On Fri, Jan 20, 2023 at 1:25 PM Carlos Llamas <cmllamas@xxxxxxxxxx> wrote: > > On Mon, Jan 09, 2023 at 09:38:06PM +0000, T.J. Mercier wrote: > > From: Hridya Valsaraju <hridya@xxxxxxxxxx> > > > > This patch introduces flags BINDER_FD_FLAG_XFER_CHARGE, and > > BINDER_FD_FLAG_XFER_CHARGE that a process sending an individual fd or > > I believe the second one was meant to be BINDER_FDA_FLAG_XFER_CHARGE. > However, I don't think a separation of flags is needed. We process each > fd in the array individually anyway. So, it's OK to reuse the FD flags > for FDAs too. Yes, thanks. > > > > 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 *_FLAG_XFER_CHARGE for fd arrays holding > > DMA-BUF fds, or individual fd objects, 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@xxxxxxxxxx> > > Signed-off-by: T.J. Mercier <tjmercier@xxxxxxxxxx> > > --- > > Documentation/admin-guide/cgroup-v2.rst | 3 ++- > > drivers/android/binder.c | 31 +++++++++++++++++++++---- > > drivers/dma-buf/dma-buf.c | 4 +--- > > include/linux/dma-buf.h | 1 + > > include/uapi/linux/android/binder.h | 23 ++++++++++++++---- > > 5 files changed, 50 insertions(+), 12 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..9830848c8d25 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 +2276,26 @@ 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)) { > > + struct dma_buf *dmabuf; > > + > > + if (unlikely(!is_dma_buf_file(file))) { > > + binder_user_error( > > + "%d:%d got transaction with XFER_CHARGE for non-dmabuf fd, %d\n", > > + proc->pid, thread->pid, fd); > > + ret = -EINVAL; > > + goto err_dmabuf; > > + } > > + > > + dmabuf = file->private_data; > > + ret = dma_buf_transfer_charge(dmabuf, target_proc->tsk); > > + 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 +2315,8 @@ 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 +2627,7 @@ 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 +3406,8 @@ 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 || > > IMO the changes to the dma-buf api should some in a separate patch. So > those can be approved and managed separately. > I've actually already dropped these based on feedback from Hillf, so there are no longer any dma-buf.c changes on this patch for the v2 I have queued up. > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > index fd6c5002032b..a65b42433099 100644 > > --- a/drivers/dma-buf/dma-buf.c > > +++ b/drivers/dma-buf/dma-buf.c > > @@ -34,8 +34,6 @@ > > > > #include "dma-buf-sysfs-stats.h" > > > > -static inline int is_dma_buf_file(struct file *); > > - > > struct dma_buf_list { > > struct list_head head; > > struct mutex lock; > > @@ -527,7 +525,7 @@ static const struct file_operations dma_buf_fops = { > > /* > > * is_dma_buf_file - Check if struct file* is associated with dma_buf > > */ > > -static inline int is_dma_buf_file(struct file *file) > > +int is_dma_buf_file(struct file *file) > > { > > return file->f_op == &dma_buf_fops; > > } > > diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h > > index 6aa128d76aa7..092d572ce528 100644 > > --- a/include/linux/dma-buf.h > > +++ b/include/linux/dma-buf.h > > @@ -595,6 +595,7 @@ dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach) > > return !!attach->importer_ops; > > } > > > > +int is_dma_buf_file(struct file *file); > > struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, > > struct device *dev); > > struct dma_buf_attachment * > > diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h > > index e72e4de8f452..696c2bdb8a7e 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_FDA_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 > > @@ -162,12 +173,16 @@ 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; > > }; > > > > +enum { > > + BINDER_FDA_FLAG_XFER_CHARGE = BINDER_FD_FLAG_XFER_CHARGE, > > +}; > > + > > I would prefer to drop this. It should avoid silly mistakes in > userspace similar to the typo in the commit message above. > Ok I'll make that work. > > > /* > > * On 64-bit platforms where user code may run in 32-bits the driver must > > * translate the buffer (and local binder) addresses appropriately. > > -- > > 2.39.0.314.g84b9a713c41-goog > > > > Thanks, > -- > Carlos Llamas
