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[197/200] mm: shmem: convert shmem_enabled_show to use sysfs_emit_at

Message ID 20201215031453.bwBJarhc5%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/200] kthread: add kthread_work tracepoints | expand

Commit Message

Andrew Morton Dec. 15, 2020, 3:14 a.m. UTC
From: Joe Perches <joe@perches.com>
Subject: mm: shmem: convert shmem_enabled_show to use sysfs_emit_at

Update the function to use sysfs_emit_at while neatening the uses of
sprintf and overwriting the last space char with a newline to avoid
possible output buffer overflow.

Miscellanea:

o in shmem_enabled_show, the removal of the indirected use of fmt
  allows __printf verification

Link: https://lkml.kernel.org/r/b612a93825e5ea330cb68d2e8b516e9687a06cc6.1605376435.git.joe@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/shmem.c |   21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)
diff mbox series

Patch

--- a/mm/shmem.c~mm-shmem-convert-shmem_enabled_show-to-use-sysfs_emit_at
+++ a/mm/shmem.c
@@ -4020,7 +4020,7 @@  out2:
 
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
 static ssize_t shmem_enabled_show(struct kobject *kobj,
-		struct kobj_attribute *attr, char *buf)
+				  struct kobj_attribute *attr, char *buf)
 {
 	static const int values[] = {
 		SHMEM_HUGE_ALWAYS,
@@ -4030,16 +4030,19 @@  static ssize_t shmem_enabled_show(struct
 		SHMEM_HUGE_DENY,
 		SHMEM_HUGE_FORCE,
 	};
-	int i, count;
+	int len = 0;
+	int i;
 
-	for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) {
-		const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s ";
-
-		count += sprintf(buf + count, fmt,
-				shmem_format_huge(values[i]));
+	for (i = 0; i < ARRAY_SIZE(values); i++) {
+		len += sysfs_emit_at(buf, len,
+				     shmem_huge == values[i] ? "%s[%s]" : "%s%s",
+				     i ? " " : "",
+				     shmem_format_huge(values[i]));
 	}
-	buf[count - 1] = '\n';
-	return count;
+
+	len += sysfs_emit_at(buf, len, "\n");
+
+	return len;
 }
 
 static ssize_t shmem_enabled_store(struct kobject *kobj,