GenWQE: Fix multithreading problems
When being used in a multithreaded application there were problems
with memory pages/cachelines accessed by multiple threads/cpus at the
same time, while doing DMA transfers to/from those. To avoid such
situations this fix is creating a copy of the first and the last page
if it is not fully used. The data is copied from user-space into those
pages and results are copied back when the DDCB-request is
successfully finished.
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
index 0d05ca7..1d2f163 100644
--- a/drivers/misc/genwqe/card_dev.c
+++ b/drivers/misc/genwqe/card_dev.c
@@ -840,15 +840,8 @@
__genwqe_del_mapping(cfile, dma_map);
genwqe_user_vunmap(cd, dma_map, req);
}
- if (req->sgl[i] != NULL) {
- genwqe_free_sgl(cd, req->sgl[i],
- req->sgl_dma_addr[i],
- req->sgl_size[i]);
- req->sgl[i] = NULL;
- req->sgl_dma_addr[i] = 0x0;
- req->sgl_size[i] = 0;
- }
-
+ if (req->sgls[i].sgl != NULL)
+ genwqe_free_sync_sgl(cd, &req->sgls[i]);
}
return 0;
}
@@ -917,7 +910,7 @@
case ATS_TYPE_SGL_RDWR:
case ATS_TYPE_SGL_RD: {
- int page_offs, nr_pages, offs;
+ int page_offs;
u_addr = be64_to_cpu(*((__be64 *)
&cmd->asiv[asiv_offs]));
@@ -955,27 +948,18 @@
page_offs = 0;
}
- offs = offset_in_page(u_addr);
- nr_pages = DIV_ROUND_UP(offs + u_size, PAGE_SIZE);
-
/* create genwqe style scatter gather list */
- req->sgl[i] = genwqe_alloc_sgl(cd, m->nr_pages,
- &req->sgl_dma_addr[i],
- &req->sgl_size[i]);
- if (req->sgl[i] == NULL) {
- rc = -ENOMEM;
+ rc = genwqe_alloc_sync_sgl(cd, &req->sgls[i],
+ (void __user *)u_addr,
+ u_size);
+ if (rc != 0)
goto err_out;
- }
- genwqe_setup_sgl(cd, offs, u_size,
- req->sgl[i],
- req->sgl_dma_addr[i],
- req->sgl_size[i],
- m->dma_list,
- page_offs,
- nr_pages);
+
+ genwqe_setup_sgl(cd, &req->sgls[i],
+ &m->dma_list[page_offs]);
*((__be64 *)&cmd->asiv[asiv_offs]) =
- cpu_to_be64(req->sgl_dma_addr[i]);
+ cpu_to_be64(req->sgls[i].sgl_dma_addr);
break;
}