svn commit: r308268 - head/sys/x86/x86

[Adrian Chadd]

Author: adrian
Date: Thu Nov  3 23:11:33 2016
New Revision: 308268
URL: https://svnweb.freebsd.org/changeset/base/308268

Log:
  Add a witness check to enforce that no non-sleeping locks are held when
  they shouldn't be.
  
  I used this during driver bring-up to find that the Linux driver holds a
  whole lot of locks whilst doing their equivalent of busdma operations.
  
  If this works out well, it should be added to the other architecture busdma
  implementations to aid in similar debugging.
  
  Tested:
  
  * bounce buffer and dmar busdma, Lenovo X230 laptop, all the internal
    hardware
  * ath(4) too
  
  Discussed with: jhb

Modified:
  head/sys/x86/x86/busdma_machdep.c

Modified: head/sys/x86/x86/busdma_machdep.c
==============================================================================
--- head/sys/x86/x86/busdma_machdep.c	Thu Nov  3 23:05:39 2016	(r308267)
+++ head/sys/x86/x86/busdma_machdep.c	Thu Nov  3 23:11:33 2016	(r308268)
@@ -197,6 +197,8 @@ bus_dma_tag_create(bus_dma_tag_t parent,
 	struct bus_dma_tag_common *tc;
 	int error;
 
+	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s", __func__);
+
 	if (parent == NULL) {
 		error = bus_dma_bounce_impl.tag_create(parent, alignment,
 		    boundary, lowaddr, highaddr, filter, filterarg, maxsize,
@@ -228,6 +230,8 @@ bus_dmamap_create(bus_dma_tag_t dmat, in
 {
 	struct bus_dma_tag_common *tc;
 
+	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s", __func__);
+
 	tc = (struct bus_dma_tag_common *)dmat;
 	return (tc->impl->map_create(dmat, flags, mapp));
 }
@@ -257,6 +261,8 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, voi
 {
 	struct bus_dma_tag_common *tc;
 
+	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "%s", __func__);
+
 	tc = (struct bus_dma_tag_common *)dmat;
 	return (tc->impl->mem_alloc(dmat, vaddr, flags, mapp));
 }