From 5a74228287be661b1b8f1667c9d657345e7f49ae Mon Sep 17 00:00:00 2001
From: Jeremy Kerr <jk@ozlabs.org>
Date: Thu, 16 Oct 2008 10:51:46 +1100
Subject: [PATCH] --- yaml --- r: 116915 b: refs/heads/master c:
 14f693eeb5b16bc47ffa38d8b8838a654aedd53f h: refs/heads/master i:   116913:
 0c75b18f808253a8736d9c619c8e9f197ff0ea5b   116911:
 28ce50b651eb1dc9cd674eeffc67dfe2c422e78b v: v3

---
 [refs]                                        |  2 +-
 .../arch/powerpc/platforms/cell/spufs/file.c  | 46 +++++++++++--------
 2 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/[refs] b/[refs]
index 52feabf066b0..dbc33705c9b5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: f5ed0eb6fe131e8f3847323b4aa569a6f7b36f56
+refs/heads/master: 14f693eeb5b16bc47ffa38d8b8838a654aedd53f
diff --git a/trunk/arch/powerpc/platforms/cell/spufs/file.c b/trunk/arch/powerpc/platforms/cell/spufs/file.c
index adb5abb9af5d..f139cd8b594d 100644
--- a/trunk/arch/powerpc/platforms/cell/spufs/file.c
+++ b/trunk/arch/powerpc/platforms/cell/spufs/file.c
@@ -2503,30 +2503,38 @@ static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
 		char tbuf[128];
 		int width;
 
-		if (file->f_flags & O_NONBLOCK) {
-			if (spufs_switch_log_used(ctx) == 0) {
+		if (spufs_switch_log_used(ctx) == 0) {
+			if (cnt > 0) {
+				/* If there's data ready to go, we can
+				 * just return straight away */
+				break;
+
+			} else if (file->f_flags & O_NONBLOCK) {
 				error = -EAGAIN;
 				break;
+
+			} else {
+				/* spufs_wait will drop the mutex and
+				 * re-acquire, but since we're in read(), the
+				 * file cannot be _released (and so
+				 * ctx->switch_log is stable).
+				 */
+				error = spufs_wait(ctx->switch_log->wait,
+						spufs_switch_log_used(ctx) > 0);
+
+				/* On error, spufs_wait returns without the
+				 * state mutex held */
+				if (error)
+					return error;
+
+				/* We may have had entries read from underneath
+				 * us while we dropped the mutex in spufs_wait,
+				 * so re-check */
+				if (spufs_switch_log_used(ctx) == 0)
+					continue;
 			}
-		} else {
-			/* spufs_wait will drop the mutex and re-acquire,
-			 * but since we're in read(), the file cannot be
-			 * _released (and so ctx->switch_log is stable).
-			 */
-			error = spufs_wait(ctx->switch_log->wait,
-					spufs_switch_log_used(ctx) > 0);
-
-			/* On error, spufs_wait returns without the
-			 * state mutex held */
-			if (error)
-				return error;
 		}
 
-		/* We may have had entries read from underneath us while we
-		 * dropped the mutex in spufs_wait, so re-check */
-		if (ctx->switch_log->head == ctx->switch_log->tail)
-			continue;
-
 		width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
 		if (width < len)
 			ctx->switch_log->tail =