1 files changed, 27 insertions, 19 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index adb5abb9af5d..f139cd8b594d 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/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 =