linux-kernel - [PATCH] mm/madvise: reduce code duplication in error handling paths

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Message-Id: <1564640896-1210-1-git-send-email-rppt@linux.ibm.com>
Date:   Thu,  1 Aug 2019 09:28:16 +0300
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Mike Rapoport <rppt@...ux.ibm.com>
Subject: [PATCH] mm/madvise: reduce code duplication in error handling paths

The madvise_behavior() function converts -ENOMEM to -EAGAIN in several
places using identical code.

Move that code to a common error handling path.

No functional changes.

Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
---
 mm/madvise.c | 52 ++++++++++++++++------------------------------------
 1 file changed, 16 insertions(+), 36 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 968df3a..55d78fd 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -105,28 +105,14 @@ static long madvise_behavior(struct vm_area_struct *vma,
 	case MADV_MERGEABLE:
 	case MADV_UNMERGEABLE:
 		error = ksm_madvise(vma, start, end, behavior, &new_flags);
-		if (error) {
-			/*
-			 * madvise() returns EAGAIN if kernel resources, such as
-			 * slab, are temporarily unavailable.
-			 */
-			if (error == -ENOMEM)
-				error = -EAGAIN;
-			goto out;
-		}
+		if (error)
+			goto out_convert_errno;
 		break;
 	case MADV_HUGEPAGE:
 	case MADV_NOHUGEPAGE:
 		error = hugepage_madvise(vma, &new_flags, behavior);
-		if (error) {
-			/*
-			 * madvise() returns EAGAIN if kernel resources, such as
-			 * slab, are temporarily unavailable.
-			 */
-			if (error == -ENOMEM)
-				error = -EAGAIN;
-			goto out;
-		}
+		if (error)
+			goto out_convert_errno;
 		break;
 	}
 
@@ -152,15 +138,8 @@ static long madvise_behavior(struct vm_area_struct *vma,
 			goto out;
 		}
 		error = __split_vma(mm, vma, start, 1);
-		if (error) {
-			/*
-			 * madvise() returns EAGAIN if kernel resources, such as
-			 * slab, are temporarily unavailable.
-			 */
-			if (error == -ENOMEM)
-				error = -EAGAIN;
-			goto out;
-		}
+		if (error)
+			goto out_convert_errno;
 	}
 
 	if (end != vma->vm_end) {
@@ -169,15 +148,8 @@ static long madvise_behavior(struct vm_area_struct *vma,
 			goto out;
 		}
 		error = __split_vma(mm, vma, end, 0);
-		if (error) {
-			/*
-			 * madvise() returns EAGAIN if kernel resources, such as
-			 * slab, are temporarily unavailable.
-			 */
-			if (error == -ENOMEM)
-				error = -EAGAIN;
-			goto out;
-		}
+		if (error)
+			goto out_convert_errno;
 	}
 
 success:
@@ -185,6 +157,14 @@ static long madvise_behavior(struct vm_area_struct *vma,
 	 * vm_flags is protected by the mmap_sem held in write mode.
 	 */
 	vma->vm_flags = new_flags;
+
+out_convert_errno:
+	/*
+	 * madvise() returns EAGAIN if kernel resources, such as
+	 * slab, are temporarily unavailable.
+	 */
+	if (error == -ENOMEM)
+		error = -EAGAIN;
 out:
 	return error;
 }
-- 
2.7.4