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rsrc.c
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rsrc.c
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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/hugetlb.h>
#include <linux/compat.h>
#include <linux/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io_uring.h"
#include "openclose.h"
#include "rsrc.h"
struct io_rsrc_update {
struct file *file;
u64 arg;
u32 nr_args;
u32 offset;
};
static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc);
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
struct io_mapped_ubuf **pimu,
struct page **last_hpage);
/* only define max */
#define IORING_MAX_FIXED_FILES (1U << 20)
#define IORING_MAX_REG_BUFFERS (1U << 14)
int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
{
unsigned long page_limit, cur_pages, new_pages;
if (!nr_pages)
return 0;
/* Don't allow more pages than we can safely lock */
page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
cur_pages = atomic_long_read(&user->locked_vm);
do {
new_pages = cur_pages + nr_pages;
if (new_pages > page_limit)
return -ENOMEM;
} while (!atomic_long_try_cmpxchg(&user->locked_vm,
&cur_pages, new_pages));
return 0;
}
static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
{
if (ctx->user)
__io_unaccount_mem(ctx->user, nr_pages);
if (ctx->mm_account)
atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
}
static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages)
{
int ret;
if (ctx->user) {
ret = __io_account_mem(ctx->user, nr_pages);
if (ret)
return ret;
}
if (ctx->mm_account)
atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
return 0;
}
static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
void __user *arg, unsigned index)
{
struct iovec __user *src;
#ifdef CONFIG_COMPAT
if (ctx->compat) {
struct compat_iovec __user *ciovs;
struct compat_iovec ciov;
ciovs = (struct compat_iovec __user *) arg;
if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
return -EFAULT;
dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
dst->iov_len = ciov.iov_len;
return 0;
}
#endif
src = (struct iovec __user *) arg;
if (copy_from_user(dst, &src[index], sizeof(*dst)))
return -EFAULT;
return 0;
}
static int io_buffer_validate(struct iovec *iov)
{
unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1);
/*
* Don't impose further limits on the size and buffer
* constraints here, we'll -EINVAL later when IO is
* submitted if they are wrong.
*/
if (!iov->iov_base)
return iov->iov_len ? -EFAULT : 0;
if (!iov->iov_len)
return -EFAULT;
/* arbitrary limit, but we need something */
if (iov->iov_len > SZ_1G)
return -EFAULT;
if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp))
return -EOVERFLOW;
return 0;
}
static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot)
{
struct io_mapped_ubuf *imu = *slot;
unsigned int i;
if (imu != ctx->dummy_ubuf) {
for (i = 0; i < imu->nr_bvecs; i++)
unpin_user_page(imu->bvec[i].bv_page);
if (imu->acct_pages)
io_unaccount_mem(ctx, imu->acct_pages);
kvfree(imu);
}
*slot = NULL;
}
static void io_rsrc_put_work(struct io_rsrc_node *node)
{
struct io_rsrc_put *prsrc = &node->item;
if (prsrc->tag)
io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0);
switch (node->type) {
case IORING_RSRC_FILE:
io_rsrc_file_put(node->ctx, prsrc);
break;
case IORING_RSRC_BUFFER:
io_rsrc_buf_put(node->ctx, prsrc);
break;
default:
WARN_ON_ONCE(1);
break;
}
}
void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
{
if (!io_alloc_cache_put(&ctx->rsrc_node_cache, &node->cache))
kfree(node);
}
void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
__must_hold(&node->ctx->uring_lock)
{
struct io_ring_ctx *ctx = node->ctx;
while (!list_empty(&ctx->rsrc_ref_list)) {
node = list_first_entry(&ctx->rsrc_ref_list,
struct io_rsrc_node, node);
/* recycle ref nodes in order */
if (node->refs)
break;
list_del(&node->node);
if (likely(!node->empty))
io_rsrc_put_work(node);
io_rsrc_node_destroy(ctx, node);
}
if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
wake_up_all(&ctx->rsrc_quiesce_wq);
}
struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
{
struct io_rsrc_node *ref_node;
struct io_cache_entry *entry;
entry = io_alloc_cache_get(&ctx->rsrc_node_cache);
if (entry) {
