Commit 51976c6c authored by Chengchang Tang's avatar Chengchang Tang Committed by Leon Romanovsky
Browse files

RDMA/core: Provide rdma_user_mmap_disassociate() to disassociate mmap pages 



Provide a new api rdma_user_mmap_disassociate() for drivers to
disassociate mmap pages for a device.

Since drivers can now disassociate mmaps by calling this api,
introduce a new disassociation_lock to specifically prevent
races between this disassociation process and new mmaps. And
thus the old hw_destroy_rwsem is not needed in this api.

Signed-off-by: default avatarChengchang Tang <tangchengchang@huawei.com>
Signed-off-by: default avatarJunxian Huang <huangjunxian6@hisilicon.com>
Link: https://patch.msgid.link/20240927103323.1897094-2-huangjunxian6@hisilicon.com


Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
parent 8cf0b939

drivers/infiniband/core/uverbs.h

+2 −0
Original line number Diff line number Diff line
@@ -160,6 +160,8 @@ struct ib_uverbs_file { 
	struct page *disassociate_page;



	struct xarray		idr;



	struct mutex disassociation_lock;

};



struct ib_uverbs_event {

drivers/infiniband/core/uverbs_main.c

+41 −2
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ static dev_t dynamic_uverbs_dev; 
static DEFINE_IDA(uverbs_ida);

static int ib_uverbs_add_one(struct ib_device *device);

static void ib_uverbs_remove_one(struct ib_device *device, void *client_data);

static struct ib_client uverbs_client;



static char *uverbs_devnode(const struct device *dev, umode_t *mode)

{
@@ -217,6 +218,7 @@ void ib_uverbs_release_file(struct kref *ref) 


	if (file->disassociate_page)

		__free_pages(file->disassociate_page, 0);

	mutex_destroy(&file->disassociation_lock);

	mutex_destroy(&file->umap_lock);

	mutex_destroy(&file->ucontext_lock);

	kfree(file);
@@ -698,8 +700,13 @@ static int ib_uverbs_mmap(struct file *filp, struct vm_area_struct *vma) 
		ret = PTR_ERR(ucontext);

		goto out;

	}



	mutex_lock(&file->disassociation_lock);



	vma->vm_ops = &rdma_umap_ops;

	ret = ucontext->device->ops.mmap(ucontext, vma);



	mutex_unlock(&file->disassociation_lock);

out:

	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);

	return ret;
@@ -721,6 +728,8 @@ static void rdma_umap_open(struct vm_area_struct *vma) 
	/* We are racing with disassociation */

	if (!down_read_trylock(&ufile->hw_destroy_rwsem))

		goto out_zap;

	mutex_lock(&ufile->disassociation_lock);



	/*

	 * Disassociation already completed, the VMA should already be zapped.

	 */
@@ -732,10 +741,12 @@ static void rdma_umap_open(struct vm_area_struct *vma) 
		goto out_unlock;

	rdma_umap_priv_init(priv, vma, opriv->entry);



	mutex_unlock(&ufile->disassociation_lock);

	up_read(&ufile->hw_destroy_rwsem);

	return;



out_unlock:

	mutex_unlock(&ufile->disassociation_lock);

	up_read(&ufile->hw_destroy_rwsem);

out_zap:

	/*
@@ -819,7 +830,7 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile) 
{

	struct rdma_umap_priv *priv, *next_priv;



	lockdep_assert_held(&ufile->hw_destroy_rwsem);

	mutex_lock(&ufile->disassociation_lock);



	while (1) {

		struct mm_struct *mm = NULL;
@@ -845,8 +856,10 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile) 
			break;

		}

		mutex_unlock(&ufile->umap_lock);

		if (!mm)

		if (!mm) {

			mutex_unlock(&ufile->disassociation_lock);

			return;

		}



		/*

		 * The umap_lock is nested under mmap_lock since it used within
@@ -876,7 +889,31 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile) 
		mmap_read_unlock(mm);

		mmput(mm);

	}



	mutex_unlock(&ufile->disassociation_lock);

}



/**

 * rdma_user_mmap_disassociate() - Revoke mmaps for a device

 * @device: device to revoke

 *

 * This function should be called by drivers that need to disable mmaps for the

 * device, for instance because it is going to be reset.

 */

void rdma_user_mmap_disassociate(struct ib_device *device)

{

	struct ib_uverbs_device *uverbs_dev =

		ib_get_client_data(device, &uverbs_client);

	struct ib_uverbs_file *ufile;



	mutex_lock(&uverbs_dev->lists_mutex);

	list_for_each_entry(ufile, &uverbs_dev->uverbs_file_list, list) {

		if (ufile->ucontext)

			uverbs_user_mmap_disassociate(ufile);

	}

	mutex_unlock(&uverbs_dev->lists_mutex);

}

EXPORT_SYMBOL(rdma_user_mmap_disassociate);



/*

 * ib_uverbs_open() does not need the BKL:
@@ -947,6 +984,8 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp) 
	mutex_init(&file->umap_lock);

	INIT_LIST_HEAD(&file->umaps);



	mutex_init(&file->disassociation_lock);



	filp->private_data = file;

	list_add_tail(&file->list, &dev->uverbs_file_list);

	mutex_unlock(&dev->lists_mutex);

include/rdma/ib_verbs.h

+8 −0
Original line number Diff line number Diff line
@@ -2948,6 +2948,14 @@ int rdma_user_mmap_entry_insert_range(struct ib_ucontext *ucontext, 
				      size_t length, u32 min_pgoff,

				      u32 max_pgoff);



#if IS_ENABLED(CONFIG_INFINIBAND_USER_ACCESS)

void rdma_user_mmap_disassociate(struct ib_device *device);

#else

static inline void rdma_user_mmap_disassociate(struct ib_device *device)

{

}

#endif



static inline int

rdma_user_mmap_entry_insert_exact(struct ib_ucontext *ucontext,

				  struct rdma_user_mmap_entry *entry,