[SCSI] iscsi_tcp: print useful error message when iscsi crc23c allocation fails

People do not read the README and seem to like to
unselect the crc32c module even though iscsi_tcp selects
it for them. This patch spits a error that tells the user
that they really do need the module. Hopefully, we will
get fewer people asking about this now.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 861cb9be40b0..c9a3abf9e7b6 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -1777,14 +1777,24 @@ iscsi_tcp_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
         tcp_conn->tx_hash.tfm = crypto_alloc_hash("crc32c", 0,
                                                   CRYPTO_ALG_ASYNC);
         tcp_conn->tx_hash.flags = 0;
-        if (IS_ERR(tcp_conn->tx_hash.tfm))
+        if (IS_ERR(tcp_conn->tx_hash.tfm)) {
+                printk(KERN_ERR "Could not create connection due to crc32c "
+                       "loading error %ld. Make sure the crc32c module is "
+                       "built as a module or into the kernel\n",
+                        PTR_ERR(tcp_conn->tx_hash.tfm));
                 goto free_tcp_conn;
+        }
 
         tcp_conn->rx_hash.tfm = crypto_alloc_hash("crc32c", 0,
                                                   CRYPTO_ALG_ASYNC);
         tcp_conn->rx_hash.flags = 0;
-        if (IS_ERR(tcp_conn->rx_hash.tfm))
+        if (IS_ERR(tcp_conn->rx_hash.tfm)) {
+                printk(KERN_ERR "Could not create connection due to crc32c "
+                       "loading error %ld. Make sure the crc32c module is "
+                       "built as a module or into the kernel\n",
+                        PTR_ERR(tcp_conn->rx_hash.tfm));
                 goto free_tx_tfm;
+        }
 
         return cls_conn;