ref_node = container_of(entry, struct io_rsrc_node, cache);
} else {
ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
if (!ref_node)
return NULL;
}
ref_node->ctx = ctx;
ref_node->empty = 0;
ref_node->refs = 1;
return ref_node;
}
__cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
struct io_ring_ctx *ctx)
{
struct io_rsrc_node *backup;
DEFINE_WAIT(we);
int ret;
/* As We may drop ->uring_lock, other task may have started quiesce */
if (data->quiesce)
return -ENXIO;
backup = io_rsrc_node_alloc(ctx);
if (!backup)
return -ENOMEM;
ctx->rsrc_node->empty = true;
ctx->rsrc_node->type = -1;
list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list);
io_put_rsrc_node(ctx, ctx->rsrc_node);
ctx->rsrc_node = backup;
if (list_empty(&ctx->rsrc_ref_list))
return 0;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 1);
smp_mb();
}
ctx->rsrc_quiesce++;
data->quiesce = true;
do {
prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
mutex_unlock(&ctx->uring_lock);
ret = io_run_task_work_sig(ctx);
if (ret < 0) {
mutex_lock(&ctx->uring_lock);
if (list_empty(&ctx->rsrc_ref_list))
ret = 0;
break;
}
schedule();
__set_current_state(TASK_RUNNING);
mutex_lock(&ctx->uring_lock);
ret = 0;
} while (!list_empty(&ctx->rsrc_ref_list));
finish_wait(&ctx->rsrc_quiesce_wq, &we);
data->quiesce = false;
ctx->rsrc_quiesce--;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 0);
smp_mb();
}
return ret;
}
static void io_free_page_table(void **table, size_t size)
{
unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
for (i = 0; i < nr_tables; i++)
kfree(table[i]);
kfree(table);
}
static void io_rsrc_data_free(struct io_rsrc_data *data)
{
size_t size = data->nr * sizeof(data->tags[0][0]);
if (data->tags)
io_free_page_table((void **)data->tags, size);
kfree(data);
}
static __cold void **io_alloc_page_table(size_t size)
{
unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE);
size_t init_size = size;
void **table;
table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT);
if (!table)
return NULL;
for (i = 0; i < nr_tables; i++) {
unsigned int this_size = min_t(size_t, size, PAGE_SIZE);
table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT);
if (!table[i]) {
io_free_page_table(table, init_size);
return NULL;
}
size -= this_size;
}
return table;
}
__cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type,
u64 __user *utags,
unsigned nr, struct io_rsrc_data **pdata)
{
struct io_rsrc_data *data;
int ret = 0;
unsigned i;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0]));
if (!data->tags) {
kfree(data);
return -ENOMEM;
}
data->nr = nr;
data->ctx = ctx;
data->rsrc_type = type;
if (utags) {
ret = -EFAULT;
for (i = 0; i < nr; i++) {
u64 *tag_slot = io_get_tag_slot(data, i);
if (copy_from_user(tag_slot, &utags[i],
sizeof(*tag_slot)))
goto fail;
}
}
*pdata = data;
return 0;
fail:
io_rsrc_data_free(data);
return ret;
}
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_rsrc_update2 *up,
unsigned nr_args)
{
u64 __user *tags = u64_to_user_ptr(up->tags);
__s32 __user *fds = u64_to_user_ptr(up->data);
struct io_rsrc_data *data = ctx->file_data;
struct io_fixed_file *file_slot;
struct file *file;
int fd, i, err = 0;
unsigned int done;
if (!ctx->file_data)
return -ENXIO;
if (up->offset + nr_args > ctx->nr_user_files)
return -EINVAL;
for (done = 0; done < nr_args; done++) {
u64 tag = 0;
if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) ||
copy_from_user(&fd, &fds[done], sizeof(fd))) {
err = -EFAULT;
break;
}
if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) {
err = -EINVAL;
break;
}
if (fd == IORING_REGISTER_FILES_SKIP)
continue;
i = array_index_nospec(up->offset + done, ctx->nr_user_files);
file_slot = io_fixed_file_slot(&ctx->file_table, i);
if (file_slot->file_ptr) {
file = (struct file *)(file_slot->file_ptr & FFS_MASK);
err = io_queue_rsrc_removal(data, i, file);
if (err)
break;
file_slot->file_ptr = 0;
io_file_bitmap_clear(&ctx->file_table, i);
}
if (fd != -1) {
file = fget(fd);
if (!file) {
err = -EBADF;
break;
}
/*
* Don't allow io_uring instances to be registered. If
* UNIX isn't enabled, then this causes a reference
* cycle and this instance can never get freed. If UNIX
* is enabled we'll handle it just fine, but there's
* still no point in allowing a ring fd as it doesn't
* support regular read/write anyway.
