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authorJens Axboe <axboe@suse.de>2006-05-01 19:59:03 +0200
committerJens Axboe <axboe@suse.de>2006-05-01 19:59:03 +0200
commitf84d751994441292593523c7069ed147176f6cab (patch)
treea1a0c4836289df86bb62e7eae5c80c66fca1643a /fs/pipe.c
parent0568b409c74f7a125d92a09a3f386785700ef688 (diff)
downloadop-kernel-dev-f84d751994441292593523c7069ed147176f6cab.zip
op-kernel-dev-f84d751994441292593523c7069ed147176f6cab.tar.gz
[PATCH] pipe: introduce ->pin() buffer operation
The ->map() function is really expensive on highmem machines right now, since it has to use the slower kmap() instead of kmap_atomic(). Splice rarely needs to access the virtual address of a page, so it's a waste of time doing it. Introduce ->pin() to take over the responsibility of making sure the page data is valid. ->map() is then reduced to just kmap(). That way we can also share a most of the pipe buffer ops between pipe.c and splice.c Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'fs/pipe.c')
-rw-r--r--fs/pipe.c39
1 files changed, 23 insertions, 16 deletions
diff --git a/fs/pipe.c b/fs/pipe.c
index 888f265..d9644fd 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -110,14 +110,14 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
page_cache_release(page);
}
-static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
+void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
return kmap(buf->page);
}
-static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe,
- struct pipe_buffer *buf)
+void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
{
kunmap(buf->page);
}
@@ -135,19 +135,24 @@ static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
return 1;
}
-static void anon_pipe_buf_get(struct pipe_inode_info *info,
- struct pipe_buffer *buf)
+void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf)
{
page_cache_get(buf->page);
}
+int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf)
+{
+ return 0;
+}
+
static struct pipe_buf_operations anon_pipe_buf_ops = {
.can_merge = 1,
- .map = anon_pipe_buf_map,
- .unmap = anon_pipe_buf_unmap,
+ .map = generic_pipe_buf_map,
+ .unmap = generic_pipe_buf_unmap,
+ .pin = generic_pipe_buf_pin,
.release = anon_pipe_buf_release,
.steal = anon_pipe_buf_steal,
- .get = anon_pipe_buf_get,
+ .get = generic_pipe_buf_get,
};
static ssize_t
@@ -183,12 +188,14 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
if (chars > total_len)
chars = total_len;
- addr = ops->map(filp, pipe, buf);
- if (IS_ERR(addr)) {
+ error = ops->pin(pipe, buf);
+ if (error) {
if (!ret)
- ret = PTR_ERR(addr);
+ error = ret;
break;
}
+
+ addr = ops->map(pipe, buf);
error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
ops->unmap(pipe, buf);
if (unlikely(error)) {
@@ -300,11 +307,11 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
void *addr;
int error;
- addr = ops->map(filp, pipe, buf);
- if (IS_ERR(addr)) {
- error = PTR_ERR(addr);
+ error = ops->pin(pipe, buf);
+ if (error)
goto out;
- }
+
+ addr = ops->map(pipe, buf);
error = pipe_iov_copy_from_user(offset + addr, iov,
chars);
ops->unmap(pipe, buf);
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