x86/kexec: simplify the logic of mem_region_callback()

The expression `mstart + resource_size(res) - 1` is actually equivalent to
`res->end`, simplify the logic of this function to improve readability.

Link: https://lkml.kernel.org/r/20231212150506.31711-1-ytcoode@gmail.com
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 1a3e2c05a8a5b6dad9d29f00fd41fc3b2a3df80b..6f8df998890efbca6fbe7f2cc98623b123ede44e 100644 (file)
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -42,12 +42,9 @@ struct init_pgtable_data {
 static int mem_region_callback(struct resource *res, void *arg)
 {
        struct init_pgtable_data *data = arg;
-       unsigned long mstart, mend;
-
-       mstart = res->start;
-       mend = mstart + resource_size(res) - 1;
 
-       return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
+       return kernel_ident_mapping_init(data->info, data->level4p,
+                                        res->start, res->end);
 }
 
 static int