[PATCH] mm: Fix checkstyle warnings in mm/mmap.c

[PATCH] mm: Fix checkstyle warnings in mm/mmap.c

[bnrkreddy]

From: Ravi Kumar Reddy <bnrkreddy@outlook.com>

    - WARNING: Missing a blank line after declarations
    - WARNING: Use #include <linux/cacheflush.h> instead of
      <asm/cacheflush.h>
    - WARNING: externs should be avoided in .c files
      extern void mt_dump(const struct maple_tree *mt);
    - WARNING: braces {} are not necessary for single statement
      blocks
    - WARNING: Block comments use a trailing */ on a separate line
    - WARNING: function definition argument 'struct file *' should
      also
      have an identifier
    - WARNING: EXPORT_SYMBOL(foo); should immediately follow its
      function/variable
    - WARNING: simple_strtoul is obsolete, use kstrtoul instead
    - WARNING: Comparisons should place the constant on the right
      side of the test

Testing:
    kernel cmdline included with:
        stack_guard_gap=-1
    kernel log:
    	[    0.018025] mmap: Invalid page count '-1' for stack
                       gap protection

Signed-off-by: Ravi Kumar Reddy <bnrkreddy@outlook.com>
---
 mm/mmap.c | 45 ++++++++++++++++++++++++++-------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 87d929316d57..5d4b0d625607 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -48,9 +48,9 @@
 #include <linux/sched/mm.h>
 
 #include <linux/uaccess.h>
-#include <asm/cacheflush.h>
+#include <linux/cacheflush.h>
 #include <asm/tlb.h>
-#include <asm/mmu_context.h>
+#include <linux/mmu_context.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/mmap.h>
@@ -124,6 +124,7 @@ void unlink_file_vma(struct vm_area_struct *vma)
 
 	if (file) {
 		struct address_space *mapping = file->f_mapping;
+
 		i_mmap_lock_write(mapping);
 		__remove_shared_vm_struct(vma, file, mapping);
 		i_mmap_unlock_write(mapping);
@@ -281,9 +282,6 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 }
 
 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
-extern void mt_validate(struct maple_tree *mt);
-extern void mt_dump(const struct maple_tree *mt);
-
 /* Validate the maple tree */
 static void validate_mm_mt(struct mm_struct *mm)
 {
@@ -572,9 +570,8 @@ inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
 	}
 
 	/* Expanding over the next vma */
-	if (remove_next && file) {
+	if (remove_next && file)
 		__remove_shared_vm_struct(next, file, mapping);
-	}
 
 	if (anon_vma) {
 		anon_vma_interval_tree_post_update_vma(vma);
@@ -946,6 +943,7 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
 	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
 	    is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
 		pgoff_t vm_pglen;
+
 		vm_pglen = vma_pages(vma);
 		if (vma->vm_pgoff + vm_pglen == vm_pgoff)
 			return 1;
@@ -1511,8 +1509,10 @@ int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot)
 	if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite))
 		return 1;
 
-	/* The open routine did something to the protections that pgprot_modify
-	 * won't preserve? */
+	/*
+	 * The open routine did something to the protections that pgprot_modify
+	 * won't preserve?
+	 */
 	if (pgprot_val(vm_page_prot) !=
 	    pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags)))
 		return 0;
@@ -1755,10 +1755,12 @@ unsigned long
 get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 		unsigned long pgoff, unsigned long flags)
 {
-	unsigned long (*get_area)(struct file *, unsigned long,
-				  unsigned long, unsigned long, unsigned long);
+	unsigned long (*get_area)(struct file *file, unsigned long addr,
+				  unsigned long len, unsigned long pgoff,
+				  unsigned long flags);
 
 	unsigned long error = arch_mmap_check(addr, len, flags);
+
 	if (error)
 		return error;
 
@@ -1792,7 +1794,6 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 	error = security_mmap_addr(addr);
 	return error ? error : addr;
 }
-
 EXPORT_SYMBOL(get_unmapped_area);
 
 /**
@@ -2079,11 +2080,16 @@ unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT;
 static int __init cmdline_parse_stack_guard_gap(char *p)
 {
 	unsigned long val;
-	char *endptr;
+	int ret;
+
+	ret = kstrtoul(p, 10, &val);
+	if (ret) {
+		pr_warn("Invalid page count '%s' for stack gap protection\n",
+			p);
+		return 1;
+	}
 
-	val = simple_strtoul(p, &endptr, 10);
-	if (!*endptr)
-		stack_guard_gap = val << PAGE_SHIFT;
+	stack_guard_gap = val << PAGE_SHIFT;
 
 	return 1;
 }
@@ -2138,7 +2144,6 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr)
 	return vma;
 }
 #endif
-
 EXPORT_SYMBOL_GPL(find_extend_vma);
 
 /*
@@ -2196,6 +2201,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 {
 	struct vm_area_struct *new;
 	int err;
+
 	validate_mm_mt(mm);
 
 	if (vma->vm_ops && vma->vm_ops->may_split) {
@@ -3365,6 +3371,7 @@ static vm_fault_t special_mapping_fault(struct vm_fault *vmf)
 
 	if (*pages) {
 		struct page *page = *pages;
+
 		get_page(page);
 		vmf->page = page;
 		return 0;
@@ -3714,12 +3721,12 @@ static int reserve_mem_notifier(struct notifier_block *nb,
 	case MEM_ONLINE:
 		/* Default max is 128MB. Leave alone if modified by operator. */
 		tmp = sysctl_user_reserve_kbytes;
-		if (0 < tmp && tmp < (1UL << 17))
+		if (tmp > 0 && tmp < (1UL << 17))
 			init_user_reserve();
 
 		/* Default max is 8MB.  Leave alone if modified by operator. */
 		tmp = sysctl_admin_reserve_kbytes;
-		if (0 < tmp && tmp < (1UL << 13))
+		if (tmp > 0 && tmp < (1UL << 13))
 			init_admin_reserve();
 
 		break;
-- 
2.31.1

Re: [PATCH] mm: Fix checkstyle warnings in mm/mmap.c

[Matthew Wilcox]

On Sun, Jan 15, 2023 at 12:16:49AM +0000, bnrkreddy@outlook.com wrote:

Please practice somewhere else, not on mm.