[PATCH] pstore/platform: build fix when crypto API are disabled

[Matteo Croce <mcroce@linux.microsoft.com>]

From: Matteo Croce <mcroce@microsoft.com>

When building a kernel with CONFIG_PSTORE=y and CONFIG_CRYPTO not set,
a build error happens:

    ld: fs/pstore/platform.o: in function `pstore_dump':
    platform.c:(.text+0x3f9): undefined reference to `crypto_comp_compress'
    ld: fs/pstore/platform.o: in function `pstore_get_backend_records':
    platform.c:(.text+0x784): undefined reference to `crypto_comp_decompress'

This because some pstore code uses crypto_comp_(de)compress
regardless of the CONFIG_CRYPTO status.
Fix it by wrapping the (de)compress usage by IS_ENABLED(CONFIG_PSTORE_COMPRESS)

Signed-off-by: Matteo Croce <mcroce@microsoft.com>
---
 fs/pstore/platform.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index a9e297eefdff..6022d8359f96 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -436,7 +436,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 					  dst_size, &dump_size))
 			break;
 
-		if (big_oops_buf) {
+		if (IS_ENABLED(CONFIG_PSTORE_COMPRESS) && big_oops_buf) {
 			zipped_len = pstore_compress(dst, psinfo->buf,
 						header_size + dump_size,
 						psinfo->bufsize);
@@ -668,7 +668,7 @@ static void decompress_record(struct pstore_record *record)
 	int unzipped_len;
 	char *unzipped, *workspace;
 
-	if (!record->compressed)
+	if (!IS_ENABLED(CONFIG_PSTORE_COMPRESS) || !record->compressed)
 		return;
 
 	/* Only PSTORE_TYPE_DMESG support compression. */
-- 
2.26.2