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Date:      Wed, 21 Oct 2015 20:49:46 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r289719 - head/sys/dev/drm2/i915
Message-ID:  <201510212049.t9LKnkkj002445@repo.freebsd.org>
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Author: jhb
Date: Wed Oct 21 20:49:45 2015
New Revision: 289719
URL: https://svnweb.freebsd.org/changeset/base/289719

Log:
  i915_gem_do_execbuffer() holds the pages backing each relocation region for
  various reasons while executing user commands.  After these commands are
  completed, the pages backing the relocation regions are unheld.
  
  Since relocation regions do not have to be page aligned, the code in
  validate_exec_list() allocates 2 extra page pointers in the array of
  held pages populated by vm_fault_quick_hold_pages().  However, the cleanup
  code that unheld the pages always assumed that only the buffer size /
  PAGE_SIZE pages were used.  This meant that non-page aligned buffers would
  not unheld the last 1 or 2 pages in the list.  Fix this by saving the
  number of held pages returned by vm_fault_quick_hold_pages() for each
  relocation region and using this count during cleanup.
  
  Reviewed by:	dumbbell, kib
  MFC after:	1 week
  Differential Revision:	https://reviews.freebsd.org/D3965

Modified:
  head/sys/dev/drm2/i915/i915_gem_execbuffer.c

Modified: head/sys/dev/drm2/i915/i915_gem_execbuffer.c
==============================================================================
--- head/sys/dev/drm2/i915/i915_gem_execbuffer.c	Wed Oct 21 19:56:16 2015	(r289718)
+++ head/sys/dev/drm2/i915/i915_gem_execbuffer.c	Wed Oct 21 20:49:45 2015	(r289719)
@@ -941,13 +941,15 @@ i915_gem_check_execbuffer(struct drm_i91
 
 static int
 validate_exec_list(struct drm_i915_gem_exec_object2 *exec, int count,
-    vm_page_t ***map)
+    vm_page_t ***map, int **maplen)
 {
 	vm_page_t *ma;
 	int i, length, page_count;
 
 	/* XXXKIB various limits checking is missing there */
 	*map = malloc(count * sizeof(*ma), DRM_I915_GEM, M_WAITOK | M_ZERO);
+	*maplen = malloc(count * sizeof(*maplen), DRM_I915_GEM, M_WAITOK |
+	    M_ZERO);
 	for (i = 0; i < count; i++) {
 		/* First check for malicious input causing overflow */
 		if (exec[i].relocation_count >
@@ -969,9 +971,10 @@ validate_exec_list(struct drm_i915_gem_e
 		page_count = howmany(length, PAGE_SIZE) + 2;
 		ma = (*map)[i] = malloc(page_count * sizeof(vm_page_t),
 		    DRM_I915_GEM, M_WAITOK | M_ZERO);
-		if (vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map,
-		    exec[i].relocs_ptr, length, VM_PROT_READ | VM_PROT_WRITE,
-		    ma, page_count) == -1) {
+		(*maplen)[i] = vm_fault_quick_hold_pages(
+		    &curproc->p_vmspace->vm_map, exec[i].relocs_ptr, length,
+		    VM_PROT_READ | VM_PROT_WRITE, ma, page_count);
+		if ((*maplen)[i] == -1) {
 			free(ma, DRM_I915_GEM);
 			(*map)[i] = NULL;
 			return (-EFAULT);
@@ -1123,6 +1126,7 @@ i915_gem_do_execbuffer(struct drm_device
 	struct drm_clip_rect *cliprects = NULL;
 	struct intel_ring_buffer *ring;
 	vm_page_t **relocs_ma;
+	int *relocs_len;
 	u32 ctx_id = i915_execbuffer2_get_context_id(*args);
 	u32 exec_start, exec_len;
 	u32 seqno;
@@ -1137,7 +1141,8 @@ i915_gem_do_execbuffer(struct drm_device
 	if (args->batch_len == 0)
 		return (0);
 
-	ret = validate_exec_list(exec, args->buffer_count, &relocs_ma);
+	ret = validate_exec_list(exec, args->buffer_count, &relocs_ma,
+	    &relocs_len);
 	if (ret != 0)
 		goto pre_struct_lock_err;
 
@@ -1411,13 +1416,11 @@ err:
 pre_struct_lock_err:
 	for (i = 0; i < args->buffer_count; i++) {
 		if (relocs_ma[i] != NULL) {
-			vm_page_unhold_pages(relocs_ma[i], howmany(
-			    exec[i].relocation_count *
-			    sizeof(struct drm_i915_gem_relocation_entry),
-			    PAGE_SIZE));
+			vm_page_unhold_pages(relocs_ma[i], relocs_len[i]);
 			free(relocs_ma[i], DRM_I915_GEM);
 		}
 	}
+	free(relocs_len, DRM_I915_GEM);
 	free(relocs_ma, DRM_I915_GEM);
 	free(cliprects, DRM_I915_GEM);
 	return ret;

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