[xen staging] ARM/vgic: Use for_each_set_bit() in gic_find_unused_lr()

[patchbot@xxxxxxx]

commit e9c703f85efcb61f67625c39b1e60c62e90d19fd
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Fri Aug 30 16:32:08 2024 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Sep 3 15:51:44 2024 +0100

    ARM/vgic: Use for_each_set_bit() in gic_find_unused_lr()
    
    There are no bits set in lr_mask beyond nr_lrs, so when substituting
    bitmap_for_each() for for_each_set_bit(), we don't need to worry about the
    upper bound.
    
    However, the type of lr_mask does matter, so switch it to be uint64_t * and
    move unsigned long * override until the find_next_zero_bit() call.
    
    Move lr_val into a narrower scope and drop used_lr as it's declared by
    for_each_set_bit() itself.
    
    Drop the nr_lrs variable and use gic_get_nr_lrs() in the one location its 
now
    used.  It hides a triple pointer dereference, and while it may not be needed
    in the PRISTINE case, it certainly doesn't need to be live across the rest 
of
    the function.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Michal Orzel <michal.orzel@xxxxxxx>
---
 xen/arch/arm/gic-vgic.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c
index 3f14aab2ef..ea48c5375a 100644
--- a/xen/arch/arm/gic-vgic.c
+++ b/xen/arch/arm/gic-vgic.c
@@ -102,25 +102,23 @@ static unsigned int gic_find_unused_lr(struct vcpu *v,
                                        struct pending_irq *p,
                                        unsigned int lr)
 {
-    unsigned int nr_lrs = gic_get_nr_lrs();
-    unsigned long *lr_mask = (unsigned long *) &this_cpu(lr_mask);
-    struct gic_lr lr_val;
+    uint64_t *lr_mask = &this_cpu(lr_mask);
 
     ASSERT(spin_is_locked(&v->arch.vgic.lock));
 
     if ( unlikely(test_bit(GIC_IRQ_GUEST_PRISTINE_LPI, &p->status)) )
     {
-        unsigned int used_lr;
-
-        bitmap_for_each ( used_lr, lr_mask, nr_lrs )
+        for_each_set_bit ( used_lr, *lr_mask )
         {
+            struct gic_lr lr_val;
+
             gic_hw_ops->read_lr(used_lr, &lr_val);
             if ( lr_val.virq == p->irq )
                 return used_lr;
         }
     }
 
-    lr = find_next_zero_bit(lr_mask, nr_lrs, lr);
+    lr = find_next_zero_bit((unsigned long *)lr_mask, gic_get_nr_lrs(), lr);
 
     return lr;
 }
--
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