X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=fs%2Fsplice.c;h=3e06611d19ae5546acb6dffa24c9afaaa786cc56;hb=7644c8231987288e7aae378d2ff3c56a980d1988;hp=0af8d150394f6a968ba37a7c2f88afad1b2914fa;hpb=0021b532b2fdd6b82cf3ff758191f00d8edd235d;p=platform%2Fkernel%2Flinux-rpi.git

diff --git a/fs/splice.c b/fs/splice.c
index 0af8d15..3e06611 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -39,6 +39,22 @@
 #include "internal.h"
 
 /*
+ * Splice doesn't support FMODE_NOWAIT. Since pipes may set this flag to
+ * indicate they support non-blocking reads or writes, we must clear it
+ * here if set to avoid blocking other users of this pipe if splice is
+ * being done on it.
+ */
+static noinline void noinline pipe_clear_nowait(struct file *file)
+{
+	fmode_t fmode = READ_ONCE(file->f_mode);
+
+	do {
+		if (!(fmode & FMODE_NOWAIT))
+			break;
+	} while (!try_cmpxchg(&file->f_mode, &fmode, fmode & ~FMODE_NOWAIT));
+}
+
+/*
  * Attempt to steal a page from a pipe buffer. This should perhaps go into
  * a vm helper function, it's already simplified quite a bit by the
  * addition of remove_mapping(). If success is returned, the caller may
@@ -1219,10 +1235,16 @@ static long __do_splice(struct file *in, loff_t __user *off_in,
 	ipipe = get_pipe_info(in, true);
 	opipe = get_pipe_info(out, true);
 
-	if (ipipe && off_in)
-		return -ESPIPE;
-	if (opipe && off_out)
-		return -ESPIPE;
+	if (ipipe) {
+		if (off_in)
+			return -ESPIPE;
+		pipe_clear_nowait(in);
+	}
+	if (opipe) {
+		if (off_out)
+			return -ESPIPE;
+		pipe_clear_nowait(out);
+	}
 
 	if (off_out) {
 		if (copy_from_user(&offset, off_out, sizeof(loff_t)))
@@ -1319,6 +1341,8 @@ static long vmsplice_to_user(struct file *file, struct iov_iter *iter,
 	if (!pipe)
 		return -EBADF;
 
+	pipe_clear_nowait(file);
+
 	if (sd.total_len) {
 		pipe_lock(pipe);
 		ret = __splice_from_pipe(pipe, &sd, pipe_to_user);
@@ -1347,6 +1371,8 @@ static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter,
 	if (!pipe)
 		return -EBADF;
 
+	pipe_clear_nowait(file);
+
 	pipe_lock(pipe);
 	ret = wait_for_space(pipe, flags);
 	if (!ret)