io_uring/zcrx: account area memory

zcrx areas can be quite large and need to be accounted and checked
against RLIMIT_MEMLOCK. In practise it shouldn't be a big issue as
the inteface already requires cap_net_admin.

Cc: stable@vger.kernel.org
Fixes: cf96310c5f9a0 ("io_uring/zcrx: add io_zcrx_area")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4b53f0c575bd062f63d12bec6cac98037fc66aeb.1752699568.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 7d7396ce876cba18c028a1a38af4368e397992da..dabce3ee0e8b7c6e7a1cc9222bf4c5931b499190 100644 (file)
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -158,6 +158,23 @@ static int io_zcrx_map_area_dmabuf(struct io_zcrx_ifq *ifq, struct io_zcrx_area
                                    area->mem.dmabuf_offset);
 }
 
+static unsigned long io_count_account_pages(struct page **pages, unsigned nr_pages)
+{
+       struct folio *last_folio = NULL;
+       unsigned long res = 0;
+       int i;
+
+       for (i = 0; i < nr_pages; i++) {
+               struct folio *folio = page_folio(pages[i]);
+
+               if (folio == last_folio)
+                       continue;
+               last_folio = folio;
+               res += 1UL << folio_order(folio);
+       }
+       return res;
+}
+
 static int io_import_umem(struct io_zcrx_ifq *ifq,
                          struct io_zcrx_mem *mem,
                          struct io_uring_zcrx_area_reg *area_reg)
@@ -180,6 +197,13 @@ static int io_import_umem(struct io_zcrx_ifq *ifq,
        if (ret)
                return ret;
 
+       mem->account_pages = io_count_account_pages(pages, nr_pages);
+       ret = io_account_mem(ifq->ctx, mem->account_pages);
+       if (ret < 0) {
+               mem->account_pages = 0;
+               return ret;
+       }
+
        mem->pages = pages;
        mem->nr_folios = nr_pages;
        mem->size = area_reg->len;
@@ -357,6 +381,9 @@ static void io_zcrx_free_area(struct io_zcrx_area *area)
                io_zcrx_unmap_area(area->ifq, area);
        io_release_area_mem(&area->mem);
 
+       if (area->mem.account_pages)
+               io_unaccount_mem(area->ifq->ctx, area->mem.account_pages);
+
        kvfree(area->freelist);
        kvfree(area->nia.niovs);
        kvfree(area->user_refs);

diff --git a/io_uring/zcrx.h b/io_uring/zcrx.h
index 89015b92391132729a3611f617ec9e770451fa06..109c4ca364344e2b73f47a068cb09b66ee1cc766 100644 (file)
--- a/io_uring/zcrx.h
+++ b/io_uring/zcrx.h
@@ -15,6 +15,7 @@ struct io_zcrx_mem {
        struct page                     **pages;
        unsigned long                   nr_folios;
        struct sg_table                 page_sg_table;
+       unsigned long                   account_pages;
 
        struct dma_buf_attachment       *attach;
        struct dma_buf                  *dmabuf;