IB/core: Replace ib_umem's offset field with a full address

In order to allow umems that do not pin memory, we need the umem to
keep track of its region's address.

This makes the offset field redundant, and so this patch removes it.

Signed-off-by: Haggai Eran <[e-mail]>
Signed-off-by: Roland Dreier <[e-mail]>

drivers/infiniband/core/umem.c

···
 
 	umem->context   = context;
 	umem->length    = size;
-	umem->offset    = addr & ~PAGE_MASK;
+	umem->address   = addr;
 	umem->page_size = PAGE_SIZE;
 	umem->pid       = get_task_pid(current, PIDTYPE_PID);
 	/*
···
 	if (!vma_list)
 		umem->hugetlb = 0;
 
-	npages = PAGE_ALIGN(size + umem->offset) >> PAGE_SHIFT;
+	npages = ib_umem_num_pages(umem);
 
 	down_write(&current->mm->mmap_sem);
 
···
 	if (!mm)
 		goto out;
 
-	diff = PAGE_ALIGN(umem->length + umem->offset) >> PAGE_SHIFT;
+	diff = ib_umem_num_pages(umem);
 
 	/*
 	 * We may be called with the mm's mmap_sem already held.  This

drivers/infiniband/hw/amso1100/c2_provider.c

···
 					 c2mr->umem->page_size,
 					 i,
 					 length,
-					 c2mr->umem->offset,
+					 ib_umem_offset(c2mr->umem),
 					 &kva,
 					 c2_convert_access(acc),
 					 c2mr);

drivers/infiniband/hw/ehca/ehca_mrmw.c

···
 	pginfo.num_kpages = num_kpages;
 	pginfo.num_hwpages = num_hwpages;
 	pginfo.u.usr.region = e_mr->umem;
-	pginfo.next_hwpage = e_mr->umem->offset / hwpage_size;
+	pginfo.next_hwpage = ib_umem_offset(e_mr->umem) / hwpage_size;
 	pginfo.u.usr.next_sg = pginfo.u.usr.region->sg_head.sgl;
 	ret = ehca_reg_mr(shca, e_mr, (u64 *)virt, length, mr_access_flags,
 			  e_pd, &pginfo, &e_mr->ib.ib_mr.lkey,

drivers/infiniband/hw/ipath/ipath_mr.c

···
 	mr->mr.user_base = start;
 	mr->mr.iova = virt_addr;
 	mr->mr.length = length;
-	mr->mr.offset = umem->offset;
+	mr->mr.offset = ib_umem_offset(umem);
 	mr->mr.access_flags = mr_access_flags;
 	mr->mr.max_segs = n;
 	mr->umem = umem;

drivers/infiniband/hw/nes/nes_verbs.c

···
 	nes_debug(NES_DBG_MR, "User base = 0x%lX, Virt base = 0x%lX, length = %u,"
 			" offset = %u, page size = %u.\n",
 			(unsigned long int)start, (unsigned long int)virt, (u32)length,
-			region->offset, region->page_size);
+			ib_umem_offset(region), region->page_size);
 
-	skip_pages = ((u32)region->offset) >> 12;
+	skip_pages = ((u32)ib_umem_offset(region)) >> 12;
 
 	if (ib_copy_from_udata(&req, udata, sizeof(req))) {
 		ib_umem_release(region);
···
 				region_length -= skip_pages << 12;
 				for (page_index = skip_pages; page_index < chunk_pages; page_index++) {
 					skip_pages = 0;
-					if ((page_count != 0) && (page_count<<12)-(region->offset&(4096-1)) >= region->length)
+					if ((page_count != 0) && (page_count << 12) - (ib_umem_offset(region) & (4096 - 1)) >= region->length)
 						goto enough_pages;
 					if ((page_count&0x01FF) == 0) {
 						if (page_count >= 1024 * 512) {

drivers/infiniband/hw/ocrdma/ocrdma_verbs.c

···
 		goto umem_err;
 
 	mr->hwmr.pbe_size = mr->umem->page_size;
-	mr->hwmr.fbo = mr->umem->offset;
+	mr->hwmr.fbo = ib_umem_offset(mr->umem);
 	mr->hwmr.va = usr_addr;
 	mr->hwmr.len = len;
 	mr->hwmr.remote_wr = (acc & IB_ACCESS_REMOTE_WRITE) ? 1 : 0;

drivers/infiniband/hw/qib/qib_mr.c

···
 	mr->mr.user_base = start;
 	mr->mr.iova = virt_addr;
 	mr->mr.length = length;
-	mr->mr.offset = umem->offset;
+	mr->mr.offset = ib_umem_offset(umem);
 	mr->mr.access_flags = mr_access_flags;
 	mr->umem = umem;
 

include/rdma/ib_umem.h

···
 struct ib_umem {
 	struct ib_ucontext     *context;
 	size_t			length;
-	int			offset;
+	unsigned long		address;
 	int			page_size;
 	int                     writable;
 	int                     hugetlb;
···
 	int             nmap;
 	int             npages;
 };
+
+/* Returns the offset of the umem start relative to the first page. */
+static inline int ib_umem_offset(struct ib_umem *umem)
+{
+	return umem->address & ((unsigned long)umem->page_size - 1);
+}
+
+/* Returns the first page of an ODP umem. */
+static inline unsigned long ib_umem_start(struct ib_umem *umem)
+{
+	return umem->address - ib_umem_offset(umem);
+}
+
+/* Returns the address of the page after the last one of an ODP umem. */
+static inline unsigned long ib_umem_end(struct ib_umem *umem)
+{
+	return PAGE_ALIGN(umem->address + umem->length);
+}
+
+static inline size_t ib_umem_num_pages(struct ib_umem *umem)
+{
+	return (ib_umem_end(umem) - ib_umem_start(umem)) >> PAGE_SHIFT;
+}
 
 #ifdef CONFIG_INFINIBAND_USER_MEM