linux-kernel - [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr

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Date:   Sun, 5 Jun 2022 11:55:56 +0800
From:   Chen Wandun <chenwandun@...wei.com>
To:     <hughd@...gle.com>, <akpm@...ux-foundation.org>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <willy@...radead.org>, <david@...hat.com>,
        <wangkefeng.wang@...wei.com>
Subject: [PATCH v2 2/3] mm/shmem: return error code directly for invalid addr

Return error code directly for addr is not PAGE_SIZE aligned or
beyond TASK_SIZE, no need to check these cases in caller.

Signed-off-by: Chen Wandun <chenwandun@...wei.com>
---
 mm/shmem.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 17f8297ece29..5e61692f2d8e 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2142,10 +2142,10 @@ unsigned long shmem_get_unmapped_area(struct file *file,
 		return addr;
 	if (IS_ERR_VALUE(addr))
 		return addr;
-	if (addr & ~PAGE_MASK)
-		return addr;
+	if (offset_in_page(addr))
+		return -EINVAL;
 	if (addr > TASK_SIZE - len)
-		return addr;
+		return -ENOMEM;
 
 	if (shmem_huge == SHMEM_HUGE_DENY)
 		return addr;
@@ -2196,7 +2196,7 @@ unsigned long shmem_get_unmapped_area(struct file *file,
 	inflated_addr = get_area(NULL, uaddr, inflated_len, 0, flags);
 	if (IS_ERR_VALUE(inflated_addr))
 		return addr;
-	if (inflated_addr & ~PAGE_MASK)
+	if (offset_in_page(inflated_addr))
 		return addr;
 
 	inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
-- 
2.25.1