On Tue, Jan 26, 2021 at 7:29 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
>
> On 22/12/2020 02:10, Noah Goldstein wrote:
> > On Sun, Dec 20, 2020 at 03:18:05PM +0000, Pavel Begunkov wrote:
> >> On 20/12/2020 06:50, noah wrote:> From: noah <goldstein.n@xxxxxxxxx>
> >>>
> >>> This patch makes it so that specify a file descriptor value of -2 will
> >>> skip updating the corresponding fixed file index.
> >>>
> >>> This will allow for users to reduce the number of syscalls necessary
> >>> to update a sparse file range when using the fixed file option.
> >>
> >> Answering the github thread -- it's indeed a simple change, I had it the
> >> same day you posted the issue. See below it's a bit cleaner. However, I
> >> want to first review "io_uring: buffer registration enhancements", and
> >> if it's good, for easier merging/etc I'd rather prefer to let it go
> >> first (even if partially).
>
> Noah, want to give it a try? I've just sent a prep patch, with it you
> can implement it cleaner with one continue.
>
Absolutely. Will get on it ASAP.
> >>
> >> diff --git a/fs/io_uring.c b/fs/io_uring.c
> >> index 941fe9b64fd9..b3ae9d5da17e 100644
> >> --- a/fs/io_uring.c
> >> +++ b/fs/io_uring.c
> >> @@ -7847,9 +7847,8 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
> >> if (IS_ERR(ref_node))
> >> return PTR_ERR(ref_node);
> >>
> >> - done = 0;
> >> fds = u64_to_user_ptr(up->fds);
> >> - while (nr_args) {
> >> + for (done = 0; done < nr_args; done++) {
> >> struct fixed_file_table *table;
> >> unsigned index;
> >>
> >> @@ -7858,7 +7857,10 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
> >> err = -EFAULT;
> >> break;
> >> }
> >> - i = array_index_nospec(up->offset, ctx->nr_user_files);
> >> + if (fd == IORING_REGISTER_FILES_SKIP)
> >> + continue;
> >> +
> >> + i = array_index_nospec(up->offset + done, ctx->nr_user_files);
> >> table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
> >> index = i & IORING_FILE_TABLE_MASK;
> >> if (table->files[index]) {
> >> @@ -7896,9 +7898,6 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
> >> break;
> >> }
> >> }
> >> - nr_args--;
> >> - done++;
> >> - up->offset++;
> >> }
> >>
> >> if (needs_switch) {
>
> --
> Pavel Begunkov
