Apply fixed_rsrc functionality for fixed buffers support.
I don't get it, requests with fixed files take a ref to a node (see
fixed_file_refs) and put it on free, but I don't see anything similar
here. Did you work around it somehow?
No that's my oversight. I think I wrongfully assumed that io_import_*fixed() would take care of that.
Should I basically do something similar to io_file_get()/io_put_file()?
If done in a dumb way, that'd mean extra pair of percpu get/put
and +8B in io_kiocb. Frankly, I don't like that idea.
However, if you don't split paths and make fixed_file_ref_node to
supports all types of resources at the same time, it should be
bearable. I.e. register removals of both types to a single node,
and use ->fixed_file_refs for all request's resources.
So you don't grow io_kiocb and do maximum one percpu_ref_get/put()
pair per request.
So something like promoting fixed_file_ref_node to fixed_rsrc_ref_node,
and ref counting all fixed resources for a given request together?
I'll send a small patch preparing grounds, because there is actually
another nasty thing from past that needs to be reworked.
Ok, I'll wait for your patch then.
Are you ok with the rest of the patches or should I address anything else?
io_import_fixed() currently can be called twice, and that would give
you 2 different bvecs. Hence after removing full quisce io_read()
retrying short reads will probably be able to partially read into 2
different buffers. That really have to be fixed.
Will you address that in your patch?
static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
struct iov_iter *iter)
{
@@ -2959,10 +2982,15 @@ static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
size_t offset;
u64 buf_addr;
+ /* attempt to use fixed buffers without having provided iovecs */
+ if (unlikely(!ctx->buf_data))
+ return -EFAULT;
I removed it for files,
because (ctx->buf_data) IFF (ctx->nr_user_bufs == 0),
so the following ctx->nr_user_bufs check is enough.
Ok, will remove the check for buffers.
