* [PATCH for-next] io_uring/rsrc: get rid of the empty node and dummy_ubuf
@ 2024-10-30 16:06 Jens Axboe
0 siblings, 0 replies; only message in thread
From: Jens Axboe @ 2024-10-30 16:06 UTC (permalink / raw)
To: io-uring; +Cc: Pavel Begunkov
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]>
---
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 3a535e9e8ac3..44a772013c09 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -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 */
diff --git a/io_uring/notif.c b/io_uring/notif.c
index 44bf21c0f810..4f02e969cf08 100644
--- a/io_uring/notif.c
+++ b/io_uring/notif.c
@@ -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;
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 378f33746457..af60d9f597be 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -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
@@ -742,7 +732,7 @@ 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 +840,6 @@ 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 +847,13 @@ 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 +948,8 @@ 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) {
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 43b19e516f5f..a40fad783a69 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -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);
diff --git a/io_uring/splice.c b/io_uring/splice.c
index deeb8bb18651..e8ed15f4ea1a 100644
--- a/io_uring/splice.c
+++ b/io_uring/splice.c
@@ -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;
}
--
Jens Axboe
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