RE: [PATCH] dmaengine: async_xor, fix zero address issue when xor highmem page

[Shi Xuelin-B29237]

Hello Dan Williams,

Do you have any comment about this patch?

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.

        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;
        src_cnt = xor_src_cnt;
        /* set destination address */
-       dest_buf = page_address(dest) + offset;
+       dest_buf = kmap_atomic(dest, KM_USER0) + offset;
 
        if (submit->flags & ASYNC_TX_XOR_ZERO_DST)
                memset(dest_buf, 0, len);
@@ -157,6 +160,11 @@ do_sync_xor(struct page *dest, struct page **src_list, 
unsigned int offset,
                src_off += xor_src_cnt;
        }
 
+       kunmap_atomic(dest_buf, KM_USER0);
+       for (i = 0; i < kmap_cnt; i++) 
+               if (src_list[i])
+                       kunmap_atomic(srcs[i], KM_USER1);
+
        async_tx_sync_epilog(submit);
 }
 
--
1.7.0.4


_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev