Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Peter Anvin:

 - Three EFI-related fixes

 - Two early memory initialization fixes

 - build fix for older binutils

 - fix for an eager FPU performance regression -- currently we don't
   allow the use of the FPU at interrupt time *at all* in eager mode,
   which is clearly wrong.

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Allow FPU to be used at interrupt time even with eagerfpu
  x86, crc32-pclmul: Fix build with older binutils
  x86-64, init: Fix a possible wraparound bug in switchover in head_64.S
  x86, range: fix missing merge during add range
  x86, efi: initial the local variable of DataSize to zero
  efivar: fix oops in efivar_update_sysfs_entries() caused by memory reuse
  efivarfs: Never return ENOENT from firmware again

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/efivarfs/file.c b/fs/efivarfs/file.c
index bfb5315..8dd524f 100644
--- a/fs/efivarfs/file.c
+++ b/fs/efivarfs/file.c
@@ -44,8 +44,11 @@ static ssize_t efivarfs_file_write(struct file *file,
 
 	bytes = efivar_entry_set_get_size(var, attributes, &datasize,
 					  data, &set);
-	if (!set && bytes)
+	if (!set && bytes) {
+		if (bytes == -ENOENT)
+			bytes = -EIO;
 		goto out;
+	}
 
 	if (bytes == -ENOENT) {
 		drop_nlink(inode);
@@ -76,7 +79,14 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
 	int err;
 
 	err = efivar_entry_size(var, &datasize);
-	if (err)
+
+	/*
+	 * efivarfs represents uncommitted variables with
+	 * zero-length files. Reading them should return EOF.
+	 */
+	if (err == -ENOENT)
+		return 0;
+	else if (err)
 		return err;
 
 	data = kmalloc(datasize + sizeof(attributes), GFP_KERNEL);