diff options
Diffstat (limited to 'arch/arm/mm/ioremap.c')
| -rw-r--r-- | arch/arm/mm/ioremap.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index 197f8eb3a775..aa08bcb72db9 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -117,16 +117,21 @@ EXPORT_SYMBOL(ioremap_page); void __check_vmalloc_seq(struct mm_struct *mm) { - unsigned int seq; + int seq; do { - seq = init_mm.context.vmalloc_seq; + seq = atomic_read(&init_mm.context.vmalloc_seq); memcpy(pgd_offset(mm, VMALLOC_START), pgd_offset_k(VMALLOC_START), sizeof(pgd_t) * (pgd_index(VMALLOC_END) - pgd_index(VMALLOC_START))); - mm->context.vmalloc_seq = seq; - } while (seq != init_mm.context.vmalloc_seq); + /* + * Use a store-release so that other CPUs that observe the + * counter's new value are guaranteed to see the results of the + * memcpy as well. + */ + atomic_set_release(&mm->context.vmalloc_seq, seq); + } while (seq != atomic_read(&init_mm.context.vmalloc_seq)); } #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE) @@ -157,7 +162,7 @@ static void unmap_area_sections(unsigned long virt, unsigned long size) * Note: this is still racy on SMP machines. */ pmd_clear(pmdp); - init_mm.context.vmalloc_seq++; + atomic_inc_return_release(&init_mm.context.vmalloc_seq); /* * Free the page table, if there was one. @@ -174,8 +179,7 @@ static void unmap_area_sections(unsigned long virt, unsigned long size) * Ensure that the active_mm is up to date - we want to * catch any use-after-iounmap cases. */ - if (current->active_mm->context.vmalloc_seq != init_mm.context.vmalloc_seq) - __check_vmalloc_seq(current->active_mm); + check_vmalloc_seq(current->active_mm); flush_tlb_kernel_range(virt, end); } |