From: Steve French <stfrench@microsoft.com>
Date: Sat, 7 Sep 2019 01:09:49 -0500
Subject: [PATCH] smb3: allow parallelizing decryption of reads
Git-commit: 35cf94a397280b9e27576ac1480f631bdd3e7b70
References: bsc#1144333
Patch-mainline: v5.4-rc1
decrypting large reads on encrypted shares can be slow (e.g. adding
multiple milliseconds per-read on non-GCM capable servers or
when mounting with dialects prior to SMB3.1.1) - allow parallelizing
of read decryption by launching worker threads.
Testing to Samba on localhost showed 25% improvement.
Testing to remote server showed very large improvement when
doing more than one 'cp' command was called at one time.
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/cifsfs.c | 17 +++++++++-
fs/cifs/cifsglob.h | 1 +
fs/cifs/smb2ops.c | 83 ++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 97 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index de90e665ef11..b0ea332af35c 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -109,6 +109,7 @@ extern mempool_t *cifs_req_poolp;
extern mempool_t *cifs_mid_poolp;
struct workqueue_struct *cifsiod_wq;
+struct workqueue_struct *decrypt_wq;
struct workqueue_struct *cifsoplockd_wq;
__u32 cifs_lock_secret;
@@ -1499,11 +1500,22 @@ init_cifs(void)
goto out_clean_proc;
}
+ /*
+ * BB Consider setting limit!=0 maybe to min(num_of_cores - 1, 3) so we
+ * don't launch too many worker threads
+ */
+ decrypt_wq = alloc_workqueue("smb3decryptd",
+ WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
+ if (!decrypt_wq) {
+ rc = -ENOMEM;
+ goto out_destroy_cifsiod_wq;
+ }
+
cifsoplockd_wq = alloc_workqueue("cifsoplockd",
WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
if (!cifsoplockd_wq) {
rc = -ENOMEM;
- goto out_destroy_cifsiod_wq;
+ goto out_destroy_decrypt_wq;
}
rc = cifs_fscache_register();
@@ -1569,6 +1581,8 @@ init_cifs(void)
cifs_fscache_unregister();
out_destroy_cifsoplockd_wq:
destroy_workqueue(cifsoplockd_wq);
+out_destroy_decrypt_wq:
+ destroy_workqueue(decrypt_wq);
out_destroy_cifsiod_wq:
destroy_workqueue(cifsiod_wq);
out_clean_proc:
@@ -1595,6 +1609,7 @@ exit_cifs(void)
cifs_destroy_inodecache();
cifs_fscache_unregister();
destroy_workqueue(cifsoplockd_wq);
+ destroy_workqueue(decrypt_wq);
destroy_workqueue(cifsiod_wq);
cifs_proc_clean();
}
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 1f53dee211d8..d66106ac031a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1892,6 +1892,7 @@ void cifs_queue_oplock_break(struct cifsFileInfo *cfile);
extern const struct slow_work_ops cifs_oplock_break_ops;
extern struct workqueue_struct *cifsiod_wq;
+extern struct workqueue_struct *decrypt_wq;
extern struct workqueue_struct *cifsoplockd_wq;
extern __u32 cifs_lock_secret;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 83b02d74d48e..c74284484947 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4017,8 +4017,58 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
return length;
}
+struct smb2_decrypt_work {
+ struct work_struct decrypt;
+ struct TCP_Server_Info *server;
+ struct page **ppages;
+ char *buf;
+ unsigned int npages;
+ unsigned int len;
+};
+
+
+static void smb2_decrypt_offload(struct work_struct *work)
+{
+ struct smb2_decrypt_work *dw = container_of(work,
+ struct smb2_decrypt_work, decrypt);
+ int i, rc;
+ struct mid_q_entry *mid;
+
+ rc = decrypt_raw_data(dw->server, dw->buf, dw->server->vals->read_rsp_size,
+ dw->ppages, dw->npages, dw->len);
+ if (rc) {
+ cifs_dbg(VFS, "error decrypting rc=%d\n", rc);
+ goto free_pages;
+ }
+
+ mid = smb2_find_mid(dw->server, dw->buf);
+ if (mid == NULL)
+ cifs_dbg(FYI, "mid not found\n");
+ else {
+ mid->decrypted = true;
+ rc = handle_read_data(dw->server, mid, dw->buf,
+ dw->server->vals->read_rsp_size,
+ dw->ppages, dw->npages, dw->len);
+ }
+
+ dw->server->lstrp = jiffies;
+
+ mid->callback(mid);
+
+ cifs_mid_q_entry_release(mid);
+
+free_pages:
+ for (i = dw->npages-1; i >= 0; i--)
+ put_page(dw->ppages[i]);
+
+ kfree(dw->ppages);
+ cifs_small_buf_release(dw->buf);
+}
+
+
static int
-receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
+receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
+ int *num_mids)
{
char *buf = server->smallbuf;
struct smb2_transform_hdr *tr_hdr = (struct smb2_transform_hdr *)buf;
@@ -4028,7 +4078,9 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
unsigned int buflen = server->pdu_size;
int rc;
int i = 0;
+ struct smb2_decrypt_work *dw;
+ *num_mids = 1;
len = min_t(unsigned int, buflen, server->vals->read_rsp_size +
sizeof(struct smb2_transform_hdr)) - HEADER_SIZE(server) + 1;
@@ -4064,6 +4116,32 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
if (rc)
goto free_pages;
+ /*
+ * For large reads, offload to different thread for better performance,
+ * use more cores decrypting which can be expensive
+ */
+
+ /* TODO: make the size limit to enable decrypt offload configurable */
+ if (server->pdu_size > (512 * 1024)) {
+ dw = kmalloc(sizeof(struct smb2_decrypt_work), GFP_KERNEL);
+ if (dw == NULL)
+ goto non_offloaded_decrypt;
+
+ dw->buf = server->smallbuf;
+ server->smallbuf = (char *)cifs_small_buf_get();
+
+ INIT_WORK(&dw->decrypt, smb2_decrypt_offload);
+
+ dw->npages = npages;
+ dw->server = server;
+ dw->ppages = pages;
+ dw->len = len;
+ queue_work(cifsiod_wq, &dw->decrypt);
+ *num_mids = 0; /* worker thread takes care of finding mid */
+ return -1;
+ }
+
+non_offloaded_decrypt:
rc = decrypt_raw_data(server, buf, server->vals->read_rsp_size,
pages, npages, len);
if (rc)
@@ -4210,8 +4288,7 @@ smb3_receive_transform(struct TCP_Server_Info *server,
/* TODO: add support for compounds containing READ. */
if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server)) {
- *num_mids = 1;
- return receive_encrypted_read(server, &mids[0]);
+ return receive_encrypted_read(server, &mids[0], num_mids);
}
return receive_encrypted_standard(server, mids, bufs, num_mids);
--
2.25.1