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axboeaxboe
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io_uring/rsrc: get rid of the empty node and dummy_ubuf
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 <[email protected]>
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6 files changed

+40
-50
lines changed

6 files changed

+40
-50
lines changed

‎io_uring/fdinfo.c

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -178,9 +178,14 @@ __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *file)
178178
}
179179
seq_printf(m, "UserBufs:\t%u\n", ctx->buf_table.nr);
180180
for (i = 0; has_lock && i < ctx->buf_table.nr; i++) {
181-
struct io_mapped_ubuf *buf = ctx->buf_table.nodes[i]->buf;
181+
struct io_mapped_ubuf *buf = NULL;
182182

183-
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);
183+
if (ctx->buf_table.nodes[i])
184+
buf = ctx->buf_table.nodes[i]->buf;
185+
if (buf)
186+
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, buf->len);
187+
else
188+
seq_printf(m, "%5u: <none>\n", i);
184189
}
185190
if (has_lock && !xa_empty(&ctx->personalities)) {
186191
unsigned long index;

‎io_uring/io_uring.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -947,8 +947,8 @@ void io_req_defer_failed(struct io_kiocb *req, s32 res)
947947
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
948948
{
949949
req->ctx = ctx;
950-
req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
951-
req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
950+
req->rsrc_nodes[IORING_RSRC_FILE] = NULL;
951+
req->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
952952
req->link = NULL;
953953
req->async_data = NULL;
954954
/* not necessary, but safer to zero */

‎io_uring/notif.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -117,8 +117,8 @@ struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)
117117
notif->file = NULL;
118118
notif->task = current;
119119
io_get_task_refs(1);
120-
notif->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
121-
notif->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
120+
notif->rsrc_nodes[IORING_RSRC_FILE] = NULL;
121+
notif->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
122122

123123
nd = io_notif_to_data(notif);
124124
nd->zc_report = false;

‎io_uring/rsrc.c

Lines changed: 21 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -32,17 +32,6 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
3232
#define IORING_MAX_FIXED_FILES (1U << 20)
3333
#define IORING_MAX_REG_BUFFERS (1U << 14)
3434

35-
static const struct io_mapped_ubuf dummy_ubuf = {
36-
/* set invalid range, so io_import_fixed() fails meeting it */
37-
.ubuf = -1UL,
38-
.len = UINT_MAX,
39-
};
40-
41-
const struct io_rsrc_node empty_node = {
42-
.type = IORING_RSRC_BUFFER,
43-
.buf = (struct io_mapped_ubuf *) &dummy_ubuf,
44-
};
45-
4635
int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
4736
{
4837
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)
116105
{
117106
unsigned int i;
118107

119-
if (node->buf != &dummy_ubuf) {
108+
if (node->buf) {
120109
struct io_mapped_ubuf *imu = node->buf;
121110

122111
if (!refcount_dec_and_test(&imu->refs))
@@ -265,20 +254,21 @@ static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
265254
err = io_buffer_validate(iov);
266255
if (err)
267256
break;
268-
if (!iov->iov_base && tag) {
269-
err = -EINVAL;
270-
break;
271-
}
272257
node = io_sqe_buffer_register(ctx, iov, &last_hpage);
273258
if (IS_ERR(node)) {
274259
err = PTR_ERR(node);
275260
break;
276261
}
262+
if (tag) {
263+
if (!node) {
264+
err = -EINVAL;
265+
break;
266+
}
267+
node->tag = tag;
268+
}
277269
i = array_index_nospec(up->offset + done, ctx->buf_table.nr);
278270
io_reset_rsrc_node(&ctx->buf_table, i);
279271
ctx->buf_table.nodes[i] = node;
280-
if (tag)
281-
node->tag = tag;
282272
if (ctx->compat)
283273
user_data += sizeof(struct compat_iovec);
284274
else
@@ -591,8 +581,11 @@ static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
591581
/* check previously registered pages */
592582
for (i = 0; i < ctx->buf_table.nr; i++) {
593583
struct io_rsrc_node *node = ctx->buf_table.nodes[i];
594-
struct io_mapped_ubuf *imu = node->buf;
584+
struct io_mapped_ubuf *imu;
595585

