diff options
| author | Frank Haverkamp <haver@linux.vnet.ibm.com> | 2014-03-20 15:11:05 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-04-16 12:12:39 -0700 |
| commit | 718f762efc454796d02f172a929d051f2d6ec01a (patch) | |
| tree | 13d8f9558b39963356082460de3ee6855454d972 /drivers/misc/genwqe/card_dev.c | |
| parent | ebb2c96bb9214ba38c7fe35d5d725f6e7cb3bbc8 (diff) | |
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>
Diffstat (limited to 'drivers/misc/genwqe/card_dev.c')
| -rw-r--r-- | drivers/misc/genwqe/card_dev.c | 38 |
1 files changed, 11 insertions, 27 deletions
diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c index 0d05ca77c458..1d2f163a1906 100644 --- a/drivers/misc/genwqe/card_dev.c +++ b/drivers/misc/genwqe/card_dev.c @@ -840,15 +840,8 @@ static int ddcb_cmd_cleanup(struct genwqe_file *cfile, struct ddcb_requ *req) __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 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req) 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 @@ static int ddcb_cmd_fixups(struct genwqe_file *cfile, struct ddcb_requ *req) 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; } |