pstore revert for v6.0-rc8

- Revert crypto acomp migration (Guilherme G. Piccoli)
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Merge tag 'pstore-v6.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore revert from Kees Cook:
 "A misbehavior with some compression backends in pstore was just
  discovered due to the recent crypto acomp migration.

  Since we're so close to release, it seems better to just simply revert
  it, and we can figure out what's going on without leaving it broken
  for a release.

   - Revert crypto acomp migration (Guilherme G. Piccoli)"

* tag 'pstore-v6.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  Revert "pstore: migrate to crypto acomp interface"

fs/pstore/platform.c

@@ -28,14 +28,11 @@
 #include <linux/crypto.h>
 #include <linux/string.h>
 #include <linux/timer.h>
-#include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/jiffies.h>
 #include <linux/workqueue.h>
 
-#include <crypto/acompress.h>
-
 #include "internal.h"
 
 /*
@@ -93,8 +90,7 @@ module_param(compress, charp, 0444);
 MODULE_PARM_DESC(compress, "compression to use");
 
 /* Compression parameters */
-static struct crypto_acomp *tfm;
+static struct crypto_comp *tfm;
-static struct acomp_req *creq;
 
 struct pstore_zbackend {
 	int (*zbufsize)(size_t size);
@@ -272,21 +268,12 @@ static const struct pstore_zbackend zbackends[] = {
 static int pstore_compress(const void *in, void *out,
 			   unsigned int inlen, unsigned int outlen)
 {
-	struct scatterlist src, dst;
 	int ret;
 
 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS))
 		return -EINVAL;
 
-	sg_init_table(&src, 1);
+	ret = crypto_comp_compress(tfm, in, inlen, out, &outlen);
-	sg_set_buf(&src, in, inlen);
-
-	sg_init_table(&dst, 1);
-	sg_set_buf(&dst, out, outlen);
-
-	acomp_request_set_params(creq, &src, &dst, inlen, outlen);
-
-	ret = crypto_acomp_compress(creq);
 	if (ret) {
 		pr_err("crypto_comp_compress failed, ret = %d!\n", ret);
 		return ret;
@@ -297,7 +284,7 @@ static int pstore_compress(const void *in, void *out,
 
 static void allocate_buf_for_compression(void)
 {
-	struct crypto_acomp *acomp;
+	struct crypto_comp *ctx;
 	int size;
 	char *buf;
 
@@ -309,7 +296,7 @@ static void allocate_buf_for_compression(void)
 	if (!psinfo || tfm)
 		return;
 
-	if (!crypto_has_acomp(zbackend->name, 0, CRYPTO_ALG_ASYNC)) {
+	if (!crypto_has_comp(zbackend->name, 0, 0)) {
 		pr_err("Unknown compression: %s\n", zbackend->name);
 		return;
 	}
@@ -328,24 +315,16 @@ static void allocate_buf_for_compression(void)
 		return;
 	}
 
-	acomp = crypto_alloc_acomp(zbackend->name, 0, CRYPTO_ALG_ASYNC);
+	ctx = crypto_alloc_comp(zbackend->name, 0, 0);
-	if (IS_ERR_OR_NULL(acomp)) {
+	if (IS_ERR_OR_NULL(ctx)) {
 		kfree(buf);
 		pr_err("crypto_alloc_comp('%s') failed: %ld\n", zbackend->name,
-		       PTR_ERR(acomp));
+		       PTR_ERR(ctx));
-		return;
-	}
-
-	creq = acomp_request_alloc(acomp);
-	if (!creq) {
-		crypto_free_acomp(acomp);
-		kfree(buf);
-		pr_err("acomp_request_alloc('%s') failed\n", zbackend->name);
 		return;
 	}
 
 	/* A non-NULL big_oops_buf indicates compression is available. */
-	tfm = acomp;
+	tfm = ctx;
 	big_oops_buf_sz = size;
 	big_oops_buf = buf;
 
@@ -355,8 +334,7 @@ static void allocate_buf_for_compression(void)
 static void free_buf_for_compression(void)
 {
 	if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && tfm) {
-		acomp_request_free(creq);
+		crypto_free_comp(tfm);
-		crypto_free_acomp(tfm);
 		tfm = NULL;
 	}
 	kfree(big_oops_buf);
@@ -693,8 +671,6 @@ static void decompress_record(struct pstore_record *record)
 	int ret;
 	int unzipped_len;
 	char *unzipped, *workspace;
-	struct acomp_req *dreq;
-	struct scatterlist src, dst;
 
 	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
 		return;
@@ -718,30 +694,16 @@ static void decompress_record(struct pstore_record *record)
 	if (!workspace)
 		return;
 
-	dreq = acomp_request_alloc(tfm);
-	if (!dreq) {
-		kfree(workspace);
-		return;
-	}
-
-	sg_init_table(&src, 1);
-	sg_set_buf(&src, record->buf, record->size);
-
-	sg_init_table(&dst, 1);
-	sg_set_buf(&dst, workspace, unzipped_len);
-
-	acomp_request_set_params(dreq, &src, &dst, record->size, unzipped_len);
-
 	/* After decompression "unzipped_len" is almost certainly smaller. */
-	ret = crypto_acomp_decompress(dreq);
+	ret = crypto_comp_decompress(tfm, record->buf, record->size,
+					  workspace, &unzipped_len);
 	if (ret) {
-		pr_err("crypto_acomp_decompress failed, ret = %d!\n", ret);
+		pr_err("crypto_comp_decompress failed, ret = %d!\n", ret);
 		kfree(workspace);
 		return;
 	}
 
 	/* Append ECC notice to decompressed buffer. */
-	unzipped_len = dreq->dlen;
 	memcpy(workspace + unzipped_len, record->buf + record->size,
 	       record->ecc_notice_size);
 
@@ -749,7 +711,6 @@ static void decompress_record(struct pstore_record *record)
 	unzipped = kmemdup(workspace, unzipped_len + record->ecc_notice_size,
 			   GFP_KERNEL);
 	kfree(workspace);
-	acomp_request_free(dreq);
 	if (!unzipped)
 		return;