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

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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: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2024-09-15 08:53:45 -06:00
parent 8b0c6025a0
commit 9753c642a5
3 changed files with 6 additions and 7 deletions
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3
io_uring/fdinfo.c
View File

@ -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;

6
io_uring/rsrc.c
View File

@ -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;
/*

4
io_uring/rsrc.h
View File

@ -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);
};