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Date:      Fri, 14 Aug 2015 20:08:17 +0000 (UTC)
From:      "Jason A. Harmening" <jah@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r286787 - head/sys/x86/x86
Message-ID:  <201508142008.t7EK8Hkt037329@repo.freebsd.org>
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Author: jah
Date: Fri Aug 14 20:08:16 2015
New Revision: 286787
URL: https://svnweb.freebsd.org/changeset/base/286787

Log:
  Use pmap_quick_enter_page() to handle bouncing of unmapped buffers in the x86 busdma_bounce implementation.  Also treat user buffers as unmapped.
  This allows two things:
  1. Sync'ing bounced maps in non-sleepable contexts.  The physcopy* calls previously used could sleep on sf_buf operations in some cases.
  2. Sync'ing user buffers outside the context of the owning process
  
  Approved by:	kib (mentor)

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

Modified: head/sys/x86/x86/busdma_bounce.c
==============================================================================
--- head/sys/x86/x86/busdma_bounce.c	Fri Aug 14 18:38:39 2015	(r286786)
+++ head/sys/x86/x86/busdma_bounce.c	Fri Aug 14 20:08:16 2015	(r286787)
@@ -79,7 +79,8 @@ struct bounce_page {
 	vm_offset_t	vaddr;		/* kva of bounce buffer */
 	bus_addr_t	busaddr;	/* Physical address */
 	vm_offset_t	datavaddr;	/* kva of client data */
-	bus_addr_t	dataaddr;	/* client physical address */
+	vm_page_t	datapage;	/* physical page of client data */
+	vm_offset_t	dataoffs;	/* page offset of client data */
 	bus_size_t	datacount;	/* client data count */
 	STAILQ_ENTRY(bounce_page) links;
 };
@@ -658,7 +659,7 @@ bounce_bus_dmamap_load_buffer(bus_dma_ta
 {
 	bus_size_t sgsize, max_sgsize;
 	bus_addr_t curaddr;
-	vm_offset_t vaddr;
+	vm_offset_t kvaddr, vaddr;
 	int error;
 
 	if (map == NULL)
@@ -681,10 +682,13 @@ bounce_bus_dmamap_load_buffer(bus_dma_ta
 		/*
 		 * Get the physical address for this segment.
 		 */
-		if (pmap == kernel_pmap)
+		if (pmap == kernel_pmap) {
 			curaddr = pmap_kextract(vaddr);
-		else
+			kvaddr = vaddr;
+		} else {
 			curaddr = pmap_extract(pmap, vaddr);
+			kvaddr = 0;
+		}
 
 		/*
 		 * Compute the segment size, and adjust counts.
@@ -696,7 +700,7 @@ bounce_bus_dmamap_load_buffer(bus_dma_ta
 		    bus_dma_run_filter(&dmat->common, curaddr)) {
 			sgsize = roundup2(sgsize, dmat->common.alignment);
 			sgsize = MIN(sgsize, max_sgsize);
-			curaddr = add_bounce_page(dmat, map, vaddr, curaddr,
+			curaddr = add_bounce_page(dmat, map, kvaddr, curaddr,
 			    sgsize);
 		} else {
 			sgsize = MIN(sgsize, max_sgsize);
@@ -757,6 +761,7 @@ bounce_bus_dmamap_sync(bus_dma_tag_t dma
     bus_dmasync_op_t op)
 {
 	struct bounce_page *bpage;
+	vm_offset_t datavaddr, tempvaddr;
 
 	if ((bpage = STAILQ_FIRST(&map->bpages)) == NULL)
 		return;
@@ -770,13 +775,19 @@ bounce_bus_dmamap_sync(bus_dma_tag_t dma
 
 	if ((op & BUS_DMASYNC_PREWRITE) != 0) {
 		while (bpage != NULL) {
-			if (bpage->datavaddr != 0) {
-				bcopy((void *)bpage->datavaddr,
-				    (void *)bpage->vaddr, bpage->datacount);
-			} else {
-				physcopyout(bpage->dataaddr,
-				    (void *)bpage->vaddr, bpage->datacount);
+			tempvaddr = 0;
+			datavaddr = bpage->datavaddr;
+			if (datavaddr == 0) {
+				tempvaddr =
+				    pmap_quick_enter_page(bpage->datapage);
+				datavaddr = tempvaddr | bpage->dataoffs;
 			}
+
+			bcopy((void *)datavaddr,
+			    (void *)bpage->vaddr, bpage->datacount);
+
+			if (tempvaddr != 0)
+				pmap_quick_remove_page(tempvaddr);
 			bpage = STAILQ_NEXT(bpage, links);
 		}
 		dmat->bounce_zone->total_bounced++;
@@ -784,14 +795,19 @@ bounce_bus_dmamap_sync(bus_dma_tag_t dma
 
 	if ((op & BUS_DMASYNC_POSTREAD) != 0) {
 		while (bpage != NULL) {
-			if (bpage->datavaddr != 0) {
-				bcopy((void *)bpage->vaddr,
-				    (void *)bpage->datavaddr,
-				    bpage->datacount);
-			} else {
-				physcopyin((void *)bpage->vaddr,
-				    bpage->dataaddr, bpage->datacount);
+			tempvaddr = 0;
+			datavaddr = bpage->datavaddr;
+			if (datavaddr == 0) {
+				tempvaddr =
+				    pmap_quick_enter_page(bpage->datapage);
+				datavaddr = tempvaddr | bpage->dataoffs;
 			}
+
+			bcopy((void *)bpage->vaddr,
+			    (void *)datavaddr, bpage->datacount);
+
+			if (tempvaddr != 0)
+				pmap_quick_remove_page(tempvaddr);
 			bpage = STAILQ_NEXT(bpage, links);
 		}
 		dmat->bounce_zone->total_bounced++;
@@ -989,7 +1005,8 @@ add_bounce_page(bus_dma_tag_t dmat, bus_
 		bpage->busaddr |= addr & PAGE_MASK;
 	}
 	bpage->datavaddr = vaddr;
-	bpage->dataaddr = addr;
+	bpage->datapage = PHYS_TO_VM_PAGE(addr & ~PAGE_MASK);
+	bpage->dataoffs = addr & PAGE_MASK;
 	bpage->datacount = size;
 	STAILQ_INSERT_TAIL(&(map->bpages), bpage, links);
 	return (bpage->busaddr);

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