[ofa-general] Re: [PATCH] core: check optional verbs before using them

[Roland Dreier]

 > Check that all optional verbs are implemented in the device
 > before using them.

Some parts make sense, eg:

 > @@ -248,7 +248,9 @@ int ib_modify_srq(struct ib_srq *srq,
 >  		  struct ib_srq_attr *srq_attr,
 >  		  enum ib_srq_attr_mask srq_attr_mask)
 >  {
 > -	return srq->device->modify_srq(srq, srq_attr, srq_attr_mask, NULL);
 > +	return srq->device->modify_srq ?
 > +		srq->device->modify_srq(srq, srq_attr, srq_attr_mask, NULL) :
 > +		-ENOSYS;

on the other hand:

 > @@ -265,6 +267,9 @@ int ib_destroy_srq(struct ib_srq *srq)
 >  	struct ib_pd *pd;
 >  	int ret;
 >  
 > +	if (!srq->device->destroy_srq)
 > +		return -ENOSYS;
 > +

I think it's safe to assume that a driver that allows SRQs to be created
will allow them to be destroyed, and code that destroys a non-existent
SRQ is buggy.  So I don't think this is worth it.  Same for dealloc MW
and dealloc FMR.

The reg_phys_mr change is sane too.  So I applied this:

commit 3926318b1e52568b10a9275b34e0a1fdef6c10e8
Author: Dotan Barak <dotanb at dev.mellanox.co.il>
Date:   Mon Mar 31 17:50:02 2008 +0300

    IB/core: Check optional verbs before using them
    
    Make sure that a device implements the modify_srq and reg_phys_mr
    optional methods before calling them.
    
    Signed-off-by: Dotan Barak <dotanb at dev.mellanox.co.il>
    Signed-off-by: Roland Dreier <rolandd at cisco.com>

diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c
index 86ed8af..8ffb5f2 100644
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -248,7 +248,9 @@ int ib_modify_srq(struct ib_srq *srq,
 		  struct ib_srq_attr *srq_attr,
 		  enum ib_srq_attr_mask srq_attr_mask)
 {
-	return srq->device->modify_srq(srq, srq_attr, srq_attr_mask, NULL);
+	return srq->device->modify_srq ?
+		srq->device->modify_srq(srq, srq_attr, srq_attr_mask, NULL) :
+		-ENOSYS;
 }
 EXPORT_SYMBOL(ib_modify_srq);
 
@@ -672,6 +674,9 @@ struct ib_mr *ib_reg_phys_mr(struct ib_pd *pd,
 {
 	struct ib_mr *mr;
 
+	if (!pd->device->reg_phys_mr)
+		return ERR_PTR(-ENOSYS);
+
 	mr = pd->device->reg_phys_mr(pd, phys_buf_array, num_phys_buf,
 				     mr_access_flags, iova_start);