6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chengchang Tang <tangchengchang@xxxxxxxxxx> [ Upstream commit 51976c6cd786151b6a1bdf8b8b3334beac0ba99c ] 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: Chengchang Tang <tangchengchang@xxxxxxxxxx> Signed-off-by: Junxian Huang <huangjunxian6@xxxxxxxxxxxxx> Link: https://patch.msgid.link/20240927103323.1897094-2-huangjunxian6@xxxxxxxxxxxxx Signed-off-by: Leon Romanovsky <leon@xxxxxxxxxx> Stable-dep-of: 615b94746a54 ("RDMA/hns: Disassociate mmap pages for all uctx when HW is being reset") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/infiniband/core/uverbs.h | 2 ++ drivers/infiniband/core/uverbs_main.c | 43 +++++++++++++++++++++++++-- include/rdma/ib_verbs.h | 8 +++++ 3 files changed, 51 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h index 821d93c8f7123..dfd2e5a86e6fe 100644 --- a/drivers/infiniband/core/uverbs.h +++ b/drivers/infiniband/core/uverbs.h @@ -160,6 +160,8 @@ struct ib_uverbs_file { struct page *disassociate_page; struct xarray idr; + + struct mutex disassociation_lock; }; struct ib_uverbs_event { diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c index 94454186ed81d..85cfc790a7bb3 100644 --- a/drivers/infiniband/core/uverbs_main.c +++ b/drivers/infiniband/core/uverbs_main.c @@ -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); diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index aa8ede439905c..9cb8b5fe7eee4 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -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, -- 2.43.0
