xtensa: remove vma linked list walks

Use the VMA iterator instead.  Since VMA can no longer be NULL in the
loop, then deal with out-of-memory outside the loop.  This means a
slightly longer run time in the failure case (-ENOMEM) - it will run to
the end of the VMAs before erroring instead of in the middle of the loop.

Link: https://lkml.kernel.org/r/20220906194824.2110408-37-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/xtensa/kernel/syscall.c b/arch/xtensa/kernel/syscall.c
index 201356faa7e6e01d19bedf684194f44f076b6409..b3c2450d6f239e6b8f534eba2969b8758d71a1fa 100644 (file)
--- a/arch/xtensa/kernel/syscall.c
+++ b/arch/xtensa/kernel/syscall.c
@@ -58,6 +58,7 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
                unsigned long len, unsigned long pgoff, unsigned long flags)
 {
        struct vm_area_struct *vmm;
+       struct vma_iterator vmi;
 
        if (flags & MAP_FIXED) {
                /* We do not accept a shared mapping if it would violate
@@ -79,15 +80,20 @@ unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
        else
                addr = PAGE_ALIGN(addr);
 
-       for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
-               /* At this point:  (!vmm || addr < vmm->vm_end). */
-               if (TASK_SIZE - len < addr)
-                       return -ENOMEM;
-               if (!vmm || addr + len <= vm_start_gap(vmm))
-                       return addr;
+       vma_iter_init(&vmi, current->mm, addr);
+       for_each_vma(vmi, vmm) {
+               /* At this point:  (addr < vmm->vm_end). */
+               if (addr + len <= vm_start_gap(vmm))
+                       break;
+
                addr = vmm->vm_end;
                if (flags & MAP_SHARED)
                        addr = COLOUR_ALIGN(addr, pgoff);
        }
+
+       if (TASK_SIZE - len < addr)
+               return -ENOMEM;
+
+       return addr;
 }
 #endif