sys_sendfile: switch to using ->splice_read, if available
This patch makes sendfile prefer to use ->splice_read(), if it's
available in the file_operations structure.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/read_write.c b/fs/read_write.c
index 4d03008..47da8a4 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -15,6 +15,7 @@
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
+#include <linux/pipe_fs_i.h>
#include "read_write.h"
#include <asm/uaccess.h>
@@ -25,7 +26,7 @@
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.mmap = generic_file_readonly_mmap,
- .sendfile = generic_file_sendfile,
+ .splice_read = generic_file_splice_read,
};
EXPORT_SYMBOL(generic_ro_fops);
@@ -708,7 +709,7 @@
struct inode * in_inode, * out_inode;
loff_t pos;
ssize_t retval;
- int fput_needed_in, fput_needed_out;
+ int fput_needed_in, fput_needed_out, fl;
/*
* Get input file, and verify that it is ok..
@@ -723,7 +724,8 @@
in_inode = in_file->f_path.dentry->d_inode;
if (!in_inode)
goto fput_in;
- if (!in_file->f_op || !in_file->f_op->sendfile)
+ if (!in_file->f_op || (!in_file->f_op->sendfile &&
+ !in_file->f_op->splice_read))
goto fput_in;
retval = -ESPIPE;
if (!ppos)
@@ -776,7 +778,21 @@
count = max - pos;
}
- retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
+ if (in_file->f_op->splice_read) {
+ fl = 0;
+#if 0
+ /*
+ * We need to debate whether we can enable this or not. The
+ * man page documents EAGAIN return for the output at least,
+ * and the application is arguably buggy if it doesn't expect
+ * EAGAIN on a non-blocking file descriptor.
+ */
+ if (in_file->f_flags & O_NONBLOCK)
+ fl = SPLICE_F_NONBLOCK;
+#endif
+ retval = do_splice_direct(in_file, ppos, out_file, count, fl);
+ } else
+ retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
if (retval > 0) {
add_rchar(current, retval);