io_uring: add full-fledged dynamic buffers support

Hook buffers into all rsrc infrastructure, including tagging and
updates.

Suggested-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/119ed51d68a491dae87eb55fb467a47870c86aad.1619356238.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 0680d24..0ab09f7 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8114,8 +8114,8 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slo
 
 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
 {
-       /* no updates yet, so not used */
-       WARN_ON_ONCE(1);
+       io_buffer_unmap(ctx, &prsrc->buf);
+       prsrc->buf = NULL;
 }
 
 static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
@@ -8359,7 +8359,7 @@ static int io_buffer_validate(struct iovec *iov)
 }
 
 static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
-                                  unsigned int nr_args)
+                                  unsigned int nr_args, u64 __user *tags)
 {
        struct page *last_hpage = NULL;
        struct io_rsrc_data *data;
@@ -8383,6 +8383,12 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
        }
 
        for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) {
+               u64 tag = 0;
+
+               if (tags && copy_from_user(&tag, &tags[i], sizeof(tag))) {
+                       ret = -EFAULT;
+                       break;
+               }
                ret = io_copy_iov(ctx, &iov, arg, i);
                if (ret)
                        break;
@@ -8394,6 +8400,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
                                             &last_hpage);
                if (ret)
                        break;
+               data->tags[i] = tag;
        }
 
        WARN_ON_ONCE(ctx->buf_data);
@@ -8406,6 +8413,62 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
        return ret;
 }
 
+static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
+                                  struct io_uring_rsrc_update2 *up,
+                                  unsigned int nr_args)
+{
+       u64 __user *tags = u64_to_user_ptr(up->tags);
+       struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
+       struct io_mapped_ubuf *imu;
+       struct page *last_hpage = NULL;
+       bool needs_switch = false;
+       __u32 done;
+       int i, err;
+
+       if (!ctx->buf_data)
+               return -ENXIO;
+       if (up->offset + nr_args > ctx->nr_user_bufs)
+               return -EINVAL;
+
+       for (done = 0; done < nr_args; done++) {
+               u64 tag = 0;
+
+               err = io_copy_iov(ctx, &iov, iovs, done);
+               if (err)
+                       break;
+               if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
+                       err = -EFAULT;
+                       break;
+               }
+
+               i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
+               imu = ctx->user_bufs[i];
+               if (imu) {
+                       err = io_queue_rsrc_removal(ctx->buf_data, up->offset + done,
+                                                   ctx->rsrc_node, imu);
+                       if (err)
+                               break;
+                       ctx->user_bufs[i] = NULL;
+                       needs_switch = true;
+               }
+
+               if (iov.iov_base || iov.iov_len) {
+                       err = io_buffer_validate(&iov);
+                       if (err)
+                               break;
+                       err = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i],
+                                                    &last_hpage);
+                       if (err)
+                               break;
+                       ctx->buf_data->tags[up->offset + done] = tag;
+               }
+       }
+
+       if (needs_switch)
+               io_rsrc_node_switch(ctx, ctx->buf_data);
+       return done ? done : err;
+}
+
 static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
 {
        __s32 __user *fds = arg;
@@ -9807,6 +9870,8 @@ static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
        switch (type) {
        case IORING_RSRC_FILE:
                return __io_sqe_files_update(ctx, up, nr_args);
+       case IORING_RSRC_BUFFER:
+               return __io_sqe_buffers_update(ctx, up, nr_args);
        }
        return -EINVAL;
 }
@@ -9857,6 +9922,9 @@ static int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
        case IORING_RSRC_FILE:
                return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
                                             rr.nr, u64_to_user_ptr(rr.tags));
+       case IORING_RSRC_BUFFER:
+               return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
+                                              rr.nr, u64_to_user_ptr(rr.tags));
        }
        return -EINVAL;
 }
@@ -9933,7 +10001,7 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
 
        switch (opcode) {
        case IORING_REGISTER_BUFFERS:
-               ret = io_sqe_buffers_register(ctx, arg, nr_args);
+               ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL);
                break;
        case IORING_UNREGISTER_BUFFERS:
                ret = -EINVAL;

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 6d8360b..e1ae466 100644 (file)
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -314,6 +314,7 @@ struct io_uring_files_update {
 
 enum {
        IORING_RSRC_FILE                = 0,
+       IORING_RSRC_BUFFER              = 1,
 };
 
 struct io_uring_rsrc_register {