*/
if (io_is_uring_fops(file)) {
fput(file);
err = -EBADF;
break;
}
err = io_scm_file_account(ctx, file);
if (err) {
fput(file);
break;
}
*io_get_tag_slot(data, i) = tag;
io_fixed_file_set(file_slot, file);
io_file_bitmap_set(&ctx->file_table, i);
}
}
return done ? done : err;
}
static int __io_sqe_buffers_update(struct io_ring_ctx *ctx,
struct io_uring_rsrc_update2 *up,
unsigned int nr_args)
{
u64 __user *tags = u64_to_user_ptr(up->tags);
struct iovec iov, __user *iovs = u64_to_user_ptr(up->data);
struct page *last_hpage = NULL;
__u32 done;
int i, err;
if (!ctx->buf_data)
return -ENXIO;
if (up->offset + nr_args > ctx->nr_user_bufs)
return -EINVAL;
for (done = 0; done < nr_args; done++) {
struct io_mapped_ubuf *imu;
u64 tag = 0;
err = io_copy_iov(ctx, &iov, iovs, done);
if (err)
break;
if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) {
err = -EFAULT;
break;
}
err = io_buffer_validate(&iov);
if (err)
break;
if (!iov.iov_base && tag) {
err = -EINVAL;
break;
}
err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage);
if (err)
break;
i = array_index_nospec(up->offset + done, ctx->nr_user_bufs);
if (ctx->user_bufs[i] != ctx->dummy_ubuf) {
err = io_queue_rsrc_removal(ctx->buf_data, i,
ctx->user_bufs[i]);
if (unlikely(err)) {
io_buffer_unmap(ctx, &imu);
break;
}
ctx->user_bufs[i] = ctx->dummy_ubuf;
}
ctx->user_bufs[i] = imu;
*io_get_tag_slot(ctx->buf_data, i) = tag;
}
return done ? done : err;
}
static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type,
struct io_uring_rsrc_update2 *up,
unsigned nr_args)
{
__u32 tmp;
lockdep_assert_held(&ctx->uring_lock);
if (check_add_overflow(up->offset, nr_args, &tmp))
return -EOVERFLOW;
switch (type) {
case IORING_RSRC_FILE:
return __io_sqe_files_update(ctx, up, nr_args);
case IORING_RSRC_BUFFER:
return __io_sqe_buffers_update(ctx, up, nr_args);
}
return -EINVAL;
}
int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct io_uring_rsrc_update2 up;
if (!nr_args)
return -EINVAL;
memset(&up, 0, sizeof(up));
if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update)))
return -EFAULT;
if (up.resv || up.resv2)
return -EINVAL;
return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args);
}
int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned size, unsigned type)
{
struct io_uring_rsrc_update2 up;
if (size != sizeof(up))
return -EINVAL;
if (copy_from_user(&up, arg, sizeof(up)))
return -EFAULT;
if (!up.nr || up.resv || up.resv2)
return -EINVAL;
return __io_register_rsrc_update(ctx, type, &up, up.nr);
}
__cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg,
unsigned int size, unsigned int type)
{
struct io_uring_rsrc_register rr;
/* keep it extendible */
if (size != sizeof(rr))
return -EINVAL;
memset(&rr, 0, sizeof(rr));
if (copy_from_user(&rr, arg, size))
return -EFAULT;
if (!rr.nr || rr.resv2)
return -EINVAL;
if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE)
return -EINVAL;
switch (type) {
case IORING_RSRC_FILE:
if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
break;
return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
case IORING_RSRC_BUFFER:
if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data)
break;
return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data),
rr.nr, u64_to_user_ptr(rr.tags));
}
return -EINVAL;
}
int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->rw_flags || sqe->splice_fd_in)
return -EINVAL;
up->offset = READ_ONCE(sqe->off);
up->nr_args = READ_ONCE(sqe->len);
if (!up->nr_args)
return -EINVAL;
up->arg = READ_ONCE(sqe->addr);
return 0;
}
static int io_files_update_with_index_alloc(struct io_kiocb *req,
unsigned int issue_flags)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
__s32 __user *fds = u64_to_user_ptr(up->arg);
unsigned int done;
struct file *file;
int ret, fd;
if (!req->ctx->file_data)
return -ENXIO;
for (done = 0; done < up->nr_args; done++) {
if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
ret = -EFAULT;
break;
}
file = fget(fd);
if (!file) {
ret = -EBADF;
break;
}
ret = io_fixed_fd_install(req, issue_flags, file,
