The patch titled
cache pipe buf page address for non-highmem arch (fix)
has been removed from the -mm tree. Its filename was
cache-pipe-buf-page-address-for-non-highmem-arch-fix.patch
This patch was dropped because it was folded into cache-pipe-buf-page-address-for-non-highmem-arch.patch
------------------------------------------------------
Subject: cache pipe buf page address for non-highmem arch (fix)
From: "Ken Chen" <kenchen@xxxxxxxxxx>
On 3/26/07, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> LTP's vmsplice01 triggers the below:
>
> Unable to handle kernel NULL pointer dereference at 0000000000000130 RIP:
> [<ffffffff8029e1b6>] pipe_to_file+0x1f3/0x2a6
Ouch, generic_pipe_buf_map() and unmap is used by both pipe and
splice, I better constrain all changes within fs/pipe.c because from
splice path, the page->private is not initialized.
Double ouch for missing test that code path. Here is an updated
patch, tested with LTP and FIO. I will write more test cases to make
sure all code path are covered.
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/pipe.c | 27 ++++++++++++++++++++++++---
1 files changed, 24 insertions(+), 3 deletions(-)
diff -puN fs/pipe.c~cache-pipe-buf-page-address-for-non-highmem-arch-fix fs/pipe.c
--- a/fs/pipe.c~cache-pipe-buf-page-address-for-non-highmem-arch-fix
+++ a/fs/pipe.c
@@ -184,13 +184,34 @@ void *generic_pipe_buf_map(struct pipe_i
{
if (atomic) {
buf->flags |= PIPE_BUF_FLAG_ATOMIC;
+ return kmap_atomic(buf->page, KM_USER0);
+ }
+
+ return kmap(buf->page);
+}
+
+void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf, void *map_data)
+{
+ if (buf->flags & PIPE_BUF_FLAG_ATOMIC) {
+ buf->flags &= ~PIPE_BUF_FLAG_ATOMIC;
+ kunmap_atomic(map_data, KM_USER0);
+ } else
+ kunmap(buf->page);
+}
+
+static void *pipe_buf_map(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf, int atomic)
+{
+ if (atomic) {
+ buf->flags |= PIPE_BUF_FLAG_ATOMIC;
return pipe_kmap_atomic(buf->page, KM_USER0);
}
return pipe_kmap(buf->page);
}
-void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
+static void pipe_buf_unmap(struct pipe_inode_info *pipe,
struct pipe_buffer *buf, void *map_data)
{
if (buf->flags & PIPE_BUF_FLAG_ATOMIC) {
@@ -225,8 +246,8 @@ int generic_pipe_buf_pin(struct pipe_ino
static const struct pipe_buf_operations anon_pipe_buf_ops = {
.can_merge = 1,
- .map = generic_pipe_buf_map,
- .unmap = generic_pipe_buf_unmap,
+ .map = pipe_buf_map,
+ .unmap = pipe_buf_unmap,
.pin = generic_pipe_buf_pin,
.release = anon_pipe_buf_release,
.steal = generic_pipe_buf_steal,
_
Patches currently in -mm which might be from kenchen@xxxxxxxxxx are
cache-pipe-buf-page-address-for-non-highmem-arch.patch
cache-pipe-buf-page-address-for-non-highmem-arch-fix.patch
cache-pipe-buf-page-address-for-non-highmem-arch-fix-tidy.patch
remove-artificial-software-max_loop-limit.patch
-
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