2012/1/10 Shi Xuelin-B29237 <b29...@freescale.com>: > Hello Dan Williams, > > Do you have any comment about this patch?
Hi, sorrry for the delay. > > Thanks, > Forrest > > -----Original Message----- > From: Shi Xuelin-B29237 > Sent: 2011年12月27日 14:31 > To: vinod.k...@intel.com; dan.j.willi...@intel.com; > linuxppc-dev@lists.ozlabs.org; linux-ker...@vger.kernel.org; Li Yang-R58472 > Cc: Shi Xuelin-B29237 > Subject: [PATCH] dmaengine: async_xor, fix zero address issue when xor > highmem page > > From: Forrest shi <b29...@freescale.com> > > we may do_sync_xor high mem pages, in this case, page_address will > return zero address which cause a failure. In what scenarios do we xor highmem? In the case of raid we currently always xor on kmalloc'd memory. > > this patch uses kmap_atomic before xor the pages and kunmap_atomic > after it. > > Signed-off-by: b29...@freescale.com <xuelin....@freescale.com> > --- > crypto/async_tx/async_xor.c | 16 ++++++++++++---- > 1 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/crypto/async_tx/async_xor.c b/crypto/async_tx/async_xor.c index > bc28337..5b416d1 100644 > --- a/crypto/async_tx/async_xor.c > +++ b/crypto/async_tx/async_xor.c > @@ -26,6 +26,7 @@ > #include <linux/kernel.h> > #include <linux/interrupt.h> > #include <linux/mm.h> > +#include <linux/highmem.h> > #include <linux/dma-mapping.h> > #include <linux/raid/xor.h> > #include <linux/async_tx.h> > @@ -126,7 +127,7 @@ do_sync_xor(struct page *dest, struct page **src_list, > unsigned int offset, > int src_cnt, size_t len, struct async_submit_ctl *submit) { > int i; > - int xor_src_cnt = 0; > + int xor_src_cnt = 0, kmap_cnt=0; > int src_off = 0; > void *dest_buf; > void **srcs; > @@ -138,11 +139,13 @@ do_sync_xor(struct page *dest, struct page **src_list, > unsigned int offset, > > /* convert to buffer pointers */ > for (i = 0; i < src_cnt; i++) > - if (src_list[i]) > - srcs[xor_src_cnt++] = page_address(src_list[i]) + > offset; > + if (src_list[i]) { > + srcs[xor_src_cnt++] = kmap_atomic(src_list[i], > KM_USER1) + offset; > + } > + kmap_cnt = xor_src_cnt; I guess this works now that we have stack based kmap_atomic, but on older kernels you could not simultaneously map that many buffers with a single kmap slot. So if you resend, drop the second parameter to kmap_atomic. ...but unless you have a non md/raid456 use case in mind, or have patches to convert md/raid to xor straight out of the incoming biovecs I don't think this patch is needed right? _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev