diff options
| -rw-r--r-- | drivers/infiniband/core/device.c | 1 | ||||
| -rw-r--r-- | drivers/infiniband/core/ib_core_uverbs.c | 236 | ||||
| -rw-r--r-- | drivers/infiniband/core/rdma_core.c | 1 | ||||
| -rw-r--r-- | drivers/infiniband/core/uverbs_cmd.c | 2 | ||||
| -rw-r--r-- | include/rdma/ib_verbs.h | 35 |
5 files changed, 275 insertions, 0 deletions
diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c index f8d383ceae05..e785bebaf16e 100644 --- a/drivers/infiniband/core/device.c +++ b/drivers/infiniband/core/device.c @@ -2642,6 +2642,7 @@ void ib_set_device_ops(struct ib_device *dev, const struct ib_device_ops *ops) SET_DEVICE_OP(dev_ops, map_mr_sg_pi); SET_DEVICE_OP(dev_ops, map_phys_fmr); SET_DEVICE_OP(dev_ops, mmap); + SET_DEVICE_OP(dev_ops, mmap_free); SET_DEVICE_OP(dev_ops, modify_ah); SET_DEVICE_OP(dev_ops, modify_cq); SET_DEVICE_OP(dev_ops, modify_device); diff --git a/drivers/infiniband/core/ib_core_uverbs.c b/drivers/infiniband/core/ib_core_uverbs.c index b74d2a2fb342..aacd84a45de6 100644 --- a/drivers/infiniband/core/ib_core_uverbs.c +++ b/drivers/infiniband/core/ib_core_uverbs.c @@ -71,3 +71,239 @@ int rdma_user_mmap_io(struct ib_ucontext *ucontext, struct vm_area_struct *vma, return 0; } EXPORT_SYMBOL(rdma_user_mmap_io); + +/** + * rdma_user_mmap_entry_get_pgoff() - Get an entry from the mmap_xa + * + * @ucontext: associated user context + * @pgoff: The mmap offset >> PAGE_SHIFT + * + * This function is called when a user tries to mmap with an offset (returned + * by rdma_user_mmap_get_offset()) it initially received from the driver. The + * rdma_user_mmap_entry was created by the function + * rdma_user_mmap_entry_insert(). This function increases the refcnt of the + * entry so that it won't be deleted from the xarray in the meantime. + * + * Return an reference to an entry if exists or NULL if there is no + * match. rdma_user_mmap_entry_put() must be called to put the reference. + */ +struct rdma_user_mmap_entry * +rdma_user_mmap_entry_get_pgoff(struct ib_ucontext *ucontext, + unsigned long pgoff) +{ + struct rdma_user_mmap_entry *entry; + + if (pgoff > U32_MAX) + return NULL; + + xa_lock(&ucontext->mmap_xa); + + entry = xa_load(&ucontext->mmap_xa, pgoff); + + /* + * If refcount is zero, entry is already being deleted, driver_removed + * indicates that the no further mmaps are possible and we waiting for + * the active VMAs to be closed. + */ + if (!entry || entry->start_pgoff != pgoff || entry->driver_removed || + !kref_get_unless_zero(&entry->ref)) + goto err; + + xa_unlock(&ucontext->mmap_xa); + + ibdev_dbg(ucontext->device, "mmap: pgoff[%#lx] npages[%#zx] returned\n", + pgoff, entry->npages); + + return entry; + +err: + xa_unlock(&ucontext->mmap_xa); + return NULL; +} +EXPORT_SYMBOL(rdma_user_mmap_entry_get_pgoff); + +/** + * rdma_user_mmap_entry_get() - Get an entry from the mmap_xa + * + * @ucontext: associated user context + * @vma: the vma being mmap'd into + * + * This function is like rdma_user_mmap_entry_get_pgoff() except that it also + * checks that the VMA is correct. + */ +struct rdma_user_mmap_entry * +rdma_user_mmap_entry_get(struct ib_ucontext *ucontext, + struct vm_area_struct *vma) +{ + struct rdma_user_mmap_entry *entry; + + if (!(vma->vm_flags & VM_SHARED)) + return NULL; + entry = rdma_user_mmap_entry_get_pgoff(ucontext, vma->vm_pgoff); + if (!entry) + return NULL; + if (entry->npages * PAGE_SIZE != vma->vm_end - vma->vm_start) { + rdma_user_mmap_entry_put(entry); + return NULL; + } + return entry; +} +EXPORT_SYMBOL(rdma_user_mmap_entry_get); + +static void rdma_user_mmap_entry_free(struct kref *kref) +{ + struct rdma_user_mmap_entry *entry = + container_of(kref, struct rdma_user_mmap_entry, ref); + struct ib_ucontext *ucontext = entry->ucontext; + unsigned long i; + + /* + * Erase all entries occupied by this single entry, this