Commit 943d0609 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: rename ->resize_lock 



->resize_lock is used for resizing rings, but it's a good idea to reuse
it in other cases as well. Rename it into mmap_lock as it's protects
from races with mmap.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/68f705306f3ac4d2fb999eb80ea1615015ce9f7f.1732886067.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 4bbf9020

include/linux/io_uring_types.h

+1 −1
Original line number Diff line number Diff line
@@ -424,7 +424,7 @@ struct io_ring_ctx { 
	 * side will need to grab this lock, to prevent either side from

	 * being run concurrently with the other.

	 */

	struct mutex			resize_lock;

	struct mutex			mmap_lock;



	/*

	 * If IORING_SETUP_NO_MMAP is used, then the below holds

io_uring/io_uring.c

+1 −1
Original line number Diff line number Diff line
@@ -350,7 +350,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) 
	INIT_WQ_LIST(&ctx->submit_state.compl_reqs);

	INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);

	io_napi_init(ctx);

	mutex_init(&ctx->resize_lock);

	mutex_init(&ctx->mmap_lock);



	return ctx;

io_uring/memmap.c

+3 −3
Original line number Diff line number Diff line
@@ -329,7 +329,7 @@ __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma) 
	unsigned int npages;

	void *ptr;



	guard(mutex)(&ctx->resize_lock);

	guard(mutex)(&ctx->mmap_lock);



	ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);

	if (IS_ERR(ptr))
@@ -365,7 +365,7 @@ unsigned long io_uring_get_unmapped_area(struct file *filp, unsigned long addr, 
	if (addr)

		return -EINVAL;



	guard(mutex)(&ctx->resize_lock);

	guard(mutex)(&ctx->mmap_lock);



	ptr = io_uring_validate_mmap_request(filp, pgoff, len);

	if (IS_ERR(ptr))
@@ -415,7 +415,7 @@ unsigned long io_uring_get_unmapped_area(struct file *file, unsigned long addr, 
	struct io_ring_ctx *ctx = file->private_data;

	void *ptr;



	guard(mutex)(&ctx->resize_lock);

	guard(mutex)(&ctx->mmap_lock);



	ptr = io_uring_validate_mmap_request(file, pgoff, len);

	if (IS_ERR(ptr))

io_uring/register.c

+4 −4
Original line number Diff line number Diff line
@@ -489,15 +489,15 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg) 
	}



	/*

	 * We'll do the swap. Grab the ctx->resize_lock, which will exclude

	 * We'll do the swap. Grab the ctx->mmap_lock, which will exclude

	 * any new mmap's on the ring fd. Clear out existing mappings to prevent

	 * mmap from seeing them, as we'll unmap them. Any attempt to mmap

	 * existing rings beyond this point will fail. Not that it could proceed

	 * at this point anyway, as the io_uring mmap side needs go grab the

	 * ctx->resize_lock as well. Likewise, hold the completion lock over the

	 * ctx->mmap_lock as well. Likewise, hold the completion lock over the

	 * duration of the actual swap.

	 */

	mutex_lock(&ctx->resize_lock);

	mutex_lock(&ctx->mmap_lock);

	spin_lock(&ctx->completion_lock);

	o.rings = ctx->rings;

	ctx->rings = NULL;
@@ -564,7 +564,7 @@ static int io_register_resize_rings(struct io_ring_ctx *ctx, void __user *arg) 
	ret = 0;

out:

	spin_unlock(&ctx->completion_lock);

	mutex_unlock(&ctx->resize_lock);

	mutex_unlock(&ctx->mmap_lock);

	io_register_free_rings(&p, to_free);



	if (ctx->sq_data)