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);
* Implementation details of the RDMA core, don't use in drivers:
*/
struct rdma_restrack_entry res;
+ struct xarray mmap_xa;
};
struct ib_uobject {
#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
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);
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)
{
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