On 3/6/2019 2:06 AM, John Hubbard wrote: > On 3/4/19 10:41 AM, ira.weiny@xxxxxxxxx wrote: >> From: Ira Weiny <ira.weiny@xxxxxxxxx> >> >> No device supports ODP MR without an invalidate_range callback. >> >> Warn on any any device which attempts to support ODP without >> supplying this callback. >> >> Then we can remove the checks for the callback within the code. >> >> This stems from the discussion >> >> https://www.spinics.net/lists/linux-rdma/msg76460.html >> >> ...which concluded this code was no longer necessary. >> >> CC: Haggai Eran <haggaie@xxxxxxxxxxxx> >> CC: Artemy Kovalyov <artemyko@xxxxxxxxxxxx> >> CC: John Hubbard <jhubbard@xxxxxxxxxx> >> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx> >> --- >> drivers/infiniband/core/umem.c | 5 +++++ >> drivers/infiniband/core/umem_odp.c | 11 ++++------- >> 2 files changed, 9 insertions(+), 7 deletions(-) >> >> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c >> index fe5551562dbc..89a7d57f9fa5 100644 >> --- a/drivers/infiniband/core/umem.c >> +++ b/drivers/infiniband/core/umem.c >> @@ -138,6 +138,11 @@ struct ib_umem *ib_umem_get(struct ib_udata *udata, unsigned long addr, >> mmgrab(mm); >> >> if (access & IB_ACCESS_ON_DEMAND) { >> + if (WARN_ON_ONCE(!context->invalidate_range)) { >> + ret = -EINVAL; >> + goto umem_kfree; >> + } >> + >> ret = ib_umem_odp_get(to_ib_umem_odp(umem), access); >> if (ret) >> goto umem_kfree; >> diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c >> index 6013cf0b8f4f..aa7f95633581 100644 >> --- a/drivers/infiniband/core/umem_odp.c >> +++ b/drivers/infiniband/core/umem_odp.c >> @@ -240,7 +240,7 @@ static struct ib_ucontext_per_mm *alloc_per_mm(struct ib_ucontext *ctx, >> per_mm->mm = mm; >> per_mm->umem_tree = RB_ROOT_CACHED; >> init_rwsem(&per_mm->umem_rwsem); >> - per_mm->active = ctx->invalidate_range; >> + per_mm->active = true; >> >> rcu_read_lock(); >> per_mm->tgid = get_task_pid(current->group_leader, PIDTYPE_PID); >> @@ -539,11 +539,10 @@ static int ib_umem_odp_map_dma_single_page( >> } >> >> out: >> - /* On Demand Paging - avoid pinning the page */ >> - if (umem->context->invalidate_range || !stored_page) >> + if (!stored_page) >> put_page(page); > > Hi Ira, > > This would introduce a change in behavior, because previously, the first > side of the "or" phrase was effectively always true. In other words, the > code has, so far, been just doing this: > > put_page(); > > ...unconditionally. (Again, because "umem->context->invalidate_range" was > always true. The "!stored_page" never got even evaluated.) > > In other words, if a == true, you cannot replace "a || b" with "b". You have > to replace it with "true". > > I don't know what the !stored_page is about without looking more closely, > but to avoid regressions you'd be safely with just doing an unconditional > put_page(), I think. Right. stored_page is there for on-demand pinning, to release the reference on the page in case the page was already in the page list. You can also remove stored_page along with this patch. > @@ -748,9 +747,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt, > */ > set_page_dirty(head_page); > } > - /* on demand pinning support */ > - if (!umem->context->invalidate_range) > - put_page(page); > + put_page(page); > umem_odp->page_list[idx] = NULL; > umem_odp->dma_list[idx] = 0; > umem->npages--; I think this is also wrong. If invalidate range is always expected to be valid when calling unmap_dmap_pages, then put_page(page) is never called, so you can just remove it. Regards, Haggai
