io_uring/kbuf: add buffer_list->is_mapped member

Rather than rely on checking buffer_list->buf_pages or ->buf_nr_pages,
add a separate member that tracks if this is a ring mapped provided
buffer list or not.

Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/kbuf.c b/io_uring/kbuf.c
index 3adc08f..db5f189 100644 (file)
--- a/io_uring/kbuf.c
+++ b/io_uring/kbuf.c
@@ -179,7 +179,7 @@ void __user *io_buffer_select(struct io_kiocb *req, size_t *len,
 
        bl = io_buffer_get_list(ctx, req->buf_index);
        if (likely(bl)) {
-               if (bl->buf_nr_pages)
+               if (bl->is_mapped)
                        ret = io_ring_buffer_select(req, len, bl, issue_flags);
                else
                        ret = io_provided_buffer_select(req, len, bl);
@@ -214,7 +214,7 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
        if (!nbufs)
                return 0;
 
-       if (bl->buf_nr_pages) {
+       if (bl->is_mapped && bl->buf_nr_pages) {
                int j;
 
                i = bl->buf_ring->tail - bl->head;
@@ -225,6 +225,7 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
                bl->buf_nr_pages = 0;
                /* make sure it's seen as empty */
                INIT_LIST_HEAD(&bl->buf_list);
+               bl->is_mapped = 0;
                return i;
        }
 
@@ -303,7 +304,7 @@ int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags)
        if (bl) {
                ret = -EINVAL;
                /* can't use provide/remove buffers command on mapped buffers */
-               if (!bl->buf_nr_pages)
+               if (!bl->is_mapped)
                        ret = __io_remove_buffers(ctx, bl, p->nbufs);
        }
        io_ring_submit_unlock(ctx, issue_flags);
@@ -448,7 +449,7 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
                }
        }
        /* can't add buffers via this command for a mapped buffer ring */
-       if (bl->buf_nr_pages) {
+       if (bl->is_mapped) {
                ret = -EINVAL;
                goto err;
        }
@@ -480,6 +481,7 @@ static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
        bl->buf_pages = pages;
        bl->buf_nr_pages = nr_pages;
        bl->buf_ring = br;
+       bl->is_mapped = 1;
        return 0;
 }
 
@@ -514,7 +516,7 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
        bl = io_buffer_get_list(ctx, reg.bgid);
        if (bl) {
                /* if mapped buffer ring OR classic exists, don't allow */
-               if (bl->buf_nr_pages || !list_empty(&bl->buf_list))
+               if (bl->is_mapped || !list_empty(&bl->buf_list))
                        return -EEXIST;
        } else {
                free_bl = bl = kzalloc(sizeof(*bl), GFP_KERNEL);
@@ -548,7 +550,7 @@ int io_unregister_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
        bl = io_buffer_get_list(ctx, reg.bgid);
        if (!bl)
                return -ENOENT;
-       if (!bl->buf_nr_pages)
+       if (!bl->is_mapped)
                return -EINVAL;
 
        __io_remove_buffers(ctx, bl, -1U);

diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
index c23e15d..61b9c7d 100644 (file)
--- a/io_uring/kbuf.h
+++ b/io_uring/kbuf.h
@@ -23,6 +23,9 @@ struct io_buffer_list {
        __u16 nr_entries;
        __u16 head;
        __u16 mask;
+
+       /* ring mapped provided buffers */
+       __u8 is_mapped;
 };
 
 struct io_buffer {