svn commit: r294677 - in stable/10/sys: kern powerpc/powerpc sparc64/sparc64 x86/x86

[Ian Lepore]

Author: ian
Date: Sun Jan 24 19:21:53 2016
New Revision: 294677
URL: https://svnweb.freebsd.org/changeset/base/294677

Log:
  MFC r289618, r290316:
  
    Fix printf format to allow for bus_size_t not being u_long on all platforms.
  
    Fix an alignment check that is wrong in half the busdma implementations.
    This will enable the elimination of a workaround in the USB driver that
    artifically allocates buffers twice as big as they need to be (which
    actually saves memory for very small buffers on the buggy platforms).
  
    When deciding how to allocate a dma buffer, armv4, armv6, mips, and
    x86/iommu all correctly check for the tag alignment <= maxsize as enabling
    simple uma/malloc based allocation.  Powerpc, sparc64, x86/bounce, and
    arm64/bounce were all checking for alignment < maxsize; on those platforms
    when alignment was equal to the max size it would fall back to page-based
    allocators even for very small buffers.
  
    This change makes all platforms use the <= check.  It should be noted that
    on all platforms other than arm[v6] and mips, this check is relying on
    undocumented behavior in malloc(9) that if you allocate a block of a given
    size it will be aligned to the next larger power-of-2 boundary.  There is
    nothing in the malloc(9) man page that makes that explicit promise (but the
    busdma code has been relying on this behavior all along so I guess it works).
  
    Arm and mips code uses the allocator in kern/subr_busdma_buffalloc.c, which
    does explicitly implement this promise about size and alignment.  Other
    platforms probably should switch to the aligned allocator.

Modified:
  stable/10/sys/kern/subr_busdma_bufalloc.c
  stable/10/sys/powerpc/powerpc/busdma_machdep.c
  stable/10/sys/sparc64/sparc64/bus_machdep.c
  stable/10/sys/x86/x86/busdma_bounce.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/kern/subr_busdma_bufalloc.c
==============================================================================
--- stable/10/sys/kern/subr_busdma_bufalloc.c	Sun Jan 24 19:12:16 2016	(r294676)
+++ stable/10/sys/kern/subr_busdma_bufalloc.c	Sun Jan 24 19:21:53 2016	(r294677)
@@ -94,8 +94,8 @@ busdma_bufalloc_create(const char *name,
 	for (i = 0, bz = ba->buf_zones, cursize = ba->min_size;
 	    i < nitems(ba->buf_zones) && cursize <= MAX_ZONE_BUFSIZE;
 	    ++i, ++bz, cursize <<= 1) {
-		snprintf(bz->name, sizeof(bz->name), "dma %.10s %lu",
-		    name, cursize);
+		snprintf(bz->name, sizeof(bz->name), "dma %.10s %ju",
+		    name, (uintmax_t)cursize);
 		bz->size = cursize;
 		bz->umazone = uma_zcreate(bz->name, bz->size,
 		    NULL, NULL, NULL, NULL, bz->size - 1, zcreate_flags);

Modified: stable/10/sys/powerpc/powerpc/busdma_machdep.c
==============================================================================
--- stable/10/sys/powerpc/powerpc/busdma_machdep.c	Sun Jan 24 19:12:16 2016	(r294676)
+++ stable/10/sys/powerpc/powerpc/busdma_machdep.c	Sun Jan 24 19:21:53 2016	(r294677)
@@ -514,14 +514,14 @@ bus_dmamem_alloc(bus_dma_tag_t dmat, voi
 
 	/* 
 	 * XXX:
-	 * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
+	 * (dmat->alignment <= dmat->maxsize) is just a quick hack; the exact
 	 * alignment guarantees of malloc need to be nailed down, and the
 	 * code below should be rewritten to take that into account.
 	 *
 	 * In the meantime, we'll warn the user if malloc gets it wrong.
 	 */
 	if ((dmat->maxsize <= PAGE_SIZE) &&
-	   (dmat->alignment < dmat->maxsize) &&
+	   (dmat->alignment <= dmat->maxsize) &&
 	    dmat->lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 	    attr == VM_MEMATTR_DEFAULT) {
 		*vaddr = malloc(dmat->maxsize, M_DEVBUF, mflags);

Modified: stable/10/sys/sparc64/sparc64/bus_machdep.c
==============================================================================
--- stable/10/sys/sparc64/sparc64/bus_machdep.c	Sun Jan 24 19:12:16 2016	(r294676)
+++ stable/10/sys/sparc64/sparc64/bus_machdep.c	Sun Jan 24 19:21:53 2016	(r294677)
@@ -521,14 +521,14 @@ nexus_dmamem_alloc(bus_dma_tag_t dmat, v
 
 	/*
 	 * XXX:
-	 * (dmat->dt_alignment < dmat->dt_maxsize) is just a quick hack; the
+	 * (dmat->dt_alignment <= dmat->dt_maxsize) is just a quick hack; the
 	 * exact alignment guarantees of malloc need to be nailed down, and
 	 * the code below should be rewritten to take that into account.
 	 *
 	 * In the meantime, we'll warn the user if malloc gets it wrong.
 	 */
 	if (dmat->dt_maxsize <= PAGE_SIZE &&
-	    dmat->dt_alignment < dmat->dt_maxsize)
+	    dmat->dt_alignment <= dmat->dt_maxsize)
 		*vaddr = malloc(dmat->dt_maxsize, M_DEVBUF, mflags);
 	else {
 		/*

Modified: stable/10/sys/x86/x86/busdma_bounce.c
==============================================================================
--- stable/10/sys/x86/x86/busdma_bounce.c	Sun Jan 24 19:12:16 2016	(r294676)
+++ stable/10/sys/x86/x86/busdma_bounce.c	Sun Jan 24 19:21:53 2016	(r294677)
@@ -402,14 +402,14 @@ bounce_bus_dmamem_alloc(bus_dma_tag_t dm
 
 	/* 
 	 * XXX:
-	 * (dmat->alignment < dmat->maxsize) is just a quick hack; the exact
+	 * (dmat->alignment <= dmat->maxsize) is just a quick hack; the exact
 	 * alignment guarantees of malloc need to be nailed down, and the
 	 * code below should be rewritten to take that into account.
 	 *
 	 * In the meantime, we'll warn the user if malloc gets it wrong.
 	 */
 	if ((dmat->common.maxsize <= PAGE_SIZE) &&
-	   (dmat->common.alignment < dmat->common.maxsize) &&
+	   (dmat->common.alignment <= dmat->common.maxsize) &&
 	    dmat->common.lowaddr >= ptoa((vm_paddr_t)Maxmem) &&
 	    attr == VM_MEMATTR_DEFAULT) {
 		*vaddr = malloc(dmat->common.maxsize, M_DEVBUF, mflags);