Josef Bacik wrote:
On Wed, Feb 10, 2010 at 01:53:50PM -0500, jim owens wrote:
+
+static int btrfs_dio_hole_read(struct btrfs_diocb *diocb, u64 hole_len)
+{
+ int err = 0;
+ diocb->umc.todo = hole_len;
+ while (diocb->umc.todo) {
+ struct bio_vec uv;
+ char *out;
+
+ err = btrfs_dio_get_user_bvec(&uv, &diocb->umc);
+ if (err)
+ goto fail;
+ diocb->start += uv.bv_len;
+ out = kmap_atomic(uv.bv_page, KM_USER0);
+ memset(out + uv.bv_offset, 0, uv.bv_len);
+ kunmap_atomic(out, KM_USER0);
+
/me hands jim a zero_user_page()
+ btrfs_dio_done_with_out(&uv, NULL);
+ }
As promised... why I'm keeping my code :)
cscope says there is no zero_user_page() so I think
you mean the same one I looked at zero_user(), which
calls the far more complicated zero_user_segments().
I did not use it for 3 reasons:
1) More generated code (but maybe gcc reduces it).
2) My btrfs_dio_done_with_out() must do (so repeat) the
flush_dcache_page which is not a noop on every arch.
3) Everywhere else in btrfs does the same as my code.
jim
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