[Xen-changelog] [xen master] xen/kexec: remove spinlock now that all KEXEC hypercall ops are protected at the top-level

[patchbot@xxxxxxx]

commit f5c842bf6364541151923d488211ec1bc50d25e0
Author:     Eric DeVolder <eric.devolder@xxxxxxxxxx>
AuthorDate: Wed Apr 19 16:01:49 2017 -0500
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Apr 20 18:11:36 2017 +0100

    xen/kexec: remove spinlock now that all KEXEC hypercall ops are protected 
at the top-level
    
    The spinlock in kexec_swap_images() was removed as
    this function is only reachable on the kexec hypercall, which is
    now protected at the top-level in do_kexec_op_internal(),
    thus the local spinlock is no longer necessary.
    
    Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
    Reviewed-by: Bhavesh Davda <bhavesh.davda@xxxxxxxxxx>
    Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
    Release-acked-by: Julien Grall <julien.grall@xxxxxxx>
---
 xen/common/kexec.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/xen/common/kexec.c b/xen/common/kexec.c
index d6568e3..fbca8a6 100644
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -820,7 +820,6 @@ static int kexec_exec(XEN_GUEST_HANDLE_PARAM(void) uarg)
 static int kexec_swap_images(int type, struct kexec_image *new,
                              struct kexec_image **old)
 {
-    static DEFINE_SPINLOCK(kexec_lock);
     int base, bit, pos;
     int new_slot, old_slot;
 
@@ -832,7 +831,7 @@ static int kexec_swap_images(int type, struct kexec_image 
*new,
     if ( kexec_load_get_bits(type, &base, &bit) )
         return -EINVAL;
 
-    spin_lock(&kexec_lock);
+    ASSERT(test_bit(KEXEC_FLAG_IN_HYPERCALL, &kexec_flags));
 
     pos = (test_bit(bit, &kexec_flags) != 0);
     old_slot = base + pos;
@@ -846,8 +845,6 @@ static int kexec_swap_images(int type, struct kexec_image 
*new,
     clear_bit(old_slot, &kexec_flags);
     *old = kexec_image[old_slot];
 
-    spin_unlock(&kexec_lock);
-
     return 0;
 }
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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