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io_uring/rsrc: get rid of the empty node and dummy_ubuf

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The empty node was used as a placeholder for a sparse entry, but it
didn't really solve any issues. The caller still has to check for
whether it's the empty node or not, it may as well just check for a NULL
return instead.

The dummy_ubuf was used for a sparse buffer entry, but NULL will serve
the same purpose there of ensuring an -EFAULT on attempted import.

Just use NULL for a sparse node, regardless of whether or not it's a
file or buffer resource.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2024-10-30 09:51:58 -06:00
parent 4007c3d8c2
commit d50f94d761
6 changed files with 40 additions and 50 deletions
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9
io_uring/fdinfo.c
View File

@ -178,9 +178,14 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file)
}
seq_printf(m, "UserBufs:\t%u\n", ctx->buf_table.nr);
for (i = 0; has_lock && i < ctx->buf_table.nr; i++) {
struct io_mapped_ubuf *buf = ctx->buf_table.nodes[i]->buf;
struct io_mapped_ubuf *buf = NULL;
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);
if (ctx->buf_table.nodes[i])
buf = ctx->buf_table.nodes[i]->buf;
if (buf)
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);
else
seq_printf(m, "%5u: <none>\n", i);
}
if (has_lock && !xa_empty(&ctx->personalities)) {
unsigned long index;

4
io_uring/io_uring.c
View File

@ -947,8 +947,8 @@ void io_req_defer_failed(struct io_kiocb *req, s32 res)
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
req->ctx = ctx;
req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
req->rsrc_nodes[IORING_RSRC_FILE] = NULL;
req->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
req->link = NULL;
req->async_data = NULL;
/* not necessary, but safer to zero */

4
io_uring/notif.c
View File

@ -117,8 +117,8 @@ struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
notif->file = NULL;
notif->task = current;
io_get_task_refs(1);
notif->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
notif->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
notif->rsrc_nodes[IORING_RSRC_FILE] = NULL;
notif->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
nd = io_notif_to_data(notif);
nd->zc_report = false;

48
io_uring/rsrc.c
View File

@ -32,17 +32,6 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
#define IORING_MAX_FIXED_FILES (1U << 20)
#define IORING_MAX_REG_BUFFERS (1U << 14)
static const struct io_mapped_ubuf dummy_ubuf = {
/* set invalid range, so io_import_fixed() fails meeting it */
.ubuf = -1UL,
.len = UINT_MAX,
};
const struct io_rsrc_node empty_node = {
.type = IORING_RSRC_BUFFER,
.buf = (struct io_mapped_ubuf *) &dummy_ubuf,
};
int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
{
unsigned long page_limit, cur_pages, new_pages;
@ -116,7 +105,7 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
{
unsigned int i;
if (node->buf != &dummy_ubuf) {
if (node->buf) {
struct io_mapped_ubuf *imu = node->buf;
if (!refcount_dec_and_test(&imu->refs))
@ -265,20 +254,21 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
err = io_buffer_validate(iov);
if (err)
break;
if (!iov->iov_base && tag) {
err = -EINVAL;
break;
}
node = io_sqe_buffer_register(ctx, iov, &last_hpage);
if (IS_ERR(node)) {
err = PTR_ERR(node);
break;
}
if (tag) {
if (!node) {
err = -EINVAL;
break;
}
node->tag = tag;
}
i = array_index_nospec(up->offset + done, ctx->buf_table.nr);
io_reset_rsrc_node(&ctx->buf_table, i);
ctx->buf_table.nodes[i] = node;
if (tag)
node->tag = tag;
if (ctx->compat)
user_data += sizeof(struct compat_iovec);
else
@ -591,8 +581,11 @@ static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
/* check previously registered pages */
for (i = 0; i < ctx->buf_table.nr; i++) {
struct io_rsrc_node *node = ctx->buf_table.nodes[i];
struct io_mapped_ubuf *imu = node->buf;
struct io_mapped_ubuf *imu;
if (!node)
continue;
imu = node->buf;
for (j = 0; j < imu->nr_bvecs; j++) {
if (!PageCompound(imu->bvec[j].bv_page))
continue;
@ -742,7 +735,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
bool coalesced;
if (!iov->iov_base)
return rsrc_empty_node;
return NULL;
node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
if (!node)
@ -850,10 +843,6 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
ret = -EFAULT;
break;
}
if (tag && !iov->iov_base) {
ret = -EINVAL;
break;
}
}
node = io_sqe_buffer_register(ctx, iov, &last_hpage);
@ -861,8 +850,13 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
ret = PTR_ERR(node);
break;
}
if (tag)
if (tag) {
if (!node) {
ret = -EINVAL;
break;
}
node->tag = tag;
}
data.nodes[i] = node;
}
@ -957,8 +951,8 @@ static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx
struct io_rsrc_node *dst_node, *src_node;
src_node = io_rsrc_node_lookup(&src_ctx->buf_table, i);
if (src_node == rsrc_empty_node) {
dst_node = rsrc_empty_node;
if (!src_node) {
dst_node = NULL;
} else {
dst_node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
if (!dst_node) {

23
io_uring/rsrc.h
View File

@ -67,9 +67,6 @@ int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
unsigned int size, unsigned int type);
extern const struct io_rsrc_node empty_node;
#define rsrc_empty_node (struct io_rsrc_node *) &empty_node
static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data,
int index)
{
@ -80,7 +77,7 @@ static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data
static inline void io_put_rsrc_node(struct io_rsrc_node *node)
{
if (node != rsrc_empty_node && !--node->refs)
if (node && !--node->refs)
io_free_rsrc_node(node);
}
@ -97,23 +94,17 @@ static inline bool io_reset_rsrc_node(struct io_rsrc_data *data, int index)
static inline void io_req_put_rsrc_nodes(struct io_kiocb *req)
{
if (req->rsrc_nodes[IORING_RSRC_FILE] != rsrc_empty_node) {
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
}
if (req->rsrc_nodes[IORING_RSRC_BUFFER] != rsrc_empty_node) {
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
}
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
req->rsrc_nodes[IORING_RSRC_FILE] = NULL;
req->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
}
static inline void io_req_assign_rsrc_node(struct io_kiocb *req,
struct io_rsrc_node *node)
{
if (node != rsrc_empty_node) {
node->refs++;
req->rsrc_nodes[node->type] = node;
}
node->refs++;
req->rsrc_nodes[node->type] = node;
}
int io_files_update(struct io_kiocb *req, unsigned int issue_flags);

2
io_uring/splice.c
View File

@ -35,7 +35,7 @@ static int __io_splice_prep(struct io_kiocb *req,
if (unlikely(sp->flags & ~valid_flags))
return -EINVAL;
sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in);
sp->rsrc_node = rsrc_empty_node;
sp->rsrc_node = NULL;
req->flags |= REQ_F_FORCE_ASYNC;
return 0;
}