is deferred + * until all VMA are closed so that the mmap offsets remain unique. + */ + xa_lock(&ucontext->mmap_xa); + for (i = 0; i < entry->npages; i++) + __xa_erase(&ucontext->mmap_xa, entry->start_pgoff + i); + xa_unlock(&ucontext->mmap_xa); + + ibdev_dbg(ucontext->device, "mmap: pgoff[%#lx] npages[%#zx] removed\n", + entry->start_pgoff, entry->npages); + + if (ucontext->device->ops.mmap_free) + ucontext->device->ops.mmap_free(entry); +} + +/** + * rdma_user_mmap_entry_put() - Drop reference to the mmap entry + * + * @entry: an entry in the mmap_xa + * + * This function is called when the mapping is closed if it was + * an io mapping or when the driver is done with the entry for + * some other reason. + * Should be called after rdma_user_mmap_entry_get was called + * and entry is no longer needed. This function will erase the + * entry and free it if its refcnt reaches zero. + */ +void rdma_user_mmap_entry_put(struct rdma_user_mmap_entry *entry) +{ + kref_put(&entry->ref, rdma_user_mmap_entry_free); +} +EXPORT_SYMBOL(rdma_user_mmap_entry_put); + +/** + * rdma_user_mmap_entry_remove() - Drop reference to entry and + * mark it as unmmapable + * + * @entry: the entry to insert into the mmap_xa + * + * Drivers can call this to prevent userspace from creating more mappings for + * entry, however existing mmaps continue to exist and ops->mmap_free() will + * not be called until all user mmaps are destroyed. + */ +void rdma_user_mmap_entry_remove(struct rdma_user_mmap_entry *entry) +{ + if (!entry) + return; + + entry->driver_removed = true; + kref_put(&entry->ref, rdma_user_mmap_entry_free); +} +EXPORT_SYMBOL(rdma_user_mmap_entry_remove); + +/** + * rdma_user_mmap_entry_insert() - Insert an entry to the mmap_xa + * + * @ucontext: associated user context. + * @entry: the entry to insert into the mmap_xa + * @length: length of the address that will be mmapped + * + * This function should be called by drivers that use the rdma_user_mmap + * interface for implementing their mmap syscall A database of mmap offsets is + * handled in the core and helper functions are provided to insert entries + * into the database and extract entries when the user calls mmap with the + * given offset. The function allocates a unique page offset that should be + * provided to user, the user will use the offset to retrieve information such + * as address to be mapped and how. + * + * Return: 0 on success and -ENOMEM on failure + */ +int rdma_user_mmap_entry_insert(struct ib_ucontext *ucontext, + struct rdma_user_mmap_entry *entry, + size_t length) +{ + struct ib_uverbs_file *ufile = ucontext->ufile; + XA_STATE(xas, &ucontext->mmap_xa, 0); + u32 xa_first, xa_last, npages; + int err; + u32 i; + + if (!entry) + return -EINVAL; + + kref_init(&entry->ref); + entry->ucontext = ucontext; + + /* + * We want the whole allocation to be done without interruption from a + * different thread. The allocation requires finding a free range and + * storing. During the xa_insert the lock could be released, possibly + * allowing another thread to choose the same range. + */ + mutex_lock(&ufile->umap_lock); + + xa_lock(&ucontext->mmap_xa); + + /* We want to find an empty range */ + npages = (u32)DIV_ROUND_UP(length, PAGE_SIZE); + entry->npages = npages; + while (true) { + /* First find an empty index */ + xas_find_marked(&xas, U32_MAX, XA_FREE_MARK); + if (xas.xa_node == XAS_RESTART) + goto err_unlock; + + xa_first = xas.xa_index; + + /* Is there enough room to have the range? */ + if (check_add_overflow(xa_first, npages, &xa_last)) + goto err_unlock; + + /* + * Now look for the next present entry. If an entry doesn't + * exist, we found an empty range and can proceed. + */ + xas_next_entry(&xas, xa_last - 1); + if (xas.xa_node == XAS_BOUNDS || xas.xa_index >= xa_last) + break; + } + + for (i = xa_first; i < xa_last; i++) { + err = __xa_insert(&ucontext->mmap_xa, i, entry, GFP_KERNEL); + if (err) + goto err_undo; + } + + /* + * Internally the kernel uses a page offset, in libc this is a byte + * offset. Drivers should not return pgoff to userspace. + */ + entry->start_pgoff = xa_first; + xa_unlock(&ucontext->mmap_xa); + mutex_unlock(&ufile->umap_lock); + + ibdev_dbg(ucontext->device, "mmap: pgoff[%#lx] npages[%#x] inserted\n", + entry->start_pgoff, npages); + + return 0; + +err_undo: + for (; i > xa_first; i--) + __xa_erase(&ucontext->mmap_xa, i - 1); + +err_unlock: + xa_unlock(&ucontext->mmap_xa); + mutex_unlock(&ufile->umap_lock); + return -ENOMEM; +} +EXPORT_SYMBOL(rdma_user_mmap_entry_insert); diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c index ccf4d069c25c..6c72773faf29 100644 --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -817,6 +817,7 @@ static void ufile_destroy_ucontext(struct ib_uverbs_file *ufile, rdma_restrack_del(&ucontext->res); ib_dev->ops.dealloc_ucontext(ucontext); + WARN_ON(!xa_empty(&ucontext->mmap_xa)); kfree(ucontext); ufile->ucontext = NULL; diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 14a80fd9f464..06ed32c8662f 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -252,6 +252,8 @@ static int ib_uverbs_get_context(struct uverbs_attr_bundle *attrs) ucontext->closing = false; ucontext->cleanup_retryable = false; + xa_init_flags(&ucontext->mmap_xa, XA_FLAGS_ALLOC); + ret = get_unused_fd_flags(O_CLOEXEC); if (ret < 0) goto err_free; diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 0626b62ed107..8865ec28180a 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -1473,6 +1473,7 @@ struct ib_ucontext { * Implementation details of the RDMA core, don't use in drivers: */ struct rdma_restrack_entry res; + struct xarray mmap_xa; }; struct ib_uobject { @@ -2258,6 +2259,21 @@ struct iw_cm_conn_param; #define DECLARE_RDMA_OBJ_SIZE(ib_struct) size_t size_##ib_struct +struct rdma_user_mmap_entry { + struct kref ref; + struct ib_ucontext *ucontext; + unsigned long start_pgoff; + size_t npages; + bool driver_removed; +}; + +/* Return the offset (in bytes) the user should pass to libc's mmap() */ +static inline u64 +rdma_user_mmap_get_offset(const struct rdma_user_mmap_entry *entry) +{ + return (u64)entry->start_pgoff << PAGE_SHIFT; +} + /** * struct ib_device_ops - InfiniBand device operations * This structure defines all the InfiniBand device operations, providers will @@ -2370,6 +2386,13 @@ struct ib_device_ops { struct ib_udata *udata); void (*dealloc_ucontext)(struct ib_ucontext *context); int (*mmap)(struct ib_ucontext *context, struct vm_area_struct *vma); + /** + * This will be called once refcount of an entry in mmap_xa reaches + * zero. The type of the memory that was mapped may differ between + * entries and is opaque to the rdma_user_mmap interface. + * Therefore needs to be implemented by the driver in mmap_free. + */ + void (*mmap_free)(struct rdma_user_mmap_entry *entry); void (*disassociate_ucontext)(struct ib_ucontext *ibcontext); int (*alloc_pd)(struct ib_pd *pd, struct ib_udata *udata); void (*dealloc_pd)(struct ib_pd *pd, struct ib_udata *udata); @@ -2815,6 +2838,18 @@ static inline int rdma_user_mmap_io(struct ib_ucontext *ucontext, return -EINVAL; } #endif +int rdma_user_mmap_entry_insert(struct ib_ucontext *ucontext, + struct rdma_user_mmap_entry *entry, + size_t length); +struct rdma_user_mmap_entry * +rdma_user_mmap_entry_get_pgoff(struct ib_ucontext *ucontext, + unsigned long pgoff); +struct rdma_user_mmap_entry * +rdma_user_mmap_entry_get(struct ib_ucontext *ucontext, + struct vm_area_struct *vma); +void rdma_user_mmap_entry_put(struct rdma_user_mmap_entry *entry); + +void rdma_user_mmap_entry_remove(struct rdma_user_mmap_entry *entry); static inline int ib_copy_from_udata(void *dest, struct ib_udata *udata, size_t len) { |