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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 /include/linux/pipe_fs_i.h
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 'include/linux/pipe_fs_i.h')
-rw-r--r--include/linux/pipe_fs_i.h21
1 files changed, 20 insertions, 1 deletions
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 3130977..b8aae1f 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -14,10 +14,23 @@ struct pipe_buffer {
unsigned int flags;
};
+/*
+ * Note on the nesting of these functions:
+ *
+ * ->pin()
+ * ->steal()
+ * ...
+ * ->map()
+ * ...
+ * ->unmap()
+ *
+ * That is, ->map() must be called on a pinned buffer, same goes for ->steal().
+ */
struct pipe_buf_operations {
int can_merge;
- void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *);
+ void * (*map)(struct pipe_inode_info *, struct pipe_buffer *);
void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *);
+ int (*pin)(struct pipe_inode_info *, struct pipe_buffer *);
void (*release)(struct pipe_inode_info *, struct pipe_buffer *);
int (*steal)(struct pipe_inode_info *, struct pipe_buffer *);
void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
@@ -50,6 +63,12 @@ struct pipe_inode_info * alloc_pipe_info(struct inode * inode);
void free_pipe_info(struct inode * inode);
void __free_pipe_info(struct pipe_inode_info *);
+/* Generic pipe buffer ops functions */
+void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *);
+void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *);
+void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *);
+int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *);
+
/*
* splice is tied to pipes as a transport (at least for now), so we'll just
* add the splice flags here.
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