linux-kernel - [PATCH v2 1/2] PM: hibernate: dynamically allocate crc->unc

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Message-ID: <86d4e558707e7b03c248ef67cb76ec635a875d9b.1757577879.git.luoxueqin@kylinos.cn>
Date: Thu, 11 Sep 2025 16:09:50 +0800
From: Xueqin Luo <luoxueqin@...inos.cn>
To: rafael@...nel.org,
	pavel@...nel.org,
	lenb@...nel.org,
	linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Xueqin Luo <luoxueqin@...inos.cn>
Subject: [PATCH v2 1/2] PM: hibernate: dynamically allocate crc->unc_len/unc for configurable threads

The current implementation uses fixed-size arrays for crc->unc_len and
crc->unc, which limits the number of compression threads to a compile-time
constant (CMP_THREADS). This patch converts them to dynamically allocated
arrays, sized according to the actual number of threads selected at runtime.

Signed-off-by: Xueqin Luo <luoxueqin@...inos.cn>
---
 kernel/power/swap.c | 44 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 40 insertions(+), 4 deletions(-)

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index 0beff7eeaaba..bd149a54c081 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -585,8 +585,8 @@ struct crc_data {
 	wait_queue_head_t go;                     /* start crc update */
 	wait_queue_head_t done;                   /* crc update done */
 	u32 *crc32;                               /* points to handle's crc32 */
-	size_t *unc_len[CMP_THREADS];             /* uncompressed lengths */
-	unsigned char *unc[CMP_THREADS];          /* uncompressed data */
+	size_t **unc_len;			              /* uncompressed lengths */
+	unsigned char **unc;			          /* uncompressed data */
 };
 
 /*
@@ -721,7 +721,21 @@ static int save_compressed_image(struct swap_map_handle *handle,
 
 	crc = kzalloc(sizeof(*crc), GFP_KERNEL);
 	if (!crc) {
-		pr_err("Failed to allocate crc\n");
+		pr_err("Failed to allocate crc structure\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc->unc_len = kcalloc(nr_threads, sizeof(size_t *), GFP_KERNEL);
+	if (!crc->unc_len) {
+		pr_err("Failed to allocate crc->unc_len for %d threads\n", nr_threads);
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc->unc = kcalloc(nr_threads, sizeof(unsigned char *), GFP_KERNEL);
+	if (!crc->unc) {
+		pr_err("Failed to allocate crc->unc for %d threads\n", nr_threads);
 		ret = -ENOMEM;
 		goto out_clean;
 	}
@@ -886,6 +900,10 @@ static int save_compressed_image(struct swap_map_handle *handle,
 out_clean:
 	hib_finish_batch(&hb);
 	if (crc) {
+		if (crc->unc)
+			kfree(crc->unc);
+		if (crc->unc_len)
+			kfree(crc->unc_len);
 		if (crc->thr)
 			kthread_stop(crc->thr);
 		kfree(crc);
@@ -1241,7 +1259,21 @@ static int load_compressed_image(struct swap_map_handle *handle,
 
 	crc = kzalloc(sizeof(*crc), GFP_KERNEL);
 	if (!crc) {
-		pr_err("Failed to allocate crc\n");
+		pr_err("Failed to allocate crc structure\n");
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc->unc_len = kcalloc(nr_threads, sizeof(size_t *), GFP_KERNEL);
+	if (!crc->unc_len) {
+		pr_err("Failed to allocate crc->unc_len for %d threads\n", nr_threads);
+		ret = -ENOMEM;
+		goto out_clean;
+	}
+
+	crc->unc = kcalloc(nr_threads, sizeof(unsigned char *), GFP_KERNEL);
+	if (!crc->unc) {
+		pr_err("Failed to allocate crc->unc for %d threads\n", nr_threads);
 		ret = -ENOMEM;
 		goto out_clean;
 	}
@@ -1507,6 +1539,10 @@ static int load_compressed_image(struct swap_map_handle *handle,
 	for (i = 0; i < ring_size; i++)
 		free_page((unsigned long)page[i]);
 	if (crc) {
+		if (crc->unc)
+			kfree(crc->unc);
+		if (crc->unc_len)
+			kfree(crc->unc_len);
 		if (crc->thr)
 			kthread_stop(crc->thr);
 		kfree(crc);
-- 
2.43.0