IORING_FILE_INDEX_ALLOC);
if (ret < 0)
break;
if (copy_to_user(&fds[done], &ret, sizeof(ret))) {
__io_close_fixed(req->ctx, issue_flags, ret);
ret = -EFAULT;
break;
}
}
if (done)
return done;
return ret;
}
int io_files_update(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update);
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_rsrc_update2 up2;
int ret;
up2.offset = up->offset;
up2.data = up->arg;
up2.nr = 0;
up2.tags = 0;
up2.resv = 0;
up2.resv2 = 0;
if (up->offset == IORING_FILE_INDEX_ALLOC) {
ret = io_files_update_with_index_alloc(req, issue_flags);
} else {
io_ring_submit_lock(ctx, issue_flags);
ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE,
&up2, up->nr_args);
io_ring_submit_unlock(ctx, issue_flags);
}
if (ret < 0)
req_set_fail(req);
io_req_set_res(req, ret, 0);
return IOU_OK;
}
int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc)
{
struct io_ring_ctx *ctx = data->ctx;
struct io_rsrc_node *node = ctx->rsrc_node;
u64 *tag_slot = io_get_tag_slot(data, idx);
ctx->rsrc_node = io_rsrc_node_alloc(ctx);
if (unlikely(!ctx->rsrc_node)) {
ctx->rsrc_node = node;
return -ENOMEM;
}
node->item.rsrc = rsrc;
node->type = data->rsrc_type;
node->item.tag = *tag_slot;
*tag_slot = 0;
list_add_tail(&node->node, &ctx->rsrc_ref_list);
io_put_rsrc_node(ctx, node);
return 0;
}
void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
int i;
for (i = 0; i < ctx->nr_user_files; i++) {
struct file *file = io_file_from_index(&ctx->file_table, i);
/* skip scm accounted files, they'll be freed by ->ring_sock */
if (!file || io_file_need_scm(file))
continue;
io_file_bitmap_clear(&ctx->file_table, i);
fput(file);
}
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff *skb;
while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
kfree_skb(skb);
}
#endif
io_free_file_tables(&ctx->file_table);
io_file_table_set_alloc_range(ctx, 0, 0);
io_rsrc_data_free(ctx->file_data);
ctx->file_data = NULL;
ctx->nr_user_files = 0;
}
int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
unsigned nr = ctx->nr_user_files;
int ret;
if (!ctx->file_data)
return -ENXIO;
/*
* Quiesce may unlock ->uring_lock, and while it's not held
* prevent new requests using the table.
*/
ctx->nr_user_files = 0;
ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
ctx->nr_user_files = nr;
if (!ret)
__io_sqe_files_unregister(ctx);
return ret;
}
/*
* Ensure the UNIX gc is aware of our file set, so we are certain that
* the io_uring can be safely unregistered on process exit, even if we have
* loops in the file referencing. We account only files that can hold other
* files because otherwise they can't form a loop and so are not interesting
* for GC.
*/
int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sk = ctx->ring_sock->sk;
struct sk_buff_head *head = &sk->sk_receive_queue;
struct scm_fp_list *fpl;
struct sk_buff *skb;
if (likely(!io_file_need_scm(file)))
return 0;
/*
* See if we can merge this file into an existing skb SCM_RIGHTS
* file set. If there's no room, fall back to allocating a new skb
* and filling it in.
*/
spin_lock_irq(&head->lock);
skb = skb_peek(head);
if (skb && UNIXCB(skb).fp->count < SCM_MAX_FD)
__skb_unlink(skb, head);
else
skb = NULL;
spin_unlock_irq(&head->lock);
if (!skb) {
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
if (!fpl)
return -ENOMEM;
skb = alloc_skb(0, GFP_KERNEL);
if (!skb) {
kfree(fpl);
return -ENOMEM;
}
fpl->user = get_uid(current_user());
fpl->max = SCM_MAX_FD;
fpl->count = 0;
UNIXCB(skb).fp = fpl;
skb->sk = sk;
skb->destructor = io_uring_destruct_scm;
refcount_add(skb->truesize, &sk->sk_wmem_alloc);
}
fpl = UNIXCB(skb).fp;
fpl->fp[fpl->count++] = get_file(file);
unix_inflight(fpl->user, file);
skb_queue_head(head, skb);
fput(file);
#endif
return 0;
}
static __cold void io_rsrc_file_scm_put(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head list, *head = &sock->sk_receive_queue;
struct sk_buff *skb;
int i;
__skb_queue_head_init(&list);
/*
* Find the skb that holds this file in its SCM_RIGHTS. When found,
* remove this entry and rearrange the file array.
