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io_uring: don't pass around fixed index for scm 

There is an old API nuisance where io_uring's SCM accounting functions
traverse fixed file tables and so requires them to be set in advance,
which leads to some implicit rules of how io_sqe_file_register() should
be used.

__io_sqe_files_scm() now works with only one file at a time, pass a file
directly and get rid of all fixed table dereferencing inside. Clean
io_sqe_file_register() callers.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fb32031d892e61a7748c70da7999725d5e798671.1649334991.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2022-04-07 13:40:03 +01:00 committed by Jens Axboe
parent dca58c6a08
commit e390510af0
1 changed files with 14 additions and 23 deletions
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37
fs/io_uring.c
View File

@ -8609,9 +8609,8 @@ static struct io_sq_data *io_get_sq_data(struct io_uring_params *p,
* files because otherwise they can't form a loop and so are not interesting
* for GC.
*/
static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int offset)
static int __io_sqe_files_scm(struct io_ring_ctx *ctx, struct file *file)
{
struct file *file = io_file_from_index(ctx, offset);
struct sock *sk = ctx->ring_sock->sk;
struct scm_fp_list *fpl;
struct sk_buff *skb;
@ -8761,8 +8760,7 @@ static void io_rsrc_put_work(struct work_struct *work)
}
}
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
int index);
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file);
static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args, u64 __user *tags)
@ -8825,14 +8823,13 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
fput(file);
goto fail;
}
file_slot = io_fixed_file_slot(&ctx->file_table, i);
io_fixed_file_set(file_slot, file);
ret = io_sqe_file_register(ctx, file, i);
ret = io_sqe_file_register(ctx, file);
if (ret) {
file_slot->file_ptr = 0;
fput(file);
goto fail;
}
file_slot = io_fixed_file_slot(&ctx->file_table, i);
io_fixed_file_set(file_slot, file);
}
io_rsrc_node_switch(ctx, NULL);
@ -8842,8 +8839,7 @@ fail:
return ret;
}
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
int index)
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
@ -8882,7 +8878,7 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
return 0;
}
return __io_sqe_files_scm(ctx, index);
return __io_sqe_files_scm(ctx, file);
#else
return 0;
#endif
@ -8942,15 +8938,11 @@ static int io_install_fixed_file(struct io_kiocb *req, struct file *file,
needs_switch = true;
}
*io_get_tag_slot(ctx->file_data, slot_index) = 0;
io_fixed_file_set(file_slot, file);
ret = io_sqe_file_register(ctx, file, slot_index);
if (ret) {
file_slot->file_ptr = 0;
goto err;
ret = io_sqe_file_register(ctx, file);
if (!ret) {
*io_get_tag_slot(ctx->file_data, slot_index) = 0;
io_fixed_file_set(file_slot, file);
}
ret = 0;
err:
if (needs_switch)
io_rsrc_node_switch(ctx, ctx->file_data);
@ -9061,14 +9053,13 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
err = -EBADF;
break;
}
*io_get_tag_slot(data, i) = tag;
io_fixed_file_set(file_slot, file);
err = io_sqe_file_register(ctx, file, i);
err = io_sqe_file_register(ctx, file);
if (err) {
file_slot->file_ptr = 0;
fput(file);
break;
}
*io_get_tag_slot(data, i) = tag;
io_fixed_file_set(file_slot, file);
}
}