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