586+
if (!node)
587+
continue;
588+
imu = node->buf;
596589
for (j = 0; j < imu->nr_bvecs; j++) {
597590
if (!PageCompound(imu->bvec[j].bv_page))
598591
continue;
@@ -742,7 +735,7 @@ static struct io_rsrc_node *io_sqe_buffer_register(struct io_ring_ctx *ctx,
742735
bool coalesced;
743736

744737
if (!iov->iov_base)
745-
return rsrc_empty_node;
738+
return NULL;
746739

747740
node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
748741
if (!node)
@@ -850,19 +843,20 @@ int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
850843
ret = -EFAULT;
851844
break;
852845
}
853-
if (tag && !iov->iov_base) {
854-
ret = -EINVAL;
855-
break;
856-
}
857846
}
858847

859848
node = io_sqe_buffer_register(ctx, iov, &last_hpage);
860849
if (IS_ERR(node)) {
861850
ret = PTR_ERR(node);
862851
break;
863852
}
864-
if (tag)
853+
if (tag) {
854+
if (!node) {
855+
ret = -EINVAL;
856+
break;
857+
}
865858
node->tag = tag;
859+
}
866860
data.nodes[i] = node;
867861
}
868862

@@ -957,8 +951,8 @@ static int io_clone_buffers(struct io_ring_ctx *ctx, struct io_ring_ctx *src_ctx
957951
struct io_rsrc_node *dst_node, *src_node;
958952

959953
src_node = io_rsrc_node_lookup(&src_ctx->buf_table, i);
960-
if (src_node == rsrc_empty_node) {
961-
dst_node = rsrc_empty_node;
954+
if (!src_node) {
955+
dst_node = NULL;
962956
} else {
963957
dst_node = io_rsrc_node_alloc(ctx, IORING_RSRC_BUFFER);
964958
if (!dst_node) {

‎io_uring/rsrc.h

Lines changed: 7 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -67,9 +67,6 @@ int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
6767
int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
6868
unsigned int size, unsigned int type);
6969

70-
extern const struct io_rsrc_node empty_node;
71-
#define rsrc_empty_node (struct io_rsrc_node *) &empty_node
72-
7370
static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data,
7471
int index)
7572
{
@@ -80,7 +77,7 @@ static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data
8077

8178
static inline void io_put_rsrc_node(struct io_rsrc_node *node)
8279
{
83-
if (node != rsrc_empty_node && !--node->refs)
80+
if (node && !--node->refs)
8481
io_free_rsrc_node(node);
8582
}
8683

@@ -97,23 +94,17 @@ static inline bool io_reset_rsrc_node(struct io_rsrc_data *data, int index)
9794

9895
static inline void io_req_put_rsrc_nodes(struct io_kiocb *req)
9996
{
100-
if (req->rsrc_nodes[IORING_RSRC_FILE] != rsrc_empty_node) {
101-
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
102-
req->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
103-
}
104-
if (req->rsrc_nodes[IORING_RSRC_BUFFER] != rsrc_empty_node) {
105-
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
106-
req->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
107-
}
97+
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_FILE]);
98+
io_put_rsrc_node(req->rsrc_nodes[IORING_RSRC_BUFFER]);
99+
req->rsrc_nodes[IORING_RSRC_FILE] = NULL;
100+
req->rsrc_nodes[IORING_RSRC_BUFFER] = NULL;
108101
}
109102

110103
static inline void io_req_assign_rsrc_node(struct io_kiocb *req,
111104
struct io_rsrc_node *node)
112105
{
113-
if (node != rsrc_empty_node) {
114-
node->refs++;
115-
req->rsrc_nodes[node->type] = node;
116-
}
106+
node->refs++;
107+
req->rsrc_nodes[node->type] = node;
117108
}
118109

119110
int io_files_update(struct io_kiocb *req, unsigned int issue_flags);

‎io_uring/splice.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -35,7 +35,7 @@ static int __io_splice_prep(struct io_kiocb *req,
3535
if (unlikely(sp->flags & ~valid_flags))
3636
return -EINVAL;
3737
sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in);
38-
sp->rsrc_node = rsrc_empty_node;
38+
sp->rsrc_node = NULL;
3939
req->flags |= REQ_F_FORCE_ASYNC;
4040
return 0;
4141
}

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