from the + * sender's cgroup and charged to the receiving process's cgroup instead. + */ + BINDER_FD_FLAG_XFER_CHARGE = 0x01, +}; + /* struct binder_buffer_object - object describing a userspace buffer * @hdr: common header structure * @flags: one or more BINDER_BUFFER_* flags @@ -141,7 +152,7 @@ enum { /* struct binder_fd_array_object - object describing an array of fds in a buffer * @hdr: common header structure - * @pad: padding to ensure correct alignment + * @flags: One or more BINDER_FD_FLAG_* flags * @num_fds: number of file descriptors in the buffer * @parent: index in offset array to buffer holding the fd array * @parent_offset: start offset of fd array in the buffer @@ -162,7 +173,7 @@ enum { */ struct binder_fd_array_object { struct binder_object_header hdr; - __u32 pad; + __u32 flags; binder_size_t num_fds; binder_size_t parent; binder_size_t parent_offset;