*/
skb = skb_dequeue(head);
while (skb) {
struct scm_fp_list *fp;
fp = UNIXCB(skb).fp;
for (i = 0; i < fp->count; i++) {
int left;
if (fp->fp[i] != file)
continue;
unix_notinflight(fp->user, fp->fp[i]);
left = fp->count - 1 - i;
if (left) {
memmove(&fp->fp[i], &fp->fp[i + 1],
left * sizeof(struct file *));
}
fp->count--;
if (!fp->count) {
kfree_skb(skb);
skb = NULL;
} else {
__skb_queue_tail(&list, skb);
}
fput(file);
file = NULL;
break;
}
if (!file)
break;
__skb_queue_tail(&list, skb);
skb = skb_dequeue(head);
}
if (skb_peek(&list)) {
spin_lock_irq(&head->lock);
while ((skb = __skb_dequeue(&list)) != NULL)
__skb_queue_tail(head, skb);
spin_unlock_irq(&head->lock);
}
#endif
}
static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
{
struct file *file = prsrc->file;
if (likely(!io_file_need_scm(file)))
fput(file);
else
io_rsrc_file_scm_put(ctx, file);
}
int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args, u64 __user *tags)
{
__s32 __user *fds = (__s32 __user *) arg;
struct file *file;
int fd, ret;
unsigned i;
if (ctx->file_data)
return -EBUSY;
if (!nr_args)
return -EINVAL;
if (nr_args > IORING_MAX_FIXED_FILES)
return -EMFILE;
if (nr_args > rlimit(RLIMIT_NOFILE))
return -EMFILE;
ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args,
&ctx->file_data);
if (ret)
return ret;
if (!io_alloc_file_tables(&ctx->file_table, nr_args)) {
io_rsrc_data_free(ctx->file_data);
ctx->file_data = NULL;
return -ENOMEM;
}
for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
struct io_fixed_file *file_slot;
if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) {
ret = -EFAULT;
goto fail;
}
/* allow sparse sets */
if (!fds || fd == -1) {
ret = -EINVAL;
if (unlikely(*io_get_tag_slot(ctx->file_data, i)))
goto fail;
continue;
}
file = fget(fd);
ret = -EBADF;
if (unlikely(!file))
goto fail;
/*
* Don't allow io_uring instances to be registered. If UNIX
* isn't enabled, then this causes a reference cycle and this
* instance can never get freed. If UNIX is enabled we'll
* handle it just fine, but there's still no point in allowing
* a ring fd as it doesn't support regular read/write anyway.
*/
if (io_is_uring_fops(file)) {
fput(file);
goto fail;
}
ret = io_scm_file_account(ctx, file);
if (ret) {
fput(file);
goto fail;
}
file_slot = io_fixed_file_slot(&ctx->file_table, i);
io_fixed_file_set(file_slot, file);
io_file_bitmap_set(&ctx->file_table, i);
}
/* default it to the whole table */
io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files);
return 0;
fail:
__io_sqe_files_unregister(ctx);
return ret;
}
static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc)
{
io_buffer_unmap(ctx, &prsrc->buf);
prsrc->buf = NULL;
}
void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
{
unsigned int i;
for (i = 0; i < ctx->nr_user_bufs; i++)
io_buffer_unmap(ctx, &ctx->user_bufs[i]);
kfree(ctx->user_bufs);
io_rsrc_data_free(ctx->buf_data);
ctx->user_bufs = NULL;
ctx->buf_data = NULL;
ctx->nr_user_bufs = 0;
}
int io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
{
unsigned nr = ctx->nr_user_bufs;
int ret;
if (!ctx->buf_data)
return -ENXIO;
/*
* Quiesce may unlock ->uring_lock, and while it's not held
* prevent new requests using the table.
*/
ctx->nr_user_bufs = 0;
ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx);
ctx->nr_user_bufs = nr;
if (!ret)
__io_sqe_buffers_unregister(ctx);
return ret;
}
/*
* Not super efficient, but this is just a registration time. And we do cache
* the last compound head, so generally we'll only do a full search if we don't
* match that one.
*
* We check if the given compound head page has already been accounted, to
* avoid double accounting it. This allows us to account the full size of the
* page, not just the constituent pages of a huge page.
*/
static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct page *hpage)
{
int i, j;
/* check current page array */
for (i = 0; i < nr_pages; i++) {
if (!PageCompound(pages[i]))
continue;
if (compound_head(pages[i]) == hpage)
return true;
}
/* check previously registered pages */
for (i = 0; i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *imu = ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++) {
if (!PageCompound(imu->bvec[j].bv_page))
continue;
if (compound_head(imu->bvec[j].bv_page) == hpage)
return true;
}
}
return false;
}
static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct io_mapped_ubuf *imu,
struct page **last_hpage)