Commit 9753c642 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring/rsrc: change ubuf->ubuf_end to length tracking 



If we change it to tracking ubuf->start + ubuf->len, then we can reduce
the size of struct io_mapped_ubuf by another 4 bytes, effectively 8
bytes, as a hole is eliminated too.

This shrinks io_mapped_ubuf to 32 bytes.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8b0c6025

io_uring/fdinfo.c

+1 −2
Original line number Diff line number Diff line
@@ -177,9 +177,8 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file) 
	seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);

	for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {

		struct io_mapped_ubuf *buf = ctx->user_bufs[i];

		unsigned int len = buf->ubuf_end - buf->ubuf;



		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len);

		seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);

	}

	if (has_lock && !xa_empty(&ctx->personalities)) {

		unsigned long index;

io_uring/rsrc.c

+3 −3
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 
static const struct io_mapped_ubuf dummy_ubuf = {

	/* set invalid range, so io_import_fixed() fails meeting it */

	.ubuf = -1UL,

	.ubuf_end = 0,

	.len = UINT_MAX,

};



int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
@@ -985,7 +985,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 
	size = iov->iov_len;

	/* store original address for later verification */

	imu->ubuf = (unsigned long) iov->iov_base;

	imu->ubuf_end = imu->ubuf + iov->iov_len;

	imu->len = iov->iov_len;

	imu->nr_bvecs = nr_pages;

	imu->folio_shift = PAGE_SHIFT;

	if (coalesced)
@@ -1086,7 +1086,7 @@ int io_import_fixed(int ddir, struct iov_iter *iter, 
	if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end)))

		return -EFAULT;

	/* not inside the mapped region */

	if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end))

	if (unlikely(buf_addr < imu->ubuf || buf_end > (imu->ubuf + imu->len)))

		return -EFAULT;



	/*

io_uring/rsrc.h

+2 −2
Original line number Diff line number Diff line
@@ -42,11 +42,11 @@ struct io_rsrc_node { 


struct io_mapped_ubuf {

	u64		ubuf;

	u64		ubuf_end;

	unsigned int	len;

	unsigned int	nr_bvecs;

	unsigned int    folio_shift;

	unsigned long	acct_pages;

	refcount_t	refs;

	unsigned long	acct_pages;

	struct bio_vec	bvec[] __counted_by(nr_bvecs);

};